The long-range goal of Dr. Brandon's research is an understanding of mechanisms of neural computation. Using the eye as a model for the brain, this work is concerned with determining how certain visual neurons distinguish the direction of motion of a visual stimulus, in both vertebrate and invertebrate visual systems.
In vertebrates, these directionally-sensitive neurons provide the brain with visually-derived information about the movement of the eye with respect to the real world; this information is then used in reflexes that control gaze. Similar neurons have been observed in the visual systems of crustaceans and insects.
The neuronal circuitry responsible for directional selectivity resides completely within the retina (in vertebrates) or the optic lobe (in invertebrates), and involves interactions among directional neurons and cholinergic and/or GABAergic interneurons. Dr. Brandon's research employs immunocytochemical methods and electron microscopy to identify the detailed connections among these cell types.