EXHIBIT 10.1
                                                                ------------
                                 NONTRANSFERABLE
                        INCENTIVE STOCK OPTION AGREEMENT


                  THIS  AGREEMENT,  dated as of the 12th day of May, 1998, is by
and between SYNAPTIC  PHARMACEUTICAL  CORPORATION,  a Delaware  corporation (the
"Company"),  and Theresa A. Branchek (the "Optionee,"  which term as used herein
shall be deemed to include any  successor to the Optionee by will or by the laws
of descent and distribution, unless the context shall otherwise require).

                              W I T N E S S E T H:

                  WHEREAS,  the  Company  and the  Optionee  are  parties  to an
Employment  Agreement dated as of April 1, 1998 (as the same may be amended from
time to time, the "Employment Agreement");

                  WHEREAS,  pursuant to the Synaptic Pharmaceutical  Corporation
1996 Incentive Plan (the "Plan"),  the Company,  acting through the Compensation
Committee (the "Committee") of its Board of Directors (the "Board"),  on May 12,
1998 (the "Start  Date"),  granted to the Optionee  options to purchase up to an
aggregate of 25,000 shares of Common Stock, $0.01 par value, of the Company (the
"Common  Stock"),  at the  price of  $14.4375  per  share,  one of such  options
covering 10,827 shares of Common Stock to be for the term and upon the terms and
conditions  hereinafter  stated and the other of such  options  covering  14,173
shares of Common Stock to be for the term and upon the terms and  conditions set
forth in the  Nontransferable  Nonqualified  Stock Option Agreement of even date
herewith;

                  WHEREAS,  the  Company's  intention is to have the two options
granted on the Start Date generally  become  exercisable  with respect to 25% of
the total  number of shares of Common  Stock  covered by both such  options each
year during a four-year period; and

                  WHEREAS, due to certain tax limitations, the option agreements
covering such options do not individually provide for four-year ratable vesting,
although  such  agreements  do, when  considered  together,  so provide for such
vesting.

                  NOW,  THEREFORE,  in  consideration of the mutual premises and
undertakings hereinafter set forth, the parties hereto agree as follows:

                  1.  Option;  Option  Price.  Pursuant  to said  action  of the
Committee,  the Company has granted to the Optionee the option (the "Option") to
purchase, upon and subject to the terms and conditions of this Agreement and the
terms and  conditions  of the Plan (which are hereby  incorporated  by reference
herein),  10,827 shares (the "Option  Shares") of Common Stock of the Company at
the price of $14.4375 per share (the "Option  Price"),  which Option is intended
to qualify for Federal income tax purposes as an "incentive stock option" within
the meaning of Section 422 of the Internal Revenue Code of 1986, as amended (the
"Code").


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                  2. Term.  The term (the  "Option  Term") of the  Option  shall
commence  on the Start  Date and  expire on the tenth  anniversary  of the Start
Date,  unless the Option shall  theretofore  have been  terminated in accordance
with the terms hereof or of the Plan.

                  3.       Exercisability; Time of Exercise.

                  (a)  General.  Unless  accelerated  in the  discretion  of the
Committee or as otherwise  provided herein,  the Option shall become exercisable
as to 1,280 of the Option Shares on April 1, 1999, as to an additional  1,399 of
the Option  Shares on April 1,  2000,  as to an  additional  2,256 of the Option
Shares on April 1, 2001,  and as to an additional  5,892 of the Option Shares on
April 1, 2002; provided,  however, that if the Optionee dies or retires with the
consent of the Company any time prior to April 1, 2002, then the Option shall be
exercisable  as to that number of Option Shares which is equal to the sum of (i)
the total  number of Option  Shares,  if any,  as to which the Option had become
exercisable through the 1st day of April immediately preceding the date of death
or retirement (the "Preceding April 1st") and (ii) that number which is equal to
the product of (A) the number of additional Option Shares as to which the Option
would have become  exercisable  during the 12-month period commencing on the day
following the Preceding  April 1st and ending on the first April 1st immediately
following  such date of death or  retirement  had such death or  retirement  not
occurred and (B) 1/12 times the number of full calendar  months which shall have
elapsed  during the period  commencing on the Preceding  April 1st and ending on
the date of the Optionee's death or retirement;  provided further, however, that
if, at any time  prior to April 1,  2002,  the  Optionee's  employment  with the
Company is  terminated in  contemplation  of, or at any time within one (1) year
following,  a Change in Control  (capitalized  terms used and not defined herein
having the  meanings  ascribed  to them in the  Employment  Agreement)  and such
termination  constitutes a Termination  Without Cause or a Resignation  for Good
Reason,  then  the  Option  shall,  as of the date of such  termination,  become
exercisable  in full as to all of the Option  Shares.  The Option  shall  remain
exercisable  as to all of such shares until the  expiration  of the Option Term,
unless it is  terminated  earlier as provided in any of the other  paragraphs of
this Section 3 or Section 6 or as provided in the Plan.

                  (b)  Termination  for Cause. If the Optionee shall cease to be
an  employee  of the  Company as a result of a  termination  by the  Company for
Cause, the Option shall automatically  terminate on, and the Optionee shall have
no further right to exercise the Option on or after, the date as of which notice
of such termination is given to the Optionee by the Company.

                  (c) Termination  without Cause.  If the Optionee's  employment
with the Company  terminates  for any reason other than Cause or the  Optionee's
death or  Disability or  Retirement  (as defined in the Plan),  the Option shall
thereafter be  exercisable  only to the extent of the purchase  rights,  if any,
which shall have accrued  pursuant to paragraph  (a) of this Section 3 as of the
date of such  termination,  and the Option and such  accrued  rights to purchase
shall in any event  terminate upon, and the Optionee shall have no further right
to exercise the Option  after,  the earlier of (i) the  expiration of the Option
Term and (ii) (A) in the case of any such termination  governed by Section 11 of
the Employment Agreement, 120 days after the date of such termination and (B) in
the case


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of any such  termination not governed by said Section 11, 90 days after the date
of  such  termination;  provided,  however,  that,  in  the  case  of  any  such
termination  other  than  a  termination   resulting  from  the  Optionee  being
"disabled"  within the meaning of Section 22(e)(3) of the Code, the Option shall
no longer be treated  as an  "incentive  stock  option"  within  the  meaning of
Section 422 of the Code unless  exercised  within three (3) months following the
date of such termination.

                  (d)  Termination as a Result of Disability or  Retirement.  If
the  Optionee's  employment  with the  Company  terminates  as a  result  of the
Optionee's Disability or Retirement,  the Option shall thereafter be exercisable
only to the extent of the  purchase  rights,  if any,  which shall have  accrued
pursuant to paragraph (a) of this Section 3 as of the date of such  termination,
and the Option and such accrued rights to purchase shall in any event  terminate
upon, and the Optionee shall have no further right to exercise the Option after,
the earlier of (i) the expiration of the Option Term and (ii) 180 days after the
date of such  termination;  provided,  however,  that,  in the  case of any such
termination  other  than  a  termination   resulting  from  the  Optionee  being
"disabled"  within the meaning of Section 22(e)(3) of the Code, the Option shall
no longer be treated  as an  "incentive  stock  option"  within  the  meaning of
Section 422 of the Code unless  exercised  within three (3) months following the
date of such termination.

                  (e)  Termination  as a  Result  of  Death.  If the  Optionee's
employment with the Company  terminates as a result of the Optionee's death, the
Option shall thereafter be exercisable by the Optionee's Designated  Beneficiary
(as defined in the Plan) or  personal  representatives,  heirs or  legatees  (as
provided in the Plan),  but only to the extent of the purchase  rights,  if any,
which shall have accrued  pursuant to paragraph  (a) of this Section 3 as of the
date of such  termination,  and the Option and such  accrued  rights to purchase
shall in any event  terminate upon, and the Optionee shall have no further right
to exercise the Option  after,  the earlier of (i) the  expiration of the Option
Term and (ii) one (1) year  after  the date of death.  Notwithstanding  anything
contained in the Plan to the contrary,  the Option shall  continue to be treated
as an  "incentive  stock  option"  within the meaning of Section 422 of the Code
even if it is not  exercised  until after the third month  following the date of
the Optionee's death.

                  (f) Death Following Disability or Retirement.  In the event of
the Optionee's  death within 180 days  following the  Optionee's  termination of
employment as a result of the Optionee's  Disability or  Retirement,  the Option
shall  thereafter be  exercisable by the  Optionee's  Designated  Beneficiary or
personal  representatives,  heirs or  legatees,  to the  extent of the  purchase
rights,  if any,  which shall have  accrued  pursuant to  paragraph  (a) of this
Section  3 as of the  date of such  termination,  for a  period  of one (1) year
following  the date of death but in no event  later than the  expiration  of the
Option  Term;  provided,  however,  that,  in the case in which  the  Optionee's
termination of employment resulted from the Optionee being "disabled" within the
meaning of Section  22(e)(3) of the Code,  the Option shall no longer be treated
as an  "incentive  stock  option"  within the meaning of Section 422 of the Code
unless exercised within one (1) year following the date of such termination; and
provided further,  however, that, in all other cases, the Option shall no longer
be treated as an "incentive  stock option"  within the meaning of Section 422 of
the Code unless  exercised  within three (3) months  following  the date of such
termination.


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                  4.  Procedure for  Exercise.  (a) The Option may be exercised,
from time to time,  in whole or in part (but for the  purchase  of whole  shares
only),  by delivery of a written  notice (the "Notice") from the Optionee to the
Secretary of the Company, which Notice shall:

                           (i) state that the  Optionee  elects to  exercise the
                  Option under this Agreement;

                           (ii) state the number of shares with respect to which
                  the Optionee is exercising the Option (the "Acquired Shares");

                           (iii)  include any  representations  of the  Optionee
                  required under Section 7(b) hereof;

                           (iv)  state the method of  payment  for the  Acquired
                  Shares pursuant to Section 4(b);

                           (v) in the event that the Option  shall be  exercised
                  by any person other than the  Optionee  pursuant to Sections 3
                  and 8, include  appropriate  proof of the right of such person
                  to exercise the Option; and

                           (vi) state the date upon which the  Optionee  desires
                  to consummate the purchase of the Acquired  Shares (which date
                  must be prior to the termination of such Option).

                  (b) Payment of the Option Price for the Acquired Shares shall,
unless  otherwise  provided by the Committee,  be made in cash or by personal or
certified check.

                  5. No Rights as a Stockholder. The Optionee shall not have any
privileges of a stockholder  with respect to any Option Shares until the date of
a stock certificate representing such Option Shares is issued to the Optionee.

                  6.       Adjustments.

                  (a) Stock  Dividends,  Splits,  Subdivisions or  Combinations.
Subject  to the other  provisions  of this  Section 6, if, at any time while the
Option is  outstanding,  the  Common  Stock is  changed  by reason of  dividends
payable in Common Stock or splits,  subdivisions  or  combinations  of shares of
Common  Stock,  then the number of shares of Common Stock  deliverable  upon the
exercise   thereafter   of  the  Option   shall  be   increased   or   decreased
proportionately,  as the case may be,  without  change in the  aggregate  Option
Price.

                  (b)  Cash  Mergers.   Upon  the  occurrence  of  a  merger  on
consolidation of the Company with another  corporation in a transaction in which
the stockholders of the Company receive cash consideration in exchange for their
shares of capital stock of the Company (a "cash


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merger"), the Option shall automatically terminate;  provided, however, that the
Optionee  shall be given (i) written notice of such cash merger at least 20 days
prior to its proposed  effective  date (as specified in such notice) and (ii) an
opportunity,  during the period  commencing  with  delivery  of such  notice and
ending ten (10) days prior to such  proposed  effective  date,  to exercise  the
Option in full as to all of the Option Shares, whether or not then vested.

                  (c)  Assumption or  Substitution  of Options.  Notwithstanding
anything contained herein or in the Plan to the contrary, Section 6(b) shall not
be applicable if provision shall be made in connection with such cash merger for
the  assumption  of the Option by, or the  substitution  for the Option of a new
option   covering  the  stock  of,  the   surviving,   successor  or  purchasing
corporation,  or a parent or subsidiary thereof, with appropriate adjustments as
to the number, kind and option price of shares subject to such option; provided,
however,  that the Board  shall,  to the extent not  inconsistent  with the best
interests  of the  Company  or  its  subsidiaries  (such  best  interests  to be
determined  in good faith by the Board,  in its sole  discretion),  use its best
efforts to ensure that any such assumption or substitution will not constitute a
modification,  extension or renewal of the Option  within the meaning of Section
424(h) of the Code and the regulations thereunder.

                  (d) Corporate Transactions. Notwithstanding anything contained
herein or in the Plan to the  contrary,  upon the  occurrence of (i) a merger or
consolidation  of the Company with another  corporation in a transaction  (other
than a cash  merger)  in which the  Company  shall not  survive  or in which the
Company  is  the  survivor  but  its  capital  stock  is  exchanged  for  stock,
securities, or property of another entity or (ii) a sale of all or substantially
all of the assets of the Company  (any  transaction  described  in clause (i) or
(ii) being referred to herein as a "corporate transaction"),  provision shall be
made in connection  with such  corporate  transaction  for the assumption of the
Option by, or the substitution for the Option of a new option covering the stock
of,  the  surviving,  successor  or  purchasing  corporation,  or  a  parent  or
subsidiary  thereof,  with  appropriate  adjustments as to the number,  kind and
option price of shares subject to such option; provided, however, that the Board
shall, to the extent not inconsistent  with the best interests of the Company or
its  subsidiaries  (such best  interests to be  determined  in good faith by the
Board,  in its sole  discretion),  use its best  efforts to ensure that any such
assumption or  substitution  will not  constitute a  modification,  extension or
renewal of the Option  within the meaning of Section  424(h) of the Code and the
regulations thereunder.

                  (e)  Termination  within One Year of Cash Merger or  Corporate
Transaction.  Notwithstanding  anything  contained  herein or in the Plan to the
contrary,  in the event the Optionee's employment with the Company or the person
which is the surviving,  successor or purchasing corporation in a cash merger to
which  Section 6(c)  applies or a corporate  transaction  to which  Section 6(d)
applies,  or a parent or subsidiary  thereof,  is  terminated  without Cause and
other than as a result of the Optionee's death or disability,  at any time prior
to the first anniversary of such transaction or merger,  the Option shall become
exercisable  in full as to all Option Shares,  whether or not vested,  as of the
date on which notice of termination  is given to the Optionee,  and the Optionee
shall  have the right to  exercise  the  Option as to any or all of such  shares
until the earlier


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of (i) the  expiration  of the Option Term and (ii) the 90th day  following  the
date of such termination, at which time the Option shall terminate.

                  7. Additional  Provisions Related to Exercise.  (a) The Option
shall be  exercisable  only on such date or dates and during such period and for
such number of shares of Common Stock as are set forth in this Agreement.

                  (b) To exercise  the Option,  the  Optionee  shall  follow the
procedures  set forth in Section 4 hereof.  Upon the exercise of the Option at a
time when there is not in effect a registration  statement  under the Securities
Act of 1933,  as amended,  relating to the shares of Common Stock  issuable upon
exercise of the  Option,  the  Optionee  shall  provide  the  Company  with such
representations and warranties as may be required by the Committee to the effect
that the Acquired  Shares are being  acquired for investment and not with a view
to  the  distribution  thereof.   Anything  contained  herein  to  the  contrary
notwithstanding,  in the  event  the  Board  shall  determine,  in its  sole and
subjective  discretion,  that the registration,  qualification or listing of the
Option  Shares upon a securities  exchange or under any state or Federal law, or
the consent or approval or any  government or  regulatory  body, is necessary or
desirable  as a condition of or in  connection  with the exercise of the Option,
the  Option  may not be  exercised,  in whole or in part,  unless and until such
registration,  qualification,  listing,  consent  or  approval  shall  have been
effected or obtained free of any conditions not acceptable to the Board.

                  (c) The Option  shall not be  affected by any change of duties
or position of the Optionee  (including  transfer to or from a  subsidiary),  so
long as the  Optionee  continues  to be an employee of the Company or one of its
subsidiaries.  Nothing in the Option  granted  hereunder  shall  confer upon the
Optionee  any  right to  continue  in the  employ of the  Company  or any of its
subsidiaries  or  interfere  in any way with the  right  of the  Company  or its
subsidiaries  or the  stockholders  of the  Company,  as the  case  may  be,  to
terminate the  Optionee's  employment or to increase or decrease the  Optionee's
compensation at any time.

                  8. Restriction on Transfer. The Option may not be transferred,
pledged, assigned, hypothecated (whether by operation of law or otherwise), sold
or otherwise  disposed of in any way by the  Optionee,  except by will or by the
laws of descent and  distribution,  and may be exercised  during the lifetime of
the  Optionee  only by the  Optionee.  If the  Optionee  dies,  the Option shall
thereafter be exercisable,  during the applicable period specified in Section 3,
by the Optionee's Designated Beneficiary or personal  representatives,  heirs or
legatees  (as  provided  in the Plan) to the full extent to which the Option was
exercisable  by the  Optionee  at the time of the  Optionee's  death as provided
herein.  The Option  shall not be subject to  execution,  attachment  or similar
process.  Any attempted transfer,  pledge,  assignment,  hypothecation,  sale or
other disposition of the Option contrary to the provisions  hereof, and the levy
of any execution,  attachment or similar process upon the Option,  shall be null
and void and without effect.

                  9.   Restrictive   Legends.   In  order  to  reflect   certain
restrictions  on disposition of the shares  acquired upon exercise of the Option
(the "Restricted Shares"), all stock certificates


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representing the Restricted Shares issued shall have affixed thereto any legends
determined by the Company to be appropriate.

                  10.  Notices.  All notices or other  communications  which are
required  or  permitted  hereunder  shall be in writing  and  sufficient  if (i)
personally delivered or sent by telecopier,  (ii) sent by  nationally-recognized
overnight  courier  or (iii)  sent by  registered  or  certified  mail,  postage
prepaid, return receipt requested, addressed as follows:

                           if to the Optionee, to:

                                    Theresa A. Branchek
                                    518 Standish Road
                                    Teaneck, New Jersey  07666

                           if to the Corporation, to:

                       Synaptic Pharmaceutical Corporation
                                    215 College Road
                                    Paramus, New Jersey  07652
                                    Attention:  President
                                    Telecopier: 201-261-0623

or to such  other  address  as the party to whom  notice is to be given may have
furnished  to each  other  party in  writing in  accordance  herewith.  Any such
communication  shall  be  deemed  to have  been  given  (i) when  delivered,  if
personally  delivered,  sent by  telecopier  or  sent  by  nationally-recognized
overnight  courier and (ii) on the third Business Day (as  hereinafter  defined)
following the date on which the piece of mail containing such  communication  is
posted, if sent by mail. As used herein,  "Business Day" means a day that is not
a Saturday,  Sunday or a day on which banking  institutions in the city to which
the notice or communication is to be sent are not required to be open.

                  11. No Waiver.  No waiver of any breach or  condition  of this
Agreement  shall be deemed to be a waiver of any other or  subsequent  breach or
condition, whether of like or different nature.

                  12. Optionee  Undertaking.  The Optionee hereby agrees to take
whatever  additional  actions  and execute  whatever  additional  documents  the
Company may in its reasonable  judgement deem necessary or advisable in order to
carry out or effect one or more of the  obligations or  restrictions  imposed on
the Optionee pursuant to the express provisions of this Agreement.

                  13.  Modification  of Rights.  The rights of the  Optionee are
subject to  modification  and  termination in certain events as provided in this
Agreement and the Plan.



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                  14.  Governing Law. This  Agreement  shall be governed by, and
construed in accordance with, the laws of the State of New Jersey without giving
effect to principles of conflicts of laws.

                  15.  Counterparts.  This  Agreement may  be executed in one or
more counterparts, each  of which shall be  deemed to be an original, but all of
which together shall constitute one and the same instrument.

                  16.  Entire   Agreement.   This   Agreement,   the  Employment
Agreement(the   provisions  relating  to  stock  options  of  which  are  hereby
incorporated  herein by reference) and the Plan constitute the entire  agreement
between the parties with respect to the subject  matter hereof and thereof,  and
supersede   all   previously   written   or  oral   negotiations,   commitments,
representations  and  agreements  with  respect  thereto.  In the  event  of any
inconsistency  among the terms of this  Agreement,  the terms of the  Employment
Agreement and the terms of the Plan, the terms of the Employment Agreement shall
control.


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                  IN WITNESS  WHEREOF,  the parties  hereto have  executed  this
Agreement as of the date first written above.



                       SYNAPTIC PHARMACEUTICAL CORPORATION



                       By:/s/ Kathleen P. Mullinix
                          -----------------------------------------------
                          Kathleen P. Mullinix
                          Chairman, President and Chief Executive Officer

                          /s/ Theresa A. Branchek
                          -----------------------------------------------
                          Theresa A. Branchek







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