Detection of Orientation Continuity and Discontinuity by Cat V1 Neurons T Xu1, L Wang2, S Xue-Mei3, C-Y Li3 |
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1Key Laboratory for Neuroinformation, University of Electronic Science and Technology, China |
| Orientation tuning properties of the non-classical receptive field (nCRF or “surround”) relative to that of the classical receptive field (CRF, or “center”) were tested for 119 neurons in cat primary visual cortex (V1). Based on the presence or absence of surround suppression measured by suppression index at the optimal orientation of the cells, we subdivided the cat V1 neurons into two categories: surround-suppressive (SS) cells and surround-non-suppressive (SN) cells. For the SS cells, strength of surround suppression was dependent on the relative orientation between CRF and nCRF, iso-orientation grating over center and surround at the optimal orientation evoked strongest suppression and surround grating orthogonal to the optimal center grating evoked weakest or no suppression. In contrast, the SN cells showed slightly increased response to iso-orientation stimulus and weak suppression to orthogonal surround gratings. This iso-/orthogonal orientation selectivity between center and surround was analyzed for 22 SN cells and 97 SS cells, respectively, and the results showed that the SN cells inclined to detect continuity or similarity of orientations between CRF and nCRF, and the SS cells mostly detected the discontinuity or difference in orientation between CRF and nCRF. |
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