Biology subjects

Perrone-Bertolotti, M.

Publications and source records attributed to Perrone-Bertolotti, M..

8 recordsLinked to original sources

bioRxiv2025

Multiple task-demands flexibly optimize neural geometry in human ventral temporal cortex

A hallmark of human intelligence is the ability to perform multiple tasks immediately upon instruction. Yet, the neural processes that implement such flexibility remain unclear. Using intracranial electrophysiology in epilepsy patients, we examined how representational geometries evolve as participants switched among three tasks - individuation, categorization, and conceptualization - on a trial-by-trial basis. Although tasks differed in the required representational geometries, neural representations across cortex were not immediately optimized following task cues. Instead, task-tailored geometries emerged gradually over successive stimulus repetitions within a trial. Ventral temporal cortex was the only region to exhibit task-specific adjustments for all three tasks, dynamically transforming within- and between-category distances in line with task demands. Importantly, these gradual representational changes were behaviorally relevant, predicting trial-level performance. Our results show that behavioral flexibility is supported by incremental, task-dependent refinement of representational geometry already within sensory cortex - far earlier in the processing hierarchy than previously thought.

neuroscience↗

bioRxiv2025

Neural activation down to the spinal cord during action language? A transcranial magnetic stimulation and peripheral nerve stimulation study.

Language comprehension is increasingly recognized as extending beyond the traditional linguistic system to engage motor and perceptual processes. This perspective is supported by numerous studies demonstrating that understanding action-related words often induces behavioral and neurophysiological changes in the motor system. However, it remains unclear whether the influence of action language on the motor system is restricted to cortical regions, or whether it also extends to spinal structures, as observed during motor imagery. To address this, we used transcranial magnetic stimulation and peripheral nerve stimulation to assess corticospinal excitability and cortico-motoneuronal transmission, respectively. Fifteen healthy and right-handed volunteers participated in four conditions: (i) rest, (ii) kinesthetic motor imagery of finger and wrist flexion, (iii) reading action sentences, and (iv) reading non-action sentences. As anticipated, corticospinal excitability increased during both kinesthetic motor imagery and action reading compared to rest. Interestingly, while kinesthetic motor imagery also led to the expected increase in cortico-motoneuronal transmission, no such modulation occurred during action reading. These findings suggest that action reading do not modulate the excitability of high-threshold motoneurons at the spinal level, contrary to motor imagery. Further investigation is needed to test whether action reading activate lower-threshold spinal structures, such as interneurons involved in spinal pre-synaptic inhibition.

neuroscience↗

bioRxiv2025

Reading about sensations recruits the posterior insula: An intracranial EEG study

When we read, how do words and sentences become concepts? Contrary to theoretical perspectives that conceptualize meaning and concepts as symbolic and abstract, embodied approaches propose that semantic access relies on mental simulations of bodily experiences□associated with the word’s meaning (e.g., simulating the act of running when we read the word ‘run’ or feeling pain when reading the word ‘burn’). If this view of cognition underpins conceptual processing, then sensory and motor cortices should play an early role during language comprehension. To test this idea, we recorded intracranial neural activity (High-Frequency Activity, 50–150 Hz) in epileptic patients while they read short sentences from different semantic categories: abstract-, action- and sensation-related. We hypothesized that reading sensation-related sentences (e.g., “he burns me”) would preferentially involve the posterior insula — a key region for processing affective and painful sensations. Our results, revealed an early functional dissociation between the anterior and posterior insula: the anterior insula showed a non-selective response across all semantic categories, whereas the posterior insula presented an early selective response (around 170 ms) for the sensation-related ones. Furthermore, the intensity of this selective neural response in the posterior insula correlated with the intensity of subjective perceived pain. These results provide direct intracranial evidence suggesting that language is deeply rooted in body-environment interactions.

neuroscience↗

bioRxiv2023

Local field potentials in human motor and non-motor brain areas encode the direction of upcoming movements: An intracerebral EEG classification study

Limb movement direction can be inferred from motor cortex activity. In humans, such decoding has been predominantly demonstrated using the spectral power of electrophysiological signals recorded in sensorimotor areas during movement execution. Yet, it remains unclear to what extent intended hand movement direction can be predicted from brain signals recorded during movement planning. Furthermore, whether other oscillatory features beyond power are also involved in direction encoding is not fully understood. Here, we set out to probe the directional-tuning of oscillatory phase, amplitude and Phase-Amplitude Coupling (PAC) during motor planning and execution, using a machine learning framework on multi-site local field potentials (LFPs) in humans. To this end, we recorded intracranial EEG data from implanted epilepsy patients as they performed a four-direction delayed center-out motor task. We found that LFP power significantly predicted hand-movement direction at execution but also during planning. While successful classification during planning primarily involved low-frequency power in a fronto-parietal circuit, decoding during execution was largely mediated by higher frequency activity in motor and premotor areas. Interestingly, LFP phase at very low frequencies (<1.5 Hz) led to significant decoding in premotor brain regions during execution. The machine learning framework also showed PAC to be uniformly modulated across directions through the task. Cross-temporal generalization analyses revealed that several stable brain patterns in prefrontal and premotor brain regions encode directions across both planning and execution. Finally, multivariate classification led to an increase in overall decoding accuracy (>80%) during both planning and execution. The novel insights revealed here extend our understanding of the role of neural oscillations in encoding motor plans.

neuroscience↗

bioRxiv2022

Unraveling the functional attributes of the language connectome: crucial subnetworks, flexibility and variability.

Language processing is a highly integrative function, intertwining linguistic operations (processing the language code intentionally used for communication) and extra-linguistic processes (e.g., attention monitoring, predictive inference, long-term memory). This synergetic cognitive architecture requires a distributed and specialized neural substrate. Brain systems have mostly been examined at rest. However, task-related functional connectivity provides additional and valuable information about how information is processed when various cognitive states are involved. We gathered thirteen language fMRI tasks in a unique database of one hundred and fifty neurotypical adults (InLang database). The tasks were designed to assess a wide range of linguistic processes and subprocesses. From this database, we applied network theory as a computational tool to model the task-related functional connectome of language (LANG). The organization of this data-driven neurocognitive atlas of language is examined at multiple levels, uncovering its major components (or crucial subnetworks) and its anatomical and functional correlates. Furthermore, we estimate its reconfiguration as a function of linguistic demand (flexibility), or several factors such as age or gender (variability). By accounting for the multifaceted nature of language and modulating factors, this study can contribute to enrich and refine existing neurocognitive models of language. The LANG atlas can also be considered as a reference for comparative or clinical studies, involving a variety of patients and conditions.

neuroscience↗

bioRxiv2019

Interactive mapping of language and memory with the GE2REC protocol

Previous studies have highlighted the importance of considering cognitive functions in a dynamic and interactive perspective and multiple evidence was brought for a language and memory interaction. In this study performed in healthy participants, we developed a new protocol entitled GE2REC that interactively accesses the neural representation of language-and-memory network. This protocol consists of three runs related to each other, providing a link between tasks, in order to assure an interactive measure of linguistic and episodic memory processes. GE2REC consists of a sentence generation (GE) in auditory modality and two recollecting (2REC) memory tasks, one recognition performed in visual modality, and another one recall performed in auditory modality. Its efficiency was evaluated in 20 healthy volunteers using a 3T MR imager. Our results corroborate the ability of GE2REC to robustly activate a fronto-temporo-parietal language network as well as temporal mesial, prefrontal and parietal cortices during encoding and recognition. GE2REC is useful because: (a) requires simultaneous and interactive language-and-memory processes and jointly maps their neural basis; (b) explores encoding and retrieval, managing to elicit activation of mesial temporal structures; (c) is short and easy to perform, hence being suitable for more restrictive settings, and (d) has an ecological dimension of tasks and stimuli. Overall, GE2REC can provide valuable information in terms of the practical foundation of exploration language and memory interconnection.

neuroscience↗

bioRxiv2019

FRONTAL MIDLINE THETA REFLECTS COGNITIVE CONTROL DURING PLANNING.

Neural correlates of cognitive planning are not understood well at present. Behavioral paradigms targeting this function are a current challenge in cognitive neuroscience. We recorded EEG activity while subjects were performing a novel behavioral paradigm that evaluates cognitive planning function. Participants showed longer reaction times and decreased accuracy during the planning condition compared to the control condition, suggesting that the planning condition is more time consuming, therefore reflecting higher cognitive demand. Moreover, cognitive planning induced a frontal midline theta (FM{theta}) frequency band originating in prefrontal cortex (PFC) as shown in previous cognitive control studies. When subjects began planning, there was a progressive and sustained increase in FM{theta} starting after 500 milliseconds (ms) of planning. Hence, we characterized for first time, both spatial and temporal FM{theta} dynamics of cognitive planning as a marker of cognitive control function.

neuroscience↗

bioRxiv2018

BLAST : a short computerized test to measure the ability to stay on task. Normative behavioral data and detailed cortical dynamics.

1.This article provides an exhaustive description of a new short computerized test to assess on a second-to-second basis the ability of individuals to << stay on task >>, that is, to apply selectively and repeatedly task-relevant cognitive processes. The task (Bron/Lyon Attention Stability Test, or BLAST) lasts around one minute, and measures repeatedly the time to find a target letter in a two-by-two letter array, with an update of all letters every new trial across thirty trials. Several innovative psychometric measures of attention stability are proposed based on the instantaneous fluctuations of reaction times throughout the task, and normative data stratified over a wide range of age are provided by a large (>6000) dataset of participants aged 8 to 70. We also detail the large-scale brain dynamics supporting the task from an in-depth study of 32 participants with direct electrophysiological cortical recordings (intracranial EEG) to prove that BLAST involves critically large-scale executive attention networks, with a marked activation of the dorsal attention network and a deactivation of the default-mode network. Accordingly, we show that BLAST performance correlates with scores established by ADHD-questionnaires.

neuroscience↗