Biology subjects

Cattaneo, Z.

Publications and source records attributed to Cattaneo, Z..

5 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

The causal role of early visual cortex in vividness of visual imagery

While numerous studies have demonstrated objective accuracy in visual imagery tasks to involve the early visual cortex (V1/V2), the role of this region in imagery vividness remains unclear. We addressed this question by combining Transcranial Magnetic Stimulation (TMS) with a cross-adaptation paradigm in which visual adaptation modulates the ability to engage in visual imagery in the adapted part of the visual field. As previously shown, in the control (Vertex) condition, mental imagery accuracy was impaired when the mental image was generated in the adapted region of visual space. This effect was removed by TMS, indicating that the locus of adaptation was the early visual cortex. In contrast, analysis of vividness ratings (collected on trial-by-trial basis) showed no effects of adaptation, indicating that the imagery vividness is somewhat orthogonal to the fidelity of the mental image. The key finding was that TMS impacted vividness ratings on trials when participants performed incorrectly in the imagery task. Thus, the effects of TMS on accuracy and vividness were observed on different trial types: TMS impaired accuracy of trials associated with high baseline performance, but increased vividness on incorrect trials. Overall, our findings suggest that the early visual cortex plays a role in both accuracy and vividness of mental images, yet these processes are dissociable.

neuroscience↗

bioRxiv2024

Timing the cerebellum and its connectivity within the social brain

The posterior cerebellum is a recently discovered hub of the affective and social brain, with different subsectors contributing to different social functions. However, very little is known about when the posterior cerebellum plays a critical role in social processing. Due to its location and anatomy, it has been difficult to use traditional approaches to directly study the chronometry of the cerebellum. To address this gap in cerebellar knowledge, here we investigated for the first time the causal contribution of the posterior cerebellum to social processing using a chronometric transcranial magnetic stimulation (TMS) approach. We show that the posterior cerebellum is recruited at an early stage of the emotional processing (starting from 100 ms after stimulus onset), simultaneously with the posterior superior temporal sulcus (pSTS), a key node of the emotional-social brain. Moreover, using a condition-and-perturb TMS approach, we found that the recruitment of the pSTS in emotional processing is dependent on cerebellar activation. Our results are the first to shed light on chronometric aspects of cerebellar function and its causal connectivity with other nodes of the social brain.

neuroscience↗

bioRxiv2017

On mechanisms of Transcranial Magnetic Stimulation (TMS): How brain state and baseline performance level determine behavioral effects of TMS

The behavioral effects of Transcranial Magnetic Stimulation (TMS) can change qualitatively when stimulation is preceded by initial state manipulations such as priming or adaptation. In addition, baseline performance level of the participant has been shown to play a role in modulating the impact of TMS. Here we examined the link between these two. This was done using data from a previous study using a TMS-priming paradigm, in which, at group level, TMS selectively facilitated targets incongruent with the prime while having no statistically significant effects on other prime-target congruencies. Correlation and linear mixed-effects analyses indicated that, for all prime-target congruencies, a significant linear relationship between baseline performance and the magnitude of the induced TMS effect was present: low levels of baseline performance were associated with TMS-induced facilitations and high baseline performance with impairments. Thus as performance level increased, TMS effects turned from facilitation to impairment. The key finding was that priming shifted the transition from facilitatory to disruptive effects for targets incongruent with the prime, such that TMS-induced facilitations were obtained until a higher level of performance than for other prime-target congruencies. Given that brain state manipulations such as priming operate via modulations of neural excitability, this result is consistent with the view that neural excitability, coupled with nonlinear neural effects, underlie behavioral effects of TMS.

neuroscience↗

bioRxiv2017

Common framework for virtual lesion and state-dependent TMS: the facilitatory/suppressive range model of online TMS effects on behavior

The behavioral effects of Transcranial Magnetic Stimulation (TMS) are often nonlinear; factors such as stimulation intensity and brain state can modulate the impact of TMS on observable behavior in qualitatively different manner. Here we propose a theoretical framework to account for these effects. In this model, there are distinct intensity ranges for facilitatory and suppressive effects of TMS: low intensities facilitate neural activity and behavior whereas high intensities induce suppression. The key feature of the model is that these ranges are shifted by changes in neural excitability: consequently, a TMS intensity, which normally induces suppression, can have a facilitatory effect if the stimulated neurons are being inhibited. For example, adaptation reduces excitability of adapted neurons; the outcome is that TMS intensities which inhibit non-adapted neurons induce a facilitation on adapted neural representations, leading to reversal of adaptation effects. In conventional virtual lesion paradigms, similar effects occur because neurons not tuned to the target stimulus are inhibited. The resulting reduction in excitability can turn high intensity inhibitory TMS to low intensity facilitatory TMS for these neurons (whereas neurons tuned to the target stimulus are inhibited), leading to a reduction in signal-to-noise ratio. Thus differential excitability levels of neural populations contributing to behavior, combined with nonlinear neural effects, can explain how TMS modulates behavior.

neuroscience↗