Exhibit 3.4

CERTIFICATE OF AMENDMENT

OF

RESTATED CERTIFICATE OF INCORPORATION

OF

CORTEX PHARMACEUTICALS, INC.,

a
Delaware corporation

(Pursuant to Section 242 of the Delaware General Corporation Law)

CORTEX PHARMACEUTICALS, INC., a corporation organized and existing under the Delaware General Corporation Law (the Corporation), does hereby
certify:

FIRST: That the Restated Certificate of Incorporation of the Corporation was filed with the Secretary of State of the State of
Delaware on April 11, 1989 and was amended by Certificate of Amendment of Certificate of Incorporation filed June 27, 1989, by Certificate of Designation filed April 29, 1991, by Certificate of Correction of Certificate of Designation
filed May 1, 1991, by Certificate of Amendment of Certificate of Designation filed June 13, 1991, by Certificate of Amendment of Certificate of Incorporation filed November 12, 1992, by Certificate of Amendment of Restated Certificate
of Incorporation filed January 11, 1995, by Certificate of Designation filed December 8, 1995, by Certificate of Designation filed October 15, 1996, by Certificate of Designation filed June 4, 1997, by Certificate of Amendment of
Restated Certificate of Incorporation filed December 21, 1998, by Certificate of Designation filed February 11, 2002, and by Certificate of Amendment of Restated Certificate of Incorporation filed December 15, 2003.

SECOND: That at a meeting of the Board of Directors of the Corporation resolutions were duly adopted setting forth a proposed amendment of the Restated
Certificate of Incorporation of the Corporation, declaring said amendment to be advisable and directing said amendment to be submitted to the stockholders of the Corporation at its Annual Meeting. The resolution setting forth the proposed amendment
is as follows:

RESOLVED, that Article Fourth, paragraph (A)(1) of the Corporations Restated Certificate of
Incorporation be amended to read in its entirety:

FOURTH: (A)(1) - AUTHORIZED CAPITAL. (a) The total number of shares of capital
stock which the Company has the authority to issue is 80,000,000 consisting of 75,000,000 shares of Common Stock, $0.001 par value per share (the Common Stock), and 5,000,000 shares of Preferred Stock, $0.001 par value per share (the
Preferred Stock).

THIRD: That thereafter, pursuant to resolution of the Board of Directors, the Annual Meeting of the
stockholders of the Corporation was duly called and held, upon notice in accordance with Section 222 of the Delaware General Corporation Law, at which meeting the necessary number of shares as required by statute were voted in favor of the
amendment.

FOURTH: Said amendment was duly adopted in accordance with the provisions of Section 242 of the Delaware General
Corporation Law.

IN WITNESS WHEREOF, the Corporation has caused this Certificate of Amendment to be executed by Roger G. Stoll, Ph.D., its
President and Chief Executive Officer, and attested to by Maria S. Messinger, its Corporate Secretary, this 12th day of December, 2005.



|       |  |                              |  |                                      
|------ |  | ---------------------------- |  | -------------------------------------
|       |  | CORTEX PHARMACEUTICALS, INC.
|       |  |                             
|[SEAL] |  | By:                          |  | /s/ Roger G. Stoll, Ph.D.            
|       |  |                              |  | Roger G. Stoll, Ph.D.                
|       |  |                              |  | President and Chief Executive Officer



|        |  |                                        
|------- |  | ---------------------------------------
|ATTEST:
|        | 
|By:     |  | /s/ Maria S. Messinger                 
|        |  | Maria S. Messinger, Corporate Secretary