Psychedelic Information Theory

Shamanism in the Age of Reason


Local cortical lesions abolish lateral inhibition at direction selective cells in cat visual cortex

Eysel, U. T, Wörgötter, Pape; Experimental Brain Research, Volume 68, Number 3 / November, 1987

Many cells in the cat visual cortex display a strong selectivity for the direction of motion of an optimally oriented stimulus. Postsynaptic inhibition has been suggested to generate this direction selectivity in simple cells, but the intracortical pathways involved have not been identified. While continuously recording from simple cells in layers 4 and 6, we have inactivated the superficial cortical layers in small regions 0.4–2.5 mm from the cortical column under study by using heat lesions, localized cooling or gamma-aminobutyric acid (GABA) microiontophoresis. When inactivation affected cortical regions retinotopically representing motion in the non-preferred direction towards the receptive field, the responses to movement in this direction increased, and the recorded cells lost direction selectivity due to loss of inhibition. Our results indicate that direction selectivity of simple cells involves asymmetric inhibition of predictable cortical topography.

Web Resource: www.springerlink.com

Keywords: lateral inhibition, orientation selectivity, visual cortex, perception