Krieger 205

During conversations we rapidly switch between listening and speaking which often requires withholding or delaying our speech in order to hear others and avoid overlap. The ability of vocal turn-taking is exhibited by non-linguistic species as well, however the neural circuit mechanisms that enable us to regulate the precise timing of our vocalizations during interactions are largely unknown. We address this issue by studying zebra finches that coordinate their calls during vocal interactions By performing intracellular recordings and pharmacological manipulation in the premotor nucleus HVC we found that inhibition regulates the coordination of social contact calls. To further study more complex vocal interactions we also study the singing behavior of nightingales. Male nightingales learn over 100 different songs which are used in order to attract mates or defend territories. We investigated auditory-induced vocal plasticity in interacting nightingales and discovered that nightingales rapidly and accurately imitated the pitch of pitch-controlled whistle playbacks. This finding highlights their capability of directly transforming an auditory input to a matching vocal response.

Songbirds learn their vocalization by listening to and imitating the song of their tutor during a critical period early in life. Once the bird reaches adulthood this song remains stable. We discovered that inhibition within the premotor area HVC plays a major role in closing this critical period by suppressing the influence of the tutor once song proficiency has been achieved. We then developed a cell-type specific viral strategy to target inhibitory neurons in adult zebra finches and were able to re-open the critical period by teaching an adult zebra finch novel song elements. This finding might have important implications to understand and expand motor skill learning capabilities or improve sensory and motor recovery after injury.