Focal optogenetic suppression in macaque area MT biases direction discrimination and choice confidence, but only transiently

Abstract

Insights from causal manipulations of brain activity depend on targeting the spatial and temporal scale most relevant for behavior. Using a sensitive perceptual decision task in monkeys, we examined the effects of randomly-interleaved, 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 on trials with visual stimuli (and concurrent suppression) longer than ~350ms. 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.

A cortical information bottleneck during decision-making

“…≤ E (z,y)∼p(z,y) log 1 q(y|z) := L CE (14) To approximate H(Y |Z), we first trained a neural network with cross-entropy loss to predict the output, Y , given the hidden activations, Z, learning a distribution q(y|z). The KL denotes the Kullback-Liebler divergence.…”

“…But why distribute computation across multiple areas? One reason is that distributed computation supports important fault tolerance in the brain which allows it to compensate when dynamics in relevant areas are altered [11][12][13][14] . But is there also a computational benefit for distributing computations across multiple areas?…”