John O'Keefe FRS FMedSci (born November 18, 1939) is an American-British neuroscientist, psychologist and a professor at University College London.

O'Keefe discovered place cells in the hippocampus, and that they show a specific kind of temporal coding in the form of theta phase precession.

[4][5][6] O'Keefe went to University College London in 1967 as a US NIMH postdoctoral research fellow working with the late Patrick Wall.

[7] O’Keefe and his student Jonathan Dostrovsky discovered place cells by systematically analyzing the environmental factors influencing the firing properties of individual hippocampal neurons.

In a 1993 paper, he and Michael Recce demonstrated that place cells spike at different phases relative to theta rhythm oscillations in the local field potential of the hippocampus.

[15] In this and subsequent papers, they presented a model of this phenomenon predicting the existence of boundary vector cells that would respond at a specific distance from barriers in the environment.

[28] In 2014 he received the Kavli Prize in Neuroscience "for the discovery of specialized brain networks for memory and cognition", together with Brenda Milner and Marcus Raichle.