Cortical construction of self-motion perception in human and non-human primates

演題

Cortical construction of self-motion perception in human and non-human primates

講演者

Dr. Alexandra Séverac Cauquil, Ph.D (In-Vest Group Leader, Head of the University of Toulouse Master degree in Neurosciences)

使用言語

English

日時

2025年10月17日(金曜日) 10：00～11：00

場所

L12

内容

In-Vest project aims at identifying and characterizing the cortical networks involved in visuo-vestibular integration in human and non-human primates, using oculometry, psychophysics, and functional magnetic resonance imaging (fMRI). Inscribed in the field of cognitive neuroscience and neuroimaging, this project adopts a comparative approach to explore the integration processes essential to spatial orientation, balance and perception of self-motion. It also seeks to validate the rhesus macaque as a relevant model in this field, and to fill gaps on the neural substrates of visuo-vestibular integration, complementing behavioural, postural, oculometric and electrophysiological studies.
The project includes several studies. The first one, in humans, explored the directional and congruence effects between galvanic vestibular stimulation (GVS) and forward/backward optic flow, targeting the cortical areas sensitive to visual self-motion. The second one compared vestibular activations in response to lateral GVS and visual (global optic flow) stimulation in macaque monkeys, to identify areas of overlap between the two modalities. The third study analysed directional preferences to optic flow (forward/backward/left/right) in both species. Despite several technical challenges, such as adapting the GVS material to MRI and the complex training of macaques to the fixation task in the scanner, the data obtained enabled us to meet our objectives. Area V6, in humans, was characterized by a dual specialization: on the one hand, its sensitivity to visuo-vestibular congruence, and on the other, its preference for forward movement. In the macaque, notable functional overlaps were observed between vestibular and visual activations, with an organization similar to that of humans, although certain regions (e.g., VIP) showed differences in directional specialization. The final protocol confirmed the directional preference of V6 in macaques for forward flow, even in purely visual stimulation.
These results demonstrate the feasibility of a comparative fMRI approach to visuo-vestibular networks. They contribute to the characterization of the cortical multisensory integration network, to a better understanding of the specialization of certain regions in the perception of self-motion, and to the validation of the rhesus macaque as a relevant model due to functional homology with humans. This work paves the way for electrophysiological studies in non-human primates, to explore in greater detail the dynamics of the regions identified. It also lays the foundations for new experimental protocols integrating oculometric and psychometric measurements to address the perceptual dimension of multisensory integration. In humans, this research is extended to the study of the impact of gravity or aging, opening up clinical prospects for the diagnosis and rehabilitation of vestibular disorders.
 

問合せ先

Systems Neurobiology and Medicine
Inagaki Naoyuki (ninagaki@bs.naist.jp)