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Abstract:
We investigate the short term dynamics of recurrent
competition and neural activity in the primary visual cortex in
terms of information processing and in the context of orientation
selectivity. We propose that after stimulus onset, the strength of
the recurrent excitation decreases due to fast synaptic depression.
As a consequence, the network is shifted from an initially highly
nonlinear to a more linear operating regime. Sharp orientation
tuning is established in the first highly competitive phase. In the
second and less competitive phase, precise signaling of multiple
orientations and long range modulation, e.g., by intra- and
inter-areal connections becomes possible (surround effects). Thus
the network first extracts the salient features from the stimulus,
and then starts to process the details. We show that this signal
processing strategy is optimal if the neurons have limited
bandwidth and their objective is to transmit the maximum amount of
information in any time interval beginning with the stimulus
onset.
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