A Dose Relationship Between Brain Functional Connectivity and Cumulative Head Impact Exposure in Collegiate Water Polo Players.

A growing body of evidence suggests that chronic, sport-related head impact exposure can impair brain functional integration and brain structure and function. Evidence of a robust inverse relationship between the frequency and magnitude of repeated head impacts and disturbed brain network function is needed to strengthen an argument for causality. In pursuing such a relationship, we used cap-worn inertial sensors to measure the frequency and magnitude of head impacts sustained by eighteen intercollegiate water polo athletes monitored over a single season of play. Participants were evaluated before and after the season using computerized cognitive tests of inhibitory control and resting electroencephalography. Greater head impact exposure was associated with increased phase synchrony [r (16) > 0.626, p < 0.03 corrected], global efficiency [r (16) > 0.601, p < 0.04 corrected], and mean clustering coefficient [r (16) > 0.625, p < 0.03 corrected] in the functional networks formed by slow-wave (delta, theta) oscillations. Head impact exposure was not associated with changes in performance on the inhibitory control tasks. However, those with the greatest impact exposure showed an association between changes in resting-state connectivity and a dissociation between performance on the tasks after the season [r (16) = 0.481, p = 0.043] that could also be attributed to increased slow-wave synchrony [F (4, 135) = 113.546, p < 0.001]. Collectively, our results suggest that athletes sustaining the greatest head impact exposure exhibited changes in whole-brain functional connectivity that were associated with altered information processing and inhibitory control

Fostering advances to neuropsychological assessment based on the Research Domain Criteria: The bridge between cognitive functioning and physiology

Objectives: The current review aimed to explore the advances in neuropsychological assessment in light of a recent research framework designed to improve our knowledge on mental health – the Research Domain Criteria (RDoC). Methods: RDoC proposals on neuropsychological tests were reviewed across the RDoC cognitive systems domain. The focus is on the physiological unit of analysis and the potential applications are illustrated given the functional relevance of RDoC constructs to psychopathological and neurological conditions. Results: The advances in neuropsychology anchored in RDoC are not observable in terms of innovative paradigms, but rather in the neurobiological correlates that may be obtained from the classical neuropsychological tasks. The behavior unit of analysis may be integrated with physiological outcomes while mapping distinct cognitive constructs simultaneously. Conclusions: Under the aegis of RDoC, the integration of multiple levels of analysis allows to obtain a more detailed and complete neuropsychological characterization with high potential to be translated into better intervention strategies.info:eu-repo/semantics/publishedVersio

Discriminative power of EEG-based biomarkers in major depressive disorder: A systematic review

Currently, the diagnosis of major depressive disorder (MDD) and its subtypes is mainly based on subjective assessments and self-reported measures. However, objective criteria as Electroencephalography (EEG) features would be helpful in detecting depressive states at early stages to prevent the worsening of the symptoms. Scientific community has widely investigated the effectiveness of EEG-based measures to discriminate between depressed and healthy subjects, with the aim to better understand the mechanisms behind the disorder and find biomarkers useful for diagnosis. This work offers a comprehensive review of the extant literature concerning the EEG-based biomarkers for MDD and its subtypes, and identify possible future directions for this line of research. Scopus, PubMed and Web of Science databases were researched following PRISMA’s guidelines. The initial papers’ screening was based on titles and abstracts; then full texts of the identified articles were examined, and a synthesis of findings was developed using tables and thematic analysis. After screening 1871 articles, 76 studies were identified as relevant and included in the systematic review. Reviewed markers include EEG frequency bands power, EEG asymmetry, ERP components, non-linear and functional connectivity measures. Results were discussed in relations to the different EEG measures assessed in the studies. Findings confirmed the effectiveness of those measures in discriminating between healthy and depressed subjects. However, the review highlights that the causal link between EEG measures and depressive subtypes needs to be further investigated and points out that some methodological issues need to be solved to enhance future research in this field

Identifying Abnormal Connectivity in Patients Using Dynamic Causal Modeling of fMRI Responses

Functional imaging studies of brain damaged patients offer a unique opportunity to understand how sensorimotor and cognitive tasks can be carried out when parts of the neural system that support normal performance are no longer available. In addition to knowing which regions a patient activates, we also need to know how these regions interact with one another, and how these inter-regional interactions deviate from normal. Dynamic causal modeling (DCM) offers the opportunity to assess task-dependent interactions within a set of regions. Here we review its use in patients when the question of interest concerns the characterization of abnormal connectivity for a given pathology. We describe the currently available implementations of DCM for fMRI responses, varying from the deterministic bilinear models with one-state equation to the stochastic non-linear models with two-state equations. We also highlight the importance of the new Bayesian model selection and averaging tools that allow different plausible models to be compared at the single subject and group level. These procedures allow inferences to be made at different levels of model selection, from features (model families) to connectivity parameters. Following a critical review of previous DCM studies that investigated abnormal connectivity we propose a systematic procedure that will ensure more flexibility and efficiency when using DCM in patients. Finally, some practical and methodological issues crucial for interpreting or generalizing DCM findings in patients are discussed

Sleep and Emotion Processing in Individuals with Insomnia Symptoms and Good Sleepers

Despite complaints of deficits in waking socioemotional functioning by individuals with insomnia, only a few studies have investigated waking emotion processing performance in this group. Additionally, the role of sleep in socioemotional processing has not been investigated using quantitative measures of sleep. The thesis investigated sleep and behavioural processing of emotionally expressive faces in individuals with insomnia symptoms (n=14) compared to healthy, good sleepers (n=15). The primary aim was to investigate the degree to which sleep predicted emotion processing. Participants completed two nights of at-home polysomnography-recorded sleep, and sleep diaries, which was followed by an afternoon of in-lab performance testing on tasks measuring processing of emotional facial expressions with an emotional Stroop task and a face categorization and intensity rating task. The insomnia group reported less total sleep time on their diary but no other differences in subjective or objective sleep were observed. No behavioural differences in emotion processing were observed overall. Post-hoc analysis of the individuals with insomnia symptoms that had a poor night of sleep on the night prior to performance assessment (n=8) revealed that a poor night of sleep in insomnia was associated with reduced time in Stage 2, REM and NREM sleep, and, there was trending support for elevated Sigma and Beta activity throughout the night as well as performance deficits for identifying emotional face expressions. For individuals with insomnia symptoms, greater levels of Beta EEG activity throughout sleep was associated with greater intensity ratings of happy, fearful, and sad faces. In conclusion, the thesis identified that the hyperarousal phenomenon in insomnia was related to altered waking salience assessments and gives promise for a new stream of research that investigates the relationship between hyperarousal in sleep and waking emotion functioning in insomnia

Neuropsychological Correlates of Chronic Pain: The Influence of Anxious Arousal on Cognitive Control

The present set of studies assessed the relation between neural, psychological, and cognitive mechanisms that have been shown to influence the experience of chronic pain. Specifically, Studies One and Two advanced our understanding of chronic pain by illustrating its unique relationship with anxious arousal and frontal neural activity on inhibitory control difficulties. Study Three focuses on targeting how anxious arousal is distinctly associated with neural correlates of inhibitory control in order to provide a framework that can be applied to individuals experiencing chronic pain. Together, these studies aim to inform the development of evidenced-based interventions that target anxious arousal in order to enhance the effectiveness of chronic pain management. Overall, the findings from this set of studies highlighted the cross-sectional relation between EF, psychological symptoms, and neural mechanisms and specifically distinguished the importance of anxious arousal, inhibitory control, and neural mechanisms measured with EEG (i.e., frontal alpha and beta) and ERP (N200, N450, Conflict SP) methodologies

Cognitive and Neural Correlates of Coping and Resilience in Depression

Depression is one of the most prevalent and devastating psychological disorders, often with a chronic or remitting/reoccurring course. The inability to effectively cope with stress and negative life events has been strongly linked to the development and maintenance of depression symptoms; yet, the cognitive and biological processes underlying the complex and multidimensional behavioral construct of coping are not well understood. Using a combination of self-report measures, computerized cognitive tasks, and scalp electroencephalography (EEG) methodologies, the present study investigated associations between specific executive function abilities (i.e., inhibition and set-shifting), underlying neural activity, coping strategy and flexibility, and depression symptoms. Results did not support the primary study hypotheses predicting coping to mediate the relation between executive dysfunction and depression symptoms. Post-hoc correlational analyses elucidated relations between various components of coping strategy and depression symptomatology, and further demonstrated associations with frontocentral N200/P300 and parietal P300 peak latencies

Investigating cortical arousal and cognition in schizophrenia and methamphetamine-induced psychotic disorder: an electroencephalography and cytokine study

Introduction: Schizophrenia (SCZ) and methamphetamine-induced psychotic disorder (MPD), are psychotic disorders characterized by positive symptoms (e.g., hallucinations and delusions), negative symptoms (e.g., social withdrawal, apathy), and impaired cognitive function. Despite the overlap in the clinical presentation of SCZ and MPD, no studies have compared electroencephalography (EEG) and inflammation across these two conditions. This study aimed to investigate key differences in brain electrical activity on EEG between SCZ and MPD by investigating; (1) relative frequency (alpha, theta, beta and delta) at rest; (2) cognitive performance and relative frequency activity during the continuous performance task (CPT) and cued target detection task (CTD); (3) differences in the P300 event-related potential waveform (ERP), a measure of attention, during the CPT and CTD; (4) cognitive performance and relative frequency and ERP (N170, P300) during the STROOP task, a measure of working memory and executive function; (5) the associations of (neuro) inflammatory markers with relative frequency and the P300 ERP waveform. Methods: 104 South African individuals, between the ages of 20 and 45 years, participated in this study: 69 outpatients (38 with SCZ (8 females/30 males), 31 with MPD (7 females/24 males)), and 35 healthy controls (CON: 15 females/20 males). All participants underwent a Structured Clinical Interview for Diagnostic Systematic Manual-IV (SCID-DSM-IV), with modifications to include changes made in DSM-5. EEG band frequency oscillations were recorded during baseline conditions: resting eyes open and resting eyes closed, and cognitive tasks (CPT, CTD and the Stroop task). Blood was drawn via venepuncture and serum was used for the analysis of cytokines (interleukin (IL) -1β IL-8, IL-10, IL-12p70, tumour necrosis factor-alpha and interferon-gamma (IFN-γ)) concentrations. Statistical analysis included assessment of normality using the Shapiro- Wilk test, with univariate one-way analysis of variance (ANOVA) of parametric data, and multiple independent Kruskal-Wallis ANOVA for non-parametric data (p