Synaptic Connectivity of Sensorimotor Circuits for Vocal Imitation in the Songbird

Sensorimotor computations for learning and behavioral performance rely on precise patterns of synaptic connectivity. Yet, in most instances we lack the synaptic wiring diagrams for long-range connections between sensory and motor circuits in the brain, thus limiting mechanistic interpretation of manipulations to circuitry for learning and producing behaviors. Here we provide the synaptic wiring diagram of the sensorimotor circuits involved with the learning and production of a natural and ethologically relevant behavior – birdsong. Using opsin-assisted circuit mapping we describe intratelencephalic and thalamic synaptic input from the 4 known sensory pathways onto the 3 known projection neuronal populations in the zebra finch cortical premotor song region HVC. Targeted whole-cell patch-clamp recordings from hundreds of projection neurons reveal the rules for monosynaptic connectivity across input-output pathways, the existence of polysynaptic ensembles of excitatory and inhibitory neuronal populations in HVC, and circuit tracing reveals novel connections between HVC’s presynaptic partners. Our data suggests a modular organization of ensemble-like networks for integrating long-range input with local circuits, providing important context for information flow and computations for behavior. ### Competing Interest Statement The authors have declared no competing interest.