Spike-frequency adaptation as a mechanism for dynamic coding in V1
We investigate the representation of visual stimuli and the short-term dynamics of activity within primary visual cortex in a free-viewing scenario with saccading eye movements modeled as a series of visual stimuli that are flashed onto the retina for the duration of a fixation period (200 ). We assume that the entire activity pattern from the beginning of fixation until time t constitutes the neural code. Given a noisy (Poissonian) representation it follows that the signal-to-noise ratio increases with time, because more spikes become available for representation. Here, we show that for archiving an optimal stimulus representation in any increasing time-window beginning with stimulus onset, the processing strategy of the network should be dynamic in the sense that an initially high recurrent cortical competition between orientation selective cells attenuates with time, i.e. mediated by the instrinsic property of spike-frequency adaptation of pyramidal cells.
primary visual cortex neural coding flashed stimuli neuromodulation