Biology subjects

Oldrati, V.

Publications and source records attributed to Oldrati, V..

3 recordsLinked to original sources

bioRxiv2024

A modulator of cognitive function: Cerebellum modifies human cortical network dynamics via integration

The cerebellum, with distinctive architecture and extensive cortical connections, has long been associated with motor control; however, evidence suggests its role extends beyond motor functions, playing a crucial role in cognitive processes. Despite these insights, how cerebellar computations modulate cortical networks remains elusive. Here, we evaluate dynamic network reconfigurations in the cerebral cortex connectivity following noninvasive inhibitory repetitive transcranial magnetic stimulation (rTMS) targeting the right cerebellum. Using dynamic community detection, we uncover the dynamic network properties by which cerebellar stimulation spreads through the cortex, inspecting the evolution of modular network structures prior to and after cerebellar stimulation. Our results indicate that: (1) flexibility, or the likelihood of network nodes to change module allegiances, increases post stimulation; (2) dynamic patterns in which module allegiances emerge and evolve are individualistic and do not follow a single functional prototype; and (3) cerebellar nodes play the role of integrators for distinct network modules. These results suggest that the cerebellum plays a pivotal role in modulating distributed cortical activity, seamlessly integrating and segregating information beyond motor control. This integrative capacity may underlie the cerebellums contributions to high-level cognitive functions and, more broadly, to the foundation of human intelligence.

neuroscience↗

bioRxiv2024

Investigating the effects of transcutaneous Vagus Nerve Stimulation on motor cortex excitability and inhibition through paired-pulse Transcranial Magnetic Stimulation

Transcutaneous Vagus Nerve stimulation (tVNS) has been proposed as a prospective treatment for clinical conditions with altered GABAergic transmission. While possible effects of tVNS on behavioral performance in inhibitory control tasks have been previously reported, neurophysiological evidence showing its effects on GABA-mediated inhibition in the motor cortex is limited. Concurrently, the possible influence of participants gender and state conditions remains unexplored. Here, we applied, single- and paired-pulse TMS to the right or the left primary motor in two different groups of participants. We measured corticospinal excitability (CSE), short and long intracortical inhibition (SICI and LICI), cortical silent period (cSP) and intracortical facilitation (ICF) indexes. The measures were taken, in separated sessions of a within-subject design, at baseline prior to tVNS and after delivering active and sham tVNS in the Cymba conchae of the left ear. To exploit state dependent effects and assess the role of tVNS in motor learning, tVNS was applied, during the execution of a computerized visuomotor task. In the left TMS group, we observed better visuomotor performance during active than sham tVNS, regardless of participants gender. Interestingly, in both groups, we found a specific increase of SICI, which is mediated by GABAa activity, after active compared to sham-tVNS and baseline evaluations, which was specifically limited to female participants. No effects on CSE, ICF or GABAb-mediated intracortical inhibition indexes were observed. The results show specific effects of tVNS on motor learning and GABAa-mediated motor inhibition, providing supportive evidence for the application of tVNS as an alternative and coadjuvant treatment for disorders featured by altered inhibition mechanisms.

neuroscience↗

bioRxiv2023

To touch or to be touched? Comparing pleasantness of vicarious execution and reception of interpersonal touch

Unmyelinated C-Tactile (CT) fibres are activated by caress-like touch, eliciting a pleasant feeling that decreases for static and faster stroking. Previous studies documented this effect also for vicarious touch, hypothesising mirror-neurons mechanisms driving the perception and appreciation of observed interpersonal touch. Notably, less is known about appreciation of vicarious execution of touch, that is as referred to the one giving gentle touch. To address this issue, 53 healthy participants were asked to view and rate a series of videoclips displaying an individual being touched by another on hairy (i.e., hand dorsum) or glabrous (i.e., palm) skin sites, with touch being delivered at CT-optimal (5 cm/s) or non-CT optimal velocities (0 cm/s or 30 cm/s). Following the observation of each clip, participants were asked to complete self- and other-directed ratings of the pleasantness of touch for both executer (toucher-referred) and receiver (touchee-referred). Consistent with the CT fibres properties, for both self- and other-directed judgements of touch execution and reception, participants provided higher ratings for touch delivered at CT-optimal than other velocities, and when CT-optimal touch was delivered to the hand-dorsum compared to the palm. However, higher ratings were attributed to reception compared to execution of CT-optimal touch. Notably, individual differences in interoceptive trusting and attitude to interpersonal touch were positively correlated with, respectively, toucher- and touchee-related overall pleasantness of touch. These findings suggest that the appreciation of both toucher- and touchee-referred vicarious touch is specifically attuned to CT-optimal touch, even though they might rely on different neurocognitive mechanisms to understand affective information conveyed by interpersonal tactile interactions.

neuroscience↗