Marie Palma, successfully defended her thesis entitled "Coritical bases of vocalizations in freely moving minipigs" on June 29th.
Thesis Summary
Investigating the fundamental cortical dynamics underlying vocal and speech production requires access to multiple cortical areas simultaneously. Such access is partly possible in humans when patients are implanted for clinical purpose with intracortical electrodes, but such cases are rare, with usually only partial coverage of involved brain areas. For this reason, animal models are useful to detail the dynamics of cortical networks underlying vocal production. To date, non-human primates, birds and recently rodents have been used, with increasing data showing that non-human primate network model of vocal production shares strong similarities with that of human speech production. The extent to which such model generalizes to other species remains however unclear. In this context, the main purpose of this thesis was to develop a novel experimental paradigm to investigate the cortical bases of vocal production using cortical electrode arrays in minipigs, a large non-primate species very keen in producing vocalizations and easy to handle by humans. This work was conducted in part within the frame of the Graphene Flagship aiming at developing low-noise cortical probes. Such implants were firstly tested in rats’ auditory cortex in response to pure sounds.
To explore minipigs’ cortical bases of vocalizations, we firstly characterized the vocalizations produced by these animals in a housing pen, in a context similar to their daily life during the experiment. The results showed 6 categories of calls, with different occurrence situations and acoustic characteristics, allowing us to explore the vocal repertoire of minipigs. Secondly, we developed an experimental setup to record cortical activity along with vocalizations in freely behaving minipigs. We used three minipigs implanted in different cortical areas of the left hemisphere of the animals. We identified key regions activated during vocal production in minipigs, including motor and premotor cortices and inferior frontal gyrus. Minipigs are hence a promising model to study vocal production cortical networks