ATTENTION TRANSFORMS THE IMPACT OF PARVALBUMIN-POSITIVE INTERNEURON ACTIVITY IN MOUSE PRIMARY VISUAL CORTEX

Modulation of sensory processing by attention is a fundamental aspect of cognitive function. In the visual cortex, neural activity becomes more selective for stimuli when they are attended, compared to when the same stimuli are viewed without attention. This enhancement in selectivity may support improved behavioural detection and discrimination of relevant sensory information and is a key neural correlate of cognitive control. However, the underlying neural circuitry responsible for attentional enhancement of stimulus selectivity is poorly understood. Here, we employed an all-optical approach to selectively inhibit or activate parvalbumin-positive (PV) interneurons while recording neuronal activity in layer 2/3 of the primary visual cortex (V1) of mice performing a cross-modal attention-switching task. We found that attention enhances neural selectivity in both PV and non-PV populations, and that photomanipulation of PV activity interacts with attention modulation. Bidirectional photomanipulation of PV activity in the non-attended condition leads to an increase in stimulus selectivity of pyramidal neurons positively modulated by attention. In contrast, the same set of neurons showed a decrease in selectivity in the attend condition with the same level of photomanipulation. To understand these results mechanistically, we developed computational models of neural circuits incorporating the interactions between PV and pyramidal neurons observed in our experiments. Our results suggest strongly connected recurrent networks of excitatory and inhibitory neurons underly these effects and indicate how context-dependent gating by PV interneurons can selectively enhance or suppress pyramidal neuron responses.