Recent experimental results and theories about the primary visual

cortex, V1, are promising new clues to the function of the cerebral

cortex in general. One clue: properties of V1 neurons, like

orientation selectivity and receptive field size, can be modified by

stimulus context. Another clue is that orientation selectivity

changes with time in a way that points to strong intracortical

inhibition as the main mechanism for high selectivity.

Quasi-oscillatory local field potentials that we measured in V1

suggest the importance of strong recurrent and feedback inhibition

in the cerebral cortex.