Amendment No 3. to Consulting Services Agreement between Vistagen Therapeutics, Inc. and FitzPatrick & Co. LLC effective July 1, 2023

Exhibit 10.159

AMENDMENT NO. 3

TO

CONSULTING SERVICES AGREEMENT

This Amendment (“Amendment No. 3”) is made between Vistagen Therapeutics, Inc., a Nevada corporation having an address at 343 Allerton Avenue, South San Francisco, California 94080 (“Vistagen”), and FitzPatrick & Co. LLC, a Delaware limited liability company, having an address at 2023 Allen Place, NW, Washington DC 20009 (“Consultant”), effective as of July 1, 2023.

WHEREAS, Vistagen and Consultant entered into a Consulting Services Agreement dated January 21, 2022, Amendment No. 1 to the Consulting Agreement dated June 1, 2022, and Amendment No. 2 to the Consulting Agreement dated January 1, 2023 (collectively, the “Agreement”); and

WHEREAS, the parties wish to amend the Agreement to extend its term.

Vistagen and Consultant, therefore, agree as follows:

AMENDMENT

Except as expressly provided in this Amendment No. 3, the Agreement remains unchanged and in full force and effect.

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Each party is signing this agreement with the party’s authorized signature.