A photo of the talk)

A hypothesis concerning how the evolution of prosociality impacted vocal learning

A photo of the talk)

A hypothesis concerning how the evolution of prosociality impacted vocal learning

Abstract

The periaqueductal gray (PAG) is a midbrain area that is involved in stress modulation and the production of innate vocalizations. The PAG works as a gate to the premotor neurons of the brain stem. Lesions in this area cause loss of the ability to vocalize in mammals, but not comprehension or voluntary movement. The PAG receives input from the vocal motor control network, but also affects it through dopaminergic projections. It has recently been shown that the PAG in juvenile zebra finches releases dopamine in the HVC nucleus, which regulates song learning. Dopamine is known to play a key role in the auditory feedback circuitry that reinforces the copying of vocalizations, and the PAG relays extensive dopaminergic efferents to the robust nucleus of the arcopallium (RA).The PAG receives extensive glutamatergic inputs from limbic and hypothalamic structures, which drives dopaminergic feedback to thalamic and hypothalamic structures, and is crucial for the mediation and moduation of the stress response. In the PAG of P. discolor, a bat species proposed to be a vocal learner, Foxp2 regulates expression networks encompassing several genes crucial for glutamatergic signaling. Importantly, some of the glutamate receptor genes most highly expressed in these regulatory networks play significant roles in the modulation of stress responses and in the maintenance of synaptic plasticity, thought to be crucial for in vocal learning species . Changes to glutamate receptor expression correlate with increased complexity in the song of the domesticated Bengalese Finch (L. domestica) compared to its wild counterpart , the white-rumped Munia (L. striata), and have been implicated more broadly in domestication and recent human evolution.We provide a mechanistic account of how changes to glutamatergic signaling affect the gating of dopaminergic outputs from the PAG, and make this an important step in the evolutionary tinkering of vocal learning capacities.

Date
Location
Zürich, Switzerland