Focal optogenetic suppression in macaque area MT biases direction discrimination and decision confidence, but only transiently
Abstract
Insights from causal manipulations of brain activity depend on targeting the spatial and temporal scales most relevant for behavior. Using a sensitive perceptual decision task in monkeys, we examined the effects of rapid, reversible inactivation on a spatial scale previously achieved only with electrical microstimulation. Inactivating neurons in area MT with consistent direction tuning produced systematic effects on choice and confidence. Behavioral effects were attenuated over the course of each session, suggesting compensatory adjustments in the downstream readout of MT over tens of minutes. Compensation also occurred on a sub-second time scale: behavior was largely unaffected when the visual stimulus (and concurrent suppression) lasted longer than 350 ms. These trends were similar for choice and confidence, consistent with the idea of a common mechanism underlying both measures. The findings demonstrate the utility of hyperpolarizing opsins for linking neural population activity at fine spatial and temporal scales to cognitive functions in primates.
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Matlab code (m-files) and data (.mat files) have been provided for Figure 1 and Figures 3-7.
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Author details
Funding
Howard Hughes Medical Institute
- Christopher R Fetsch
- Naomi N Odean
- Danique Jeurissen
- Michael N Shadlen
National Eye Institute (EY11378)
- Christopher R Fetsch
- Naomi N Odean
- Danique Jeurissen
- Michael N Shadlen
National Eye Institute (EY018849)
- Yasmine El-Shamayleh
- Greg Horwitz
Simons Foundation (Simons Collaboration on the Global Brain Postdoctoral Fellowship)
- Danique Jeurissen
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the Public Health Service Policy on Humane Care and Use of Laboratory Animals. The animals were handled according to an approved institutional animal care and use committee (IACUC) protocol (#AAAN4900) of Columbia University. Surgery was performed under isoflurane anesthesia in aseptic conditions, and every effort was made to minimize suffering.
Copyright
© 2018, Fetsch et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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