Biology subjects

Colombari, E.

Publications and source records attributed to Colombari, E..

3 recordsLinked to original sources

bioRxiv2024

The role of extra-striate areas in conscious motor behavior: a registered report with Fast-Optical Imaging

Disclosing the brain areas responsible for the emergence of visual awareness and their timing of activation represents one of the major challenges in consciousness research. In particular, isolating the neural processes strictly related to consciousness from concurrent neural dynamics either related to prerequisites or post-perceptual processing has long engaged consciousness research. In this framework, the present study aims at unravelling the spatio-temporal dynamics underlying conscious vision by adopting a distinctive experimental design in which both awareness and motor response are manipulated, allowing the segregation of neural activity strictly related to awareness from response-related mechanisms. To this aim, we will employ a GO/NOGO detection task, in which participants will respond or withhold responding according to the experimental condition. Critically, during the performance of the task, participants brain activity will be recorded by means of Event-Related Optical Signal (EROS) technique, which provides accurate information about brain functions both from the temporal and spatial point of view, simultaneously. The combination of this experimental design with EROS recording will enable us to pinpoint the neural correlates underlying conscious vision and to disentangle them from processes related to the response. In addition, by coupling conventional EROS analysis with Granger Causality analysis, we will be able to clarify the potential interplay between consciousness-related extra-striate areas and response-related motor areas.

neuroscience↗

bioRxiv2023

Multiple independent components contribute to event-related potential correlates of conscious vision

Research has revealed two major event-related potential (ERP) markers of visual awareness: the earlier Visual Awareness Negativity (VAN, around 150-250 ms after stimulus onset), and the following Late Positivity (LP, around 300-500 ms after stimulus onset). Understanding the neural sources that give rise to VAN and LP is important in order to understand what kind of neural processes enable conscious visual perception. Although the ERPs afford high temporal resolution, their spatial resolution is limited because multiple separate sources sum up at the scalp level. In the present study, we sought to characterize the locations and time-courses of independent neural sources underlying the ERP correlates of visual awareness by means of Independent Component Analysis (ICA). ICA allows identifying and localizing the temporal dynamics of different neural sources that contribute to the ERP correlates of conscious perception. The present results show that while LP reflects a combination of multiple sources distributed among frontal, parietal and occipito-temporal cortex, the sources of VAN are localized to posterior areas including occipital and temporal cortex. In addition, our analysis reveals that activity in very early sources (roughly -100-100 ms after stimulus onset) in temporal and fronto-parietal cortices correlates with conscious vision.

neuroscience↗

bioRxiv2021

The Carotid Body Detects Circulating Tumor Necrosis Factor-Alpha to Activate a Sympathetic Anti-Inflammatory Reflex

Recent evidence has suggested that the carotid bodies might act as immunological sensors, detecting pro-inflammatory mediators and signalling to the central nervous system, which, in turn, orchestrates autonomic responses. Here, we demonstrated that the TNF- receptor type I is expressed in the carotid bodies of rats. The systemic administration of TNF- increased carotid body afferent discharge and activated glutamatergic neurons in the nucleus tractus solitarius (NTS) that project to the rostral ventrolateral medulla (RVLM), where the majority of pre-sympathetic neurons reside. The activation of these neurons was accompanied by generalized activation of the sympathetic nervous system. Carotid body ablation blunted the TNF--induced activation of RVLM-projecting NTS neurons and the increase in splanchnic sympathetic nerve activity. Finally, plasma and spleen levels of cytokines after TNF- administration were higher in rats subjected to either carotid body ablation or splanchnic sympathetic denervation. Collectively, our findings indicate that the carotid body detects circulating TNF- to activate a counteracting sympathetic anti-inflammatory mechanism.

neuroscience↗