John H.R. Maunsell, PhD

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 and mice 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 and optical microstimulation to explore how different regions in visual cortex contribute to visual perceptions. By measuring the stimulus strength 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.

Neuronal Effects of Spatial and Feature Attention Differ Due to Normalization.
Ni AM, Maunsell JHR. Neuronal Effects of Spatial and Feature Attention Differ Due to Normalization. J Neurosci. 2019 Jul 10; 39(28):5493-5505.
PMID: 31068439

Different Inhibitory Interneuron Cell Classes Make Distinct Contributions to Visual Contrast Perception.
Cone JJ, Scantlen MD, Histed MH, Maunsell JHR. Different Inhibitory Interneuron Cell Classes Make Distinct Contributions to Visual Contrast Perception. eNeuro. 2019 Jan-Feb; 6(1).
PMID: 30868104

Electrical Microstimulation of Visual Cerebral Cortex Elevates Psychophysical Detection Thresholds.
Cone JJ, Ni AM, Ghose K, Maunsell JHR. Electrical Microstimulation of Visual Cerebral Cortex Elevates Psychophysical Detection Thresholds. eNeuro. 2018 Sep-Oct; 5(5).
PMID: 30406199

Attentional Changes in Either Criterion or Sensitivity Are Associated with Robust Modulations in Lateral Prefrontal Cortex.
Luo TZ, Maunsell JHR. Attentional Changes in Either Criterion or Sensitivity Are Associated with Robust Modulations in Lateral Prefrontal Cortex. Neuron. 2018 03 21; 97(6):1382-1393.e7.
PMID: 29503191

Spatially tuned normalization explains attention modulation variance within neurons.
Ni AM, Maunsell JHR. Spatially tuned normalization explains attention modulation variance within neurons. J Neurophysiol. 2017 09 01; 118(3):1903-1913.
PMID: 28701536

Attention-related changes in correlated neuronal activity arise from normalization mechanisms.
Verhoef BE, Maunsell JHR. Attention-related changes in correlated neuronal activity arise from normalization mechanisms. Nat Neurosci. 2017 Jul; 20(7):969-977.
PMID: 28553943

Attention operates uniformly throughout the classical receptive field and the surround.
Verhoef BE, Maunsell JH. Attention operates uniformly throughout the classical receptive field and the surround. Elife. 2016 08 22; 5.
PMID: 27547989

Graded Neuronal Modulations Related to Visual Spatial Attention.
Mayo JP, Maunsell JH. Graded Neuronal Modulations Related to Visual Spatial Attention. J Neurosci. 2016 05 11; 36(19):5353-61.
PMID: 27170131

Neuronal Mechanisms of Visual Attention.
Maunsell JHR. Neuronal Mechanisms of Visual Attention. Annu Rev Vis Sci. 2015 Nov 24; 1:373-391.
PMID: 28532368

A Refined Neuronal Population Measure of Visual Attention.
Mayo JP, Cohen MR, Maunsell JH. A Refined Neuronal Population Measure of Visual Attention. PLoS One. 2015; 10(8):e0136570.
PMID: 26296083

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