Recruitment of frontal sensory circuits during visual discrimination.

A long-range circuit linking the medial frontal cortex to the primary visual cortex (V1) has been proposed to mediate visual selective attention in mice during visually guided behavior. Here, we use in vivo two-photon functional imaging to measure the endogenous activity of axons of A24b/M2 neurons from this region projecting to layer 1 of V1 (A24b/M2-V1(axons)) in mice either passively viewing stimuli or performing a go/no-go visually guided task. We observe that while A24b/M2-V1(axons) are recruited under these conditions, this is not linked to enhancement of neural or behavioral measures of sensory coding. Instead, A24b/M2-V1(axon) activity is associated with licking behavior, modulated by reward, and biased toward the sensory cortical hemisphere representing the stimulus currently being discriminated.