Neuroscience at The University of Chicago

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Education

Ph.D., California Institute of Technology

Contact

Email: maunsell@uchicago.edu

John Maunsell, Ph.D.

Professor

Director, Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior

Research Interests
  • Computational & Theoretical
  • Systems / Behavior / Cognitive
Our research is aimed at understanding how neuronal signals in visual cerebral cortex generate perceptions and guide behavior. Our approach is to record from individual neurons in trained, behaving monkeys while they perform visual tasks. Much of our work is directed at understanding how paying attention to specific visual targets affects the way that they are represented in the brain, and how changes in the sensory representation caused by attention relate to changes in perception and behavior. We have shown that attention increases the strength of neuronal responses without changing their selectivity, effectively representing the attended stimulus as if it were more intense than it really is. Paired measurements of neuronal responses and behavioral performance have shown that much of the behavioral advantage conferred by attention may be explained by this change it causes in the sensory representation, rather than decision processes. Another line of research has been exploring the more general question of how the activity of given neurons contributes to specific visual behaviors. Measurements of the trial-to-trial correlation between the strength of a neuron's responses to a weak stimulus and the animal's performance detecting that stimulus have shown that different neurons contribute to a greater or lesser degree to particular behaviors depending on which stimuli they are most sensitive to. We also use electrical microstimulation to explore how different regions in visual cortex contribute to visual perceptions. By measuring the amount of current needed to produce a just-detectable stimulus in different cortical areas, we have found that all regions of cerebral cortex are comparable in their ability to produce detectable percepts.

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Cohen, M.R., Maunsell, J.H.R. (2009) Attention improves performance primarily by reducing interneuronal correlations. Nature Neuroscience 12:1594-1601. Lee, J., Maunsell, J.H.R. (2010) Attentional modulation of MT neurons with single or multiple stimuli in their receptive fields. Journal of Neuroscience 30:3058-3066 Ni, A.M., Maunsell, J.H.R. (2010) Microstimulation reveals limits in detecting different signals from a local cortical region. Current Biology 20:48-828. Cohen, M.R., Maunsell, J.H.R. (2010) A neuronal population measure of attention predicts behavioral performance on individual trials. Journal of Neuroscience 30:15241-15232. Lee, J., Maunsell, J.H.R. (2010) The effect of attention on neuronal responses to high and low contrast stimuli. Journal of Neurophysiology 104:960-971. Ray, S., Maunsell, J.H.R. (2010) Differences in gamma frequencies across visual cortex restrict their possible use in computation. Neuron 67:885-896. Bosking, W.H., Maunsell, J.H.R. (2011) Effects of stimulus direction on the correlation between behavior and single units in MT during a motion detection task. Journal of Neuroscience 31:8230-8238. Cohen, M.R., Maunsell, J.H.R. (2011) Using neuronal populations to study the mechanisms underlying spatial and feature attention. Neuron 70:1192-1204. Ray, S., Maunsell, J.H.R. (2011) Network rhythms influence the relationship between spike-triggered local field potential and functional connectivity. Journal of Neuroscience 31:12674-12682. Cohen, M.R., Maunsell, J.H.R. (2011) When attention wanders: how uncontrolled fluctuations in attention affect performance. Journal of Neuroscience 31:15802-15806. Histed, M.H., Carvalho, L.A., Maunsell, J.H.R. (2012) Psychophysical measurement of contrast sensitivity in the behaving mouse. Journal of Neurophysiology 107:758-765. Ghose, K., Maunsell, J.H.R. (2012) A strong constraint to the joint processing of pairs of cortical signals. Journal of Neuroscience 32:15922-15933. Histed, M.H., Carvalho, L.A., Maunsell, J.H.R. (2012) Psychophysical measurement of contrast sensitivity in the behaving mouse. Journal of Neurophysiology 107:758-765.  Ni, A.M., Ray, S., Maunsell, J.H.R. (2012) Tuned normalization explains the size of attention modulations. Neuron 73:803-813. Ray, S., Ni, A.M., Maunsell, J.H.R. (2013) Strength of gamma rhythm depends on normalization. PLoS Biology, 11, e1001477.