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INTRODUCTION AND FRAMEWORK: Sleep capital contributes to individual and societal wellbeing, productivity, and economic outcomes and involves a novel aspect of brain capital. It encompasses the quality and quantity of sleep as integral components that influence cognitive abilities, mental and brain health, and physical health, affecting workplace productivity, learning, decision-making, and overall economic performance. Here, we bring a framework to understand the complex relationship between sleep quality, health, wellbeing, and economic productivity. Then we outline the multilevel impact of sleep on cognitive abilities, mental/brain health, and economic indicators, providing evidence for the substantial returns on investment in sleep health initiatives. Moreover, sleep capital is a key factor when considering brain health across the lifespan, especially for the aging population. DISCUSSION: We propose specific elements and main variables to develop specific indexes of sleep capital to address its impacts on health, wellbeing and productivity. CONCLUSION: Finally, we suggest policy recommendations, workplace interventions, and individual strategies to promote sleep health and brain capital. Investing in sleep capital is essential for fostering a healthier, happier, fairer and more productive society.
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The mediodorsal nucleus of the thalamus (MD), with its extensive connections to the lateral pFC, has been implicated in human working memory and executive functions. However, this understanding is based solely on indirect evidence from human lesion and imaging studies and animal studies. Direct, causal evidence from humans is missing. To obtain direct evidence for MD's role in humans, we studied patients treated with deep brain stimulation (DBS) for refractory epilepsy. This treatment is thought to prevent the generalization of a seizure by disrupting the functioning of the patient's anterior nuclei of the thalamus (ANT) with high-frequency electric stimulation. This structure is located superior and anterior to MD, and when the DBS lead is implanted in ANT, tip contacts of the lead typically penetrate through ANT into the adjoining MD. To study the role of MD in human executive functions and working memory, we periodically disrupted and recovered MD's function with high-frequency electric stimulation using DBS contacts reaching MD while participants performed a cognitive task engaging several aspects of executive functions. We hypothesized that the efficacy of executive functions, specifically working memory, is impaired when the functioning of MD is perturbed by high-frequency stimulation. Eight participants treated with ANT-DBS for refractory epilepsy performed a computer-based test of executive functions while DBS was repeatedly switched ON and OFF at MD and at the control location (ANT). In comparison to stimulation of the control location, when MD was stimulated, participants committed 2.26 times more errors in general (total errors; OR = 2.26, 95% CI [1.69, 3.01]) and 2.86 times more working memory-related errors specifically (incorrect button presses; OR = 2.88, CI [1.95, 4.24]). Similarly, participants committed 1.81 more errors in general ( OR = 1.81, CI [1.45, 2.24]) and 2.08 times more working memory-related errors ( OR = 2.08, CI [1.57, 2.75]) in comparison to no stimulation condition. "Total errors" is a composite score consisting of basic error types and was mostly driven by working memory-related errors. The facts that MD and a control location, ANT, are only few millimeters away from each other and that their stimulation produces very different results highlight the location-specific effect of DBS rather than regionally unspecific general effect. In conclusion, disrupting and recovering MD's function with high-frequency electric stimulation modulated participants' online working memory performance providing causal, in vivo evidence from humans for the role of MD in human working memory.
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Núcleo Mediodorsal do Tálamo/fisiologia , Memória de Curto Prazo/fisiologia , Adulto , Análise de Variância , Estimulação Encefálica Profunda , Epilepsia Resistente a Medicamentos/fisiopatologia , Epilepsia Resistente a Medicamentos/psicologia , Epilepsia Resistente a Medicamentos/terapia , Função Executiva/fisiologia , Feminino , Humanos , Modelos Logísticos , Masculino , Núcleo Mediodorsal do Tálamo/fisiopatologia , Atividade Motora/fisiologia , Testes Neuropsicológicos , Tempo de ReaçãoRESUMO
OBJECTIVE: To examine factors relating to return to work (RTW) following mild traumatic brain injury (mTBI). PARTICIPANTS: One hundred and nine patients (Age: M = 37.4 years, SD = 13.2; 52.3% women) who sustained an mTBI. DESIGN: Inception cohort design with questionnaires and neuropsychological testing completed approximately 3 to 4 weeks postinjury. SETTING: Emergency Department of Tampere University Hospital, Finland. MAIN OUTCOME MEASURES: Self-report (postconcussion symptoms, depression, fatigue, and general health) and neurocognitive measures (attention and memory). RESULTS: The cumulative RTW rates were as follows: 1 week = 46.8%, 2 weeks = 59.6%, 3 weeks = 67.0%, 4 weeks = 70.6%, 2 months = 91.7%, and 1 year = 97.2%. Four variables were significant predictors of the number of days to RTW: age, multiple bodily injuries, intracranial abnormality at the day of injury, and fatigue ratings (all P < .001). The largest amount of variance accounted for by these variables in the prediction of RTW was at 30 days following injury (P < .001, R = 0.504). Participants who returned to work fewer than 30 days after injury (n = 82, 75.2%) versus more than 30 days (n = 27, 24.8%) did not differ on demographic or neuropsychological variables. CONCLUSIONS: The vast majority of this cohort returned to work within 2 months. Predictors of slower RTW included age, multiple bodily injuries, intracranial abnormality at the day of injury, and fatigue.
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Lesões Encefálicas/epidemiologia , Retorno ao Trabalho , Adulto , Fatores Etários , Encéfalo/patologia , Estudos de Coortes , Fadiga/epidemiologia , Feminino , Finlândia/epidemiologia , Seguimentos , Humanos , Modelos Logísticos , Imageamento por Ressonância Magnética , Masculino , Traumatismo Múltiplo/epidemiologia , Testes Neuropsicológicos , Inquéritos e Questionários , Tomografia Computadorizada por Raios XRESUMO
Introduction: As burnout has become a global pandemic, there is a call for improved understanding and detection of alterations in brain functions related to it. We have previously reported challenges in executive functions (EFs) in daily life, especially in metacognition, in subjects with occupational burnout, along with alterations in cardiac physiology. In the current study, we focused on the impact of burnout on brain physiology during a task requiring EF. Methods: Fifty-four volunteers filled in inventories of burnout, depression, and EF in daily life (BBI-15, BDI, and BRIEF-A). Based on the BBI-15 score, subjects were divided into burnout and non-burnout groups. Subjects performed a Go/NoGo test (Executive RT test) engaging several EFs, while their EEG was recorded. The inventory scores, cognitive performance scores, and event-related potential (N2, P3) amplitudes, latencies, and interpeak latencies (IPLs) were compared between the groups. Results: There were significant differences in the BDI and BRIEF-A scores between the groups, with more symptoms of depression and challenges in daily life in the burnout group. There were no differences in objective performance measures in the EF task between the groups. However, centroparietal P3 amplitude was larger, and while there were no differences in N2 or P3 latencies, N2-P3 IPL was longer in the Go condition in the burnout than in non-burnout group. Both ERP measures correlated significantly with burnout symptoms. A regression model from centroparietal P3 amplitude and N2-P3 IPL predicted significantly both the BBI-15 score and the BRIEF-A metacognition index. Discussion: We conclude that burnout is linked with challenges in EF in daily life and alterations in the underlying neural processes. While cognitive performance in the task was equal, electrophysiological measures differed between the groups. Prolonged N2-P3 IPL points toward slowed transition from one cognitive process to another. Increased P3 amplitude, on the other hand, reflects increased allocation of neural processing resources. This may be a compensatory mechanism, allowing for equal performance with controls. These electrophysiological measures, obtained during the EF task, show promise as brain physiology-based biomarkers of burnout, contributing to its improved and objective detection. In addition, these results indicate occupational burnout is linked with objective alterations in brain physiology.
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OBJECTIVES: The purpose of this study was to examine the reliability, validity and clinical usefulness of the Barrow Neurological Institute Fatigue Scale (BNI-FS) in patients with mild traumatic brain injuries (MTBI). METHODS AND PROCEDURE: Participants were 125 patients enrolled from the Emergency Department (ED) of Tampere University Hospital, Finland who had sustained an MTBI. The average number of days from injury to the interview and questionnaires was 24.1 (SD = 5.4, Range = 8-38). The patients were compared to a healthy control sample. Patients completed the Barrow Neurological Institute Fatigue Scale, Fatigue Impact Scale (FIS), Beck Depression Inventory-Second Edition (BDI-II), Rivermead Post-concussion Symptom Questionnaire (RPSQ) and the health assessment measure EuroQol five Dimension (EQ-5D) Visual Analogue Scale (VAS). RESULTS: The MTBI group had significantly greater total scores on the BNI-FS than the control group (p < 0.005, Cohen's d = 0.40). The internal consistency reliability for the BNI-FS, as measured by Cronbach's alpha, was 0.96 for the MTBI group and 0.87 for the control group. The 10 items were submitted to an exploratory principal components factor analysis with varimax rotation in the MTBI group. A one-factor solution, accounting for 73.3% of the total variance, appropriately summarized the data. The correlation between the BNI-FS and other measures was rs = 0.68 (p < 0.001) for the BDI-II, rs = 0.68 (p < 0.001) for the RPSQ, rs = -0.39 (p < 0.001) for the EQ-5D VAS and rs = 0.84 (p < 0.001) for the FIS. Fatigue ratings correlated positively with number of days post-injury before returning to work (rs = 0.27, p < 0.006). CONCLUSION: The BNI-FS is a relatively new, brief and highly reliable measure of fatigue.
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Fadiga/diagnóstico , Síndrome Pós-Concussão/diagnóstico , Adolescente , Adulto , Fadiga/epidemiologia , Fadiga/fisiopatologia , Feminino , Finlândia/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Pós-Concussão/epidemiologia , Síndrome Pós-Concussão/fisiopatologia , Psicometria , Qualidade de Vida , Reprodutibilidade dos Testes , Autorrelato , Inquéritos e Questionários , Adulto JovemRESUMO
Burnout is becoming a global pandemic jeopardizing brain health, with a huge impact on quality of life, available workforce, and the economy. Knowledge of the impact of burnout on cognition, physiology, and physical activity (PA) in daily life allows for an improved understanding of the health consequences and everyday ramifications of burnout. Twenty-eight volunteers participated in a three-day recording of daily physiology and PA, including heart rate (HR) and daily steps, with a wearable device. They filled in questionnaires screening for burnout (BBI-15), depression (BDI), and executive functions (EFs) in daily life (BRIEF-A). The subjects with burnout had more challenges in EFs, higher average HRs and lower numbers of steps in daily life than those without it. The BBI-15 scores correlated positively with the BDI scores and BRIEF-A indices and negatively with the awake HR variability (HRV) and daily steps. The metacognition index correlated negatively with the HRV. In conclusion, burnout is linked with compromised EFs along with alterations in cardiac physiology and PA in daily life. Such alterations may be easily detected with wearable devices, opening possibilities for novel biomarkers of burnout and other neuropsychiatric disorders. We suggest that physical activity and heart and brain health are intimately intertwined and that burnout interacts with each of them bidirectionally.
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Hemispheric asymmetries in affective and cognitive functions have been extensively studied. While both cerebral hemispheres contribute to most affective and cognitive processes, neuroscientific literature and neuropsychological evidence support an overall right hemispheric dominance for emotion, attention and arousal. Emotional stimuli, especially those with survival value such as threat, tend to be prioritized in attentional resource competition. Arousing unpleasant emotional stimuli have prioritized access, especially to right-lateralized attention networks. Interference of task performance may be observed when limited resources are exhausted by task- and emotion-related processing. Tasks that rely on right hemisphere-dependent processing, like attending to the left visual hemifield or global-level visual features, are especially vulnerable to interference due to attention capture by unpleasant emotional stimuli. The aim of this review is to present literature regarding the special role of the right hemisphere in affective and attentional brain processes and their interaction. Furthermore, clinical and technological implications of this interaction will be presented. Initially, the effects of focal right hemisphere lesion or atrophy on emotional functions will be introduced. Neurological right hemisphere syndromes including aprosodia, anosognosia and neglect, which further point to the predominance of the intact right hemisphere in emotion, attention and arousal will be presented. Then there will be a brief review of electrophysiological evidence, as well as evidence from patients with neglect that support attention capture by emotional stimuli in the right hemisphere. Subsequently, experimental work on the interaction of emotion, attention and cognition in the right hemispheres of healthy subjects will be presented. Finally, clinical implications for better understanding and assessment of alterations in emotion-attention interaction due to brain disorder or treatment, such as neuromodulation, that impact affective brain functions will be discussed. It will be suggested that measuring right hemispheric emotion-attention interactions may provide basis for novel biomarkers of brain health. Such biomarkers allow for improved diagnostics in brain damage and disorders and optimized treatments. To conclude, future technological applications will be outlined regarding brain physiology-based measures that reflect engagement of the right hemisphere in affective and attentional processes.
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Background: Alterations in executive functions, emotion regulation, and their interaction are common concomitants of depression. Executive dysfunction frequently lingers after treatment, has adverse effects on daily life, and predisposes to recurrence of depression. Yet, sensitive measures of executive function for reliable assessment of cognitive outcomes are still lacking in clinical practice. To better understand the impact of depression and its most effective treatment, electroconvulsive therapy (ECT), on cognition, we assessed executive functions pre- and post-ECT and whether objective measures reflecting alterations in emotion-executive function interaction correlate with depression severity or with cognitive outcome. Methods: Executive functions were assessed in 21 patients with major depressive disorder (MDD) before and after ECT using subjective measures from the Behavior Rating Inventory of Executive Function-Adult version (BRIEF-A) and objective cognitive performance measures derived from computer-based test of executive function, Executive Reaction Time (RT) Test. In addition, we created novel indices reflecting emotional modulation of cognitive performance by subtracting different performance measures in the context of neutral distractors from those in the context of threat-related distractors. We correlated these indices with Beck Depression Inventory (BDI) and BRIEF-A scores. Results: Depression was significantly alleviated, and executive functions improved post-ECT, as seen in reduced BDI scores, BRIEF-A scores, and number of errors in Executive RT Test. Pre-ECT BDI scores correlated with threat modulation of RT (tmRT) and threat modulation of working memory (tmWM). Post-ECT tmRT correlated with several Behavioral Regulation scales and tmWM with several Metacognition scales of BRIEF-A. Conclusion: While caution is warranted, results from both subjective and objective measures suggest that ECT significantly improves executive functions and emotion regulation along with alleviation of depression. Novel indices derived from threat modulation of executive function and working memory show promise as objective biomarkers of depression severity pre-ECT and cognitive outcome post-ECT with potential for guiding depression treatments.
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Objective findings of brain injury or dysfunction are typically lacking in mild traumatic brain injury (MTBI) despite prolonged post-concussion symptoms in some patients. Thus, there is a need for objective biomarkers of MTBI that reflect altered brain physiology underlying subjective symptoms. We have previously reported increased attention to threat-related stimuli in subjects with MTBI, suggesting a physiological vulnerability to depression. Vulnerability to depression has been linked with relatively greater activity of the right than left frontal cortex reflected in inverse pattern in frontal alpha with greater power on the left than right. We investigated whether patients with previous MTBI show this pattern of frontal activity reflected in more negative frontal alpha asymmetry (FAA) scores. Furthermore, in search for potential biomarkers of MTBI, we created a novel index, emotional modulation of FAA (eFAA) and investigated whether it correlates with subjective symptoms. EEG was recorded while subjects with previous MTBI and controls performed a computer-based reaction time task integrating different cognitive executive functions and containing either threat-related or emotionally neutral visual stimuli. Post-concussion symptoms and depression were assessed using the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and Beck's depression inventory (BDI). Task-induced FAA was assessed and eFAA calculated by subtracting FAA in the context of neutral stimuli from FAA in the context of emotional stimuli. The MTBI group showed FAA scores reflecting relatively greater right-sided frontal activity compared to healthy controls. eFAA differentiated the symptomatic MTBI from non-symptomatic MTBI group and from healthy controls. eFAA also correlated with RPQ and BDI scores. In conclusion, FAA pattern previously linked with vulnerability to depression, was observed in patients with previous MTBI. Furthermore, eFAA has potential as a biomarker of altered affective brain functions in MTBI.
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We have previously shown invasive vagus nerve stimulation to improve attention and working memory and alter emotion-attention interaction in patients with refractory epilepsy, suggesting that VNS might be useful in the treatment of cognitive impairment. The current research focuses on whether non-invasive, transcutaneous vagus nerve stimulation (tVNS) has similar effects to VNS. Furthermore, we aimed to assess whether tVNS has an impact on cognitive control in general or on underlying brain physiology in a task that mimics everyday life demands where multiple executive functions are engaged while encountering intervening emotional stimuli. Event-related potentials (ERP) evoked in such a task, specifically centro-parietal P3 and frontal N2 were used as biomarkers for attention allocation and cognitive control required to carry out the task. A single-blinded, sham-controlled, within-subject study on healthy subjects (n = 25) was conducted using Executive Reaction Time Test (RT-test), a Go/NoGo task engaging multiple executive functions along with intervening threat-related distractors while EEG was recorded. tVNS at the left tragus and sham stimulation at the left ear lobe was alternately delivered throughout the task. To assess the impact of tVNS on neural activity underlying attention and cognitive control, centro-parietal P3 and frontal N2 peak amplitudes were measured in Go and NoGo conditions. Task performance was assessed with RTs and different error types reflecting cognitive control in general and distinct executive functions, such as working memory and response inhibition.No significant effects due to tVNS on performance in the Executive RT-test were observed. For N2 there was a main effect of stimulator status and a significant interaction of trial type (Go, NoGo) and stimulator status. Post hoc analysis revealed that tVNS resulted in a significant reduction of frontal N2 only in the NoGo condition. No significant effects were observed for P3 nor were there any effects of emotion. Diminished NoGo-N2 potential along with unaltered task performance during tVNS suggests fewer cognitive control resources were required to successfully withhold a prepotent response. Though caution is warranted, we suggest that tVNS may lead to more efficient neural processing with fewer resources needed for successful cognitive control, providing promise for its potential use in cognitive enhancement.
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Executive functions (EF) rely on intact fronto-subcortical networks. An insult, disorder or treatment compromising brain health may impair the functioning of these widespread networks and consequently disrupt EF. Changes in brain health due to treatment or disorder can be assessed by repeating an EF test at different time points, but practice effect may confound the results. In this study we examined reliability of repeated testing using a computer-based test of EF, Executive Reaction Time (RT) Test, that allows assessment of different executive functions and emotion-attention interaction. In addition, we investigated whether performance measures correlate with scores derived from a clinically validated questionnaire of executive functions, Behavior Rating Inventory of Executive Function, Adult version (BRIEF-A). Healthy subjects performed the test twice, 3-4 weeks apart. When the entire tests were compared, subjects were faster and their odds to make an error reflecting disruption of working memory was lower in the second test. When two (error analysis) or four (RT analysis) blocks out of total eight test blocks were removed from the beginning of the test, the differences disappeared. In the first test emotional distractors prolonged RTs of younger, but not older, participants. In the second test emotional distractors had no effect on RTs of either age group. RTs correlated with Global Executive Composite score of BRIEF-A. Test-retest reliability analysis showed that the Executive RT Test is reliable in repeated testing with 0.83 intraclass correlation coefficient for RTs, 0.72 for total errors and 0.68 for working memory related errors. In summary, performance speed in the Executive RT Test correlate with subjective evaluations of executive functions and is reliable in repeated assessment when enough practice is ensured before the actual test. Thus, the Executive RT test holds promise as a potential indicator of brain health reflecting level of executive functions linked with daily life demands as well as typical emotion-attention interaction or possible aberrations in it.
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Patients with lesion to the orbitofrontal cortex (OFC) experience challenges in emotional control and emotion-guided behaviors. The OFC is known to participate in executive functions and attentional control of emotion and our previous research suggests OFC lesion alters the balance between voluntary and involuntary attention and cognitive control within the context of emotion. To better understand how OFC lesion affects the dynamics and interaction of these functions, we studied EEG and performance of 12 patients with lesion to the OFC and 11 control subjects with intact OFC in a Go/NoGo visual reaction time (RT) task with neutral targets and intervening threat-related emotional distractors (Executive RT Test). Event-related potentials (ERPs), specifically N2P3 peak-to-peak amplitude and the following late positive potential (LPP), were used to measure allocation of attention and cognitive control to emotional distractors. Task performance and Behavior Rating Inventory of Executive Functions-Adult version (BRIEF-A) scores were used to assess executive functions. As expected, the Control group showed increased N2P3 amplitude in the context of threat-related distractors, particularly over the right hemisphere, while LPP was not modulated by these distractors. In contrast, patients with OFC lesion showed no such impact of threat-related distractors on N2P3 amplitude but exhibited increased and prolonged left-lateralized impact of threat on LPP in the Go-condition. In NoGo-condition, the N2P3 amplitude was increased in both groups due to threat, but the impact was seen earlier, i.e., at the N2 peak in the OFC group and later at the P3 peak in Controls. The OFC group committed more errors in the Executive RT Test and reported more problems in BRIEF-A, thus both objective and subjective evidence for challenges in executive functions was obtained in patients with orbitofrontal lesion. Furthermore, the time-course of attention allocation and cognitive control towards task-irrelevant emotional stimuli was altered as evidenced by ERPs. We conclude that orbitofrontal lesion is associated with altered neural dynamics underlying the interaction of involuntary attention to emotion and cognitive control. These alterations in brain dynamics may underlie some of the challenges patients encounter in everyday life when emotional events interact with cognitive demands.
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Rapid interaction of the emotional and attentional networks is critical for adaptive behavior. Here, we examined the effects of emotional stimulation on hemifield attention allocation using event-related potential and behavioral measures. Participants performed a visual-discrimination task on nonemotional targets presented randomly in the left or right hemifield. A brief task-irrelevant emotional (pleasant or unpleasant; 150-ms duration) or neutral picture was presented centrally 350 ms before the next target (150-ms duration). Unpleasant stimuli interfered with the left visual field attention capacity, slowing behavioral responses to attended left field stimuli. In keeping with the behavioral data, event-related potential responses to nonemotional attended left field stimuli were reduced over the right parietal regions when preceded by an unpleasant event. The results provide electrophysiological and behavioral evidence that unpleasant, emotionally arousing stimuli interfere with the right hemisphere-dependent attention capacity.
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Nível de Alerta/fisiologia , Atenção/fisiologia , Córtex Cerebral/fisiologia , Emoções/fisiologia , Campos Visuais/fisiologia , Percepção Visual/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Córtex Cerebral/anatomia & histologia , Aprendizagem por Discriminação/fisiologia , Eletroencefalografia , Potenciais Evocados/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Testes Neuropsicológicos , Estimulação Luminosa , Tempo de Reação/fisiologiaRESUMO
Neuromodulation techniques targeting limbic circuits can be used to treat refractory psychiatric or neurological disorders. However, objective measure for the impact of neuromodulation on affective brain circuits is lacking. Deep brain stimulation at a key node of the limbic circuit, the anterior thalamic nuclei (ANT-DBS), is used to treat refractory epilepsy. While effective in reducing seizures, patients have reported subjective depressive symptoms as a side effect. In line with potential vulnerability to depression, we have previously shown ANT-DBS to increase attention allocation to threat evidenced by behavior and brain physiology. Rightward frontal alpha asymmetry with greater right hemispheric activation is thought to reflect brain physiology linked with depression and anxiety. To that end, we investigated whether high-frequency electric stimulation at ANT influences frontal alpha asymmetry. Furthermore, we explored the impact of DBS on emotional modulation of frontal alpha asymmetry and whether it is linked with emotional modulation of response speed. Electrical stimulation at ANT led to an increased rightward frontal alpha asymmetry compared to situations where stimulation was off (F(1,12) = 14.09, p = 0.003) or the thalamic control location was stimulated (F(1,12) = 10.19, p = 0.008), along with prolonged reaction times in the context of emotional distractors (F(1,7) = 16.66, p = 0.005). The change was specifically driven by increased activity in the right hemisphere. Furthermore, we found a correlation between the emotional modulation of frontal alpha asymmetry and emotional interference of response speed due to ANT stimulation (r = 0.78, p = 0.02). In conclusion, DBS at ANT increased relative right hemispheric activity and this was linked with emotional modulation of behavior. Previous studies have linked frontal alpha asymmetry with emotion related symptoms and furthermore, Vagus Nerve Stimulation (VNS) has been shown to modulate alpha asymmetry. Thus, in the light of the previous literature and the current findings, we suggest that frontal alpha asymmetry along with emotional interference of response speed might be a feasible biomarker for the effects of neuromodulation on brain's affective circuitry in general.
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Vagus nerve stimulation (VNS) is used for treating refractory epilepsy and major depression. While the impact of this treatment on seizures has been established, its impact on human cognition remains equivocal. The goal of this study is to elucidate the immediate effects of vagus nerve stimulation on attention, cognition, and emotional reactivity in patients with epilepsy. Twenty patients (12 male and 8 female; 45 ± 13 years old) treated with VNS due to refractory epilepsy participated in the study. Subjects performed a computer-based test of executive functions embedded with emotional distractors while their brain activity was recorded with electroencephalography. Subjects' cognitive performance, early visual event-related potential N1, and frontal alpha asymmetry were studied when cyclic vagus nerve stimulation was on and when it was off. We found that vagus nerve stimulation improved working memory performance as seen in reduced errors on a subtask that relied on working memory, odds ratio (OR) = 0.63 (95% confidence interval, CI [0.47, 0.85]) and increased N1 amplitude, F(1, 15) = 10.17, p = .006. In addition, vagus nerve stimulation resulted in longer reaction time, F(1, 16) = 8.23, p = .019, and greater frontal alpha asymmetry, F(1, 16) = 11.79, p = .003, in response to threat-related distractors. This is the first study to show immediate improvement in working memory performance in humans with clinically relevant vagus nerve stimulation. Furthermore, vagus nerve stimulation had immediate effects on emotional reactivity evidenced in behavior and brain physiology.
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Epilepsia Resistente a Medicamentos/terapia , Potenciais Evocados/fisiologia , Função Executiva/fisiologia , Memória de Curto Prazo/fisiologia , Estimulação do Nervo Vago/métodos , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Injury to the orbitofrontal cortex (OFC) is a frequent consequence of head injury and may lead to dysfunctional regulation of emotional and social behavior. Dysfunctional emotional behavior may partly be related to the role of the OFC in emotion-attention interaction, as reported previously. In order to better understand its role in emotion-attention and emotion-cognitive control interactions, we investigated attention allocation to task-relevant and task-irrelevant threat-related emotional stimuli during a task requiring cognitive control in patients with lesion to the OFC. We measured the behavioral performance and event-related potentials (ERP) of 13 patients with OFC lesion and 11 control subjects during a Go/NoGo visual discrimination task. In the task, line drawings of threatening (spider) and neutral (flower) figures served as either task-relevant Go or NoGo signals, or as task-irrelevant distractors. Overall performance did not differ between the groups. In contrast to the control group performance, the orbitofrontal group performance was improved by relevant threat signal in comparison with neutral signal. Further, task-relevant threat signals evoked larger frontocentral N2-P3 amplitude in the orbitofrontal group. Taken together, behavioral and electrophysiological results suggest that patients with OFC injury allocated more attentional and cognitive control resources in the context of task-relevant emotional stimuli. This study provides new evidence for the role of the OFC in emotion-attention and emotion-cognitive control interactions. Further, the OFC seems to contribute to the balance between voluntary and involuntary attention networks in context of emotional stimuli. Better understanding of alterations in emotion-attention interaction offers insight into affective dysfunction due to OFC lesion.
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Atenção/fisiologia , Emoções/fisiologia , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/lesões , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Adulto , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodosRESUMO
OBJECTIVES: Aortic valve replacement (AVR) surgery is associated with potential risk to cerebral injury. On the other hand, improved cardiovascular functioning after the surgery may have positive impact on brain health. The aim of this preliminary study was to investigate the impact of AVR surgery on cognition, specifically on higher cognitive control functions, i.e. executive functions, that are typically implicated in cognitive decline due to vascular origin. METHODS: Patients (n = 16) undergoing elective AVR surgery due to aortic stenosis were recruited and their cognitive performance was assessed using a computer-based Executive Reaction Time (RT) test. Testing was performed 1 day prior to AVR surgery and â¼3 months after the surgery. In addition, the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) was used to assess everyday challenges in executive functions and self-regulation. Patient's postoperative test results were compared with each patient's preoperative results to determine changes in executive functions. RESULTS: Subjects' overall cognitive performance improved after AVR surgery. After surgery, patients responded in the Executive RT test more accurately with the same response speed (change from 297 to 298 ms). Their overall probability to commit an error (total errors) was reduced by 47%, reflecting improved executive functions in general (OR = 0.53, 95% CI = 0.46-0.59, error rate change from 44.8 to 28.0%). Furthermore, one key component of executive functions, inhibitory control, was improved after AVR surgery. This was seen in reduced probability of failing to withhold a response, i.e. making a commission error, by 89% (OR = 0.11, CI = 0.08-0.16, error rate change from 11.8 to 2.6%). The probability of missing a response was reduced by 48%, reflecting improved attention (OR = 0.52, 0.44-0.64, error rate change from 18.1 to 11.0%). No statistically significant differences in BRIEF-A scores were found. CONCLUSIONS: There was a marked improvement in cognitive performance following AVR surgery, specifically in executive control functions indicating improved cognitive flexibility. Cognitive improvement, as opposed to the typical trajectory of cognitive decline in an elderly population with vascular disease, emphasizes the importance of these results and points to AVR surgery as having potential benefits on brain health in general. CLINICAL TRIALS IDENTIFIER: NCT01953068. https://www.clinicaltrials.gov/ct2/show/NCT01953068?term=NCT01953068&rank=1.
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Estenose da Valva Aórtica/cirurgia , Valva Aórtica/cirurgia , Transtornos Cognitivos/etiologia , Cognição/fisiologia , Função Executiva/fisiologia , Implante de Prótese de Valva Cardíaca/métodos , Idoso , Idoso de 80 Anos ou mais , Estenose da Valva Aórtica/complicações , Transtornos Cognitivos/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
Transcranial extraocular light affects the brains of birds and modulates their seasonal changes in physiology and behavior. However, whether the human brain is sensitive to extraocular light is unknown. To test whether extraocular light has any effect on human brain functioning, we measured brain electrophysiology of 18 young healthy subjects using event-related potentials while they performed a visual attention task embedded with emotional distractors. Extraocular light delivered via ear canals abolished normal emotional modulation of attention related brain responses. With no extraocular light delivered, emotional distractors reduced centro-parietal P300 amplitude compared to neutral distractors. This phenomenon disappeared with extraocular light delivery. Extraocular light delivered through the ear canals was shown to penetrate at the base of the scull of a cadaver. Thus, we have shown that extraocular light impacts human brain functioning calling for further research on the mechanisms of action of light on the human brain.
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Encéfalo/fisiologia , Meato Acústico Externo , Eletroencefalografia , Adulto , Atenção/fisiologia , Meato Acústico Externo/fisiologia , Potenciais Evocados , Feminino , Humanos , Luz , Masculino , Experimentação Humana não Terapêutica , Lobo TemporalRESUMO
Patients treated with deep brain stimulation (DBS) provide an opportunity to study affective processes in humans with "lesion on demand" at key nodes in the limbic circuitries, such as at the anterior thalamic nuclei (ANT). ANT has been suggested to play a role in emotional control with its connection to the orbitofrontal cortex and the anterior cingulate cortex. However, direct evidence for its role in emotional function in human subjects is lacking. Reported side effects of ANT-DBS in the treatment of refractory epilepsy include depression related symptoms. In line with these mood-related clinical side effects, we have previously reported that stimulating the anterior thalamus increased emotional interference in a visual attention task as indicated by prolonged reaction times due to threat-related emotional distractors. We used event-related potentials to investigate potential attentional mechanism behind this behavioural observation. We hypothesized that ANT-DBS leads to greater attention capture by threat-related distractors. We tested this hypothesis using centro-parietal N2-P3 peak-to-peak amplitude as a measure of allocated attentional resources. Six epileptic patients treated with deep brain stimulation at ANT participated in the study. Electroencephalography was recorded while the patients performed a computer based Executive-Reaction Time test with threat-related emotional distractors. During the task, either ANT or a thalamic control location was stimulated, or the stimulation was turned off. Stimulation of ANT was associated with increased centro-parietal N2-P3 amplitude and increased reaction time in the context of threat-related emotional distractors. We conclude that high frequency electric stimulation of ANT leads to greater attentional capture by emotional stimuli. This is the first study to provide direct evidence from human subjects with on-line electric manipulation of ANT for its role in emotion-attention interaction.
Assuntos
Núcleos Anteriores do Tálamo/fisiologia , Atenção/fisiologia , Emoções/fisiologia , Adulto , Núcleos Anteriores do Tálamo/fisiopatologia , Núcleos Anteriores do Tálamo/cirurgia , Estimulação Encefálica Profunda , Eletroencefalografia , Epilepsia/fisiopatologia , Epilepsia/terapia , Potenciais Evocados , Função Executiva/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação , Processamento de Sinais Assistido por Computador , Percepção Visual/fisiologia , Adulto JovemRESUMO
Mild traumatic brain injury (mTBI) may be associated with compromised executive functioning and altered emotional reactivity. Despite frequent affective and cognitive symptoms in mTBI, objective evidence for brain dysfunction is often lacking. Previously we have reported compromised performance in symptomatic mTBI patients in an executive reaction time (RT) test, a computer-based RT test engaging several executive functions simultaneously. Here, we investigated the cognitive control processes in mTBI in context of threat-related stimuli. We used behavioral measures and event-related potentials (ERP) to investigate attentional capture by task-relevant and task-irrelevant emotional stimuli during a Go-NoGo task requiring cognitive control. We also assessed subjective cognitive, somatic, and emotional symptoms with questionnaires. Twenty-seven subjects with previous mTBI and 17 controls with previous ankle injury participated in the study over 9 months post-injury. Electroencephalogram (EEG) was recorded while patients performed a modified executive RT-test. N2-P3 ERP component was used as a general measure of allocated attentional and executive processing resources. Although at the time of the testing, the mTBI and the control groups did not differ in symptom endorsement, mTBI patients reported having had more emotional symptoms overall since the injury than controls. The overall RT-test performance levels did not differ between groups. However, when threat-related emotional stimuli were used as Go-signals, the mTBI group was faster than the control group. In comparison to neutral stimuli, threat-related stimuli were associated with increased N2-P3 amplitude in all conditions. This threat-related enhancement of the N2-P3 complex was greater in mTBI patients than in controls in response to Go signals and NoGo signals, independent of relevance. We conclude that mTBI may be associated with enhanced attentional and executive resource allocation to threat-related stimuli. Along with behavioral evidence for enhanced attention allocation to threat stimuli, increased brain responses to threat were observed in mTBI. Enhanced attention capture by threat-related emotional stimuli may reflect inefficient top-down control of bottom-up influences of emotion, and might contribute to affective symptoms in mTBI.