[Receptive fields of detectors of bar and cross-like figures in classical and combined mapping]

Excitatory and inhibitory zones of receptive fields (RF) of detectors of cross-like figures and bars were studied in a primary visual cortex of cats under conditions of classical and combined mapping. Factor and correlation analysis demonstrated that detectors of bars and crosses differ in those interrelations, which are formed between the basic characteristics of neurons and their RF in each of group. The factor analysis of these connections showed that variables with the greatest weights, combined into the same factor, are different for different detectors. In detectors of bars, positive correlation was found between the background activity and weight characteristics of the RF excitatory and inhibitory zones. In detectors of crosses, inhibition indices showed a positive correlation with sensitivity to this figure, characteristics of excitatory RF zone and the background activity. Enlargement of the additional excitatory zones of cross detectors in combined mapping was significantly greater than in bar detectors. Formation of the RF and orientation sensitivity of bar and cross detectors is discussed, with account made of the finding that the sensitivity to bars is mostly formed by direct excitatory connections, whereas sensitivity to cross-like stimuli is formed by direct and recurrent intracortical inhibitory connections between the nearby neurons.