\<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-K/A
                          (AMENDMENT NO. 1 TO FORM 10K)

(Mark One)
[X]      ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

For the fiscal year ended                   September 30, 2000
                              --------------------------------------------------


[ ]      TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
         EXCHANGE ACT OF 1934

For the transition period from                  to
                               ----------------    -----------------

Commission file number                1-10285
                       ------------------------------------------

                                4-D NEUROIMAGING

             (Exact name of registrant as specified in its charter)

              CALIFORNIA                              95-2647755
--------------------------------------------------------------------------------
     (State or other jurisdiction         (IRS Employer Identification Number)
   of incorporation or organization)


   9727 PACIFIC HEIGHTS BOULEVARD, SAN DIEGO, CALIFORNIA          92121-3719
--------------------------------------------------------------------------------
          (Address of principal executive offices)                (zip code)

Registrant's telephone number, including area code              (858) 453-6300
                                                  ------------------------------

Securities registered pursuant to Section 12(b) of the Act:  NONE

Securities registered pursuant to Section 12(g) of the Act: COMMON STOCK, NO PAR
VALUE PER SHARE

Indicate by check mark whether the registrant: (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. [x] Yes [ ] No

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [ ]

The aggregate market value of the voting stock (which consists solely of shares
of Common Stock) held by non-affiliates of the registrant as of December 20,
2000 was $5,097,198 based on the closing price on that date on the Nasdaq Over
the Counter Bulletin Board. Shares of Common Stock held by each officer,
director, and holder of 10% or more of the outstanding Common Stock have been
excluded in that such persons may be deemed to be affiliates. This determination
of affiliate status is not necessarily a conclusive determination for other
purposes.

The number of shares outstanding of the registrant's Common Stock, no par value,
as of December 20, 2000 was 84,975,008 shares.

                       DOCUMENTS INCORPORATED BY REFERENCE

<PAGE>

1.     Certain portions of Registrant's Definitive Proxy Statement, to be filed
       not later than 120 days after September 30, 2000 pursuant to Regulation
       14A of the Securities Exchange Act of 1934, as amended in connection with
       the 2001 Annual Meeting of Shareholders are incorporated by reference
       into Part III of this report where indicated.

2.     Certain Exhibits filed with the Registrant's prior registration
       statements and reports are incorporated herein by reference into Part IV
       of this report.

<PAGE>

The registrant hereby files this report on Form 10-K/A to amend its Annual
Report on Form 10-K for the year ended September 30, 2000 to amend Part IV, Item
14 to include the Annual Report of the Biomagnetic Technologies, Inc. 1992
Employee Stock Purchase Plan as Exhibit 99.2 and the Consent of Arthur Andersen
LLP as Exhibit 23.2. No other items in the registrant's Annual Report on Form
10-K for the year ended September 30, 2000 are amended.


                                     PART IV

ITEM 14.      EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K.

       (a)    The following documents are filed as part of this report:

              (1)   Financial Statements

<TABLE>

<S>                                                                                           <C>
                    Report of Independent Public Accountants...................................33

                    Consolidated Balance Sheets at September 30, 2000 and 1999.................34

                    Consolidated Statements of Operations for the three year
                    ended September 30, 2000...................................................35

                    Consolidated Statement of Shareholders' Equity (Deficit) for the
                    three years ended September 30, 2000.......................................36

                    Consolidated Statements of Cash Flows for the three years
                    ended September 30, 2000...................................................37

                    Notes to Consolidated Financial Statements.................................38
</TABLE>

              (2)   Financial Statement Schedule

                    Schedule II - Consolidated Valuation and Qualifying Accounts

                    Annual Report of 1992 Employee Stock Purchase Plan and
                    related financial statements are contained in attached
                    Exhibit 9

                    All other schedules are omitted because they are not
                    applicable or the required information is shown in the
                    consolidated financial statements or notes thereto.

              (3)   Exhibits

                    The Exhibits listed in the accompanying Exhibit Index are
                    filed or incorporated by reference as part of this report.

       (b)    Reports on Form 8-K during the fourth quarter:

              None.

       (c)    Exhibits

              The following documents are exhibits to this Form 10-K:

<PAGE>

 Exhibit
       No.     Description of Document

    3.1 (1)   Fifth Amended and Restated Articles of Incorporation.

    3.2 (2)   Restated Bylaws.

    3.3 (9)   Certificate of Amendment of Fourth Restated Articles of
              Incorporation (numbered originally as 10.73)

   10.1 (5)   Loan Agreement between 4-D Neuroimaging and BDN, a company based
              in Spain.

   10.2 (5)   Loan Agreement between 4-D Neuroimaging and BDN, a company based
              in Spain.

+  10.3(12)   The Company's 1997 Stock Option Plan, as amended.

+  10.6 (4)   The Company's 1987 Stock Option Plan, as amended.

+  10.7 (4)   Form of Incentive Stock Option and related exercise documents.

+  10.49(7)   Biomagnetic Technologies, Inc. 1992 Employee Stock Purchase Plan.

   10.58(6)   Real Estate Lease, dated April 3, 1989, between the Company and
              Cornerstone Income Properties, plus First and Second Amendments to
              the Real Estate Lease.

   10.64(8)   Form of Purchase Option Agreement, as amended.

   10.68(6)   Letter Agreement between the Company and Dassesta International
              S.A. regarding the purchase of 25,000,000 Shares of Common Stock
              of the Company.

   10.71(10)  Offshore Subscription Agreement between the Company and Dassesta
              International S.A. (Numbered originally as Exhibit 2.1).

   10.76(11)  Form of Offshore Stock Subscription Agreements For August 1998
              Sale of Company Common Stock.

   10.77(11)  Joint Venture Agreement with Magnesensors.

   10.78(13)  Real estate lease, dated March 3, 2000 between Neuromag Oy and
              Instrumentarium and an English language summary of such lease.

      21(13)  Subsidiaries of the Company

    23.1(13)  Consent of Arthur Andersen LLP

       23.2   Consent of Arthur Andersen LLP

      27(13)  Data Schedule

       99.2   Annual Report of the Biomagnetic Technologies, Inc. 1992 Employee
              Stock Purchase Plan

(1)    This exhibit was previously filed as part of, and is hereby incorporated
       by reference to, the same numbered exhibit in the Quarterly Report on
       Form 10-Q for the quarterly period ended March 31, 2000, filed with the
       Securities and Exchange Commission on May 15, 2000.

(2)    These exhibits were previously filed as part of, and are hereby
       incorporated by reference to, the same numbered exhibits (except as
       otherwise indicated) in the Registration Statement filed pursuant to the

<PAGE>

       Securities Act of 1933 on Form S-1, Registration Statement No. 33-29095,
       filed June 7, 1989, as amended by Amendment No. 1, filed June 13, 1989,
       Amendment No. 2, filed July 21, 1989 and Amendment No. 3, filed July 28,
       1989.

(3)    These exhibits were previously filed as a part of, and are hereby
       incorporated by reference to, the same numbered exhibits (except as
       otherwise indicated) in the Fiscal 1991 Form 10-K.

(4)    These exhibits were previously filed as part of, and are hereby
       incorporated by, reference to the same numbered exhibits (except as
       otherwise indicated) in the Fiscal 1992 Form 10-K.

(5)    This exhibit was previously filed as part of, and is hereby incorporated
       by reference to, the same numbered exhibit in the Quarterly Report on
       Form 10-Q for the quarterly period ended June 30, 2000, filed with the
       Securities and Exchange Commission on July 15, 2000.

(6)    These exhibits were previously filed as part of, and are hereby
       incorporated by reference to, the same numbered exhibits (except as
       otherwise indicated) in the Registration Statement filed pursuant to the
       Securities Act of 1933 on Form S-1, Registration Statement No. 33-46758,
       filed March 26, 1992, as amended by Amendment No. 1, filed May 8, 1992.

(7)    These exhibits were previously filed as part of, and are hereby
       incorporated by reference to the same numbered exhibits (except as
       otherwise indicated) in the Registration Statement filed pursuant to the
       Securities Act of 1933 on Form S-8, Registration Statement No. 33-68136
       filed August 27, 1993.

(8)    These exhibits were previously filed as part of, and are hereby
       incorporated by reference to, the same numbered exhibits (except as
       otherwise indicated) in Fiscal 1995 Form 10-K.

(9)    These exhibits were previously filed as part of, and are hereby
       incorporated by reference to, the same numbered exhibits (except as
       otherwise indicated) in form 8-K, filed April 14, 1995.

(10)   These exhibits were previously filed as part of, and are hereby
       incorporated by reference, to the same numbered exhibits (except as
       otherwise indicated) in Fiscal 1998 Form 10-K.

(11)   These exhibits were previously filed as part of, and are hereby
       incorporated by reference, to the same numbered exhibits (except as
       otherwise indicated) in Fiscal 1999 Form 10-K.

(12)   These exhibits were previously filed as part of, and are hereby
       incorporated by, reference to Exhibit 99.1 to the Form S-8, Registration
       Statement No. 333-96267 filed February 7, 2000.

(13)   This exhibit was previously filed as part of, and is hereby incorporated
       by reference, to the same numbered exhibit (except as otherwise
       indicated) in Fiscal 2000 Form 10-K.

+      Management contract or compensatory plan or arrangement.


SUPPLEMENTAL INFORMATION

Proxy materials have not been sent to shareholders as of the date of this
report. The Proxy materials will be furnished to the Company's shareholders
subsequent to the filing of this report and the Company will furnish such
material to the Securities and Exchange Commission at that time.

<PAGE>

                                   SIGNATURES


Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange
Act of 1934, the registrant has duly caused this report to be signed on its
behalf by the undersigned, thereunto duly authorized.


4-D NEUROIMAGING



By   /s/   D. Scott Buchanan                             January 29, 2001
     --------------------------------------              ------------------
     D. Scott Buchanan                             Date
     President, Chief Executive Officer,
     Principal Financial Officer