Cortical Contributions to Innate Vocalizations

Vocalization is an essential medium for communication in almost all mammalian species, including our own.

Vocal patterns can be either learned, as with human speech, or innate, as the various affiliative and agonistic vocalizations produced by mammals.

A major unresolved issue is the relationship between ancestral mammalian circuits for innate vocalizations and the derived circuitry that enables vocal learning.

One hypothesis is that motor cortical structures are also active during innate vocalizations, and interact with subcortical vocal circuits important to vocal patterning, thus providing the architectural foundation from which learned vocalizations evolved.

In support of this idea, recent studies in non-human primates show that certain neurons in the ventrolateral prefrontal cortex and anterior cingulate cortex are highly active before and during innate vocal production.

Perhaps even more surprisingly, a very recent study found a strong involvement of prelimbic cortex and cingulate area 2 in the production of ultrasonic vocalizations (USVs) in rats.

Nonetheless, most of the advanced genetic tools necessary to map, monitor, and manipulate the cortical neurons active during innate vocal behaviors are not applicable in monkeys and rats.

Thus, the functional and anatomical relationship between these neuronal circuits important to innate vocal patterning remain unknown.

Here, we propose to exploit the wide range of genetic and physiological tools available in the mouse, including the ability to optogenetically elicit USVs in head-fixed mice, to identify PLC and C2 neurons that are active during USV production and explore how they interact with subcortical vocal circuits.