Ocular dominance in kitten cortex: induced changes of single cells while they are recorded

We have monitored extracellularly individual neurons in the striate cortex of 4-week-old unparalyzed kittens with the aim of changing the ocular dominance of these cells during recording. To do this, we elicited conjugate eye movements using a bipolar stimulating electrode positioned in the internal medullary lamina (IML) of the thalamus. During electrical stimulation of this region, one eye was occluded and the other was visually activated with optimal stimuli. Receptive fields were studied subjectively and objectively and relative response strengths were assessed. Of 42 cells studied in detail, 62% underwent changes on ocular dominance following conditioning periods of, generally, 15-20 min. Control experiments suggest that this plasticity is: age-related; requires both visual stimulation and activation of pathways associated with eye movement; and does not appear to be caused solely by increased arousal levels.