In order to perceive their environment and constructively interact with it in a variety of situations, animals need to interpret sensory bottom-up input from the physical world in the context of internally-generated top-down information representing previous experiences and current aims. Although such top-down information is essential for many higher brain functions, most research on the sensory neocortex has so far focused on encoding of sensory bottom-up signals.

Neocortical layer 1 is a major site of convergence for a variety of brain-wide afferents carrying top-down information, which are integrated and processed in apical tuft dendrites of pyramidal neurons. Here, we aim to dissect how two distinct types of inhibitory interneurons controlling these apical dendrites shape the representation of top-down information in mouse auditory cortex.

Based on our preliminary evidence suggesting key differences in their synaptic inputs, their postsynaptic effects and their in vivo plasticity, we hypothesize a division of labor between the two interneuron types.