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INTRODUCTION: Work-related traumatic brain injury is a frequent cause of chronic morbidity, mortality, and high treatment costs. Its causes are highly environmentally determined and were affected by COVID-19 pandemic lockdowns. OBJECTIVE: We aimed to describe traumatic brain injury (TBI) epidemiology in working population and evaluate its modifications during the COVID-19 pandemic. METHODS: We performed a 2-year retrospective epidemiological analysis of TBI patients hospitalized in a tertiary work-related hospital before and during the COVID-19 pandemic. RESULTS: In the prepandemic period, TBI patients were predominantly men, with a bimodal age distribution. Crash accidents were the leading work-related traumatic brain injury cause. During COVID-19 pandemic lockdowns, there was a positive correlation between street traffic and TBI rate, presenting increased motor crash accidents as a cause of TBI. CONCLUSIONS: These results are relevant for planning and focalization of resources for TBI prevention.

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Emotion-based decision making (EBDM) is the capacity to make decisions based on prior emotional consequences of actions. Several neuropsychological tasks, using different gambling paradigms and with different levels of complexity, have been designed to assess EBDM. The Bangor Gambling Task (BGT) was created as a brief and simple card gambling-task to assess EBDM. BGT contains a single-card deck and requires participants to decide whether to gamble or not, which can result in wins or losses. Unknown to the participant, the winning probabilities decrease throughout the task (from 0.75 in the first block to 0.25 in the fifth block), requiring participants to reduce their gambling probability to avoid long-term losses. A few studies have offered evidence regarding the BGT convergent validity. However, there are no computerized versions of BGT available, thus slowing the process of gathering information to explore the EBDM mechanisms behind the task, its validity, and clinical usefulness. In this article, we present a computerized version of the BGT using the Matlab environment and make all our code available. We explore BGT's replicability and analyze its probabilistic structure, providing trial-level and block-level analyses. Eighty-one participants performed the computerized version, which followed the same structure as the original version. It took participants 8.5 ± 3.3 minutes to complete the task, which is faster than the paper version. Replicating previous studies, participants diminished their gambling probability throughout the task, learning to inhibit the initially rewarded gambling behavior. This change in gambling probability could be considered a proxy for EBDM. Our analyses suggest that the last blocks are especially sensitive to capturing deficits in EBDM, and we propose some modifications to BGT's original version to enhance the initial exploratory and learning phase. Our results show that the BGT constitutes a quick and simple task to evaluate EBDM capacities.

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Social isolation can be a consequence of acquired brain injury (ABI). Few studies have examined the relationship between social isolation and mental health after ABI. In this cross-sectional and case-control study, we compared 51 ABI survivors and 51 matched healthy controls on measures of social isolation (network size, social support and loneliness) mental health and mental health problems. We explored the relationship between structural, functional and subjective components of social isolation and examined whether they were associated with mental health outcomes. No group differences were found on size of the network and perceived social support. The ABI group exhibited marginally higher levels of loneliness. The ABI group presented higher levels of depression, lower levels of quality of life and emotional wellbeing. In both groups, perception of social support was inversely related to subjective experience of loneliness. The relationship between network size and loneliness was only significant in the ABI group. Only loneliness significantly predicted quality of life, emotional wellbeing, depression and anxiety in people with brain injury. The relationship between social isolation variables in ABI is discussed, as well as the theoretical and clinical implications of focusing on loneliness to improve mental health after brain injury.

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Recent studies have shown that slow cortical potentials in archi-, paleo- and neocortex can phase-lock with nasal respiration. In some of these areas, gamma activity (γ: 30-100 Hz) is also coupled to the animal's respiration. It has been hypothesized that these functional relationships play a role in coordinating distributed neural activity. In a similar way, inter-cortical interactions at γ frequency have also been associated as a binding mechanism by which the brain generates temporary opportunities necessary for implementing cognitive functions. The aim of the present study is to explore whether nasal respiration entrains inter-cortical functional interactions at γ frequency during both wakefulness and sleep. Six adult cats chronically prepared for electrographic recordings were employed in this study. Our results show that during wakefulness, slow cortical respiratory potentials are present in the olfactory bulb and several areas of the neocortex. We also found that these areas exhibit cross-frequency coupling between respiratory phase and γ oscillation amplitude. We demonstrate that respiratory phase modulates the inter-cortical gamma coherence between neocortical electrode pairs. On the contrary, slow respiratory oscillation and γ cortical oscillatory entrainments disappear during non-rapid eye movement and rapid eye movement sleep. These results suggest that a single unified phenomenon involves cross-frequency coupling and long-range γ coherence across the neocortex. This fact could be related to the temporal binding process necessary for cognitive functions during wakefulness.

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Attention Deficit/Hyperactive Disorder (ADHD) is diagnosed based on observed behavioral outcomes alone. Given that some brain attentional networks involve circuits that control the eye pupil, we monitored pupil size in ADHD- diagnosed children and also in control children during a visuospatial working memory task. We present here the full dataset, consisting of pupil size time series for each trial and subject. There are data from, 22 control, and 28 ADHD-diagnosed children. There are also data from a subset of 17 ADHD children that performed the task twice, on- and off-medication. In addition, our dataset also includes gaze position data from each trial and subject, and also scores from the Weschler Intelligence Scale for Children. In this context, the dataset can serve as a resource to analyze dynamic eye movement and pupil changes as a function of known behavioral changes and scores in neuropsychological tests, which reflect neurocognitive processing.

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OBJECTIVE: The P300 component of a sensory event-related potential is one of the major electrophysiological markers used to explore remnants of cognitive function in patients with disorders of consciousness (DoC). However, measuring the P300 in patients is complicated by significant inter-trial variability commonly observed in levels of arousal and awareness. To overcome this limitation, we analyzed single-trial modulation of power in the delta and theta frequency bands, which underlie the P300. METHODS: In a preliminary cross-sectional study using a 24-channel EEG and a passive own-name oddball paradigm, we analyzed event-related synchronization (ERS) across trials in the delta and theta bands in a sample of 10 control and 12 DoC subjects. RESULTS: In comparison to controls, DoC subjects presented a low percentage of trials where delta ERS was observed. In particular, coordinated modulation between delta and theta in response to the stimulus was absent, with a high percentage of trials where only theta ERS was observed. Further, we found a positive correlation between the percentage of epochs with delta ERS and the strength of the P300. CONCLUSIONS: Reduced modulation of spectral activity in the delta band in response to stimuli indicates a dissociation in the activity of the neural networks that oscillate in delta and theta ranges and contribute to the generation of the P300. SIGNIFICANCE: The reduction in spectral modulation observed in DoC provides a deeper understanding of neurophysiological dysfunction and the means to develop a more fine-grained marker of residual cognitive function in individual patients.

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An important unresolved question about neural processing is the mechanism by which distant brain areas coordinate their activities and relate their local processing to global neural events. A potential candidate for the local-global integration are slow rhythms such as respiration. In this study, we asked if there are modulations of local cortical processing that are phase-locked to (peripheral) sensory-motor exploratory rhythms. We studied rats on an elevated platform where they would spontaneously display exploratory and rest behaviors. Concurrent with behavior, we monitored whisking through electromyography and the respiratory rhythm from the olfactory bulb (OB) local field potential (LFP). We also recorded LFPs from dorsal hippocampus, primary motor cortex, primary somatosensory cortex, and primary visual cortex. We defined exploration as simultaneous whisking and sniffing above 5 Hz and found that this activity peaked at ~8 Hz. We considered rest as the absence of whisking and sniffing, and in this case, respiration occurred at ~3 Hz. We found a consistent shift across all areas toward these rhythm peaks accompanying behavioral changes. We also found, across areas, that LFP gamma (70-100 Hz) amplitude could phase-lock to the animal's OB respiratory rhythm, a finding indicative of respiration-locked changes in local processing. In a subset of animals, we also recorded the hippocampal theta activity and found that occurred at frequencies overlapped with respiration but was not spectrally coherent with it, suggesting a different oscillator. Our results are consistent with the notion of respiration as a binder or integrator of activity between brain regions.

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Recently, a novel type of fast cortical oscillatory activity that occurs between 110 and 160 Hz (high-frequency oscillations (HFO)) was described. HFO are modulated by the theta rhythm in hippocampus and neocortex during active wakefulness and REM sleep. As theta-HFO coupling increases during REM, a role for HFO in memory consolidation has been proposed. However, global properties such as the cortex-wide topographic distribution and the cortico-cortical coherence remain unknown. In this study, we recorded the electroencephalogram during sleep and wakefulness in the rat and analyzed the spatial extent of the HFO band power and coherence. We confirmed that the HFO amplitude is phase-locked to theta oscillations and is modified by behavioral states. During active wakefulness, HFO power was relatively higher in the neocortex and olfactory bulb compared to sleep. HFO power decreased during non-REM and had an intermediate level during REM sleep. Furthermore, coherence was larger during active wakefulness than non-REM, while REM showed a complex pattern in which coherence increased only in intra and decreased in inter-hemispheric combination of electrodes. This coherence pattern is different from gamma (30-100 Hz) coherence, which is reduced during REM sleep. This data show an important HFO cortico-cortical dialog during active wakefulness even when the level of theta comodulation is lower than in REM. In contrast, during REM, this dialog is highly modulated by theta and restricted to intra-hemispheric medial-posterior cortical regions. Further studies combining behavior, electrophysiology and new analytical tools are needed to plunge deeper into the functional significance of the HFO.

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