The effects of neural gain on attention and learning

Attention is commonly thought to be manifest through local variations in neural gain. However, what would be the effects of brain-wide changes in gain? Here, we hypothesize that global fluctuations in gain modulate the breadth of attention, and thus, the degree to which processing is focused on aspects of the environment to which one is predisposed to attend. In accordance with this hypothesis, we show that measures of pupil diameter, which are thought to track levels of LC-NE activity and neural gain, are correlated with the degree to which learning is focused on stimulus dimensions that individual human participants are more predisposed to process. In support of our interpretation of this effect in terms of global changes in gain, we further show that the measured pupillary and behavioral variables are strongly correlated with global changes in the strength and clustering of functional connectivity, as brain-wide fluctuations of gain would predict.