Orienting response and detection of thalamic stimulation: Mechanism of perceptual learning in the cat.

Hypothesized that attention facilitates the neural mechanisms that permit responding to significant input. In the present experiment, the orienting response was used as an index of the action of the neural mechanisms of attention in 7 cats. Results demonstrate that Ss could not use thalamic stimulation as a signal to perform a behavioral response when stimulus intensities were too weak to evoke orienting behavior. Responses were quickly learned at higher intensities of stimulation, and with continued training, the Ss were able to respond to the weaker, previously ineffective stimulus. This increase in sensitivity was not due to changes in tonic arousal and appeared to be relatively specific to the stimulated nucleus. The procedures may be useful in exploring the neural mechanisms of perceptual learning. Findings are consistent with B. Libet's (1982) report that EPs in sensory cortex may not be sufficient to produce conscious experience in humans and suggest that input to the cerebral cortex from sense organs is not a sufficient condition even for discrimination. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)