Abstract
Despite extensive research on the properties of visual perceptual learning and its specificity to the stimulus parameters employed during training, few studies have investigated the relevant pharmacological underpinnings. Here, we present results from a double-blind crossover study of the effects of cholinergic enhancement on the magnitude and specificity of texture discrimination learning. Each subject participated in two sets of training and testing sessions during which they self-administered either 5 mg of the cholinesterase inhibitor donepezil, which boosts the signaling of endogenous acetylcholine, or placebo, daily for 10 consecutive days. The two training and testing sets were separated by two weeks to permit complete elimination of donepezil (if present). We found substantial perceptual learning of texture discrimination following training with both donepezil and placebo, and the magnitude of this learning was significantly greater after donepezil training compared to placebo training. We also examined the specificity of learning to both the trained location (visual field quadrant) and feature (background element orientation). Training under donepezil had no effect on location specificity of learning and resulted in reduced specificity for stimulus orientation. These findings suggest that future applications of perceptual learning could benefit from an improved understanding of the associated pharmacological mechanisms.
Acknowledgement: NEI R01 EY025278 (MAS)