Electroencephalographic Activity Research Articles

The neural representation of stereotype content

Judgments about social groups are characterized by their position in a representational space defined by two axes, warmth and competence. We examined serial dependence (SD) in evaluations of warmth and competence while measuring participants’ electroencephalographic (EEG) activity, as a means to address the independence between these two psychological axes. SD is the attraction of perceptual reports towards things seen in the recent past and has recently been intensely investigated in vision. SD occurs at multiple levels of visual processing, from basic features to meaningful objects. The current study aims to (1) measure whether SD occurs between non-visual objects, in particular social groups and (2) uncover the neural correlates of social group evaluation and SD using EEG. Participants’ judgments about social groups such as “nurses” or “accountants” were serially dependent, but only when the two successive groups were close in representational space. The pattern of results argues in favor of a non-separability between the two axes, because groups nearby on one dimension but far on the other were not subject to SD, even though that other dimension was irrelevant to the task at hand. Using representational similarity analysis, we found a brain signature that differentiated social groups as a function of their position in the representational space. Our results thus argue that SD may be a ubiquitous cognitive phenomenon, that social evaluations are serially dependent, and that reproducible neural signatures of social evaluations can be uncovered.

Brain wave modulation and EEG power changes during auditory beats stimulation

BackgroundAuditory beats stimulation (ABS) has received increased attention for its potential to modulate neural oscillations through a phenomenon described as brain entrainment (i.e synchronization of brain’s electrocortical activity to external stimuli at a specific frequency). Recently, a new form of ABS has emerged, inspired by isochronic tones stimulation (ITd). ObjectiveThis study investigated neural oscillatory responses induced by ITd in comparison with formerly well-established ABS protocols, such as gamma-binaural beats (BB) and white noise (WN). MethodsWe recorded the electroencephalographic brain activity in 28 participants during 4 min of BB, ITd, and WN presentation. ResultsData demonstrated that while both BB and WN enhanced oscillatory power on the EEG gamma band, consistently with the expected brain entrainment effect, ITd yielded greater changes in EEG power (p < 0.001). This was confirmed by time-based analysis, which showed a progressive increase in normalized EEG power within the ITd window compared to BB (p < 0.05). Findings also revealed that ITd elicited acute changes in the alpha band of EEG oscillations, through a progressive decrease in power over time, which is distinctly different from the pattern observed while listening BB and WN. Such dual alpha-gamma effects underline the promising and unique potential of ITd to modulate neural oscillations which selectively differ from BB and WN. ConclusionThis study contributes to the evolution of ABS research, highlighting the promise of ITd for cognitive enhancement and clinical applications.

Inhibitory control of gait initiation in humans: An electroencephalography study.

Response inhibition is a crucial component of executive control. Although mainly studied in upper limb tasks, it is fully implicated in gait initiation. Here, we assessed the influence of proactive and reactive inhibitory control during gait initiation in healthy adult participants. For this purpose, we measured kinematics and electroencephalography (EEG) activity (event-related potential [ERP] and time-frequency data) during a modified Go/NoGo gait initiation task in 23 healthy adults. The task comprised Go-certain, Go-uncertain, and NoGo conditions. Each trial included preparatory and imperative stimuli. Our results showed that go-uncertainty resulted in delayed reaction time, without any difference for the other parameters of gait initiation. Proactive inhibition, that is, Go uncertain versus Go certain conditions, influenced EEG activity as soon as the preparatory stimulus. Moreover, both proactive and reactive inhibition influenced the amplitude of the ERPs (central P1, occipito-parietal N1, and N2/P3) and theta and alpha/low beta band activities in response to the imperative-Go-uncertain versus Go-certain and NoGo versus Go-uncertain-stimuli. These findings demonstrate that the uncertainty context; induced proactive inhibition, as reflected in delayed gait initiation. Proactive and reactive inhibition elicited extended and overlapping modulations of ERP and time-frequency activities. This study shows the protracted influence of inhibitory control in gait initiation.

Neuronal network controlling REM sleep.

Rapid eye movement sleep is a state characterized by concomitant occurrence of rapid eye movements, electroencephalographic activation and muscle atonia. In this review, we provide up to date knowledge on the neuronal network controlling its onset and maintenance. It is now accepted that muscle atonia during rapid eye movement sleep is due to activation of glutamatergic neurons localized in the pontine sublaterodorsal tegmental nucleus. These neurons directly project and excite glycinergic/γ-aminobutyric acid-ergic pre-motoneurons localized in the ventromedial medulla. The sublaterodorsal tegmental nucleus rapid eye movement-on neurons are inactivated during wakefulness and non-rapid eye movement by rapid eye movement-off γ-aminobutyric acid-ergic neurons localized in the ventrolateral periaqueductal grey and the adjacent dorsal deep mesencephalic reticular nucleus. Melanin-concentrating hormone and γ-aminobutyric acid-ergic rapid eye movement sleep-on neurons localized in the lateral hypothalamus would inhibit these rapid eye movement sleep-off neurons initiating the state. Finally, the activation of a few limbic cortical structures during rapid eye movement sleep by the claustrum and the supramammillary nucleus as well as that of the basolateral amygdala would be involved in the function(s) of rapid eye movement sleep. In summary, rapid eye movement sleep is generated by a brainstem generator controlled by forebrain structures involved in autonomic control.

Trying to forget alcohol: Brain mechanisms underlying memory suppression in young binge drinkers

People are able to voluntarily suppress unwanted thoughts or memories, a phenomenon known as suppression-induced forgetting or memory suppression. Despite harmful alcohol use, such as binge drinking, has been linked to impaired inhibitory control (IC) and augmented alcohol-cue reactivity, no study to date has assessed memory inhibition abilities towards alcohol-related cues in binge drinkers (BDs). Thus, the present preregistered study aimed to evaluate the behavioral and neurofunctional mechanisms associated with memory inhibition, specifically those related to the suppression of alcohol-related memories, in young BDs. For this purpose, electroencephalographic activity was recorded in eighty-two college students aged between 18 and 24 years old from the University of Minho (50% females; 40 non/low-drinkers [N/LDS] and 42 BDs) while they performed the Think/No-Think Alcohol task. Brain functional connectivity (FC) was calculated using the phase locking value and, subsequently, a dynamic seed-based analysis was conducted to explore the FC patterns between IC and memory networks. Comparatively to N/LDs, BDs exhibited decreased alpha-band FC between the anterior cingulate cortex and the left fusiform gyrus during attempts to suppress non-alcohol memories, accompanied by unsuccessful forgetting of those memories. Conversely, BDs displayed augmented gamma-band FC between the IC network and memory regions –i.e., hippocampus, parahippocampus and fusiform gyrus- during suppression of alcohol-related memories. Inhibitory abnormalities in BDs may lead to hypoconnectivity between IC and memory networks and deficient suppression of non-alcohol-related memories. However, while suppressing highly salient and reward-predicting stimuli, such as alcohol-related memories, BDs display a hyperconnectivity pattern between IC and memory networks, likely due to their augmented attention towards intrusive alcoholic memories and the attempts to compensate for potential underlying IC deficits. These findings hold important implications for alcohol research and treatment, as they open up new avenues for reducing alcohol use by shifting the focus to empowering suppression/control over alcohol-related memories. Clinical trial registration[http://www.ClinicalTrials.gov], identifier [NCT05237414].

Spatio-temporal electroencephalographic power distribution in experimental pigs receiving propofol.

When assessing the spatio-temporal distribution of electroencephalographic (EEG) activity, characteristic patterns have been identified for several anesthetic drugs in humans. A shift in EEG power from the occipital to the prefrontal regions has been widely observed during anesthesia induction. This has been called "anteriorization" and has been correlated with loss of consciousness in humans. The spatio-temporal distribution of EEG spectral power in pigs and its modulation by anesthetics have not been described previously. The aim of the present study was to analyze EEG power across an anterior-posterior axis in pigs receiving increasing doses of propofol to 1) characterize the region of highest EEG power during wakefulness, 2) depict its spatio-temporal modification during propofol infusion, and 3) determine the region demonstrating the most significant modulations across different doses administered. Six pigs with a body weight of 33.3 ± 3.6 kg and aged 11.3 ± 0.5 weeks were included in a prospective experimental study. Electroencephalographic activity was collected at the occipital, parietal and prefrontal regions at increasing doses of propofol (starting at 10 mg kg-1 h-1 and increasing it by 10 mg kg-1 h-1 every 15 minutes). The EEG power was assessed using a generalized linear mixed model in which propofol doses and regions were treated as fixed effects, whereas pig was used as a random effect. Pairwise comparisons of marginal linear predictions were used to assess the change in power when the specific propofol dose (or region) was considered. During both wakefulness and propofol infusion, the highest EEG power was located in the prefrontal region (p<0.001). The EEG power, both total and for each frequency band, mostly followed the same pattern, increasing from awake until propofol 20 mg kg-1 h-1 and then decreasing at propofol 30 mg kg-1 h-1. The region showing the strongest differences in EEG power across propofol doses was the prefrontal. In juvenile pigs receiving increasing doses of propofol, the prefrontal region showed the highest EEG power both during wakefulness and propofol administration and was the area in which the largest frequency-band specific variations were observed across different anesthetic doses. The assessment of the spectral EEG activity at this region could be favorable to distinguish DoA levels in pigs.

Resting state electroencephalographic brain activity in neonates can predict age and is indicative of neurodevelopmental outcome

ObjectiveElectroencephalography (EEG) can be used to estimate neonates’ biological brain age. Discrepancies between postmenstrual age and brain age, termed the brain age gap, can potentially quantify maturational deviation. Existing brain age EEG models are not well suited to clinical cot-side use for estimating neonates’ brain age gap due to their dependency on relatively large data and pre-processing requirements. MethodsWe trained a deep learning model on resting state EEG data from preterm neonates with normal neurodevelopmental Bayley Scale of Infant and Toddler Development (BSID) outcomes, using substantially reduced data requirements. We subsequently tested this model in two independent datasets from two clinical sites. ResultsIn both test datasets, using only 20 min of resting-state EEG activity from a single channel, the model generated accurate age predictions: mean absolute error = 1.03 weeks (p-value = 0.0001) and 0.98 weeks (p-value = 0.0001). In one test dataset, where 9-month follow-up BSID outcomes were available, the average neonatal brain age gap in the severe abnormal outcome group was significantly larger than that of the normal outcome group: difference in mean brain age gap = 0.50 weeks (p-value = 0.04). ConclusionsThese findings demonstrate that the deep learning model generalises to independent datasets from two clinical sites, and that the model’s brain age gap magnitudes differ between neonates with normal and severe abnormal follow-up neurodevelopmental outcomes. SignificanceThe magnitude of neonates’ brain age gap, estimated using only 20 min of resting state EEG data from a single channel, can encode information of clinical neurodevelopmental value.

Patterns of spontaneous neural activity associated with social communication abilities among infants and toddlers showing signs of autism.

Early disruptions to social communication development, including delays in joint attention and language, are among the earliest markers of autism spectrum disorder (autism, henceforth). Although social communication differences are a core feature of autism, there is marked heterogeneity in social communication-related development among infants and toddlers exhibiting autism symptoms. Neural markers of individual differences in joint attention and language abilities may provide important insight into heterogeneity in autism symptom expression during infancy and toddlerhood. This study examined patterns of spontaneous electroencephalography (EEG) activity associated with joint attention and language skills in 70 community-referred 12- to 23-month-olds with autism symptoms and elevated scores on an autism diagnostic instrument. Data-driven cluster-based permutation analyses revealed significant positive associations between relative alpha power (6-9Hz) and concurrent response to joint attention skills, receptive language, and expressive language abilities. Exploratory analyses also revealed significant negative associations between relative alpha power and measures of core autism features (i.e., social communication difficulties and restricted/repetitive behaviors). These findings shed light on the neural mechanisms underlying typical and atypical social communication development in emerging autism and provide a foundation for future work examining neural predictors of social communication growth and markers of intervention response.

Frontal delta and theta power reflect strategy changes during human spatial memory retrieval in a virtual water maze task: an exploratory analysis

Brain oscillations in humans play a role in a wide range of cognitive processes, including navigation and memory. The oscillatory dynamics contributing to successful spatial memory recall in humans are not well-understood. To investigate specific oscillatory frequency bands during the recall process in human navigation, we recorded electroencephalographic (EEG) activity during a recall trial in healthy young adults (n = 15) following the learning of a goal location in a Virtual Water Maze task. We compared this to the activity during the same trial length, in a group of participants who did not learn a target location and navigated freely but were time-matched to the learning group (non-learning, n = 15). We compared relative power in Delta (2–4 Hz), Theta (5–7 Hz), Alpha (8–12 Hz), Beta (15–29 Hz), and Gamma (30–40 Hz) bands across the scalp. We found that delta and theta activity were greater during recall in our learning group, as opposed to our non-learning group. We also demonstrated clear suppression in the alpha band at posterior sites during memory-guided navigation compared to our non-learning group. Additionally, when goal-directed navigation switches to focused searching behavior, power becomes greater at the frontal region; with increases in the delta and theta bands reflecting this strategy change. There was also greater beta and gamma activity at posterior sites in our learning group. We discuss the results further in terms of the possible roles and functions of these oscillations during human navigation and hope this exploratory analysis can provide hypotheses for future spatial navigation and memory work.

Seizure suppression and neuroprotection in soman-exposed rats following delayed intramuscular treatment of adenosine A1 receptor agonist as an adjunct to standard medical treatment

Soman produces excitotoxic effects by inhibiting acetylcholinesterase in the cholinergic synapses and neuromuscular junctions, resulting in soman-induced sustained status epilepticus (SSE). Our previous work showed delayed intramuscular (i.m.) treatment with A1 adenosine receptor agonist N-bicyclo-[2.2.1]-hept-2-yl-5′-chloro-5′-deoxyadenosine (ENBA) alone suppressed soman-induced SSE and prevented neuropathology. Using this same rat soman seizure model, we tested if delayed therapy with ENBA (60 mg/kg, i.m.) would terminate seizure, protect neuropathology, and aid in survival when given in conjunction with current standard medical countermeasures (MCMs): atropine sulfate, 2-PAM, and midazolam (MDZ). Either 15- or 30-min following soman-induced SSE onset, male rats received atropine and 2-PAM plus either MDZ or MDZ + ENBA. Electroencephalographic (EEG) activity, physiologic parameters, and motor function were recorded. Either 2- or 14-days following exposure surviving rats were euthanized and perfused for histology. All animals treated with MDZ + ENBA at both time points had 100% EEG seizure termination and reduced total neuropathology compared to animals treated with MDZ (2-day, p = 0.015 for 15-min, p = 0.002 for 30-min; 14-day, p < 0.001 for 15-min, p = 0.006 for 30-min), showing ENBA enhanced MDZ's anticonvulsant and neuroprotectant efficacy. However, combined MDZ + ENBA treatment, when compared to MDZ treatment groups, had a reduction in the 14-day survival rate regardless of treatment time, indicating possible enhancement of MDZ's neuronal inhibitory effects by ENBA. Based on our findings, ENBA shows promise as an anticonvulsant and neuroprotectant in a combined treatment regimen following soman exposure; when given as an adjunct to standard MCMs, the dose of ENBA needs to be adjusted.

Event-related Potentials Indicate Target Processing in the Absence of Distractor Suppression during Rapid Serial Visual Presentation.

In our modern world we are exposed to a steady stream of information containing important as well as irrelevant information. Therefore, our brains have to constantly select relevant over distracting items and further process the selected information. Whereas there is good evidence that even in rapid serial streams of presented information relevant targets can be actively selected, it is less clear whether and how distracting information is de-selected and suppressed in such scenarios. To address this issue we recorded electroencephalographic activity during a rapid serial visual presentation paradigm in which healthy, young human volunteers had to encode visual targets into short-term memory while salient visual distractors and neutral filler items needed to be ignored. Event-related potentials were analyzed in 3D source space and compared between stimulus types. A negative wave between around 170 and 230 ms after stimulus onset resembling the N2pc component was identified that dissociated between target stimuli and distractors as well as filler items. This wave appears to reflect target selection processes. However, there was no electrophysiological signature identified that would indicate an active distractor suppression mechanism. The obtained results suggest that unlike in situations where target stimuli and distractors are presented simultaneously, targets can be selected without the need for active suppression of distracting information in serial presentations with a clear and regular temporal structure. It is assumed that temporal expectation supports efficient target selection by the brain.

Advanced perioperative assessment of neurological function in acute Stanford A aortic dissection

Objective Acute Stanford Type A aortic dissection (AAAD) is a critical condition in vascular surgery, and total aortic arch replacement surgery is the preferred method to save patients’ lives. In recent years, as clinical research has advanced, there has been a growing realization of the close association between poor postoperative outcomes in patients and neurological functional deficits. Neurological function monitoring is a medical technique used to evaluate and monitor the functional status of the nervous system. Methods This monitoring involves the assessment of various aspects of the nervous system, including but not limited to nerve conduction velocity, neuromuscular function, electroencephalographic activity, and sensory nerve transmission. Neurological function monitoring has broad clinical applications and can be used to diagnose and monitor many neurological disorders, helping physicians understand patients’ neurological functional status and guide treatment plans. During the postoperative recovery process, neurological function monitoring can assist physicians in assessing the potential impact of surgery on the nervous system and monitor the recovery of patients’ neurological function. Results Studies have shown that neurological function monitoring holds promise in predicting neurological functional prognosis and interventions for patients with aortic dissection. Conclusion Therefore, the primary objective of this study is to evaluate the effectiveness and reliability of various intraoperative neurological monitoring techniques, neuroimaging examinations, and biomarkers in predicting and assessing postoperative neurological outcomes in patients undergoing AAAD surgery.

Negative central activity in extremely preterm newborns: EEG characterization and relationship with brain injuries and neurodevelopmental outcome

ObjectiveTo characterize Negative Central Activity (NCA), an overlooked electroencephalographic activity of preterm newborns and investigate its relationship with brain injuries, dysfunction, and neurodevelopmental outcome. Methods109 preterm infants (23–28 weeks) were retrospectively included. NCA were selected at the negative peak on EEG. Individual averaged NCA were automatically characterized. Brain structural data were collected from cranial ultrasounds (cUS). The neurodevelopmental outcome at two years of age was assessed by the Denver Developmental Screening Test-II. ResultsThirty-six (33%) children showed NCA: 6,721 NCA were selected, a median of 75 (interquartile range, 25/157.3) per EEG. NCA showed a triphasic morphology, with a mean amplitude and duration of the negative component of 24.6–40.0 µV and 222.7–257.3 ms. The presence of NCA on EEG was associated with higher intraventricular haemorrhage (IVH) grade on the first (P = 0.016) and worst neonatal cUS (P < 0.001) and poorer neurodevelopmental outcome (P < 0.001). ConclusionsNCA is an abnormal EEG feature of extremely preterm newborns that may correspond to the functional neural impact of a vascular pathology. SignificanceThe NCA relationships with an adverse outcome and the presence/severity of IVH argue for considering NCA in the assessment of pathological processes in the developing brain network and for early outcome prediction.

Effects of self-efficacy on frontal midline theta power and golf putting performance.

Self-efficacy (SE), defined as an individual's belief in their ability to complete a task, is linked to top-down attentional control, influencing motor performance in sports. Although the behavioral effects of SE are well-documented, there is a lack of research on the mechanisms through which SE affects sports performance. Our research aims to elucidate the neurophysiological mechanisms that underlie the impact of self-efficacy on sports performance. Specifically, we intend to explore the effects of low and high SE on frontal midline theta (Fmθ) activity, associated with sustained top-down attention, and on motor performance. We recruited thirty-four professional golfers to perform 60 putts, during which their electroencephalographic activity was monitored. SE levels were assessed using a visual analog scale from 0 to 10 before each putt, with scores categorized into higher or lower SE based on each golfer's individual average score. Paired t-tests indicated that trials with higher SE scores had a higher putting success rate than those with lower SE scores (53.3% vs. 46.7%). Furthermore, trials associated with higher SE scores exhibited lower Fmθ activity compared to those with lower SE scores (4.49 vs. 5.18). Our results suggest that higher SE is associated with reduced top-down attentional control, leading to improved putting performance. These findings support Bandura's theory of SE, which suggests that the effects of efficacy beliefs are mediated by cognitive, motivational, emotional, and decision-making processes. This study sheds light on the intermediate processes of SE by examining its impact on the anticipation of outcomes, sports performance, and attentional control prior to putting.

EEG decoders track memory dynamics

Encoding- and retrieval-related neural activity jointly determine mnemonic success. We ask whether electroencephalographic activity can reliably predict encoding and retrieval success on individual trials. Each of 98 participants performed a delayed recall task on 576 lists across 24 experimental sessions. Logistic regression classifiers trained on spectral features measured immediately preceding spoken recall of individual words successfully predict whether or not those words belonged to the target list. Classifiers trained on features measured during word encoding also reliably predict whether those words will be subsequently recalled and further predict the temporal and semantic organization of the recalled items. These findings link neural variability predictive of successful memory with item-to-context binding, a key cognitive process thought to underlie episodic memory function.

Study on the Effect of Dalbergia pinnata (Lour.) Prain Essential Oil on Electroencephalography upon Stimulation with Different Auditory Effects.

Dalbergia pinnata (Lour.) Prain (D. pinnata) is a valuable medicinal plant, and its volatile parts have a pleasant aroma. In recent years, there have been a large number of studies investigating the effect of aroma on human performance. However, the effect of the aroma of D. pinnata on human psychophysiological activity has not been reported. Few reports have been made about the effects of aroma and sound on human electroencephalographic (EEG) activity. This study aimed to investigate the effects of D. pinnata essential oil in EEG activity response to various auditory stimuli. In the EEG study, 30 healthy volunteers (15 men and 15 women) participated. The electroencephalogram changes of participants during the essential oil (EO) of D. pinnata inhalation under white noise, pink noise and traffic noise stimulations were recorded. EEG data from 30 electrodes placed on the scalp were analyzed according to the international 10-20 system. The EO of D. pinnata had various effects on the brain when subjected to different auditory stimuli. In EEG studies, delta waves increased by 20% in noiseless and white noise environments, a change that may aid sleep and relaxation. In the presence of pink noise and traffic noise, alpha and delta wave activity (frontal pole and frontal lobe) increased markedly when inhaling the EO of D. pinnata, a change that may help reduce anxiety. When inhaling the EO of D. pinnata with different auditory stimuli, women are more likely to relax and get sleepy compared to men.

146 Intracranial Correlates of Fear Memory in Freely Moving Humans During Virtual Reality

INTRODUCTION: Distressing reactions to perceived threats in safe environments is a hallmark feature of anxiety-related disorders such as post-traumatic stress disorder (PTSD) and generalized anxiety disorder (GAD). The development of targeted neural circuit therapies requires an understanding of how neurophysiological activity relates to behavior and subjective emotional experience. METHODS: The task induced memories fear memories, a critical component of anxiety-related disorders etiology, using a novel virtual reality platform. Here, participants freely explored a virtual reality environment via walking or joystick. Participants were instructed to stop movement following color change of the room. When the room turned green (CS+), a noxious virtual reality stimulus (insect) attacked the participant (US) 6 seconds following color change onset. When the room turned blue (CS-), no noxious VR stimulus occurred. In addition to intracranial electroencephalography (iEEG) activity, we recorded physiological and behavioral metrics of fear. RESULTS: We found that the same neural signature indicative of fear memory retrieval in rodents (increased amygdala theta oscillations) was significantly elevated for the fear compared to the neutral cue in freely behaving humans. CONCLUSIONS: These findings represent an important step in translating decades of research in rodents to humans and provide putative electrophysiological signatures of fear behavior that can be used as putative targets for treatment with closed loop brain stimulation therapies. We believe that this combined collection of simultaneous autonomic responses to subjective emotional (fear ratings and physiology), clinical symptoms (anxiety scales) and neural activity has immense transdiagnostic clinical potential for anxiety-related disorders and can inform neurosurgical approaches to treating severe psychopathology.

EEG band power and phase‐amplitude coupling in patients with Dravet syndrome

AbstractObjectiveDravet syndrome (DS) is an epileptic encephalopathy caused by haploinsufficiency of the SCN1A gene. SCN1A gene deficiency limits the firing rates of fast‐spiking inhibitory interneurons, which should reflect in abnormal aggregate network oscillatory electroencephalography (EEG) activity that can be measured by spectral power and phase‐amplitude coupling (PAC) analysis. In this retrospective pilot study, we tested whether spectral EEG frequency band power and PAC metrics distinguish children with DS from age‐matched controls, an early step toward establishing EEG markers of target engagement by gene or drug therapy.MethodsEEG data were collected from patients with DS (N = 6) and age‐matched control pediatric participants (N = 11) and analyzed for cumulative spectral power and PAC and classification capacity of these metrics, by logistic regression analysis. For this initial spectral and PAC analysis, we focused on sleep EEG, where myogenic artifact is minimal and where δ–γ and θ–γ coupling is otherwise expected to be robust.ResultsCumulative δ (1– &lt;4 Hz) and θ (4–7 Hz) power was significantly reduced in the DS group, compared with age‐matched controls (p = 0.001 and p = 0.02, respectively). The δ power was a stronger classifier of separating DS from controls than θ power, with 87% and 83% accuracy, respectively. The γ power trended toward significant reduction (p = 0.08) in the DS group. We found significantly lower PAC between 1–2 Hz phase and 63–80 Hz amplitude in patients with DS compared with the age‐matched controls (p = 0.003), with 78% classification accuracy between groups for PAC.InterpretationIn this pilot study assessing EEG patterns during sleep, we found lower δ–θ power and PAC in patients with DS versus controls, which may reflect abnormal aggregate macroscale network communication patterns resulting from SCN1A deficiency. These measures may be useful metrics of therapeutic target engagement, particularly if the therapy restores the underlying DS pathophysiology. The sorting capacity of these metrics distinguished patients with DS from patients without DS and may in turn facilitate near‐future development of disease and therapy target engagement biomarkers in this syndrome.

Personalized repetitive transcranial magnetic stimulation guided by the spectral electroencephalogram may enhance and democratize therapy for autism spectrum disorder

Autism spectrum disorder (ASD) is a genetically heterogeneous group of neurodevelopmental disorders that affect 1 in 36 children (CDC data) and have recognizable core deficits in common, including repetitive stereotyped behaviors and difficulties in social interaction and communication. Pharmacological interventions moderate some ASD comorbidities, but do not alleviate core deficits and have significant side effects. While many behavioral therapies are inadequate, a very intensive form called applied behavioral analysis (ABA) is demonstrably effective. ABA is based on graded progression and immediate feedback. ABA has raised concerns over its intensive nature and has triggered unease about being too harsh. One solution may derive from a widespread hypothesis of ASD pathogenesis, which posits that the brain in ASD is overexcited, i.e., excitation dominates over inhibition, and electroencephalographic (EEG) alpha band oscillatory activity is altered, which degrades sensory input and task management. This may also disrupt the brain mesolimbic dopaminergic reward cascade causing social interactions to be unrewarding, leading to deleterious social behavior and poor communication. We hypothesize that a comprehensive, personalized form of spectral EEG guided repetitive transcranial magnetic stimulation that we term PrTMS, can normalize alpha EEG oscillations, E/I balance, and dopaminergic reward signaling, to facilitate improved psychosocial behavior. The goal is for PrTMS to synergize with behavioral interventions, so that ABA for example, could be less intensive. This may hold the promise of making self-determination more readily attainable for ASD persons, and could also democratize ASD therapy by rendering it more affordable.

Exposure to Non-Steady-State Oxygen Is Reflected in Changes to Arterial Blood Gas Values, Prefrontal Cortical Activity, and Systemic Cytokine Levels.

Onboard oxygen-generating systems (OBOGSs) provide increased inspired oxygen (FiO2) to mitigate the risk of neurologic injury in high altitude aviators. OBOGSs can deliver highly variable oxygen concentrations oscillating around a predetermined FiO2 set point, even when the aircraft cabin altitude is relatively stable. Steady-state exposure to 100% FiO2 evokes neurovascular vasoconstriction, diminished cerebral perfusion, and altered electroencephalographic activity. Whether non-steady-state FiO2 exposure leads to similar outcomes is unknown. This study characterized the physiologic responses to steady-state and non-steady-state FiO2 during normobaric and hypobaric environmental pressures emulating cockpit pressures within tactical aircraft. The participants received an indwelling radial arterial catheter while exposed to steady-state or non-steady-state FiO2 levels oscillating ± 15% of prescribed set points in a hypobaric chamber. Steady-state exposure to 21% FiO2 during normobaria produced arterial blood gas values within the anticipated ranges. Exposure to non-steady-state FiO2 led to PaO2 levels higher upon cessation of non-steady-state FiO2 than when measured during steady-state exposure. This pattern was consistent across all FiO2 ranges, at each barometric condition. Prefrontal cortical activation during cognitive testing was lower following exposure to non-steady-state FiO2 >50% and <100% during both normobaria and hypobaria of 494 mmHg. The serum analyte levels (IL-6, IP-10, MCP-1, MDC, IL-15, and VEGF-D) increased 48 h following the exposures. We found non-steady-state FiO2 levels >50% reduced prefrontal cortical brain activation during the cognitive challenge, consistent with an evoked pattern of neurovascular constriction and dilation.