Kelly Byrne and Billie Beckwith-Cohen


Kelly Byrne and Billie Beckwith-Cohen

Date and Time

Monday, February 11, 2019
11:10 am - 12:30 pm


489 Minor Hall
Berkeley, CA

Kelly Byrne's Abstract

Cholinergic facilitation of visual perceptual learning of texture discrimination

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. I will discuss results from a
double-blind crossover study of the effects of cholinergic enhancement on 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 both the magnitude and rate 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.

Billie Beckwith-Cohen's Abstract

Augmenting vision in retinal degeneration by inhibiting the retinoic acid pathway

Retinitis pigmentosa is a blinding disease caused by photoreceptor degeneration, depriving downstream neurons of light-sensitive input. concurrently, photoreceptor degeneration triggers hyperactive firing of RGCs obscuring any light responses initiated by surviving photoreceptors. Previously we showed that retinoic acid (RA) signaling through its receptor (RAR) is the trigger for this hyperactivity. Inhibition of RAR via the drug BMS or gene therapy reduces hyperactivity in degenerating retinas. Treated animals show unmasked light responses in RGCs as well as innate and learned light-elicited behaviors. Using 2-photon Calcium imaging I aim to identify the types of RGCs that respond to RAR inhibition. These experiments will be followed by behavioral studies to asses affects on visual acuity and contrast sensitivity.