Biology subjects

Chancel, M.

Publications and source records attributed to Chancel, M..

3 recordsLinked to original sources

bioRxiv2025

Parietal alpha frequency shapes own-body perception by modulating the temporal integration of bodily signals

An influential proposal in the field of cognitive neuroscience suggests that alpha-frequency brain oscillations constrain the temporal sampling of external sensory signals, shaping the temporal binding window (TBW)--the interval during which sensory signals are integrated. However, whether alpha frequency modulates the integration of self-related sensory signals and the perception of the body as ones own (body ownership) remains unknown. Here, we demonstrate that individual alpha frequency (IAF) from the parietal cortex predicted TBWs and perceptual sensitivities in body ownership and visuotactile simultaneity judgment tasks, with faster frequencies narrowing TBWs and increasing sensitivities, and vice versa. Modulating IAF through brain stimulation altered TBWs and sensitivities, establishing a causal relationship. Computational modeling linked IAF to uncertainty in asynchrony information within the causal inference process, providing a mechanism. These findings demonstrate that parietal alpha frequency shapes the sense of body ownership by modulating the temporal integration of bodily sensory signals.

neuroscience↗

bioRxiv2023

The Sense of Body Ownership and the Neural Processes of Memory Encoding and Reinstatement

Every event we experience that results in a memory involves experiencing our conscious self at its heart. The spatial and perceptual experience of ones own body is the most basic form of selfhood. Disrupting bodily selfhood during memory formation impairs functioning of the hippocampus during retrieval, which implies a weakening of encoding mechanisms. However, neural activity present as individuals encode memories during manipulations of bodily selfhood have yet to be assessed. We investigated how body ownership, a core aspect of bodily selfhood, impacts encoding processes in the hippocampus and additional core memory regions (e.g. posterior parietal cortex). Further, we assessed the degree to which memories are reinstated according to body ownership during encoding and vividness during retrieval as a measure of memory strength. Participants viewed immersive videos through VR glasses, which depicted everyday events that included a first-person view of a mannequins body aligned with participants real bodies during fMRI scanning. We manipulated feelings of body ownership over the mannequin using a perceptual full-body illusion. One week later, participants retrieved memories for the videos during fMRI scanning. We observed that patterns of activity in several regions including the hippocampus and posterior parietal cortex distinguished between videos encoded with strong versus weak illusory body ownership. Moreover, these same regions reinstated memories to a greater degree when they were formed with a strong sense of body ownership and retrieved with increasing levels of vividness. Our findings demonstrate how the fundamental sense of owning ones body shape neural signatures of memory formation and strengthen reinstatement at retrieval.

neuroscience↗

bioRxiv2022

Modeling tactile pleasantness across skin types at the individual level reveals a reliable and stable basic function

Touch is perceived most pleasant when delivered at velocities known to optimally activate C Tactile afferents. At the group level, pleasantness ratings of touch delivered at velocities in the range 0.3-30 cm/s follows an inverted-U shape curve, with maximum pleasantness between 1 and 10 cm/s. However, the prevalence, reliability, and stability of this function at the individual level and across skin types remains unknown. Here, we tested a range of seven velocities delivered with a soft brush, on both hairy and non-hairy skin in 123 participants. We showed that the relationship between pleasantness and velocity of touch is significantly best described by a negative quadratic model at the individual level in the majority of participants both on hairy (67.1%) and non-hairy skin (62.6%). Higher interoceptive accuracy and self-reported depression were related to a better fit of the quadratic model and to the steepness of the curve, respectively. The prevalence of the quadratic model was stable across body sites (62.6%), across two experimental sessions (73-78%,), and regardless of the number of trials. Thus, the individual perception of tactile pleasantness follows a characteristic velocity-dependent function across skin types and shows trait characteristics, making it a possible biomarker for mental health disorders.

neuroscience↗