EXHIBIT 99.4

                                  EXHIBIT 99.4




        FULL CANCELLATION OF INDEBTEDNESS EFFECTIVE AS OF APRIL 26, 2001


              BETWEEN 4-D AND SWISSPARTNERS INVESTMENT NETWORK LTD.







                                                                   EXHIBIT 99.4


                        FULL CANCELLATION OF INDEBTEDNESS

     This full cancellation of indebtedness (this "Cancellation") is entered
into effective as of April 26, 2001, by and between 4-D Neuroimaging, a
California corporation based in San Diego, California ("Borrower"), and
Swisspartners Investment Network Ltd., a company based in Zurich, Switzerland
("Lender").

         WHEREAS, Xxxxxx entered into a loan agreement with Borrower on or about
         April 15, 2001 for an amount of US$224,462 (the "Loan"), and

         WHEREAS, Xxxxxx has agreed to accept Xxxxxxxx's common stock as payment
         in full for the remaining principal balance and all accrued interest
         outstanding under the Loans on the terms and conditions set forth
         below, and

         WHEREAS, in connection with this Cancellation, Xxxxxx has entered into
         that certain Common Stock Purchase Agreement of even date herewith (the
         "Purchase Agreement") by and between Borrower, Lender and certain other
         investors, pursuant to which Lender will receive 1,070,833 shares of
         Borrower's common stock.

         NOW, THEREFORE, Xxxxxx and Xxxxxxxx represent and agree as follows:

         Lender hereby accepts as full and final payment of all principal and
         accrued interest outstanding under the Loan 1,070,833 shares of
         Borrower's common stock pursuant to the Purchase Agreement.

         Xxxxxx agrees to mark as cancelled and to return all evidences of
         indebtedness of Borrower including, but not limited to, the loan
         agreements evidencing the Loan.

         Lender represents and warrants that Xxxxxx has not assigned, pledged or
         otherwise transferred the Loan or any rights thereunder to any third
         party and agrees to indemnify Borrower against any and all claims by
         third parties asserting any right to payment pursuant to such Loans.

         Lender represents that it is duly authorized to enter into this
         Cancellation, that this Cancellation is a binding obligation of Lender,
         enforceable against Lender in accordance with its terms, and that no
         governmental or other third party consent is required to approve the
         transactions contemplated hereby.

         This Cancellation and any dispute, including without limitation any
arbitration, arising from the performance or breach of this Cancellation shall
be governed by and construed and enforced in accordance with the laws of the
state of California, without reference to conflicts of laws principles. Both
parties hereby submit to the jurisdiction of the state and federal courts
sitting in the state of California, to the exclusion of any other courts which
might have jurisdiction apart from this provision.





         IN WITNESS WHEREOF, this Cancellation has been executed by the persons
below as of the date first indicated above, each person being the duly appointed
representative of the respective Parties.





  /S/  XXXXXX XXXX                           /S/  X. XXXXX XXXXXXXX
  -------------------------------------      ----------------------------------
  Xx. Xxxxxx Xxxx, Managing Partner          X. Xxxxx Xxxxxxxx, President & CEO
  Swisspartners Investment Network Ltd.      4-D Neuroimaging
  Xxxxxx                                     Xxxxxxxx