Mriganka Sur, Ph.D.
Department of Brain and Cognitive Sciences
Sherman Fairchild Professor of Neuroscience
Head, Department of Brain and Cognitive Sciences
B.Tech., Electrical Engg., Math, Indian Institute of Technology, Kanpur, 1974
M.S., Elec. Engg., Psychology, Vanderbilt University, Nashville, TN, 1975
Ph.D., Elec. Engg., Neurobiology, Vanderbilt University, Nashville, TN, 1978
1983 Assistant Professor, Section of Neuroanatomy, Yale University School of Medicine
1986 Associate Professor of Neuroscience, Dept. of Brain and Cognitive Sciences, M.I.T.
1993 Professor of Neuroscience, Dept. of Brain and Cognitive Sciences, M.I.T.
1994 Associate Head, Dept. of Brain and Cognitive Sciences, M.I.T.
1998 Head, Dept. of Brain and Cognitive Sciences, M.I.T.
The developing brain requires a genetic blueprint but also is acutely sensitive to the environment. The adult brain constantly adapts to changes in stimuli, and this plasticity is manifest not only as learning and memory but also as dynamic changes in information transmission and processing. The goal of my laboratory is to understand neural plasticity, which is the process by which the brain changes as it develops and as it functions. We are investigating two basic issues in the visual cortex: how the brain is wired and how this brain wiring leads to brain function. We approach these studies through the use of state-of-the-art techniques such as multiple electrode/ single unit recording, optical imaging of brain activity, whole-cell intracellular recording in brain slices and in the intact brain, high-resolution imaging of single neurons in vitro and in vivo by two-photon microscopy, microarrays to identify genes in specific tissues, and gain- and loss-of-function experiments to understand gene function.
Genes, Electrical Activity and Control of Brain Wiring
A large proportion of the genes in the human genome are expressed in the cerebral cortex, which makes up 80% of the brain in higher mammals. Understanding how the cortex develops and changes is critical to understanding how the brain works. We study the genes that lay down a scaffold for wiring in the visual and other cortex, and the ways in which patterned electrical activity shapes gene expression and neuronal connectivity. We approach this work from several levels: the function of individual genes, the interactions between genes, and the processes by which external stimuli influence molecules of the developing cortex to create neuronal networks that process sensory information.
Cortical Networks and Visual Function
Complex information processing in the brain requires the coordinated behavior of millions of cells that are wired together into networks. Although vision occurs seamlessly, it involves massive processing of information in a manner that is dynamically influenced by context. Neurons of the visual cortex take simple inputs and transform them into outputs that form the building blocks of vision. We study how cortical networks carry out such transformations, and how the transformations are influenced by the spatial and temporal context of visual stimuli as well as by the internal state of the organism, such as expectation and attention. For example, we are visualizing functioning synapses in the cortex in vivo in order to directly relate structural changes in single neurons to functional changes in networks that accompany visual learning and memory.
- Dragoi, V., and M. Sur. Dynamic properties of local interactions between inhibitory interneurons in primary visual cortex: Contrast and orientation dependence of contextual effects. J. Neurophysiol. 83:1019-1030, 2000.
- Sharma, J., A. Angelucci and M. Sur. Induction of visual orientation modules in auditory cortex. Nature 404: 841-847, 2000.
- Von Melchner, L., S. Pallas, and M. Sur. Visual Behaviour mediated by retinal projections directed to the auditory pathway. Nature 404: 871-876, 2000.
- Angelucci, A., J. Sharma and M. Sur. Modifiability of neocortical connections and function during development. In: The Mutable Brain, J.H. Kaas, ed, Harwood Academic Publishers, pp 351-392, 2000.
- Dragoi, V., J. Sharma and M. Sur. Adaptation-induced plasticity of orientation tuning in primary visual cortex. Neuron 28: 287-298, 2000.
- Hohnke, C.D., S. Oray and M. Sur. Activity-dependent patterning of retinogeniculate axons proceeds with a constant contribution from AMPA and NMDA receptors. J. Neuroscience 20: 8051-8060, 2000.
- Rivadulla, C., J. Sharma and M. Sur. Specific roles of NMDA and AMPA receptors in direction-selective and complex cell responses in visual cortex. J. Neuroscience 21: 1710-1719, 2001.
- Dragoi, V., C. Rivadulla and M. Sur. Foci of plasticity in adult visual cortex. Nature 411: 80-86, 2001.
- Hohnke, C.D., and M. Sur. Neural activity and the development of brain circuits. In: Encyclopedia of Life Sciences, London: Nature Publishing Group, vol. 13, pp. 19-27, 2001.
- Leamey, C., C. Ho-Pao and M. Sur. Disruption of retinogeniculate pattern formation by inhibition of soluble guanylyl cyclase and protein kinase G. J. Neuroscience 21: 3871-3880, 2001.
- Weng, J., J. McClelland, A. Pentland, O. Sporns, I. Stockman, M. Sur and E. Thelen. Autonomous mental development by robots and animals. Science 291: 599-600, 2001.
- Sur, M. and C. Leamey. Development and plasticity of cortical areas and networks. Nature Reviews Neurosci. 2: 251-262, 2001.
- Sur, M. Cortical development: Transplantation and rewiring studies. International Encyclopedia of the Social and Behavioral Sciences 4: 2837-2842, 2001.
- Dragoi, V., C. Turcu and M. Sur. Stability of cortical responses and the statistics of natural scenes. Neuron 32: 1181-1192, 2001.
- Lyckman, A., S. Jhaveri, D. Feldheim, P. Vanderhaeghen, J. Flanagan and M. Sur. Enhanced plasticity of retinothalamic compartmentalization in an ephrin-A2/A5 double null mutant. Journal of Neuroscience 21: 7684-7690, 2001.
- Sur, M., J. Schummers and V. Dragoi. Cortical plasticity: Time for a change. Current Biology 12: R168-170, 2002.
- Somers, D., V.Dragoi and M. Sur. Orientation selectivity and its modulation by local and long-range connections in visual cortex. In: úThe Cat Primary Visual Cortex?, A.Peters and B. Payne, eds., Academic Press, pp 471-520, 2002.
- Leamey, C.A. and M. Sur. The thalamus: A new proposal. Neuron 34: 507-508, 2002.
- Lyckman, A. and M. Sur. The role of afferent activity in the development of cortical specification. In: Cortical Development I: Results and Problems in Cell Differentiation, C. Hohmann, ed., Springer-Verlag, 39:139-156, 2002.
- Dragoi, V., C. Rivadulla and M. Sur. Contributions of ascending thalamic and local intracortical connections to visual cortical function. In: Virtual Lesions: Understanding perception and behavior with reversible deactivation techniques, S. Lomber and R. Galuske, eds., Oxford University Press, pp 41-60, 2002.
- Dragoi, V., J. Sharma, E.K. Miller and M. Sur. Dynamics of neuronal selectivity in visual cortex and local feature discrimination. Nature Neuroscience 5: 883-891, 2002.
- Schummers, J., J. Marino and M. Sur. Synaptic integration by V1 neurons depends on location within the orientation map. Neuron 36: 969-978, 2002.
- Sharma, J., V. Dragoi, J. B. Tenenbaum, E. K. Miller and M. Sur. Modulation of V1 responses during acquisition of an internal representation of stimulus location.
- Sur, M., J. Schummers and V. Dragoi.Cortical plasticity:Time for a change. Current Biology 12:R168-R170, 2002.
- Sharma, J., V. Dragoi, J.B. Tenenbaum, E.K. Miller and M. Sur. V1 neurons signal acquisition of an internal representation of stimulus location.Science 300: 1758-1763, 2003.
- Leamey, C.A., C. Ho-Pao and M. Sur. The role of calcineurin in activity-dependent pattern formation in the dorsal lateral geniculate nucleus of the ferret.Journal of Neurobiology 56: 153-162, 2003.
- Sur, M. Rewiring cortex: Cross-modal plasticity and its implications for cortical development and function. In: "Handbook of Multisensory Processing", B. Stein, ed., MIT Press (in press), 2003.
- Dragoi, V. and M. Sur. Plasticity of orientation processing in adult visual cortex. In: "The Visual Neurosciences", L.M. Chalupa and J.S. Werner, eds., MIT Press (in press), 2003.
- Newton, J.R., and M. Sur. Plasticity of cerebral cortex in development. Encylopedia of Neuroscience (in press), 2003.
- Dragoi, V., J. Sharma and M. Sur. Response plasticity in primary visual cortex and its role in vision and visuomotor behavior: Bottom up and top-down influences of orientation processing in adult visual cortex. IETE Journal of Research (in press), 2003.
- Sur, M. and Jayadeva. Cognitive science: sensation, perception and learning.Editorial, Special Issue on Cognitive Science, IETE Journal of Research (in press), 2003.
- Majewska, A. and M. Sur. Motility of dendritic spines in visual cortex in vivo: changes during the critical period and effects of visual deprivation. Submitted.
Last Updated: April 15, 2008