[Accurate establishment of the retinotopic topography of area 17 in cats by intrinsic signal optical imaging].
The retinotopic topography of area 17 in cats was measured by optical imaging based on intrinsic signals. When stimulated with two neighboring gratings oriented orthogonally each other, which were positioned respectively in the upper and lower visual fields, one piece of cortex that had the retinal projection corresponding to the area around the border of the two stimulus gratings became blurred in the resultant function orientation map, because the neurons in this site received excitatory signals from both the horizontal and the vertical gratings via indirect ways. This functional map of the same cortex was compared with that elicited only by a horizontal or vertical grating stimulation in the whole visual field. Accordingly, the accurate position of the retinotopic eccentricity of the cortex in visual field can be demarcated by calculating the cross correlation coefficient of the two functional maps. Furthermore, compared with the electrophysiological measure of receptive fields of single cortical neurons, the retinotopic eccentricities revealed by optical imaging were identical. This experiment provides a fast and relatively accurate method to calculate the retinotopic eccentricities in a large cortical area of the visual cortex.
Chen
Xin
X
Center for Brain Science Research, School of Life Science, Fudan University, Shanghai 200433.
Shou
Tian-De
TD
D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D002415:Cats; D005071:Evoked Potentials; D012160:Retina / Q000502:physiology; D041622:Tomography, Optical; D014785:Vision, Ocular / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology