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                                                                     EXHIBIT 4.6

                                                                [EXECUTION COPY]

                          REGISTRATION RIGHTS AGREEMENT

         This Registration Rights Agreement (this "Agreement") is made this 22nd
of July, 1998, by and among Memory Pharmaceuticals Corp. ("Memory" or the
"Company") and the Trustees of Columbia University in the City of New York
("Columbia" or the "Holder").

         WHEREAS, pursuant to the terms of a Stock Subscription and Right of
First Refusal Agreement of even date herewith, Memory has agreed to issue and
sell to Columbia, and Columbia has agreed to purchase from Memory, 100,000
shares (the "Shares") of the Company's Common Stock, $.001 par value per share
(the "Common Stock"), in partial consideration for the execution and delivery by
Columbia of an exclusive License Agreement with the Company of even date
herewith;

         WHEREAS, all of the Shares are "restricted securities" within the
meaning of the Securities Act of 1933, as amended; and

         WHEREAS, Memory is willing to grant to Columbia certain registration
rights with respect to the Shares subject to the conditions set forth herein.

         NOW, THEREFORE, in consideration of the License Agreement and
Subscription Agreement and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto,
intending to be legally bound, hereby agree as follows:

         SECTION 1. Certain Definitions. As used in this Agreement, the
following terms shall have the following respective meanings:

                  "Commission" shall mean the Securities and Exchange
Commission, or any other federal agency at the time administering the Securities
Act and the Exchange Act.

                  "Initial Public Offering" means the first underwritten public
offering of Common Stock of the Company and offered on a "firm commitment" or
"best efforts" basis pursuant to an offering registered under the Securities Act
with the Commission.

                  "Registrable Shares" shall mean (i) the Shares, (ii) any
shares of the Common Stock of the Company issued as a dividend or other
distribution with respect to, or in exchange for or in replacement of, the
Shares and (iii) any other shares of Common Stock issued with respect to the
Shares by reason of stock dividends, stock splits, recapitalizations,
reorganizations or similar corporate action; provided, however, that shares of
Common Stock which are Registrable Shares shall cease to be Registrable Shares
(A) upon any sale pursuant to a registration statement under the Securities Act,
Section 4(1) of the Securities Act or Rule 144 promulgated under the Securities
Act, (B) upon any sale, transfer or assignment in any manner to any entity or
person who, by virtue of Section 14 hereof, is not entitled to the rights
provided by this Agreement, (C) during such period (but only during such period)
as such shares of Common

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Stock are eligible for resale (or for "delegending" as restricted securities)
under Rule 144(k) of the Securities Act (or any successor rule thereto) and (D)
during such period (but only during such period) as such shares of Common Stock
may be sold or otherwise disposed of within a three month period under Rule 144
of the Securities Act, or any similar rule promulgated by the Commission
permitting the resale of restricted securities without the necessity of a
registration statement under the Securities Act.

                  "Registration Expenses" and "Selling Expenses" shall mean the
expenses described in Section 5.

                  "Securities Act" shall mean the Securities Act of 1933, as
amended, and the rules and regulations of the Commission thereunder, as the same
shall be in effect from time to time.

         SECTION 2. Incidental Registration. If the Company for itself or any of
its security holders shall at any time or times after the Initial Public
Offering determine to register under the Securities Act any shares of its
capital stock or other securities (other than the registration of an offer, sale
or other disposition of securities (i) to employees of, or other persons
providing services to, the Company or any subsidiary pursuant to an employee or
similar benefit plan, registered on Form S-8, a comparable or successor form or
another form which is used solely for the purpose of registering such plan, or
(ii) relating to a merger, acquisition or other transaction of the type
described in Rule 145 under the Securities Act or comparable or successor rule,
registered on Form S-4 or similar or successor forms), the Company will notify
the Holder of such determination, and, upon written request received from the
Holder by the Company within ten (10) days after the notice is given by the
Company, the Company will use its best efforts, as soon as practicable
thereafter, to cause any of the Registrable Shares specified by the Holder to be
included in such registration statement to the extent and under the conditions
such registration is permissible under the Securities Act. Notwithstanding the
foregoing, in the event the proposed registration is in whole or in part an
underwritten public offering and if the managing underwriter(s) determine(s) and
advises the Company that the inclusion of some or all of the Registrable Shares
requested to be included in the registration concurrently with the securities
being registered by the Company or other securityholders would interfere with
the successful marketing of such securities, then the number of Registrable
Shares otherwise to be included in the registration statement by the Holders
shall be reduced to the required level (1) first, by reducing the participation
of such requesting Holders in such offering pro rata amongst all participating
holders, other than shares included in the offering pursuant to the following
Clause (2), and (2) second, by excluding shares pursuant to the terms of that
certain Investor Rights Agreement dated April 24,1998, as amended, modified or
supplemented, and any other agreements by the Company then in effect.
Notwithstanding the foregoing provisions, the Company may withdraw any
registration statement referred to in this Section 2 without thereby incurring
any liability to the holders of Registrable Shares. If the Holder disapproves of
the terms of any such underwriting, such Holder may elect to withdraw therefrom
by written notice to the Company and the managing underwriter(s). Any
Registrable Shares withdrawn from such underwriting shall be withdrawn from such
registration.

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         The Company agrees that until all of the Registrable Shares have been
sold under a registration statement or pursuant to Rule 144 under the Securities
Act, it shall keep current in filing all reports, statements and other materials
required to be filed with the Commission to permit the Holder of the Registrable
Shares to sell such securities pursuant to Rule 144 under the Securities Act.

         SECTION 3. Conditions of Obligation to Register Registrable Shares. As
conditions to the Company's obligation hereunder to cause a registration
statement to be filed or Registrable Shares to be included in a registration
statement, the Holder shall (a) provide such information and execute such
documents as may reasonably be required in connection with such registration,
(b) agree to sell their Registrable Shares on the basis provided in any
underwriting arrangements and (c) complete and execute all questionnaires,
powers of attorney, indemnities, underwriting agreements and other documents
reasonably required under the terms of such underwriting arrangements, which
arrangements shall not be inconsistent herewith.

         SECTION 4. Registration Procedures. If and whenever the Company is
required by the provisions of this Agreement to use its best efforts to include
any of the Registrable Shares in a registration statement filed under the
Securities Act, the Company shall, as expeditiously as possible:

                  4.1      Prepare and file with the Commission a registration
         statement with respect to such Registrable Shares and use its best
         efforts to cause such registration statement to become and remain
         effective.

                  4.2      Prepare and file with the Commission such amendments
         and supplements to such registration statement and the prospectus used
         in connection therewith as may be necessary to keep such registration
         statement effective for not more than three months from the date of its
         effectiveness (plus such additional time during which the Holder must
         cease making offers and sales, as provided in Section 4.5) or (unless
         otherwise required by the Securities Act) until the Registrable Shares
         covered thereunder have been sold, whichever is earlier.

                  4.3      Furnish to the Holder such number of copies of the
         prospectus contained in such registration statement (including each
         preliminary prospectus), in conformity with the requirements of the
         Securities Act, and such other documents as the Holder may reasonably
         request in order to facilitate the disposition of its Registrable
         Shares.

                  4.4      Use its best efforts to register or qualify the
         Registrable Shares covered by such registration statement under the
         securities or blue sky laws of such jurisdictions as the managing
         underwriter(s) shall reasonably request, and use its best efforts to do
         any and all other acts and things which may be necessary or advisable
         so to register or qualify the Registrable Shares to enable the Holder
         to consummate the disposition of the Registrable Shares owned by the
         Holder in such jurisdictions during the period covered in Section 4.2;
         provided that the Company shall not be obligated to qualify to do
         business in any jurisdiction where it is not then so qualified or to
         take any action

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         which would subject it to the service of process in suits other than
         those arising out of the offer or sale of the securities covered by the
         registration statement in any jurisdiction where it is not then so
         subject.

                  4.5      Immediately notify the Holder of any Registrable
         Shares covered by such registration statement at any time when a
         prospectus relating thereto is required to be delivered under the
         Securities Act of the happening of any event as a result of which the
         prospectus contained in such registration statement, as then in effect,
         includes an untrue statement of a material fact or omits to state any
         material fact required to be stated therein or necessary to make the
         statements therein not misleading in the light of the circumstances
         then existing. The Holder agrees upon receipt of such notice, forthwith
         to cease making offers and sales of the Registrable Shares pursuant to
         such registration statement or deliveries of the prospectus contained
         therein for any purpose and to return to the Company, for modification
         and exchange, the copies of such prospectus not theretofore delivered
         by such Holder; provided, that the Company shall forthwith prepare and
         furnish, after securing such approvals as may be necessary, to the
         Holder a reasonable number of copies of any supplement to or amendment
         of such prospectus that may be necessary so that, as thereafter
         delivered to the purchasers of such Registrable Shares, such prospectus
         shall not include an untrue statement of a material fact or omit to
         state a material fact required to be stated therein or necessary to
         make the statements therein not misleading in the light of the
         circumstances then existing.

                  4.6      Promptly notify the Holder of any stop order or
         similar proceeding initiated by state or Federal regulatory bodies and
         use its best efforts to take all necessary steps expeditiously to
         remove such stop order or similar proceeding.

         SECTION 5. Description of Expenses. All expenses incurred by the
Company in complying with any of the foregoing provisions of this Agreement,
including, without limitation, all Federal (including Commission and National
Association of Securities Dealers, Inc.) and state registration qualification
and filing fees, printing expenses, any premium involved in securing a policy or
policies of registration insurance (but only if the Company in its sole
discretion shall choose to secure such a policy or policies, such policy or
policies to be herein referred to as "registration insurance"), fees and
disbursements of counsel for the Company, and accountants fees and expenses (but
excluding the compensation of regular employees of the Company which shall be
paid in any event by the Company), incident to or required by any such
registration are herein called "Registration Expenses". All underwriting
discounts, selling commissions and transfer taxes applicable to the sale of
Registrable Shares hereunder are herein called "Selling Expenses".

         If the Company is required by the provisions of this Agreement to use
its best efforts to effect the registration of any of the Registrable Shares
under the Securities Act, all Selling Expenses incurred in connection with
registration statements covering Registrable Shares shall be borne by the Holder
(or by the Holders participating in such registration, pro rata) and all
Registration Expenses shall be borne by the Company.

         SECTION 6. Indemnification; Underwriting Agreements.

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         Registrations. In the event that the Company registers any shares under
the Securities Act pursuant to the provisions of this Agreement:

                  6.1      The Company agrees to indemnify and hold harmless the
         Holder against any and all losses, claims, damages, liabilities or
         expenses, joint or several, arising out of or based upon (i) any
         violation of the Securities Act, the Securities Exchange Act of 1934,
         as amended, any rules and regulations promulgated thereunder or any
         untrue statement or alleged untrue statement of a material fact in any
         related registration statement, prospectus, offering circular,
         notification or other document or any omission or alleged omission of
         any material fact required to be stated therein or necessary to make
         the statements therein not misleading, (ii) any omission or alleged
         omission to state in any such registration statement, prospectus,
         amendment or supplement or in any Blue Sky Applications executed or
         filed by the Company, a material fact required to be stated therein or
         necessary to make the statements therein not misleading, (iii) any
         violation by the Company or its agents of the Securities Act or any
         rule or regulation promulgated under the Securities Act applicable to
         the Company or its agents and relating to action or inaction required
         of the Company in connection with such registration, or (iv) any
         failure to register or qualify the Registrable Securities in any state
         where the Company or its agents has affirmatively undertaken or agreed
         in writing that the Company (the undertaking of any underwriter chosen
         by the Company being attributed to the Company) will undertake such
         registration or qualification (provided that in such instance the
         Company shall not be so liable if it has used its best efforts to so
         register or qualify the Registrable Securities) and will reimburse each
         such Holder for any legal or other expenses reasonably incurred by them
         in connection with investigating or defending any such loss, claim,
         damage, liability or action, promptly after being so incurred,
         provided, however, that the Company will not be liable in any of the
         above cases if and to the extent that any such loss, claim, damage,
         liability or expense arises out of or is based upon an untrue statement
         or alleged untrue statement or omission or alleged omission so made in
         conformity with or in reliance upon written information furnished by or
         on behalf of any such Holder in writing for use in such registration
         statement or prospectus, or a failure by such Holder to furnish any
         statement with respect to such Holder required to be included therein.
         Promptly after receipt by the Holder of notice of the commencement of
         any action in respect of which indemnity may be sought against the
         Company, such Holder shall notify the Company in writing of the
         commencement thereof, and, subject to the provisions hereinafter
         stated, receipt of such notice and such Holder's reasonable
         cooperation, the Company shall assume the defense of such action
         (including the employment of counsel, who shall be counsel reasonably
         satisfactory to such Holder, and the payment of expenses and such
         counsel's fees) insofar as such action shall relate to any alleged
         liability in respect of which indemnity may be sought against the
         Company. Such Holder shall have the right to employ separate counsel in
         any such action and to participate in the defense thereof, but the fees
         and expenses of such counsel shall not be at the expense of the Company
         unless the employment of such counsel has been specifically authorized
         by the Company or unless such Holder shall have in good faith
         reasonably concluded that there may be a conflict of interest between
         the Company and such Holder in the conduct of the defense of the
         action. In connection with any offering under this Agreement which is
         to be underwritten, the Company further agrees to enter into an
         underwriting agreement in usual

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         and standard form, reasonably satisfactory to the Holder, respecting
         such offering; provided that the terms of such underwriting agreement
         shall not be inconsistent or conflict with the provisions of this
         Agreement.

                  6.2      The obligations of the Company under this Agreement
         are subject to the following conditions, which the Holder hereby agrees
         to fulfill: (a) such Holder shall agree, in writing, prior to the
         filing of such registration or qualification, and hereby does agree to
         indemnify and hold harmless the Company, each person, if any, who
         controls the Company within the meaning of the Securities Act and the
         officers and directors of the Company, against any and all losses,
         claims, damages, liabilities or expenses arising out of or based upon
         any untrue statement or alleged untrue statement of a material fact in
         any related registration statement, prospectus, offering circular,
         notification or other document or alleged omission of any material fact
         required to be stated therein or necessary to make the statements
         therein not misleading, but only with reference to statements or
         omissions made in reliance upon a statement in writing furnished by or
         on behalf of such Holder for inclusion therein and with reference to
         statements or omissions made in reliance upon an omission or failure by
         such Holder to furnish any statement with respect to such Holder
         required to be included therein and (b) if such registration or
         qualification relates to an offering which is to be underwritten, that
         such Holder enters into an underwriting agreement in usual and standard
         form respecting such offering; provided, further, that the terms of
         such underwriting agreement shall not be inconsistent or conflict with
         the provisions of this Agreement. Promptly after receipt of notice of
         the commencement of any action in respect of which indemnity may be
         sought against a Holder, the Company will notify such Holder in writing
         of the commencement thereof, and such Holder shall, subject to the
         provisions hereinafter stated, assume the defense of such action
         (including the employment of counsel, who shall be counsel reasonably
         satisfactory to the Company, and the payment of expenses and such
         counsel's fees) insofar as such action shall relate to the alleged
         liability in respect of which indemnity may be sought against such
         Holder. The Company and each such director, officer, or controlling
         person shall have the right to employ separate counsel in any such
         action and to participate in the defense thereof but the fees and
         expenses of such counsel shall not be at the expense of such Holder
         unless employment of such counsel has been specifically authorized by
         such Holder or unless an Indemnified Party (as defined in Section 6.3,
         below) shall have in good faith reasonably concluded that there may be
         a conflict of interest between the Indemnified Party and such Holder in
         the conduct of the defense of the action.

                  6.3      A party required to indemnify another party pursuant
         to this Section 6 ("Indemnifying Party") shall not be liable for any
         settlement of any action or claim relating to such liability or expense
         effected without its consent, but if any settlement is effected with
         its consent or if a final judgment for the plaintiff is entered in any
         such action, such Indemnifying Party agrees to indemnify and hold
         harmless the party so indemnified ("Indemnified Party") from and
         against any loss or liability by reason of any such settlement or
         judgment. The Indemnifying Party shall indemnify the Indemnified Party
         for expenses, including but not limited to fees and disbursements of
         counsel,

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         incurred by the Indemnified Party in connection with the
         indemnification proceeding as such expenses are incurred.

                  6.4      In order to provide for just and equitable
         contribution to joint liability under the Securities Act in any case in
         which either (i) a Holder of Registrable Securities exercising rights
         under this Agreement makes a claim for indemnification pursuant to this
         Section 6 but it is judicially determined (by the entry of a final
         judgment or decree by a court of competent jurisdiction and the
         expiration of time to appeal or the denial of the last right of appeal)
         that such indemnification may not be enforced in such case
         notwithstanding the fact that this Section 6 provides for
         indemnification in such case, or (ii) contribution under the Securities
         Act may be required on the part of any such selling Holder in
         circumstances for which indemnification is provided under this Section
         6; then, and in each such case, the Company and such Holder will
         contribute to the aggregate losses, claims, damages or liabilities to
         which they may be subject (after contribution from others) in such
         proportion so that such Holder is responsible for the portion
         represented by the percentage that the public offering price of its
         Registrable Securities offered by the registration statement bears to
         the public offering price of all securities offered by such
         registration statement, and the Company is responsible for the
         remaining portion; provided, however, that, in any such case, (A) no
         such Holder of Registrable Securities will be required to contribute
         any amount in excess of the proceeds received from the sale of all such
         Registrable Securities offered by it pursuant to such registration
         statement; and (B) no person or entity guilty of fraudulent
         misrepresentation (within the meaning of Section 11(f) of the
         Securities Act) will be entitled to contribution from any person or
         entity who was not guilty of such fraudulent misrepresentation.

         SECTION 7. Mergers, etc. The Company shall not, directly or indirectly,
enter into any merger, consolidation or reorganization in which the Company
shall not be the surviving corporation unless the proposed surviving corporation
shall, prior to such merger, consolidation or reorganization, agree in writing
to assume the obligations of the Company under this Agreement and, for that
purpose, references hereunder to "Registrable Shares" shall be deemed to be
references to the securities which the Holder would be entitled to receive in
exchange for Registrable Shares under any such merger, consolidation or
reorganization and other securities to which they subsequently give rise;
provided, that this Section 7 shall not apply if the Holder shall receive,
pursuant to such merger, consolidation or reorganization, in exchange for the
Registrable Shares, (a) registered securities listed on the New York Stock
Exchange or the American Stock Exchange, or with respect to which prices are
reported by the National Association of Securities Dealers Automated Quotation
System, Inc., or (b) registration and related rights on terms no less favorable
to the Holder than those contained in this Agreement.

         SECTION 8. Market Stand-off. The Holder agrees, if requested by the
Company and/or the representative of the underwriters underwriting the Initial
Public Offering of the Common Stock (or other securities) of the Company, not to
sell or otherwise transfer or dispose of any Common Stock (or other securities)
of the Company held by such Holder during the one hundred and eighty (180) day
period following the effective date of the registration statement of the Company
filed under the Securities Act pursuant to such Initial Public Offering;
provided that all of (a) the Company's directors and officers, (b) the holders
of at least 5% of the outstanding

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Common Stock (or securities convertible into at least 5% of the Common Stock),
and (c) the other holders of securities of the Company participating in the
underwriting enter into similar agreements.

         Such agreement shall be in writing in a form satisfactory to the
Company and such representative. The Company may impose stop-transfer
instructions with respect to the shares (or securities) subject to the foregoing
restriction until the end of said one hundred and eighty (180) day period.

         SECTION 9. Rule 144 and 144A Reporting. With a view to making available
the benefits of certain rules and regulations of the Commission which may at any
time permit the sale of the Registrable Securities to the public without
registration, except as provided in paragraph (c) below, at all times after any
registration statement covering a public offering of securities of the Company
under the Securities Act shall have become effective, the Company agrees to:

                  (a)      use its best efforts to comply with all of the
         reporting requirements of the Exchange Act (whether or not it shall be
         required to do so) and shall comply with all other public information
         reporting requirements of the Commission as a condition to the
         availability of an exemption from the Securities Act for the sale of
         any of the Registrable Securities by the Holder (including any such
         exemption pursuant to Rule 144 or Rule 144A thereof, as amended form
         time to time, or any successor rule thereto or otherwise);

                  (b)      cooperate with the Holder in supplying such
         information as may be necessary for such Holder to complete and file
         any information reporting forms presently or hereafter required by the
         Commission as a condition to the availability of an exemption from the
         Securities Act (under Rule 144 or Rule 144A thereunder or otherwise)
         for the sale of any of the Registrable Securities by the Holder; and

                  (c)      furnish to the Holder forthwith upon request a
         written statement by the Company as to its compliance with the
         reporting requirements of such Rule 144 or Rule 144A (or any successor
         rule) and, at any time after it has become subject to such reporting
         requirements, of the Securities Act and the Exchange Act, a copy of the
         most recent annual or quarterly report of the Company, and such other
         reports and documents so filed by the Company as such Holder may
         reasonably request in availing itself of any rule or regulation of the
         Commission allowing such Holder to sell any Registrable Securities
         without registration.

         SECTION 10. Notices. All notices, requests, consents and other
communications hereunder shall be in writing, shall be addressed to the
receiving party's address set forth below or to such other address as a party
may designate by notice hereunder, and shall be either (i) delivered by hand,
(ii) made by telecopy or facsimile transmission, (iii) sent by recognized
overnight courier, or (iv) sent by registered or certified mail, return receipt
requested, postage prepaid:

         If to the Company:       Memory Pharmaceuticals Corp.
                                  3960 Broadway, 3rd Floor

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                             New York, NY 10032
                             (212) 781-3030 (Telephone)
                             (212)781-2121 (Fax)
                             Attn: Dr. Axel Unterbeck

         With copies to:     Mintz, Levin, Conn, Ferris, Glovsky and Popeo, P.C.
                             One Financial Center
                             Boston, MA 02111
                             617-542-6000 (Telephone)
                             617-542-2241 (Fax)
                             Attn: Lewis J. Geffen, Esq.

         If to Holder:       Columbia Innovation Enterprise
                             Columbia University
                             Engineering Terrace, Suite 363, Mailcode 2206
                             500 West 120th Street
                             New York, NY 10027
                             (212) 854-8444 (Telephone)
                             (212) 854-8453 (Fax)
                             Attn: Executive Director

         With a copy to:     Office of the General Counsel
                             Columbia University
                             110 Low Memorial Library, Mailcode 4308
                             New York, NY 10027

All notices, requests, consents and other communications hereunder shall be
deemed to have been received (i) if by hand, at the time of the delivery thereof
to the receiving party at the address of such party set forth above or as so
designated, (ii) if made by telecopy or facsimile transmission, at the time that
receipt thereof has been acknowledged by electronic confirmation or otherwise,
(iii) if sent by overnight courier, on the next business day (or if sent
overseas, on the second business day) following the day such notice is delivered
to the courier service or (iv) if sent by registered or certified mail, on the
date delivery is made at the address of such party set forth above.

         SECTION 11. Entire Agreement. This Agreement embodies the entire
agreement and understanding between the parties hereto with respect to the
subject matter hereof and supersedes all prior oral or written agreements and
understandings relating to the subject matter hereof. No statement,
representation, warranty, covenant or agreement of any kind not expressly set
forth in this Agreement shall affect, or be used to interpret, change or
restrict, the express terms and provisions of this Agreement.

         SECTION 12. Modifications and Amendments. The terms and provisions of
this Agreement may be amended, modified, supplemented or waived only by written
agreement executed by all parties hereto.

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         SECTION 13. No Waiver of Rights, Powers and Remedies. No failure or
delay by a party hereto in exercising any right, power or remedy under this
Agreement, and no course of dealing between the parties hereto, shall operate as
a waiver of any such right, power or remedy of the party. No single or partial
exercise of any right, power or remedy under this Agreement by a party hereto,
nor any abandonment or discontinuance of steps to enforce any such right, power
or remedy, shall preclude such party from any other or further exercise thereof
or the exercise of any other right, power or remedy hereunder. The election of
any remedy by a party hereto shall not constitute a waiver of the right of such
party to pursue other available remedies. No notice to or demand on a party not
expressly required under this Agreement shall entitle the party receiving such
notice or demand to any other or further notice or demand in similar or other
circumstances or constitute a waiver of the rights of the party giving such
notice or demand to any other or further action in any circumstances without
such notice or demand. The terms and provisions of this Agreement may be waived,
or consent for the departure therefrom granted, only by written document
executed by the party entitled to the benefits of such terms or provisions. No
such waiver or consent shall be deemed to be or shall constitute a waiver or
consent with respect to any other terms or provisions of this Agreement, whether
or not similar. Each such waiver or consent shall be effective only in the
specific instance and for the purpose for which it was given, and shall not
constitute a continuing waiver or consent.

         SECTION 14. Assignment. Neither this Agreement, nor any right or
obligation hereunder, may be assigned by any of the parties hereto without the
prior written consent of the other parties, except that the right to cause the
Company to register Registrable Securities pursuant to this Agreement may be
assigned (but only with all related obligations) by the Holder to a transferee
or assignee of such securities who is not engaged in a business activity
competitive with the Company (as reasonably determined by the Company's Board of
Directors) and who, after such assignment or transfer, holds at least 50,000
shares of Registrable Securities (subject to appropriate adjustment for stock
splits, stock dividends, combinations and similar recapitalization events),
provided the Company is, within a reasonable time after such transfer, furnished
with written notice of the name and address of such transferee or assignee and
the securities with respect to which such registration rights are being
assigned; and provided, further, that such assignment shall be effective only if
(i) immediately following such transfer the further disposition of such
securities by the transferee or assignee is restricted under the Act and (ii)
the transferee or assignee shall acknowledge in writing that the transferred or
assigned Registrable Securities shall remain subject to this Agreement. For the
purposes of determining the number of shares of Registrable Securities held by a
transferee or assignee, the holdings of transferees and assignees of a
partnership who are partners or retired partners of such partnership (including
spouses and ancestors, lineal descendants and siblings of such partners or
spouses who acquire Registrable Securities by gift, will or intestate
succession) shall be aggregated together and with the partnership; provided that
all assignees and transferees who would not qualify individually for assignment
of registration rights shall have a single attorney-in-fact for the purpose of
exercising any rights, receiving notices or taking any actin under this
Agreement.

         SECTION 15. Parties in Interest. This Agreement shall be binding upon
and inure solely to the benefit of each party hereto and their permitted
assigns, and nothing in this Agreement, express or implied, (i) is intended to
confer upon any other person any rights or remedies of any

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nature whatsoever under or by reason of this Agreement or (ii) shall be
construed to create any rights or obligations except among the parties hereto,
and no person shall be regarded as a third-party beneficiary of this Agreement.

         SECTION 16. Governing Law. This Agreement and the rights and
obligations of the parties hereunder shall be construed in accordance with and
governed by the internal laws of the State of New York, without giving effect to
the conflicts of law principles thereof.

         SECTION 17. Severability. In the event that any court of competent
jurisdiction shall finally determine that any provision, or any portion thereof,
contained in this Agreement shall be void or unenforceable in any respect, then
such provision shall be deemed limited to the extent that such court determines
it enforceable, and as so limited shall remain in full force and effect. In the
event that such court shall determine that any such provision, or portion
thereof, is wholly unenforceable, the remaining provisions of this Agreement
shall nevertheless remain in full force and effect.

         SECTION 18. Headings and Captions. The headings and captions of the
various subdivisions of this Agreement are for convenience of reference only and
shall in no way modify, or affect, or be considered in construing or
interpreting the meaning or construction of any of the terms or provisions
hereof.

         SECTION 19. Enforcement. Each of the parties hereto acknowledges and
agrees that the rights acquired by each party hereunder are unique and that
irreparable damage would occur in the event that any of the provisions of this
Agreement to be performed by the other party were not performed in accordance
with their specific terms or were otherwise breached. Accordingly, in addition
to any other remedy to which the parties hereto are entitled at law or in
equity, each party hereto shall be entitled to an injunction or injunctions to
prevent breaches of this Agreement by the other party and to enforce
specifically the terms and provisions hereof in any federal or state court of
competent jurisdiction.

         SECTION 20. Expenses. Except as expressly provided in Section 5 hereof,
each of the parties hereto shall pay its own fees and expenses (including the
fees of any attorneys, accountants, appraisers or others engaged by such party)
in connection with this Agreement and the transactions contemplated hereby
whether or not the transactions contemplated hereby are consummated.

         SECTION 21. Publicity. No party hereto may issue any press release or
otherwise make any public statement with respect to any registration that is the
subject of this Agreement without the prior written consent of the other parties
hereto, except as may be required by applicable law. Prior to making any public
disclosure so required by applicable law, the disclosing party shall give the
other parties a copy of the proposed disclosure and reasonable opportunity to
prescribe or limit the same.

         SECTION 22. Counterparts. This Agreement may be executed in one or more
counterparts, and by the parties hereto in separate counterparts, each of which
shall be deemed an original, but all of which together shall constitute one and
the same instrument.

                                     - 11 -
<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement as of the day and year first set forth above.

                                   MEMORY PHARMACEUTICALS CORP.

                                   By     /s/ Axel Unterbeck
                                      -----------------------------------
                                   Name:  Axel Unterbeck, Ph.D.
                                   Title: President and Chief Scientific Officer

                                   THE TRUSTEES OF COLUMBIA UNIVERSITY
                                   IN THE CITY OF NEW YORK

                                   By:    /s/ Jack M. Granowitz
                                       ----------------------------------
                                   Name:  Jack M. Granowitz
                                   Title: Executive Director,
                                          Columbia Innovation Enterprise

                                     - 12 -<PAGE>

                                                                    EXHIBIT 10.1

                          MEMORY PHARMACEUTICALS CORP.

            1998 EMPLOYEE, DIRECTOR AND CONSULTANT STOCK OPTION PLAN

1.       DEFINITIONS.

         Unless otherwise specified or unless the context otherwise requires,
         the following terms, as used in this Memory Pharmaceuticals Corp. 1998
         Employee, Director and Consultant Stock Option Plan, have the following
         meanings:

                  Administrator means the Board of Directors, unless it has
                  delegated power to act on its behalf to the Committee, in
                  which case the Administrator means the Committee.

                  Affiliate means a corporation which, for purposes of Section
                  424 of the Code, is a parent or subsidiary of the Company,
                  direct or indirect.

                  Board of Directors means the Board of Directors of the
                  Company.

                  Code means the United States Internal Revenue Code of 1986, as
                  amended.

                  Committee means the committee of the Board of Directors to
                  which the Board of Directors has delegated power to act under
                  or pursuant to the provisions of the Plan.

                  Common Stock means shares of the Company's common stock, $.001
                  par value per share.

                  Company means Memory Pharmaceuticals Corp., a Delaware
                  corporation.

                  Disability or Disabled means permanent and total disability as
                  defined in Section 22(e)(3) of the Code.

                  Fair Market Value of a Share of Common Stock means:

                  (1)      If the Common Stock is listed on a national
                  securities exchange or traded in the over-the-counter market
                  and sales prices are regularly reported for the Common Stock,
                  the closing or last price of the Common Stock on the Composite

<PAGE>

                  Tape or other comparable reporting system for the trading day
                  immediately preceding the applicable date;

                  (2)      If the Common Stock is not traded on a national
                  securities exchange but is traded on the over-the-counter
                  market, if sales prices are not regularly reported for the
                  Common Stock for the trading day referred to in clause (1),
                  and if bid and asked prices for the Common Stock are regularly
                  reported, the mean between the bid and the asked price for the
                  Common Stock at the close of trading in the over-the-counter
                  market for the trading day on which Common Stock was traded
                  immediately preceding the applicable date; and

                  (3)      If the Common Stock is neither listed on a national
                  securities exchange nor traded in the over-the-counter market,
                  such value as the Administrator, in good faith, shall
                  determine.

                  ISO means an option meant to qualify as an incentive stock
                  option under Section 422 of the Code.

                  Key Employee means an employee of the Company or of an
                  Affiliate (including, without limitation, an employee who is
                  also serving as an officer or director of the Company or of an
                  Affiliate), designated by the Administrator to be eligible to
                  be granted one or more Options under the Plan.

                  Non-Qualified Option means an option which is not intended to
                  qualify as an ISO.

                  Option means an ISO or Non-Qualified Option granted under the
                  Plan.

                  Option Agreement means an agreement between the Company and a
                  Participant delivered pursuant to the Plan, in such form as
                  the Administrator shall approve.

                  Participant means a Key Employee, director or consultant to
                  whom one or more Options are granted under the Plan. As used
                  herein, "Participant" shall include "Participant's Survivors"
                  where the context requires.

                  Plan means this Memory Pharmaceuticals Corp. 1998 Employee,
                  Director and Consultant Stock Option Plan.

                  Shares means shares of the Common Stock as to which Options
                  have been or may be granted under the Plan or any shares of
                  capital stock into which the Shares are changed or for which
                  they are exchanged within the provisions of Paragraph 3 of the
                  Plan. The Shares issued upon exercise of Options granted under
                  the Plan may be authorized and unissued shares or shares held
                  by the Company in its treasury, or both.

                                       2
<PAGE>

                  Survivors means a deceased Participant's legal representatives
                  and/or any person or persons who acquired the Participant's
                  rights to an Option by will or by the laws of descent and
                  distribution.

2.       PURPOSES OF THE PLAN.

         The Plan is intended to encourage ownership of Shares by Key Employees
and directors of and certain consultants to the Company in order to attract such
people, to induce them to work for the benefit of the Company or of an Affiliate
and to provide additional incentive for them to promote the success of the
Company or of an Affiliate. The Plan provides for the granting of ISOs and
Non-Qualified Options.

3.       SHARES SUBJECT TO THE PLAN.

         The number of Shares which may be issued from time to time pursuant to
this Plan shall be 9,500,000, or the equivalent of such number of Shares after
the Administrator, in its sole discretion, has interpreted the effect of any
stock split, stock dividend, combination, recapitalization or similar
transaction in accordance with Paragraph 16 of the Plan.

         If an Option ceases to be "outstanding", in whole or in part, the
Shares which were subject to such Option shall be available for the granting of
other Options under the Plan. Any Option shall be treated as "outstanding" until
such Option is exercised in full, or terminates or expires under the provisions
of the Plan, or by agreement of the parties to the pertinent Option Agreement.

4.       ADMINISTRATION OF THE PLAN.

         The Administrator of the Plan will be the Board of Directors, except to
the extent the Board of Directors delegates its authority to the Committee, in
which case the Committee shall be the Administrator. Subject to the provisions
of the Plan, the Administrator is authorized to:

         a.       Interpret the provisions of the Plan or of any Option or
                  Option Agreement and to make all rules and determinations
                  which it deems necessary or advisable for the administration
                  of the Plan;

         b.       Determine which employees of the Company or of an Affiliate
                  shall be designated as Key Employees and which of the Key
                  Employees, directors and consultants shall be granted Options;

         c.       Determine the number of Shares for which an Option or Options
                  shall be granted, provided, however, that in no event shall
                  Options to purchase more than 1,000,000 Shares be granted to
                  any Participant in any fiscal year; and

                                       3
<PAGE>

         d.       Specify the terms and conditions upon which an Option or
                  Options may be granted;

provided, however, that all such interpretations, rules, determinations, terms
and conditions shall be made and prescribed in the context of preserving the tax
status under Section 422 of the Code of those Options which are designated as
ISOs. Subject to the foregoing, the interpretation and construction by the
Administrator of any provisions of the Plan or of any Option granted under it
shall be final, unless otherwise determined by the Board of Directors, if the
Administrator is the Committee.

5.       ELIGIBILITY FOR PARTICIPATION.

         The Administrator will, in its sole discretion, name the Participants
in the Plan, provided, however, that each Participant must be a Key Employee,
director or consultant of the Company or of an Affiliate at the time an Option
is granted. Notwithstanding the foregoing, the Administrator may authorize the
grant of an Option to a person not then an employee, director or consultant of
the Company or of an Affiliate; provided, however, that the actual grant of such
Option shall be conditioned upon such person becoming eligible to become a
Participant at or prior to the time of the delivery of the Option Agreement
evidencing such Option. ISOs may be granted only to Key Employees. Non-Qualified
Options may be granted to any Key Employee, director or consultant of the
Company or an Affiliate. The granting of any Option to any individual shall
neither entitle that individual to, nor disqualify him or her from,
participation in any other grant of Options.

6.       TERMS AND CONDITIONS OF OPTIONS.

         Each Option shall be set forth in writing in an Option Agreement, duly
executed by the Company and, to the extent required by law or requested by the
Company, by the Participant. The Administrator may provide that Options be
granted subject to such terms and conditions, consistent with the terms and
conditions specifically required under this Plan, as the Administrator may deem
appropriate including, without limitation, subsequent approval by the
shareholders of the Company of this Plan or any amendments thereto.

         A.       Non-Qualified Options: Each Option intended to be a
                  Non-Qualified Option shall be subject to the terms and
                  conditions which the Administrator determines to be
                  appropriate and in the best interest of the Company, subject
                  to the following minimum standards for any such Non-Qualified
                  Option:

                  a.       Option Price: Each Option Agreement shall state the
                           option price (per share) of the Shares covered by
                           each Option, which option price shall be determined
                           by the Administrator but shall not be less than the
                           par value per share of Common Stock.

                                       4
<PAGE>

                  b.       Each Option Agreement shall state the number of
                           Shares to which it pertains;

                  c.       Each Option Agreement shall state the date or dates
                           on which it first is exercisable and the date after
                           which it may no longer be exercised, and may provide
                           that the Option rights accrue or become exercisable
                           in installments over a period of months or years, or
                           upon the occurrence of certain conditions or the
                           attainment of stated goals or events; and

                  d.       Exercise of any Option may be conditioned upon the
                           Participant's execution of a Share purchase agreement
                           in form satisfactory to the Administrator providing
                           for certain protections for the Company and its other
                           shareholders, including requirements that:

                           i.       The Participant's or the Participant's
                                    Survivors' right to sell or transfer the
                                    Shares may be restricted; and

                           ii.      The Participant or the Participant's
                                    Survivors may be required to execute letters
                                    of investment intent and must also
                                    acknowledge that the Shares will bear
                                    legends noting any applicable restrictions.

         B.       ISOs: Each Option intended to be an ISO shall be issued only
                  to a Key Employee and be subject to the following terms and
                  conditions, with such additional restrictions or changes as
                  the Administrator determines are appropriate but not in
                  conflict with Section 422 of the Code and relevant regulations
                  and rulings of the Internal Revenue Service:

                  a.       Minimum standards: The ISO shall meet the minimum
                           standards required of Non-Qualified Options, as
                           described in Paragraph 6(A) above, except clause (a)
                           thereunder.

                  b.       Option Price: Immediately before the Option is
                           granted, if the Participant owns, directly or by
                           reason of the applicable attribution rules in Section
                           424(d) of the Code:

                           i.       Ten percent (10%) or less of the total
                                    combined voting power of all classes of
                                    share capital of the Company or an
                                    Affiliate, the Option price per share of the
                                    Shares covered by each Option shall not be
                                    less than one hundred percent (100%) of the
                                    Fair Market Value per share of the Shares on
                                    the date of the grant of the Option.

                           ii.      More than ten percent (10%) of the total
                                    combined voting power of all classes of
                                    stock of the Company or an Affiliate, the
                                    Option price per share of the Shares covered
                                    by each Option shall not be

                                       5
<PAGE>

                                    less than one hundred ten percent (110%) of
                                    the said Fair Market Value on the date of
                                    grant.

                  c.       Term of Option: For Participants who own

                           i.       Ten percent (10%) or less of the total
                                    combined voting power of all classes of
                                    share capital of the Company or an
                                    Affiliate, each Option shall terminate not
                                    more than ten (10) years from the date of
                                    the grant or at such earlier time as the
                                    Option Agreement may provide.

                           ii.      More than ten percent (10%) of the total
                                    combined voting power of all classes of
                                    stock of the Company or an Affiliate, each
                                    Option shall terminate not more than five
                                    (5) years from the date of the grant or at
                                    such earlier time as the Option Agreement
                                    may provide.

                  d.       Limitation on Yearly Exercise: The Option Agreements
                           shall restrict the amount of Options which may be
                           exercisable in any calendar year (under this or any
                           other ISO plan of the Company or an Affiliate) so
                           that the aggregate Fair Market Value (determined at
                           the time each ISO is granted) of the stock with
                           respect to which ISOs are exercisable for the first
                           time by the Participant in any calendar year does not
                           exceed one hundred thousand dollars ($100,000),
                           provided that this subparagraph (d) shall have no
                           force or effect if its inclusion in the Plan is not
                           necessary for Options issued as ISOs to qualify as
                           ISOs pursuant to Section 422(d) of the Code.

7.       EXERCISE OF OPTIONS AND ISSUE OF SHARES.

         An Option (or any part or installment thereof) shall be exercised by
giving written notice to the Company at its principal executive office address,
together with provision for payment of the full purchase price in accordance
with this Paragraph for the Shares as to which the Option is being exercised,
and upon compliance with any other condition(s) set forth in the Option
Agreement. Such written notice shall be signed by the person exercising the
Option, shall state the number of Shares with respect to which the Option is
being exercised and shall contain any representation required by the Plan or the
Option Agreement. Payment of the purchase price for the Shares as to which such
Option is being exercised shall be made (a) in United States dollars in cash or
by check, or (b) at the discretion of the Administrator, through delivery of
shares of Common Stock having a Fair Market Value equal as of the date of the
exercise to the cash exercise price of the Option, or (c) at the discretion of
the Administrator, by having the Company retain from the shares otherwise
issuable upon exercise of the Option, a number of shares having a Fair Market
Value equal as of the date of exercise to the exercise price of the Option, or
(d) at the discretion of the Administrator, by delivery of the grantee's
personal recourse note bearing interest payable not less than annually at no
less than 100% of the applicable Federal rate, as defined in Section 1274(d) of
the Code, or (e) at the discretion of the Administrator, in accordance with a
cashless exercise program established with a securities brokerage firm, and

                                       6
<PAGE>

approved by the Administrator, or (f) at the discretion of the Administrator, by
any combination of (a), (b), (c), (d) and (e) above. Notwithstanding the
foregoing, the Administrator shall accept only such payment on exercise of an
ISO as is permitted by Section 422 of the Code.

         The Company shall then reasonably promptly deliver the Shares as to
which such Option was exercised to the Participant (or to the Participant's
Survivors, as the case may be). In determining what constitutes "reasonably
promptly," it is expressly understood that the delivery of the Shares may be
delayed by the Company in order to comply with any law or regulation (including,
without limitation, state securities or "blue sky" laws) which requires the
Company to take any action with respect to the Shares prior to their issuance.
The Shares shall, upon delivery, be evidenced by an appropriate certificate or
certificates for fully paid, non-assessable Shares.

         The Administrator shall have the right to accelerate the date of
exercise of any installment of any Option; provided that the Administrator shall
not accelerate the exercise date of any installment of any Option granted to any
Key Employee as an ISO (and not previously converted into a Non-Qualified Option
pursuant to Paragraph 19) if such acceleration would violate the annual vesting
limitation contained in Section 422(d) of the Code, as described in Paragraph
6.B.d.

         The Administrator may, in its discretion, amend any term or condition
of an outstanding Option provided (i) such term or condition as amended is
permitted by the Plan, (ii) any such amendment shall be made only with the
consent of the Participant to whom the Option was granted, or in the event of
the death of the Participant, the Participant's Survivors, if the amendment is
adverse to the Participant, and (iii) any such amendment of any ISO shall be
made only after the Administrator, after consulting the counsel for the Company,
determines whether such amendment would constitute a "modification" of any
Option which is an ISO (as that term is defined in Section 424(h) of the Code)
or would cause any adverse tax consequences for the holder of such ISO.

8.       RIGHTS AS A SHAREHOLDER.

         No Participant to whom an Option has been granted shall have rights as
a shareholder with respect to any Shares covered by such Option, except after
due exercise of the Option and tender of the full purchase price for the Shares
being purchased pursuant to such exercise and registration of the Shares in the
Company's share register in the name of the Participant.

9.       ASSIGNABILITY AND TRANSFERABILITY OF OPTIONS.

         By its terms, an Option granted to a Participant shall not be
transferable by the Participant other than (i) by will or by the laws of descent
and distribution, or (ii) as otherwise determined by the Administrator and set
forth in the applicable Option Agreement. The designation of a beneficiary of an
Option by a Participant shall not be deemed a transfer prohibited by this
Paragraph. Except as provided above, an Option shall be exercisable, during the
Participant's

                                       7
<PAGE>

lifetime, only by such Participant (or by his or her legal representative) and
shall not be assigned, pledged or hypothecated in any way (whether by operation
of law or otherwise) and shall not be subject to execution, attachment or
similar process. Any attempted transfer, assignment, pledge, hypothecation or
other disposition of any Option or of any rights granted thereunder contrary to
the provisions of this Plan, or the levy of any attachment or similar process
upon an Option, shall be null and void.

10.      EFFECT OF TERMINATION OF SERVICE OTHER THAN "FOR CAUSE" OR DEATH OR
         DISABILITY.

         Except as otherwise provided in the pertinent Option Agreement, in the
event of a termination of service (whether as an employee, director or
consultant) with the Company or an Affiliate before the Participant has
exercised all Options, the following rules apply:

         a.       A Participant who ceases to be an employee, director or
                  consultant of the Company or of an Affiliate (for any reason
                  other than termination "for cause", Disability, or death for
                  which events there are special rules in Paragraphs 11, 12, and
                  13, respectively), may exercise any Option granted to him or
                  her to the extent that the Option is exercisable on the date
                  of such termination of service, but only within such term as
                  the Administrator has designated in the pertinent Option
                  Agreement.

         b.       Except as provided in Subparagraph (c) below, or Paragraph 12
                  or 13, in no event may an Option Agreement provide, if the
                  Option is intended to be an ISO, that the time for exercise be
                  later than three (3) months after the Participant's
                  termination of employment.

         c.       The provisions of this Paragraph, and not the provisions of
                  Paragraph 12 or 13, shall apply to a Participant who
                  subsequently becomes Disabled or dies after the termination of
                  employment, director status or consultancy, provided, however,
                  in the case of a Participant's Disability or death within
                  three (3) months after the termination of employment, director
                  status or consultancy, the Participant or the Participant's
                  Survivors may exercise the Option within one (1) year after
                  the date of the Participant's termination of employment, but
                  in no event after the date of expiration of the term of the
                  Option.

         d.       Notwithstanding anything herein to the contrary, if subsequent
                  to a Participant's termination of employment, termination of
                  director status or termination of consultancy, but prior to
                  the exercise of an Option, the Board of Directors determines
                  that, either prior or subsequent to the Participant's
                  termination, the Participant engaged in conduct which would
                  constitute "cause", then such Participant shall forthwith
                  cease to have any right to exercise any Option.

         e.       A Participant to whom an Option has been granted under the
                  Plan who is absent from work with the Company or with an
                  Affiliate because of temporary disability

                                       8
<PAGE>

                  (any disability other than a permanent and total Disability as
                  defined in Paragraph 1 hereof), or who is on leave of absence
                  for any purpose, shall not, during the period of any such
                  absence, be deemed, by virtue of such absence alone, to have
                  terminated such Participant's employment, director status or
                  consultancy with the Company or with an Affiliate, except as
                  the Administrator may otherwise expressly provide.

         f.   Except as required by law or as set forth in the pertinent Option
              Agreement, Options granted under the Plan shall not be affected by
              any change of a Participant's status within or among the Company
              and any Affiliates, so long as the Participant continues to be an
              employee, director or consultant of the Company or any Affiliate.

11.      EFFECT OF TERMINATION OF SERVICE "FOR CAUSE".

         Except as otherwise provided in the pertinent Option Agreement, the
following rules apply if the Participant's service (whether as an employee,
director or consultant) with the Company or an Affiliate is terminated "for
cause" prior to the time that all his or her outstanding Options have been
exercised:

         a.       All outstanding and unexercised Options as of the time the
                  Participant is notified his or her service is terminated "for
                  cause" will immediately be forfeited.

         b.       For purposes of this Plan, "cause" shall include (and is not
                  limited to) dishonesty with respect to the Company or any
                  Affiliate, insubordination, substantial malfeasance or
                  non-feasance of duty, unauthorized disclosure of confidential
                  information, and conduct substantially prejudicial to the
                  business of the Company or any Affiliate. The determination of
                  the Administrator as to the existence of "cause" will be
                  conclusive on the Participant and the Company.

         c.       "Cause" is not limited to events which have occurred prior to
                  a Participant's termination of service, nor is it necessary
                  that the Administrator's finding of "cause" occur prior to
                  termination. If the Administrator determines, subsequent to a
                  Participant's termination of service but prior to the exercise
                  of an Option, that either prior or subsequent to the
                  Participant's termination the Participant engaged in conduct
                  which would constitute "cause," then the right to exercise any
                  Option is forfeited.

         d.       Any definition in an agreement between the Participant and the
                  Company or an Affiliate, which contains a conflicting
                  definition of "cause" for termination and which is in effect
                  at the time of such termination, shall supersede the
                  definition in this Plan with respect to such Participant.

                                       9
<PAGE>

12.      EFFECT OF TERMINATION OF SERVICE FOR DISABILITY.

         Except as otherwise provided in the pertinent Option Agreement, a
Participant who ceases to be an employee, director or consultant of the Company
or of an Affiliate by reason of Disability may exercise any Option granted to
such Participant:

         a.       To the extent exercisable but not exercised on the date of
                  Disability; and

         b.       In the event rights to exercise the Option accrue
                  periodically, to the extent of a pro rata portion of any
                  additional rights as would have accrued had the Participant
                  not become Disabled prior to the end of the accrual period
                  which next ends following the date of Disability. The
                  proration shall be based upon the number of days of such
                  accrual period prior to the date of Disability.

         A Disabled Participant may exercise such rights only within the period
ending one (1) year after the date of the Participant's termination of
employment, directorship or consultancy, as the case may be, notwithstanding
that the Participant might have been able to exercise the Option as to some or
all of the Shares on a later date if the Participant had not become disabled and
had continued to be an employee, director or consultant or, if earlier, within
the originally prescribed term of the Option.

         The Administrator shall make the determination both of whether
Disability has occurred and the date of its occurrence (unless a procedure for
such determination is set forth in another agreement between the Company and
such Participant, in which case such procedure shall be used for such
determination). If requested, the Participant shall be examined by a physician
selected or approved by the Administrator, the cost of which examination shall
be paid for by the Company.

13.      EFFECT OF DEATH WHILE AN EMPLOYEE, DIRECTOR OR CONSULTANT.

         Except as otherwise provided in the pertinent Option Agreement, in the
event of the death of a Participant while the Participant is an employee,
director or consultant of the Company or of an Affiliate, such Option may be
exercised by the Participant's Survivors:

         a.       To the extent exercisable but not exercised on the date of
                  death; and

         b.       In the event rights to exercise the Option accrue
                  periodically, to the extent of a pro rata portion of any
                  additional rights which would have accrued had the Participant
                  not died prior to the end of the accrual period which next
                  ends following the date of death. The proration shall be based
                  upon the number of days of such accrual period prior to the
                  Participant's death.

         If the Participant's Survivors wish to exercise the Option, they must
take all necessary steps to exercise the Option within one (1) year after the
date of death of such Participant, notwithstanding that the decedent might have
been able to exercise the Option as to some or all

                                       10
<PAGE>

of the Shares on a later date if he or she had not died and had continued to be
an employee, director or consultant or, if earlier, within the originally
prescribed term of the Option.

14.      PURCHASE FOR INVESTMENT.

         Unless the offering and sale of the Shares to be issued upon the
particular exercise of an Option shall have been effectively registered under
the Securities Act of 1933, as now in force or hereafter amended (the "1933
Act"), the Company shall be under no obligation to issue the Shares covered by
such exercise unless and until the following conditions have been fulfilled:

         a.       The person(s) who exercise(s) such Option shall warrant to the
                  Company, prior to the receipt of such Shares, that such
                  person(s) are acquiring such Shares for their own respective
                  accounts, for investment, and not with a view to, or for sale
                  in connection with, the distribution of any such Shares, in
                  which event the person(s) acquiring such Shares shall be bound
                  by the provisions of the following legend which shall be
                  endorsed upon the certificate(s) evidencing their Shares
                  issued pursuant to such exercise or such grant:

                           "The shares represented by this certificate have been
                           taken for investment and they may not be sold or
                           otherwise transferred by any person, including a
                           pledgee, unless (1) either (a) a Registration
                           Statement with respect to such shares shall be
                           effective under the Securities Act of 1933, as
                           amended, or (b) the Company shall have received an
                           opinion of counsel satisfactory to it that an
                           exemption from registration under such Act is then
                           available, and (2) there shall have been compliance
                           with all applicable state securities laws."

         b.       At the discretion of the Administrator, the Company shall have
                  received an opinion of its counsel that the Shares may be
                  issued upon such particular exercise in compliance with the
                  1933 Act without registration thereunder.

15.      DISSOLUTION OR LIQUIDATION OF THE COMPANY.

         Upon the dissolution or liquidation of the Company, all Options granted
under this Plan which as of such date shall not have been exercised will
terminate and become null and void; provided, however, that if the rights of a
Participant or a Participant's Survivors have not otherwise terminated and
expired, the Participant or the Participant's Survivors will have the right
immediately prior to such dissolution or liquidation to exercise any Option to
the extent that the Option is exercisable as of the date immediately prior to
such dissolution or liquidation.

                                       11
<PAGE>

16.      ADJUSTMENTS.

         Upon the occurrence of any of the following events, a Participant's
rights with respect to any Option granted to him or her hereunder which has not
previously been exercised in full shall be adjusted as hereinafter provided,
unless otherwise specifically provided in the pertinent Option Agreement:

         A.       Stock Dividends and Stock Splits. If (i) the shares of Common
Stock shall be subdivided or combined into a greater or smaller number of shares
or if the Company shall issue any shares of Common Stock as a stock dividend on
its outstanding Common Stock, or (ii) additional shares or new or different
shares or other securities of the Company or other non-cash assets are
distributed with respect to such shares of Common Stock, the number of shares of
Common Stock deliverable upon the exercise of such Option may be appropriately
increased or decreased proportionately, and appropriate adjustments may be made
in the purchase price per share to reflect such events.

         B.       Acquisition; Consolidation; Merger; Change of Control.

                  1.       Acquisitions. If the Company is to be consolidated
         with or acquired by another entity in a merger, sale of all or
         substantially all of the Company's assets or shares of stock or
         otherwise (an "Acquisition"), the Administrator or the board of
         directors of any entity assuming the obligations of the Company
         hereunder (the "Successor Board"), shall, as to outstanding Options,
         take any one or a combination of the following actions, but need not
         take the same action as to each such Option: (i) make appropriate
         provision for the continuation of such Options by substituting on terms
         no less favorable to the Participant and on an equitable basis for the
         Shares then subject to such Options either the consideration payable
         with respect to the outstanding shares of Common Stock in connection
         with the Acquisition or securities of any successor or acquiring
         entity; or (ii) upon written notice to the Participants, provide that
         all Options must be exercised (either to the extent then exercisable
         or, at the discretion of the Administrator, all Options being made
         fully exercisable for purposes of this subparagraph), within a
         specified number of days of the date of such notice, at the end of
         which period the Options shall terminate; or (iii) terminate all
         Options in exchange for a cash payment equal to the excess of the Fair
         Market Value of the shares subject to such Options (either to the
         extent then exercisable or, at the discretion of the Administrator, all
         Options being made fully exercisable for purposes of this subparagraph)
         over the exercise price thereof. If the Company is to be consolidated
         or merged with another entity in a merger, sale of less than
         substantially all of the Company's assets or shares of stock or
         otherwise (other than an Acquisition), the Administrator or the board
         of directors of any entity assuming the obligations of the Company
         hereunder (the "Successor Board") may, in its discretion, as to
         outstanding Options, take any one or a combination of the actions
         specified in the preceding sentence, but need not take the same action
         as to each such Option shall, as to outstanding Options.

                  2.       Election to Cash-Out Options Upon Certain
         Acquisitions. If an Acquisition occurs in which the holders of all or
         substantially all of the outstanding

                                       12
<PAGE>

         shares of the company's Common Stock are entitled to receive a cash
         payment for each share exchanged or surrendered in the Acquisition, and
         if the Administrator or Successor Board has not made or provided for
         the termination of all Options in exchange for a cash payment equal to
         the excess of the Fair Market Value of the shares subject to such
         Options over the exercise price thereof, and if any Options (including
         any continuing Options substituted pursuant to clause (i) of paragraph
         1 above) outstanding thereafter are exercisable for Common Stock or
         other securities that are not Publicly Traded (as defined below) at the
         time of exercise, then the Participant may elect, upon exercise of any
         such Option, to receive a cash payment equal to the excess of the Fair
         Market Value of the shares subject to such Option over the exercise
         price thereof, in lieu of the Common Stock or other securities which
         such Participant otherwise would be entitled to receive upon such
         exercise. "Publicly Traded" means, with respect to any securities of a
         kind acquirable upon exercise of an Option, that there are shares of
         such class of securities that are traded on or through a national
         securities exchange or the National Association of Securities Dealers
         Automated Quotation System or any similar public securities market.

                  3.       Acceleration of Exercisability Upon Acquisition. Upon
         an Acquisition, the exercisability of outstanding Options shall
         accelerate and such Options shall become exercisable as follows:

                  (i)      If following an Acquisition, the Company or the
                           successor or acquiring entity does not continue the
                           Service (as defined below) of any Participant in a
                           position and on terms (including compensation,
                           benefits, work location and responsibilities)
                           substantially similar to (or more favorable than) the
                           position and terms on which such Participant was
                           providing Service to the Company immediately prior
                           thereto, then such Options shall become fully
                           exercisable; provided that no such acceleration shall
                           occur if such Participant declines to accept an offer
                           of such continued employment or if such Participant
                           is terminated for Cause (as defined in Section 11(d)
                           or in the pertinent Option Agreement). "Service"
                           means, with respect to any Participant, such
                           Participant's service as an employee, officer or
                           director of, or consultant or advisor to, the Company
                           or the successor or acquiring entity, as the case may
                           be.

                  (ii)     If within one year following an Acquisition, the
                           Company or the successor or acquiring entity
                           terminates the service of any Participant other than
                           for Cause, then any Options held by such Participant
                           shall become fully exercisable on the date of such
                           termination.

                  (iii)    Except insofar as any Options have become or later
                           become exercisable to a greater extent pursuant to
                           preceding clauses (i) and (ii), each outstanding
                           Option shall become exercisable immediately prior to
                           the consummation of an Acquisition with respect to
                           that number of Unvested Shares (as defined below)
                           which equals twenty-five percent (25%) of the total
                           number of shares originally subject to such Option,
                           and shall become exercisable with respect to the
                           remainder (if any) of the Unvested Shares in equal
                           monthly installments over the twelve (12) month
                           period immediately following the Acquisition, unless
                           the remainder of the Unvested Shares would vest
                           sooner at the original rate of vesting under

                                       13
<PAGE>

                           such Option, in which case that original rate of
                           vesting will continue to apply to the remainder.
                           "Unvested Shares" means, with respect to any Option
                           at any time, any shares that are not then acquirable
                           upon exercise of such Option but that will become
                           acquirable at a future date if the Participant
                           continues to provide Service to the Company through
                           that date. Unvested Shares do not include any shares
                           that will become exercisable only if specified
                           performance targets are met.

                  (iv)     Notwithstanding the foregoing, any Options that
                           become exercisable with respect to Unvested Shares by
                           virtue of the provisions of this subparagraph 3 may
                           only be exercised if and to the extent that any other
                           conditions or requirements applicable to such
                           exercise (such as, for example, a requirement that an
                           Option be exercised only while the Participant
                           continues in the Service of the Company or during a
                           specified period thereafter, or a requirement that an
                           Option be exercised prior to its expiration) are
                           satisfied.

                  4.       Pooling. Notwithstanding anything in this Paragraph B
         to the contrary, if, in the opinion of the Company's independent public
         accountants, giving effect to any of the acceleration of vesting or
         other provisions of this Paragraph B (or any provisions contained in
         any Option Agreement) would render "pooling of interest" treatment
         unavailable in connection with any Acquisition which the Board of
         Directors of the Company wishes to be so treated, then any such
         provision shall be given effect to the maximum extent, if any,
         consistent with "pooling of interest" treatment and with the original
         intent of such provision, but otherwise shall be inoperative and shall
         have no force or effect in connection with such transaction.

                  5.       Substitute Options. The Company may grant Options in
         substitution for options held by employees of another corporation who
         become employees of the Company or a subsidiary of the Company, as the
         result of a merger or consolidation of the employing corporation with
         the Company or a subsidiary of the Company, or as a result of the
         acquisition by the Company, or one of its subsidiaries, of property or
         stock of the employing corporation. The Administrator may direct that
         substitute Options be granted on such terms and conditions as the
         Company's Board of Directors considers appropriate in the
         circumstances.

                  6.       Options and Shares Outside This Plan. With respect to
         any awards or grants of capital stock or of options not made under this
         Plan (or any shares of common stock issued upon exercise thereof), in
         the event of an Acquisition any securities, cash or other property
         received in exchange for such capital stock, options or shares shall
         continue to be governed by the provisions of any agreement pursuant to
         which they were awarded or granted and not by the provisions of this
         Paragraph B.

         C.       Recapitalization or Reorganization. In the event of a
recapitalization or reorganization of the Company (other than a transaction
described in Subparagraph B above) pursuant to which securities of the Company
or of another corporation are issued with respect to the outstanding shares of
Common Stock, a Participant upon exercising an Option shall be entitled to
receive for the purchase price paid upon such exercise the securities which
would

                                       14
<PAGE>

have been received if such Option had been exercised prior to such
recapitalization or reorganization.

         D.       Modification of ISOs. Notwithstanding the foregoing, any
adjustments made pursuant to Subparagraph A, B or C with respect to ISOs shall
be made only after the Administrator, after consulting with counsel for the
Company, determines whether such adjustments would constitute a "modification"
of such ISOs (as that term is defined in Section 424(h) of the Code) or would
cause any adverse tax consequences for the holders of such ISOs. If the
Administrator determines that such adjustments made with respect to ISOs would
constitute a modification of such ISOs, it may refrain from making such
adjustments, unless the holder of an ISO specifically requests in writing that
such adjustment be made and such writing indicates that the holder has full
knowledge of the consequences of such "modification" on his or her income tax
treatment with respect to the ISO.

17.      ISSUANCES OF SECURITIES.

         Except as expressly provided herein, no issuance by the Company of
shares of stock of any class, or securities convertible into shares of stock of
any class, shall affect, and no adjustment by reason thereof shall be made with
respect to, the number or price of shares subject to Options. Except as
expressly provided herein, no adjustments shall be made for dividends paid in
cash or in property (including without limitation, securities) of the Company.

18.      FRACTIONAL SHARES.

         No fractional shares shall be issued under the Plan and the person
exercising such right shall receive from the Company cash in lieu of such
fractional shares equal to the Fair Market Value thereof.

19.      CONVERSION OF ISOs INTO NON-QUALIFIED OPTIONS; TERMINATION OF ISOs.

         The Administrator, at the written request of any Participant, may in
its discretion take such actions as may be necessary to convert such
Participant's ISOs (or any portions thereof) that have not been exercised on the
date of conversion into Non-Qualified Options at any time prior to the
expiration of such ISOs, regardless of whether the Participant is an employee of
the Company or an Affiliate at the time of such conversion. Such actions may
include, but not be limited to, extending the exercise period or reducing the
exercise price of the appropriate installments of such Options. At the time of
such conversion, the Administrator (with the consent of the Participant) may
impose such conditions on the exercise of the resulting Non-Qualified Options as
the Administrator in its discretion may determine, provided that such conditions
shall not be inconsistent with this Plan. Nothing in the Plan shall be deemed to
give any Participant the right to have such Participant's ISOs converted into
Non-Qualified Options, and no such conversion shall occur until and unless the
Administrator takes appropriate action.

                                       15
<PAGE>

The Administrator, with the consent of the Participant, may also terminate any
portion of any ISO that has not been exercised at the time of such conversion.

20.      WITHHOLDING.

         In the event that any federal, state, or local income taxes, employment
taxes, Federal Insurance Contributions Act ("F.I.C.A.") withholdings or other
amounts are required by applicable law or governmental regulation to be withheld
from the Participant's salary, wages or other remuneration in connection with
the exercise of an Option or a Disqualifying Disposition (as defined in
Paragraph 21), the Company may withhold from the Participant's compensation, if
any, or may require that the Participant advance in cash to the Company, or to
any Affiliate of the Company which employs or employed the Participant, the
amount of such withholdings unless a different withholding arrangement,
including the use of shares of the Company's Common Stock or a promissory note,
is authorized by the Administrator (and permitted by law). For purposes hereof,
the fair market value of the shares withheld for purposes of payroll withholding
shall be determined in the manner provided in Paragraph 1 above, as of the most
recent practicable date prior to the date of exercise. If the fair market value
of the shares withheld is less than the amount of payroll withholdings required,
the Participant may be required to advance the difference in cash to the Company
or the Affiliate employer. The Administrator in its discretion may condition the
exercise of an Option for less than the then Fair Market Value on the
Participant's payment of such additional withholding.

21.      NOTICE TO COMPANY OF DISQUALIFYING DISPOSITION.

         Each Key Employee who receives an ISO must agree to notify the Company
in writing immediately after the Key Employee makes a Disqualifying Disposition
of any shares acquired pursuant to the exercise of an ISO. A Disqualifying
Disposition is any disposition (including any sale) of such shares before the
later of (a) two years after the date the Key Employee was granted the ISO, or
(b) one year after the date the Key Employee acquired Shares by exercising the
ISO. If the Key Employee has died before such stock is sold, these holding
period requirements do not apply and no Disqualifying Disposition can occur
thereafter.

22.      TERMINATION OF THE PLAN.

         The Plan will terminate on March 6, 2008, the date which is ten (10)
years from the earlier of the date of its adoption and the date of its approval
by the shareholders of the Company. The Plan may be terminated at an earlier
date by vote of the shareholders of the Company; provided, however, that any
such earlier termination shall not affect any Option Agreements executed prior
to the effective date of such termination.

                                       16
<PAGE>

23.      AMENDMENT OF THE PLAN AND AGREEMENTS.

         The Plan may be amended by the shareholders of the Company. The Plan
may also be amended by the Administrator, including, without limitation, to the
extent necessary to qualify any or all outstanding Options granted under the
Plan or Options to be granted under the Plan for favorable federal income tax
treatment (including deferral of taxation upon exercise) as may be afforded
incentive stock options under Section 422 of the Code, and to the extent
necessary to qualify the shares issuable upon exercise of any outstanding
Options granted, or Options to be granted, under the Plan for listing on any
national securities exchange or quotation in any national automated quotation
system of securities dealers. Any amendment approved by the Administrator which
the Administrator determines is of a scope that requires shareholder approval
shall be subject to obtaining such shareholder approval. Any modification or
amendment of the Plan shall not, without the consent of a Participant, adversely
affect his or her rights under an Option previously granted to him or her. With
the consent of the Participant affected, the Administrator may amend outstanding
Option Agreements in a manner which may be adverse to the Participant but which
is not inconsistent with the Plan. In the discretion of the Administrator,
outstanding Option Agreements may be amended by the Administrator in a manner
which is not adverse to the Participant.

24.      EMPLOYMENT OR OTHER RELATIONSHIP.

         Nothing in this Plan or any Option Agreement shall be deemed to prevent
the Company or an Affiliate from terminating the employment, consultancy or
director status of a Participant, nor to prevent a Participant from terminating
his or her own employment, consultancy or director status or to give any
Participant a right to be retained in employment or other service by the Company
or any Affiliate for any period of time.

25.      GOVERNING LAW.

         This Plan shall be construed and enforced in accordance with the law of
the State of Delaware.

                                       17

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