Society of Neuroscience(SfN) is having its annual meeting in Washington D.C.–I will be presenting a poster at SfN on the mouse visual system and the relevance of electrical coupling in vision.
Laminar Distribution of Gap Junctions in Mouse Primary Visual Cortex Naqi Haider, Michael Chary, and Ehud Kaplan Department of Neuroscience & Friedman Brain Institute The Neuron Doctrine, proposed by Santiago Ramon y Cajal, dominates neuroscience today. It describes the nervous system as composed of discrete anatomical and functional unitsneurons.The Reticular Theory, a competing view of neuroscience supported by Camillo Golgi, viewed the nervous system as a giant syncytium of interconnected cells. We now know that neurons are often electrically coupled to each other by gap junctions, which allow for the transmission of subthreshold currents and molecules. Electrical coupling can form networks between specific types of neurons. Gap Junctions also form connections between neurons and glia. Electrical coupling between neurons through gap junctions can change those neuron’s response properties. In the mammalian cortex, inhibitory neurons are more frequently coupled electrically than excitatory neurons. Hubel and Wiesel (1962) demonstrated orientation selective cells in the cat primary visual cortex (V1), where inhibitory neurons are thought to sharpen a neuron's orientation tuning. Therefore, understanding how inhibition affects orientation tuning, it is important to determine the spatial distribution of gap junctions across V1. Here we present preliminary immunohistochemical data showing the laminar distribution of connexin36 gap junctions in the mouse primary visual cortex among parvalbumin positive inhibitory neurons. Companion simulations indicate that the distribution of gap junctions is important for the sharpening of the orientation tuning curve mediated by intracortical inhibition. We anticipate this study to lay the groundwork for studies on whether gap junctions are important in the temporal evolution of orientation tuning curves. Furthermore, our approach demonstrates how to include the effect of gap junctions into quantitative models of the visual system. FullPoster: Laminar Distribution of Gap Junctions in Mouse Primary Visual Cortex