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.