RESEARCH SUMMARY

Our laboratory's major interest is the role of neural activity in the development and plasticity of precise connections within the central nervous system. Most of the work of the laboratory is on the visual system, and particularly on the developing visual cortex. In this structure, as is likely to be the case in many areas of the brain, the major excitatory inputs initially make connections that are approximately correct topographically but are functionally diffuse. These are rearranged during normal development to a state of high precision through the action of activity-dependent mechanisms of neural plasticity. We induce activity-dependent plasticity experimentally in order to discover what cellular mechanisms and what changes in cortical circuitry are responsible for rapid, long lasting changes in neuronal responses. We induce these changes by manipulations of visual experience, pharmacology, and in mice by genetically alterations, and we analyze their effects using microelectrode recordings, novel techniques for measurement of optical and metabolic signals related to neural activity, and anatomical and neurochemical tracing of connections.

Current experimental work in the laboratory focuses on four areas: (a) Understanding the coupling between the physiological and anatomical changes responsible for neuronal plasticity. We have recently found activity-dependent changes in one type of anatomical connection in the upper layers of cortex that are at least as rapid and dramatic any change in neuronal responses, and blocking these prevents the physiological change. We want to know how and where activity does this. (b) Understanding the cellular mechanisms of of activity-dependent cortical plasticity, primarily through the use of transgenic mice. (c) Understanding the mechanism by which sleep promotes cortical plasticity, a phenomenon that we have recently demonstrated. (d) Understanding the functional organization of visual cortex in relation to computer vision models in animals with highly developed visual systems.

See current experimental work listed above.

CURRENT PROJECTS