Visually evoked oscillations of membrane potential in cells of cat visual cortex.

In response to visual stimulation, cells of the cat visual cortex fire rhythmically at frequencies between 30 and 60 hertz. This rhythmic firing can be synchronized among cells in widespread areas of the visual cortex. The visual stimulus conditions under which this process occurs suggest that the synchronization may contribute to the integration of information across broadly displaced parts of the visual field. An intricate mechanism must control the regularity of firing and its synchronization. In vivo whole-cell patch recordings from cells in area 17 have now shown that robust oscillations of membrane potential underlie the regularity of firing seen extracellularly. In the cells studied, the characteristics of the oscillations of membrane potential suggest that such oscillations are produced by rhythmic activity in synaptic inputs. These rhythmic synaptic inputs form the most likely mechanism for the synchronization of activity in neighboring cortical cells.