In addition to understanding the mechanisms by which signals about the visual world are produced in cortical neurons, it is important to establish which of these signals are used by the subject for perception. This is particularly challenging when a perceptual decision depends upon the conjunction of multiple stimulus features. For example, neurons in MT are selective for motion direction and binocular disparity. When examined as separate visual parameters, recording and electrical microstimulation experiments show MT neurons selective for these parameters make causal contributions to perceptual signals for motion. However, whether the brain reads out this activity in way that is specific both properties simultaneously has never before been tested. Using a task that depends upon detecting conjunctions between binocular disparity and motion direction, we have previously reported that sensory neurons in primate area MT carry information not only about the visual stimulus, but also about the animals upcoming choices. This suggests that fluctuations in the activity of these neurons plays a causal role in determining the animals decisions. In order to establish this link, we used electrical microstimulation in area MT while monkeys performed the discrimination. Microstimulation systematically altered animals reports in the direction predicted by a causal role. This cannot result from simply boosting neuronal signals for either left or right motion direction alone without reference to binocular disparity: this would boost signals in the near and far surfaces without any consistent effect upon cylinder rotation. Our data confirm this specificity: the effect of stimulation reversed sign with disparity preference. The effect of microstimulation was larger than those reported in previous studies - all using tasks depending on a single stimulus property. This further supports the idea of a readout that is based on the conjunction of multiple properties as there are fewer neurons available to signal a given conjunction, the sub-population activated by our electrical stimulation forms a larger fraction of the decision pool.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
1ZIAEY000404-12
Application #
8737630
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
12
Fiscal Year
2013
Total Cost
$969,207
Indirect Cost
Name
U.S. National Eye Institute
Department
Type
DUNS #
City
State
Country
Zip Code
Quaia, Christian; Optican, Lance M; Cumming, Bruce G (2018) Binocular summation for reflexive eye movements. J Vis 18:7
Seemiller, Eric S; Cumming, Bruce G; Candy, T Rowan (2018) Human infants can generate vergence responses to retinal disparity by 5 to 10 weeks of age. J Vis 18:17
Quaia, Christian; Optican, Lance M; Cumming, Bruce G (2017) Suppression and Contrast Normalization in Motion Processing. J Neurosci 37:11051-11066
Quaia, Christian; Optican, Lance M; Cumming, Bruce G (2017) Combining 1-D components to extract pattern information: It is about more than component similarity. J Vis 17:21
Tarawneh, Ghaith; Nityananda, Vivek; Rosner, Ronny et al. (2017) Invisible noise obscures visible signal in insect motion detection. Sci Rep 7:3496
Clery, Stephane; Cumming, Bruce G; Nienborg, Hendrikje (2017) Decision-Related Activity in Macaque V2 for Fine Disparity Discrimination Is Not Compatible with Optimal Linear Readout. J Neurosci 37:715-725
Joiner, Wilsaan M; Cavanaugh, James; Wurtz, Robert H et al. (2017) Visual Responses in FEF, Unlike V1, Primarily Reflect When the Visual Context Renders a Receptive Field Salient. J Neurosci 37:9871-9879
Read, Jenny C A; Cumming, Bruce G (2017) Visual Perception: Neural Networks for Stereopsis. Curr Biol 27:R594-R596
McFarland, James M; Cumming, Bruce G; Butts, Daniel A (2016) Variability and Correlations in Primary Visual Cortical Neurons Driven by Fixational Eye Movements. J Neurosci 36:6225-41
Cumming, Bruce G; Nienborg, Hendrikje (2016) Feedforward and feedback sources of choice probability in neural population responses. Curr Opin Neurobiol 37:126-132

Showing the most recent 10 out of 36 publications