Task-specific contribution of area MT to stereoscopic depth discrimination

Decision-related feedback in visual cortex lacks spatial selectivity

Feedback in the brain is thought to convey contextual information that underlies our flexibility to perform different tasks. Empirical and computational work on the visual system suggests this is achieved by targeting task-relevant neuronal subpopulations. We combine two tasks, each resulting in selective modulation by feedback, to test whether the feedback reflected the combination of both selectivities. We used visual feature-discrimination specified at one of two possible locations and uncoupled the decision formation from motor plans to report it, while recording in macaque mid-level visual areas. Here we show that although the behavior is spatially selective, using only task-relevant information, modulation by decision-related feedback is spatially unselective. Population responses reveal similar stimulus-choice alignments irrespective of stimulus relevance. The results suggest a common mechanism across tasks, independent of the spatial selectivity these tasks demand. This may reflect biological constraints and facilitate generalization across tasks. Our findings also support a previously hypothesized link between feature-based attention and decision-related activity.

Feedback modulates visual neurons, thought to help achieve flexible task performance. Here, the authors show decision-related feedback is not only relayed to task-relevant neurons, suggesting a broader mechanism and supporting a previously hypothesized link to feature-based attention.

Correlations between the activity of sensory neurons and behavior: how much do they tell us about a neuron's causality?

How the activity of sensory neurons elicits perceptions and guides behavior is central to our understanding of the brain and is a subject of intense investigation in neuroscience. Correlations between the activity of sensory neurons and behavior have been widely observed and are sometimes used to infer how neurons are used to guide a certain behavior. This view is challenged firstly by theoretical considerations that these correlations rely on the existence of correlated noise and its structure, and secondly by recent empirical observations suggesting that such correlated noise is not a fixed network property but that it depends on various sources, and varies with a subject's mental state.