Cortical Plasticity
Description
Plasticity shapes the brain during development, and mechanisms of plasticity continue into adulthood to enable learning and memory. Nearly all brain functions are influenced by past events, reinforcing the view that the confluence of plasticity and computation in the same circuit elements is a core component of biological intelligence. My laboratory studies plasticity in the cerebral cortex during development, and plasticity during behavior that is manifest as cortical dynamics. I will describe how cortical plasticity is implemented by learning rules that involve not only Hebbian changes and synaptic scaling but also dendritic renormalization. By using advanced techniques such as optical measurements of single-synapse function and structure in identified neurons in awake behaving mice, we have recently demonstrated locally coordinated plasticity in dendrites whereby specific synapses are strengthened and adjacent synapses with complementary features are weakened. Together, these changes cooperatively implement functional plasticity in neurons. Such plasticity relies on the dynamics of activity-dependent molecules within and between synapses. Alongside, it is increasingly clear that risk genes associated with neurodevelopmental disorders disproportionately target molecules of plasticity. Deficits in renormalization contribute fundamentally to dysfunctional neuronal circuits and computations, and may be a unifying mechanistic feature of these disorders.
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Speaker Bio
Mriganka Sur is the Newton Professor of Neuroscience and Director of the Simons Center for the Social Brain at MIT, which he founded after 15 years as head of the MIT Department of Brain and Cognitive Sciences. Mriganka’s laboratory studies the development, plasticity and dynamics of the cerebral cortex of the brain using experimental and theoretical approaches. His seminal work on cortical plasticity induced by rewiring visual projections to the auditory pathway overturned an innate labeled-line hypothesis of cortical function. His laboratory has discovered fundamental principles by which networks of the cerebral cortex are wired during development and change dynamically during learning. They have identified gene networks underlying cortical plasticity, and pioneered high resolution imaging methods for studying neurons, astrocytes, synapses and circuits of the intact brain. This work has led to understanding how mechanisms of plasticity provide insights into developmental disorders of the brain. His group has discovered novel mechanisms underlying neurodevelopmental disorders and proposed innovative strategies for treating such disorders. Analyzing cortical circuits, his laboratory has identified principles of inhibitory-excitatory neuronal interactions in the cerebral cortex and revealed dynamics of information flow and sensory-motor transformation across cortical areas during goal-directed behavior.
Mriganka received the B. Tech. degree in Electrical Engineering from the Indian Institute of Technology, Kanpur, and the PhD degree in Electrical Engineering from Vanderbilt University, Nashville. He has trained nearly 100 doctoral students and postdoctoral fellows, and received awards for outstanding teaching and advising. He has been elected Fellow of the Royal Society of the UK, and a member of the National Academy of Medicine, the American Academy of Arts and Sciences, the American Association for the Advancement of Science, the World Academy of Sciences, and the Indian National Science Academy. His recent awards include the Krieg Cortical Discover Prize and Doctor of Science honoris causa from IIT Kanpur.