Belief states as a framework to explain extra-retinal influences in visual cortex

•Perceptual inference is associated with the updating of beliefs.•Large scale recordings of neuronal activity provide insights into belief states.•Belief states may impact on sensory neurons through feedback.•Belief states may influence firing rates and tuning properties in sensory areas.•Belief states may help understand noise-correlations and choice probabilities.

The activity of sensory neurons is modulated by non-sensory influences, but the role of these influences in cognition is only partially understood. Here we review how the large-scale recording of neuronal activity within and across brain regions allows researchers to examine the interactions between simultaneously recorded neurons as they are jointly influenced by fluctuations in an animal's mental state. We focus on studies on the visual cortex of non-human primates to examine the relationship between extra-retinal influences and beliefs about the state of the sensory world. We explore how these influences can be understood within theoretical frameworks that propose how the continuous updating of belief states supports perceptual inference.