Biology subjects

Huepe, D.

Publications and source records attributed to Huepe, D..

5 recordsLinked to original sources

bioRxiv2024

Cardiometabolic state links neurovascular burden with brain structure and function across age: evidence from EEG and MRI

Aging affects brain structure and function alongside metabolic and vascular processes leading to energetic impairments. While local neurometabolic dysfunction in aging is well-documented, the influence of systemic cardiometabolic and vascular markers on brain structure and function remains less understood. We examine the link between cardiometabolic dysfunction (measured by an allostatic load index) and neurovascular burden (measured by white matter hyperintensities) with brain changes, including ventricular and hippocampal volume, as well as EEG activity, across age. Analyzing data from 196 healthy individuals across age (20-75 years), we found a significant positive correlation between allostatic load index and white-matter hyperintensities, irrespective of age. White-matter hyperintensities are also positively linked with ventricular enlargement, but not hippocampal atrophy. The allostatic load index mediated the relationship between white-matter hyperintensities and ventricular volume. Regarding brain function, changes in the spectral aperiodic exponent but not periodic alpha power were linked to white-matter hyperintensities and the allostatic load index. Such index mediated the relationship between spectral aperiodic exponent and white-matter hyperintensities. Thus, findings suggest that the cardiometabolic state, as measured by an allostatic load index, plays a crucial role in brain health across age, particularly influencing ventricular enlargement and increased aperiodic activity.

neuroscience↗

bioRxiv2023

Slow-wave brain connectivity predicts executive functioning and group belonging in socially vulnerable individuals

Important efforts have been made to describe the neural and cognitive features of healthy and clinical populations. However, the neural and cognitive features of socially vulnerable individuals remain largely unexplored, despite their proneness to developing neurocognitive disorders. Socially vulnerable individuals can be characterised as socially deprived, having a low socioeconomic status, suffering from chronic social stress, and exhibiting poor social adaptation. While it is known that such individuals are likely to perform worse than their peers on executive function tasks, studies on healthy but socially vulnerable groups are lacking. In the current study, we explore whether neural power and connectivity signatures can characterise executive function performance in healthy but socially vulnerable individuals, shedding light on the impairing effects that chronic stress and social disadvantages have on cognition. We measured resting-state electroencephalography and executive functioning in 38 socially vulnerable participants and 38 matched control participants. Our findings indicate that while neural power was uninformative, lower delta and theta phase synchrony are associated with worse executive function performance in all participants, whereas delta phase synchrony is higher in the socially vulnerable group compared to the control group. Finally, we found that delta phase synchrony and years of schooling are the best predictors for belonging to the socially vulnerable group. Overall, these findings suggest that exposure to chronic stress due to socioeconomic factors and a lack of education are associated with changes in slow-wave neural connectivity and executive functioning.

neuroscience↗

bioRxiv2023

Neural and behavioural dynamics of the individual and collective self(s)

Usually considered as internal representations of self-concepts, the individual-self and the collective-self have been primarily studied in social and personality psychology while the experimental and theoretical advances of the cognitive and neurophysiological mechanisms of these self-representations are poorly understood. Two competing hypotheses emerge to understand their structure: first, each self-representation corresponds to a specific and independent dimension of self-concept and is therefore conceptualized as separate cognitive components and different brain networks are predicted; and second, both "selfs", collective and individual, are part of the same structure and interdependent, sharing similar networks and showing a hierarchical organization from a core-self. Both perspectives have some support from current theories in social psychology but are still speculative and faintly supported by empirical evidence. To test this, we designed an experiment using sentences that would activate the individual or collective-self representations in 80 healthy right-handed participants. We use reaction times during a decision-making task, in combination with individualism/collectivism scales and characterize the neural dynamics throughout the experiment using event-related potentials and fronto-parietal informational connectivity networks. Participants reacted slower to the collective than individual self conditions and showed differences in neural activity and information Integration level that distinguished between each type of self. More importantly, the neural integration measure representing the core-self (subtraction between individual and collective wSMI) was only associated with the individualism scores but not collectivism, lending further support for the core-self perspective. We interpret that the collective self, in the broader sense, is a part of the self-concept and therefore probably assembled from the core-self.

animal behavior and cognition↗

bioRxiv2021

Hypnotic visual hallucination induces greater lateralised brain activity than visual imagery

Hypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. Here we used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.

neuroscience↗

bioRxiv2019

In your phase! Neural phase synchronization underlies visual imagery of faces

Mental imagery is the process through which we retrieve and recombine information from our memory to elicit the subjective impression of "seeing with the minds eye". In the social domain, we imagine other individuals while recalling our encounters with them or modelling alternative social interactions in future. Many studies using imaging and neurophysiological techniques have shown several similarities in brain activity between visual imagery and visual perception, and have identified frontoparietal, occipital and temporal neural components of visual imagery. However, the neural connectivity between these regions during visual imagery of socially relevant stimuli have not been studied. Here we used electroencephalography to investigate neural connectivity and its dynamics between frontal, parietal, occipital and temporal electrodes during visual imagery of faces. We found that voluntary visual imagery of faces is associated with long-range phase synchronisation in the gamma frequency range between frontoparietal electrode pairs and between occipitoparietal electrode pairs. In contrast, no effect of imagery was observed in the connectivity between occipitotemporal electrode pairs. Gamma range synchronisation between occipitoparietal electrode pairs predicted subjective ratings of the contour definition of imagined faces. Furthermore, we found that visual imagery of faces is associated with an increase of short-range frontal synchronisation in the theta frequency range, which temporally preceded the long-range increase in the gamma synchronisation. We speculate that the local frontal synchrony in the theta frequency range might be associated with an effortful top-down mnemonic reactivation of faces. In contrast, the long-range connectivity in the gamma frequency range along the fronto-parieto-occipital axis might be related to the endogenous binding and subjective clarity of facial visual features.

neuroscience↗