POWER OF ATTORNEY

        Know all by these presents, that the undersigned hereby constitutes and
appoints Jon Kuwahara and Ryan A. Murr, with full power of substitution,
the undersigned's true and lawful attorney-in-fact to:

        (1)     prepare, execute in the undersigned's name and on the
                undersigned's behalf, and submit to the U.S. Securities and
                Exchange Commission (the "SEC") a Form ID, including amendments
                thereto, and any other documents necessary or appropriate to
                obtain codes, passwords and passphrases enabling the undersigned
                to make electronic filings with the SEC of reports required by
                the Securities Exchange Act of 1934 or any rule or regulation of
                the SEC;

        (2)     execute for and on behalf of the undersigned, in the
                undersigned's capacity as an officer and/or director of Novus
                Therapeutics, Inc. (the "Company"), Forms 3, 4, and 5 in
                accordance with Section 16(a) of the Securities Exchange Act of
                1934 and the rules thereunder;

        (3)     do and perform any and all acts for and on behalf of the
                undersigned which may be necessary or desirable to complete and
                execute any such Form 3, 4, or 5, complete and execute any
                amendment or amendments thereto, and timely file such form with
                the SEC and any securities exchange or similar authority; and

        (4)     take any other action of any type whatsoever in connection with
                the foregoing which, in the opinion of such attorney-in-fact,
                may be of benefit to, in the best interest of, or legally
                required by, the undersigned, it being understood that the
                documents executed by such attorney-in-fact on behalf of the
                undersigned pursuant to this Power of Attorney shall be in such
                form and shall contain such terms and conditions as such
                attorney-in-fact may approve in such attorney-in-fact's
                discretion.

        The undersigned hereby grants to such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted. The undersigned also ratifies hereby any action previously taken by
each attorney-in-fact that would have been authorized by this power of attorney
if it has been in effect at the time such action was taken. The undersigned
acknowledges that the foregoing attorney-in-fact, in serving in such capacity at
the request of the undersigned, is not assuming, nor is the Company assuming,
any of the undersigned's responsibilities to comply with Section 16 of the
Securities Exchange Act of 1934, as amended.

        This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorney-in-fact.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 15th day of September 2020.

                                        /s/ David-Alexandre Gros
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                                        Signature

                                        David-Alexandre Gros
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