[Comparison of its and orientation tuning dynamics in neurons located in different functional domains of cat's primary visual cortex].

ABSTRACT

Orientation tuning and its dynamics of cat's primary visual cortex neurons located in pinwheel centers and orientation columns were studied during development of response in time. Functional domains in the Cortex were revealed by intrinsic signal optical imaging on functional and vascular maps of cortex. Both maps were used for precise placement of electrodes during recordings. Orientation tuning dynamic of each neuron was analyzed by temporary slices technique. Several types of neurons were observed in different functional domains neurons with stable preferred orientation (14.5%); cells with preferred orientation dynamically shifted by 102 +/- 5 degrees (40.8%) and neurons with mixed dynamics type (44.7%). In pinwheel centers neurons with stable preferred orientation are differed from neurons with unstable preferred orientation in their features. In particular, they are showing greater response strength for preferred orientation. In orientation columns neurons with stable tuning are demonstrating larger latent periods for all orientations including preferred and non-preferred in comparison to cells with unstable response dynamics. We observed better detection quality of stable orientation neurons than in unstable preferred orientation neurons. Further coding features of neurons belonging to one functional type but located in different domains were compared. In general, located in pinwheel centers stable neurons have shorter latencies and stronger responses than for the stable cells located in orientation columns. Detection features were similar for this functional type of neurons. Unstable neurons located in different functional domains don't differ from each other in orientation tuning characteristics. Functional significance of neurons with stable and unstable preferred orientation located in pinwheel center and orientation columns in visual information processing are discussed.