Laminar distribution of choice and stimulus related signals in sensory cortical areas

The anatomical logic of the cerebral cortex relies on its laminar organization, which defines rules of connectivity vertically and horizontally across hierarchically connected layers. However, clear functional correlates of the different cortical layers during behavior are still rare. We have been studying the involvement of neurons in the deep and superficial layers of the mouse auditory cortex during a delayed frequency discrimination task. Our results reveal a functional dissociation between deep and mid-superficial neurons. Information about the identity of the sound (distributed across layers but larger in mid-superficial layers) is largest right after stimulus onset, but decays almost completely by the end of the delay period. In contrast, information about the upcoming choice is largely restricted to the deep layers and gradually builds up during the delay period. This temporal separation of stimulus- and choice-related signals, as well as analysis of noise correlations, suggests a top-down origin for choice-related signals in the deep layers of auditory cortex.