EEG Theta Power Research Articles

Habitual night waking associates with dynamics of waking cortical theta power in infancy.

The implications of the substantial individual differences in infant sleep for early brain development remain unclear. Here, we examined whether night sleep quality relates to daytime brain activity, operationalized through measures of EEG theta power and its dynamic modulation, which have been previously linked to later cognitive development. For this longitudinal study, 76 typically developing infants were studied (age: 4-14 months, 166 individual study visits) over the course of 6months with one, two, three, or four lab visits. Habitual sleep was measured with a 7-day sleep diary and actigraphy, and the Brief Infant Sleep Questionnaire. Twenty-channel EEG was recorded while infants watched multiple rounds of videos of women singing nursery rhymes; oscillatory power in the theta band was extracted. Key metrics were average theta across stimuli and the slope of change in theta within the first novel movie. Both objective and subjective sleep assessment methods showed a relationship between more night waking and higher overall theta power and reduced dynamic modulation of theta over the course of the novel video stimuli. These results may indicate altered learning and consolidation in infants with more disrupted night sleep, which may have implications for cognitive development.

O068 Slow frequency wake EEG and hypoxemia during sleep predicts vigilance performance following extended wakefulness in patients with OSA

Abstract Study Objectives Obstructive sleep apnea is highly prevalent, but heterogeneous making identifying patients at risk of driving impairment challenging. Resting wake electroencephalography (qEEG) is associated with vigilance performance in healthy subjects. We examined if qEEG and clinical measures predict vigilance impairment in OSA. Methods Fifty-four patients underwent baseline PSG and 28hr extended wakefulness (EW) with 2 hourly psychomotor vigilance test (PVT) and Karolinska drowsiness test and driving simulator performance at baseline and following EW. Resting wake EEG was subjected to fast Fourier transform analysis to derive EEG power in delta, theta, alpha and beta ranges. Cluster analysis assigned participants into groups of either resistant (n=39) or vulnerable (n=15) to alertness failure based on PVT and driving performance. Backward stepwise regression models were used to determine the strongest clincal and wake EEG predictors vigilance impairment. Results Compared with resistant patients, the vulnerable group exhibited increased wake EEG delta (p<0.001) and theta (p=0.003) power during eyes open across all testing periods. The only significant predictors of vulnerability to alertness failure (PVT and driving) included O2Nadir from baseline PSG and baseline wake EEG theta and delta (eyes open) respectively explaining 42 and 32% of the variance in vigilance outcome in models that included Age, BMI, ESS, SOL, TST, AHI, O2 Nadir. Conclusions Slow frequency wake EEG (delta and theta) and hypoxemia are predictive of future alertness failure and driving impairments in patients with OSA. These findings are important for fitness to drive assessment in OSA but require validation in independent sample.

Neurodynamic correlates for the cross-frequency coupled transcranial alternating current stimulation during working memory performance.

Transcranial current stimulation is a neuromodulation technique used to modulate brain oscillations and, in turn, to enhance human cognitive function in a non-invasive manner. This study investigated whether cross-frequency coupled transcranial alternating current stimulation (CFC-tACS) improved working memory performance. Participants in both the tACS-treated and sham groups were instructed to perform a modified Sternberg task, where a combination of letters and digits was presented. Theta-phase/high-gamma-amplitude CFC-tACS was administered over electrode F3 and its four surrounding return electrodes (Fp1, Fz, F7, and C3) for 20 min. To identify neurophysiological correlates for the tACS-mediated enhancement of working memory performance, we analyzed EEG alpha and theta power, cross-frequency coupling, functional connectivity, and nodal efficiency during the retention period of the working memory task. We observed significantly reduced reaction times in the tACS-treated group, with suppressed treatment-mediated differences in frontal alpha power and unidirectional Fz-delta-phase to Oz-high-gamma-amplitude modulation during the second half of the retention period when network analyses revealed tACS-mediated fronto-occipital dissociative neurodynamics between alpha suppression and delta/theta enhancement. These findings indicate that tACS modulated top-down control and functional connectivity across the fronto-occipital regions, resulting in improved working memory performance. Our observations are indicative of the feasibility of enhancing cognitive performance by the CFC-formed tACS.

Homeostatic response to sleep deprivation and circadian rhythmicity are intact in older adults with insomnia.

We examined whether homeostatic sleep drive and circadian rhythmicity differ in older adults with insomnia (OAI) compared to older good sleepers (GS). OAI (n = 37) and GS (n = 30) participated in a 60-h in-lab study with sleep deprivation and constant routine paradigms. Homeostatic sleep drive was assessed by examining the effect of sleep deprivation on delta EEG power and theta EEG power, and repeated sleep latency tests. Circadian rhythm was assessed with salivary melatonin (phase and amplitude), core body temperature (phase, amplitude, and mesor), and sleep latency during a constant routine paradigm. Mixed models were used to assess interactions of group (OAS vs GS) with homeostatic sleep and circadian effects. Compared to GS, OAI showed a greater linear increase in waking theta power during sleep deprivation, but the two groups did not show differential responses to sleep deprivation in delta EEG, or in repeated sleep latency tests. The two groups did not differ in circadian phase or amplitude of melatonin or core body temperature rhythms. OAI had a significantly elevated core body temperature mesor compared to GS. Homeostatic response to sleep deprivation was intact in OAI compared to GS; theta EEG power suggested a greater homeostatic response in OAI. Circadian rhythm amplitude and phase were similar in OAI compared to GS. Elevated body temperature mesor in OAI may indicate elevated physiological arousal. These findings suggest that effective treatments for insomnia in older adults may leverage intact sleep and circadian regulatory mechanisms, rather than repair defective sleep and circadian regulation.

Theta but not beta activity is modulated by freedom of choice during action selection

Large-scale neurophysiological markers of action competition have been almost exclusively investigated in the context of instructed choices, hence it remains unclear whether these markers also apply to free choices. This study aimed to compare the specific brain dynamics underlying instructed and free decisions. Electroencephalography (EEG) was recorded while 31 participants performed a target selection task; the choice relied either on stimulus–response mappings (instructed) or on participants’ preferences (free). Choice difficulty was increased by introducing distractors in the informative stimulus in instructed choices, and by presenting targets with similar motor costs in free choices. Results revealed that increased decision difficulty was associated with higher reaction times (RTs) in instructed choices and greater choice uncertainty in free choices. Midfrontal EEG theta (4–8 Hz) power increased with difficulty in instructed choices, but not in free choices. Although sensorimotor beta (15–30 Hz) power was correlated with RTs, it was not significantly influenced by choice context or difficulty. These results suggest that midfrontal theta power may specifically increase with difficulty in externally-driven choices, whereas sensorimotor beta power may be predictive of RTs in both externally- and internally-driven choices.

0176 Comparing Sleep and Homeostatic Sleep Drive Between Retired Night Shift Workers and Retired Day Workers

Abstract Introduction Retired night shift workers report poorer sleep quality compared to retired day workers, even after returning to a nocturnal sleep schedule, suggesting a potential “scarring” of night shift work on sleep. History of sleep deprivation and sleep at an unfavorable circadian phase may compromise sleep and homeostatic sleep regulation, potentially contributing to poor sleep quality in retired night shift workers. This study compared sleep efficiency and homeostatic sleep regulation in response to sleep deprivation (delta EEG power during NREM sleep, theta EEG power during wakefulness) between retired night shift workers and retired day workers. Methods Participants (N = 75, mean age: 68.3 +/-5.5 years, 51% females, 87% non-Hispanic White) were 35 retired night shift workers and 40 age-, sex-, and race-equated retired day workers. Participants completed a 60-hour laboratory study including one baseline night of sleep, followed by 36 hours of sleep deprivation, followed by one recovery night of sleep. Sleep efficiency and NREM delta EEG power were measured by polysomnography on both nights, and waking theta EEG power was measured every other hour during the 36-hour sleep deprivation period. We analyzed the effects of group (retired night shift workers vs. retired day workers), time (baseline vs. recovery night for sleep efficiency and delta EEG power, hour for theta EEG power), and their interaction on each outcome using linear mixed models. Results Groups did not differ in sleep efficiency averaged across nights (F=1.48, p>0.05) or from baseline to recovery nights (F=0.05, p>0.05). Delta EEG responses to sleep deprivation did not differ by group (F=0.33, p>0.05). Compared to retired day workers, retired night shift workers showed greater overall waking EEG theta power during sleep deprivation (F=13.20, p<0.001). The group by time interaction was not significant (F=0.36, p>0.05), suggesting that group differences in theta EEG power were not due to increased sleep deprivation. Conclusion Sleep efficiency and homeostatic sleep regulation appeared to be preserved in retired night shift workers. Theta EEG power findings suggested greater sleep propensity during wakefulness in retired night shift workers. Interventions to improve sleep quality in retired night shift workers may leverage intact homeostatic sleep regulation mechanisms. Support (If Any) R01AG047139, T32HL082610, T32HL07560, T32MH019986

Evaluating Changes in Mental Workload in Indoor and Outdoor Ultra-Distance Cycling.

Whilst increasing mental workload has been shown to have a detrimental effect on cycling performance and more generally to increase the risk of harm, no studies have measured how mental workload changes as a function of ultra-distance cycling, indoors or outdoors. Our objective was to measure the difference in mental workload, as indicated by changes in EEG theta power, components of HRV and psychomotor vigilance and as reported using the ‘NASA Task Load Index questionnaire’, before and after a 5 h indoor ride and outdoor ride completed at 65% of functional threshold power. Results of the NASA-TLX indicated the mental demand of outdoor cycling to be significantly less than that of indoor cycling. There were significant differences in the PVT results between the pre and the post outdoor ride average and median response times. The slowest 10% PVT responses were significantly slower pre than post the indoor ride. There were significant differences in HRV between pre and post outdoor and indoor rides, specifically, in the average RR intervals, RMSSD (ms2), LFPower (ms2), NN50. There were modest changes in indicators of mental workload during an ultra-distance cycle ride. As such, mental workload during ultra-distance cycling is unlikely to be a contributory factor to decreases in performance or to an increased likelihood of accident and injury.

Multimodal Virtual Reality-Based Assessment of Adult ADHD: A Feasibility Study in Healthy Subjects.

Neuropsychological assessments are often surprisingly inaccurate in mapping clinically-reported attention-deficit hyperactivity disorder (ADHD) symptoms, presumably due to their low ecological validity. Virtual reality (VR) might offer a potential solution for this problem, given its capability to generate standardized and yet highly realistic virtual environments. As the first adaptation of existing virtual classroom scenarios to an adult population, we developed a Virtual Seminar Room (VSR) for multimodal characterization of ADHD symptoms. To test its feasibility, N = 35 healthy participants were immersed into the VSR via a head-mounted display and carried out a VR-embedded continuous performance task (CPT) under varying levels of distractions in two experimental blocks (24 min each). CPT performance, electroencephalography (EEG) measures, and head movements (actigraphy) were simultaneously recorded and analyzed offline. Although CPT performance remained constant throughout the task, head movements increased significantly from Block 1 to Block 2. In addition, EEG theta (4-7 Hz) and beta (13-30 Hz) power was higher during Block 1 than Block 2, and during distractor-present than distractor-absent phases. Moreover, P300 amplitudes were higher during Block 1 than Block 2, and P300 latencies were prolonged in distractor-absent compared with distractor-present phases. Although the paradigm awaits further improvements, this study confirms the general feasibility of the VSR and provides a first step toward a multimodal, ecologically valid, and reliable VR-based adult ADHD assessment.

Bright light alone or combined with caffeine improves sleepiness in chronically sleep-restricted young drivers

BackgroundYoung drivers are over-involved in sleepiness-related crashes. The alerting effects of bright light offer a potential countermeasure for driver sleepiness, either replacing or in conjunction with current countermeasures such as the use of caffeine. MethodsThirty young (18–25) chronically sleep-restricted drivers drove in a simulator under randomized conditions of continuous bright light (‘Light,’ 500 nm, 230μw/cm2), caffeine (‘Caffeine,’ 100 mg caffeinated gum), or light and caffeine together (‘Light + Caffeine’), after driving under a placebo condition (‘Placebo,’ decaffeinated gum, 555 nm light, 0.3 μW/cm2) on three consecutive days. Using mixed-effects linear models, the associations between these conditions and physiological outcomes (EEG alpha and theta power, heart rate, and beat-to-beat intervals), driving performance (lateral lane and steering-related outcomes and lateral acceleration), and subjective sleepiness was assessed. ResultsRelative to Placebo, all conditions improved driving performance outcomes (P < 0.0001), with effects of Light + Caffeine equal to Light but greater than Caffeine. Light + Caffeine reduced EEG alpha power more than Light or Caffeine (P < 0.0006), but ECG outcomes were generally worse under all conditions relative to Placebo. Subjective sleepiness improved under the Light + Caffeine condition only (P < 0.0001). ConclusionsCombining bright light and caffeine enhances their alerting effects on lateral lane variability and subjective sleepiness. A bright light could be a practical alternative to caffeine for sleepy drivers who avoid caffeine. The alerting effects of bright light could alleviate chronic community-level mild sleep restriction and provide on-road benefits to reduce severe injuries and fatal sleepiness-related crashes.

Let Complexity Bring Clarity: A Multidimensional Assessment of Cognitive Load Using Physiological Measures.

The effects of cognitive load on driver behavior and traffic safety are unclear and in need of further investigation. Reliable measures of cognitive load for use in research and, subsequently, in the development and implementation of driver monitoring systems are therefore sought. Physiological measures are of interest since they can provide continuous recordings of driver state. Currently, however, a few issues related to their use in this context are not usually taken into consideration, despite being well-known. First, cognitive load is a multidimensional construct consisting of many mental responses (cognitive load components) to added task demand. Yet, researchers treat it as unidimensional. Second, cognitive load does not occur in isolation; rather, it is part of a complex response to task demands in a specific operational setting. Third, physiological measures typically correlate with more than one mental state, limiting the inferences that can be made from them individually. We suggest that acknowledging these issues and studying multiple mental responses using multiple physiological measures and independent variables will lead to greatly improved measurability of cognitive load. To demonstrate the potential of this approach, we used data from a driving simulator study in which a number of physiological measures (heart rate, heart rate variability, breathing rate, skin conductance, pupil diameter, eye blink rate, eye blink duration, EEG alpha power, and EEG theta power) were analyzed. Participants performed a cognitively loading n-back task at two levels of difficulty while driving through three different traffic scenarios, each repeated four times. Cognitive load components and other coinciding mental responses were assessed by considering response patterns of multiple physiological measures in relation to multiple independent variables. With this approach, the construct validity of cognitive load is improved, which is important for interpreting results accurately. Also, the use of multiple measures and independent variables makes the measurements (when analyzed jointly) more diagnostic-that is, better able to distinguish between different cognitive load components. This in turn improves the overall external validity. With more detailed, diagnostic, and valid measures of cognitive load, the effects of cognitive load on traffic safety can be better understood, and hence possibly mitigated.

Reader fatigue - Electroencephalography findings: A case study in students.

Mental fatigue is usually accompanied by a sense of weariness, reduced alertness, and reduced mental performance, which can lead to accidents, decrease of productivity in workplace and several other health hazards. The aim of this study was to assess mental fatigue of students while reading for a prolonged duration of time by application of electroencephalography (EEG). Ten healthy students (27.57±3.4 years; 5 females and 5 males), participated in the study. The experimental design consisted of 5 blocks of 15-min length, in total 75 min for each participant. The experiment was done without any reading activities at the first block. In the following, participants studied the texts and corrected the mistakes. In each block EEG (beta, alpha, and theta power), and the Karolinska Sleepiness Scale (KSS) were recorded. The mean of the self-assessment of sleepiness by KSS from the first to final 15 minutes were 2.3, 3.4, 4.3, 5.2, and 6.1, respectively. The average power in the theta band decreased from 1.23μV2/Hz at the first 15-min period to 1.02μV2/Hz at the last 15-min period. Also, mean power in the alpha band decreased from 0.85μV2/Hz at the first 15-min period to 0.59μV2/Hz at the last 15-min period. The study showed that the KSS and EEG activity indicate sleepiness which were highly correlated, with both changing along with performance.

Associations between REM‐sleep EEG spectral power, the cholinergic basal forebrain volume and episodic memory in ageing

AbstractBackgroundOur research team has demonstrated that quantitative electroencephalography (qEEG) slowing during rapid‐eye movement (REM) sleep is a more powerful tool to discriminate patients with mild cognitive impairment (MCI) or Alzheimer Disease (AD) from healthy controls than waking EEG. Cortical activation during REM sleep highly depends on the cholinergic basal forebrain system (BFCS) neurons, while other neuronal systems are less active compared to wakefulness. However, the BFCS degenerates early in AD. Here, we tested the hypothesis that REM sleep EEG activity could be strongly associated with neurodegeneration of the BFCS, before the onset of dementia.Method134 participants (mean age 68.45 ± 7.8 years; 52 women; 61 with MCI) underwent a polysomnography, structural magnetic resonance imaging, and a neuropsychological evaluation. T1‐weighted images were preprocessed using CAT12 and the DARTEL algorithm, and the JuBrain Anatomy Toolbox was used to extract bilateral BFCS volumes (i.e., Ch1‐2‐3, Ch4 and total volume). Based on prior evidence, theta (4‐8Hz) and alpha (8‐13Hz) absolute EEG power during REM sleep were computed on temporal electrodes (T3‐T4‐T5‐T6). A composite episodic memory score was calculated as the mean of Z‐scores obtained on the Rey Auditory Verbal Learning Test immediate and delayed free recalls. Multiple regressions were performed between (i) spectral power values or (ii) episodic memory performance, and basal forebrain volumes controlling for age, sex, the apnea‐hypopnea index, and the total intracranial volume. Complementary analyses were performed by stratifying the cohort by sex.ResultBoth Ch4 (r=0.24, p=0.006) and total BFCS (r=0.25, p=0.005) volumes were positively associated with episodic memory performance. Ch4 (r=‐0.21; p=0.025) and total BFCS (r=‐0.22; p=0.02) volumes were negatively associated with temporal theta power. Moreover, total BFCS (r=‐0.22; p=0.023) volumes were negatively associated with temporal alpha power. Sex‐stratified analyses revealed that the associations between BFCS volumes, REM‐sleep spectral power and episodic memory were significant in women, but not in men.ConclusionThese results confirmed that cortical activation during REM sleep is sensitive to volume loss in the BFCS, a cholinergic region known to degenerate early in AD. Why this association was only observed in women is intriguing and will need further investigation.

Striatal BOLD and midfrontal theta power express motivation for action

Action selection is biased by the valence of anticipated outcomes. To assess mechanisms by which these motivational biases are expressed and controlled, we measured simultaneous EEG-fMRI during a motivational Go/NoGo learning task (N = 36), leveraging the temporal resolution of EEG and subcortical access of fMRI. VmPFC BOLD encoded cue valence, importantly predicting trial-by-trial valence-driven response speed differences and EEG theta power around cue onset. In contrast, striatal BOLD encoded selection of active Go responses and correlated with theta power around response time. Within trials, theta power ramped in the fashion of an evidence accumulation signal for the value of making a “Go” response, capturing the faster responding to reward cues. Our findings reveal a dual nature of midfrontal theta power, with early components reflecting the vmPFC contribution to motivational biases, and late components reflecting their striatal translation into behavior, in line with influential recent “value of work” theories of striatal processing.

Psychophysiological response of military pilots in different combat flight maneuvers in a flight simulator

Objective: To analyze the psychophysiological response during takeoff, landing, air-air attack and air-ground attack maneuvers. Methods: A total of 11 expert pilots (age=33.36 (5.37)) from the Spanish Air Force participated in this cross-sectional study. Participants had to complete in a flight simulator the following missions: 1) takeoff; 2) Air-air attack; 3) Air-Ground attack, and 4) Landing. The electroencephalographic activity (EEG) and heart rate variability (HRV) were collected during all these maneuvers. Results: Significant higher values of theta (during takeoff, air-air attack and air-ground attack) EEG power spectrum were obtained when compared to baseline. Significant difference in the P3 scalp location was observed between landing and takeoff maneuvers in the beta EEG power spectrum. Furthermore, significant lower values of HRV were obtained during takeoff, landing, air-air attack and air-ground attack when compared to baseline values. Also, landing showed a higher sympathetic response when compared to takeoff maneuver. Conclusion: Takeoff, landing, air-air attack or air-ground attack maneuvers performed in a flight simulator produced significant changes in the electroencephalographic activity and autonomic modulation of professional pilots. Beta EEG power spectrum modifications suggest that landing maneuvers induced more attentional resources than takeoff. In the same line, a reduced HRV during landing was obtained when compared to takeoff. These results should be considered to training purposes.

Memory binding and theta EEG during middle childhood.

The ability to bind together the contextual details associated with an event undergoes dramatic improvement during childhood. However, few studies have examined the neural correlates of memory binding encoding and retrieval during middle childhood. We examined age-related encoding and retrieval differences using continuous electroencephalogram (EEG) measures in a sample of 6- and 8-year-olds. For the memory binding task, children were tested on memory for individual items (i.e., objects and backgrounds only) and combined object-backgrounds pairings (combination condition). Memory for individual item information was comparable across both age groups. However, younger children experienced greater difficulty (i.e., higher false alarm rate) in the combination condition. Theta (4-7Hz) neuronal oscillations were analyzed to compare memory encoding and retrieval processes. Widespread retrieval-related increases in theta band EEG power (compared with baseline and encoding-related activation) were evident in both 6- and 8-year-olds. Regression analyses revealed that parietal theta EEG power during retrieval accounted for variability in memory binding performance. These findings suggest that theta rhythms are intricately linked to memory binding processes during middle childhood.

Specific Electroencephalographic Signatures for Pain and Descending Pain Inhibitory System in Spinal Cord Injury.

The pain related to spinal cord injury (SCI) is difficult to treat, and it is associated with significant morbidity. One aspect to improve therapeutics is to explore markers of pain and its correlates in SCI. In this cross-sectional neurophysiological analysis of a randomized, double-blind controlled trial, 39 patients with SCI were included. We analyzed conditioned pain modulation (CPM) efficiency as the index of the descending pain inhibitory system, EEG variables, and clinical pain levels as measured by the Visual Analogue Scale. Regression analyses were performed to assess the relationship among EEG variables, pain levels, and CPM. We included 39 SCI patients, 74% reported SCI-related pain. We found that (1) less alpha and beta power are related to pain presence, (2) less alpha and beta power are associated with higher pain levels among patients with pain, (3) patients with pain have decreased peak alpha-theta frequency compared to no-pain group, (4) more relative theta power are related to the presence of low CPM efficiency, (5) higher relative theta power is associated with lower CPM efficiency. Our results confirm and provide additional data on the relationship between decreased alpha and beta frequencies and higher pain levels. One important finding, though, was a specific and different EEG signature for the descending inhibitory pain system, as we showed that increased theta EEG power is related to decreased CPM efficiency; suggesting that, although low CPM efficiency plays a major role in pain in these participants, it does seem to be associated with a specific oscillatory brain rhythm different from clinical pain. These findings have significant implications for future research on EEG-based biomarkers of pain in post-SCI and new interventions as neurofeedback to manage pain in this population.

Shared and Distinct Neural Mechanisms Underlying Pediatric BFRBs and Obsessive-Compulsive Disorder

Pediatric body-focused repetitive behaviors (BFRBs) are under-researched, and there is little information on their neural underpinnings. We examined error-related negativity (ERN)-amplitude and theta-EEG power differences among youth with TTM, OCD, and healthy controls (HC).

Alprazolam-induced EEG spectral power changes in rhesus monkeys: a translational model for the evaluation of the behavioral effects of benzodiazepines.

Benzodiazepines induce electroencephalography (EEG) changes in rodents and humans that are associated with distinct behavioral effects and have been proposed as quantitative biomarkers for GABAA receptor modulation. Specifically, central EEG beta and occipital EEG delta activity have been associated with anxiolysis and sedation, respectively. The extent to which nonhuman primates show the same dose- and topography-dependent effects remained unknown. We aimed at establishing a nonhuman primate model for the evaluation of benzodiazepine EEG pharmacology. Four adult male rhesus monkeys were prepared with fully implantable telemetry devices that monitored activity, peripheral body temperature, and contained two EEG (central and occipital), one electromyography (EMG), and one electrooculography channel. We investigated daytime alprazolam-induced changes in EEG spectral power, sleep-wake states, EMG activity, locomotor activity, and body temperature. Alprazolam (0.01-1.8 mg/kg, i.m.) or vehicle was administered acutely, and telemetry recording was conducted for 1 h. Daytime alprazolam dose-dependently increased central EEG power (including beta activity), increased occipital EEG delta power, and decreased occipital EEG alpha, theta, and sigma power. There was an ~8-fold difference in the potency of alprazolam to increase central EEG beta vs. occipital EEG delta activity (based on relative EEG power). The highest dose, which increased both central EEG beta and occipital EEG delta relative power, induced sedative effects (increased time spent in N1 and N2 sleep stages) and decreased peripheral body temperature and locomotor activity. Alprazolam induces dose- and topography-dependent EEG changes in rhesus monkeys and provides a valuable model for studying benzodiazepine pharmacology.

Shared and unique neural mechanisms underlying pediatric trichotillomania and obsessive compulsive disorder

BackgroundLittle is known about the neural underpinnings of pediatric trichotillomania (TTM). We examined error-related negativity (ERN)-amplitude and theta-EEG power differences among youth with TTM, OCD, and healthy controls (HC). MethodsForty channel EEG was recorded from 63 pediatric participants (22 with TTM, 22 with OCD, and 19 HC) during the Eriksen Flanker Task. EEG data from inhibitory control were used to derive estimates of ERN amplitude and event-related spectral power associated with motor inhibition. ResultsTTM and HC were similar in brain activity patterns in frontal and central regions and TTM and OCD were similar in the parietal region. Frontal ERN-amplitude was significantly larger in OCD relative to TTM and HC, who did not differ from each other. The TTM group had higher theta power compared to OCD in frontal and central regions, and higher theta than both comparison groups in right motor cortex and superior parietal regions. Within TTM, flanker task performance was correlated with EEG activity in frontal, central, and motor cortices whereas global functioning and impairment were associated with EEG power in bilateral motor and parietal cortices. ConclusionsFindings are discussed in terms of shared and unique neural mechanisms in TTM and OCD and treatment implications.

Electrical and Hemodynamic Neural Functions in People With ALS: An EEG-fNIRS Resting-State Study.

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease that causes the progressive loss of voluntary muscle control. Recent studies have reported conflicting results on alterations in resting-state functional brain networks in ALS by adopting unimodal techniques that measure either electrophysiological or vascular-hemodynamic neural functions. However, no study to date has explored simultaneous electrical and vascular-hemodynamic changes in the resting-state brain in ALS. Using complementary multimodal electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) recording and analysis techniques, we explored the underlying multidimensional neural contributions to altered oscillations and functional connectivity in people with ALS. 10 ALS patients and 9 age-matched controls underwent multimodal EEG-fNIRS recording in the resting state. Resting-state functional connectivity (RSFC) and power spectra of both modalities in both groups were analyzed and compared statistically. Increased fronto-parietal EEG connectivity in the alpha and beta bands and increased interhemispheric and right intra-hemispheric fNIRS connectivity in the frontal and prefrontal regions were observed in ALS. Frontal, central, and temporal theta and alpha EEG power decreased in ALS, as did parietal and occipital alpha EEG power, while frontal and parietal hemodynamic spectral power increased in ALS. These results suggest that electro-vascular disruption in neuronal networks extends to the extra-motor regions in ALS patients, which can ultimately introduce novel neural markers of ALS that can be exploited further as diagnostic and prognostic tools.