Mailing Address:
Department of Neurology, Department of Physics and Astronomy Knudsen Hall UNITED STATES
Fax Number:
4018631074
Work Phone Number:
4018639727
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Our research addresses the following questions at the interface of systems and computational neuroscience. 1) How is information represented in ensembles of neurons? 2) How do the neural representations evolve with learning? 3) What are the cellular mechanisms responsible for the evolution of neural representations? 4) What is the role of brain rhythms in these processes? 5) How does sleep influence learning?
To address these questions we measure the activity of ensembles of well isolated neurons using tetrodes and whole cell patch, from many hippocampal and neocortical areas simultaneously during learning and during sleep. Further we develop data analysis tools to decipher the neural activity patterns and field potentials. Finally, we develop computational models to explain these findings, relate them to underlying cellular mechanisms and make experimentally testable predictions.
Our past research has shown that there are very rapid and large changes in the activity patterns of hippocampal place cells with experience and our theoretical work shows that these changes could occur via the spike timing-dependent synaptic plasticity. Further, neural oscillations play a key role in organizing the neural activity patterns to generate a temporal code that can facilitate synaptic plasticity and learning. Finally, our recent findings suggest that during sleep, the neocortical activity may inhibit the hippocampal output for brief periods, thereby pruning the memory traces from the hippocampus. Paradoxically, this could improve the signal to noise ratio between memories and improve behavioral performance on learning and memory.
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Ahmed, O. J. Mehta, M. R. The hippocampal rate code: anatomy, physiology and theory.
Trends Neurosci.
2009; 32( 6):
329-38.
Mehta, M. R. Cortico-hippocampal interaction during up-down states and memory consolidation.
Nat Neurosci.
2007; 10( 1):
13-5.
Hahn, T. T. Sakmann, B. Mehta, M. R. Differential responses of hippocampal subfields to cortical up-down states.
Proc Natl Acad Sci U S A.
2007; 104( 12):
5169-74.
Hoffman, K. L. Battaglia, F. P. Harris, K. MacLean, J. N. Marshall, L. Mehta, M. R. The upshot of up states in the neocortex: from slow oscillations to memory formation.
J Neurosci.
2007; 27( 44):
11838-41.
Hahn, T. T. Sakmann, B. Mehta, M. R. Phase-locking of hippocampal interneurons' membrane potential to neocortical up-down states.
Nat Neurosci.
2006; 9( 11):
1359-61.
Mehta, M. R. Role of rhythms in facilitating short-term memory.
Neuron.
2005; 45( 1):
7-9.
Mehta, M. R. Role of rhythms in facilitating short-term memory.
Neuron.
2005; 45( 1):
7-9.
Mehta, M. R. Cooperative LTP can map memory sequences on dendritic branches.
Trends Neurosci.
2004; 27( 2):
69-72.
Petersen, C. C. Hahn, T. T. Mehta, M. Grinvald, A. Sakmann, B. Interaction of sensory responses with spontaneous depolarization in layer 2/3 barrel cortex.
Proc Natl Acad Sci U S A.
2003; 100( 23):
13638-43.
Mehta, M. R. Lee, A. K. Wilson, M. A. Role of experience and oscillations in transforming a rate code into a temporal code.
Nature.
2002; 417( 6890):
741-6.
Mehta, M. R. Neuronal dynamics of predictive coding.
Neuroscientist.
2001; 7( 6):
490-5.
Mehta, M. R. Quirk, M. C. Wilson, M. A. Experience-dependent asymmetric shape of hippocampal receptive fields.
Neuron.
2000; 25( 3):
707-15.
Mehta, M. R., and Wilson, M.A. From Hippocampus to V1: Effect of LTP on Spatio-Temporal Dynamics of Receptive Fields.
Neurocomputing.
2000; 32(number):
905-911.
Mehta, M. R. Barnes, C. A. McNaughton, B. L. Experience-dependent, asymmetric expansion of hippocampal place fields.
Proc Natl Acad Sci U S A.
1997; 94( 16):
8918-21.
Mehta, M. R. Bergman, H. Loss of frequencies in autocorrelations and a procedure to recover them.
J Neurosci Methods.
1995; 62( 1-2):
65-71.
Mehta, M. R. Dasgupta, C. Ullal, G. R. A neural network model for kindling of focal epilepsy: basic mechanism.
Biol Cybern.
1993; 68( 4):
335-40.
Mehta, M. R. Euclideanization, Topological Theories, Higher Dimensionsl and All That.
Physics Letters B.
1992; 274(number):
53-58..
Mehta, M. R. Path-integral derivation of the superconformal anomaly for the N=1 supersymmetric Yang-Mills theory.
Phys Rev D Part Fields.
1991; 44( 10):
3303-3312.
Mehta, M. R. Path-integral derivation of the superconformal anomaly for the Wess-Zumino model.
Phys Rev D Part Fields.
1991; 44( 4):
1228-1238.
Mehta, M. R. Euclidean continuation of the Dirac fermion.
Phys Rev Lett.
1990; 65( 16):
1983-1986.
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