Neural correlates of motion after-effects in cat striate cortical neurones: interocular transfer
- 35 Downloads
Interocular transfer of motion after-effects was assessed in the lightly-anaesthetized feline striate cortex. Neurones were adapted with squarewave gratings of optimal orientation and spatial frequency, or with randomly textured fields, drifting continuously at optimal velocity in their preferred or null directions. Neural after-effects were assessed as consequent changes in directional bias, using similar test patterns swept back-and-forth in the same directions and presented to the same or opposite eyes. All results were compared with controls, embodying similar tests following a period of exposure to a uniform background or stationary textured field. The majority of binocularly-driven complex and simple cells tested evinced positive interocular transfer of after-effects. After-effects, whether elicited monocularly or interocularly, were direction-specific. With gratings, after-effects elicited interocularly were always weaker than those obtained monocularly. After-effects evoked monocularly by texture adaptation were weak in comparison to those evoked by gratings; interocular transfer in this case was negligible. In neurones strongly dominated by one eye, adaptation of the non-driving eye yielded, at best, extremely weak after-effects through the other eye. In purely monocular neurones, no transfer could be induced. These results confirm the expectation that motion after-effects arise cortically rather than precortically. The partial interocular transfer seen in binocularly-driven cortical cells suggests that these neurones represent a second-stage processing of inputs from lower-order complex (or simple) cells, themselves driven monocularly or strongly dominated by one eye.
Key wordsVision Visual cortex Interocular transfer
Unable to display preview. Download preview PDF.
- Albrecht DG, Farrar SB, Hamilton DB (1984) Spatial contrast adaptation characteristics of neurones recorded in the cat’s visual cortex. J Physiol (Lond) 347: 713–739Google Scholar
- Cleland BG, Levick WR (1974a) Brisk and sluggish concentrically organized ganglion cells in the cat’s retina. J Physiol (Lond) 240: 421–456Google Scholar
- Cleland BG, Levick WR (1974b) Properties of rarely encountered types of ganglion cells in the cat’s retina and an overall classification. J Physiol (Lond) 240: 457–492Google Scholar
- Cleland BG, Levick WR, Morstyn R, Wagner HG (1976) Lateral geniculate relay of slowly conducting retinal afferents to cat visual cortex. J Physiol (Lond) 255: 299–320Google Scholar
- Hammond P (1974) Cat retinal ganglion cells: size and shape of receptive field centres. J Physiol (Lond) 242: 99–118Google Scholar
- Hammond P, Mouat GSV (1986) Interocular transfer of motion after-effects in complex cells of feline striate cortex. J Physiol (Lond) 381: 99PGoogle Scholar
- Levick WR, Thibos LN (1983) Analysis of orientation bias in cat retina. J Physiol (Lond) 329: 243–261Google Scholar
- Wolfe J, Blake R (1985) Monocular and binocular processes in human vision. In: Rose D, Dobson VG (eds) Models of the visual cortex, Chapt 19. Wiley, New York, pp 192–199Google Scholar