Journal Article

Network anatomy and in vivo physiology of visual cortical neurons

Hood, Greg, Andermann, Mark L., Bock, Davi D., Reid, R. Clay, Lee, Wei-Chung Allen, Kim, Hyon Suk, Yurgenson, Sergey, Kerlin, Aaron M., Soucy, Edward R., Wetzel, Arthur W.

2011

Overview

In the cerebral cortex, local circuits consist of tens of thousands of neurons, each of which makes thousands of synaptic connections. Perhaps the biggest impediment to understanding these networks is that we have no wiring diagrams of their interconnections. Even if we had a partial or complete wiring diagram, however, understanding the network would also require information about each neuron's function. Here we show that the relationship between structure and function can be studied in the cortex with a combination of in vivo physiology and network anatomy. We used two-photon calcium imaging to characterize a functional property—the preferred stimulus orientation—of a group of neurons in the mouse primary visual cortex. Large-scale electron microscopy of serial thin sections was then used to trace a portion of these neurons’ local network. Consistent with a prediction from recent physiological experiments, inhibitory interneurons received convergent anatomical input from nearby excitatory neurons with a broad range of preferred orientations, although weak biases could not be rejected. Untangling neural nets in the visual system Connectivity forms the basis of functional computations performed by neural circuits, but it is notoriously difficult to follow the complex structural wiring between neurons to the function of individual cells. Now, using a combination of functional imaging and three-dimensional serial electron-microscopic reconstruction at an unprecedented scale, two groups present detailed representations of the connectivity of single cells in the mouse visual system. Davi Bock et al . in Clay Reid's lab investigate connectivity in the primary visual cortex, and find that inhibitory neurons receive input from excitatory cells with widely varying functions, consistent with predictions from recent physiological studies of the mouse cortex. Kevin Briggman, Moritz Helmstaedter and Winfried Denk show that direction-selective ganglion cells receive more synapses from a starburst amacrine cell dendrite if their preferred directions are opposites, suggesting that the directional sensitivity of retinal ganglion cells arises from the asymmetry in their wiring with amacrine cells. To date, various aspects of connectivity have been inferred from electron microscopy (EM) of synaptic contacts, light microscopy of axonal and dendritic arbors, and correlations in activity. However, until now it has not been possible to relate the complex structural wiring between neurons to the function of individual cells. Using a combination of functional imaging and three-dimensional serial EM reconstruction at unprecedented scale, two papers now describe the connectivity of single cells in the mouse visual system. This study investigates the connectivity of inhibitory interneurons in primary visual cortex.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/378/2613/1875 / 631/378/548 / 692/698/1688/512/2613 / Anatomy / Animals / Biological and medical sciences / Calcium Signaling / Cameras / Cortical columns / Fundamental and applied biological sciences. Psychology / Humanities and Social Sciences / Interneurons - physiology / Male / Medical examination / Mice / Microscopy, Electron, Transmission / Microscopy, Fluorescence / Microtomy / multidisciplinary / Nerve Net - anatomy & histology / Nerve Net - cytology / Nerve Net - physiology / Nerve Net - ultrastructure / Neural Inhibition - physiology / Neurology / Neurons / Neurons - physiology / Neurons - ultrastructure / Physiology / Pyramidal Cells - physiology / Pyramidal Cells - ultrastructure / Science / Science (multidisciplinary) / Structure / Synapses - physiology / Vertebrates: nervous system and sense organs / Visual Cortex - anatomy & histology / Visual Cortex - cytology / Visual Cortex - physiology / Visual Cortex - ultrastructure