Influence Of Stimulation In Integration Field On Orientation Selectivity Of Neurons In Primary Visual Cortex

We have investigated how the non-classical receptive field (nCRF) affects dynamic orientation selectivity of cells in the primary visual cortex (V1) in anesthetized and paralyzed cats using the reverse correlation method. We found that tuning to the orientation of the test stimulus depends on the size of the stimulation area. A significant sharpening of orientation tuning was induced by nCRF stimulation, with the magnitude of the effect increasing with the size of stimulation. The effect of nCRF on the temporal dynamics of orientation tuning was also investigated by examining the tuning over a range of delays from stimulus onset. We found small but detectable changes in both the preferred orientation and the bandwidth of tuning over time when the classical receptive field (CRF) was stimulated alone. Stimulation in nCRF significantly increased the magnitude of these temporal changes. The information per spike and the efficiency of information transmission were correlated with the bandwidth and the temporal dynamics of orientation tuning, which were calculated via the information theory method. Both parameters were increased significantly by the stimulation in nCRF. Thus, nCRF stimulation not only enhances the overall orientation selectivity, but also enriches the temporal dynamics of cortical neurons, which may increase the computational power of the visual cortex in information processing.