Frontal EEG Activity Research Articles

Frontal EEG alterations induced by hippocampal amyloid pathology in rats

PurposeIn this study, it was aimed to determine the dose-dependent effects of hippocampal amyloid beta (Aβ) on frontal EEG activity and to elucidate the possible non-invasive biomarkers by recording spontaneous EEG in free-moving rats. Material and methodsMale albino Wistar rats aged 3 months were randomly divided into 4 groups (n ​= ​8 for each group), obtained by intrahippocampal injection of saline or different doses of Aβ1-42 i.e. 0.01 ​μg/μl, 0.1 ​μg/μl, and 1 ​μg/μl. After two weeks of recovery period, spontaneous EEG recordings were obtained from frontal regions and spectral power analyses were performed. ResultsWe detected a general slowdown in the brain activity two weeks after Aβ1-42 injection.We observed significant increases in frontal alpha power (p ​= ​0.0021) and significant decreases in frontal beta power (p ​= ​0.0003) between the Sh and Aβ1-42-injected groups. More specifically, the ratio of the frontal EEG beta and alpha power (rFBA) was significantly affected by the intrahippocampal injection of Aβ1-42 (p ​< ​0.0001). Also, we observed that rFBA was negatively and strongly correlated with hippocampal Aβ1-42 peptide levels (r ​= ​−0.781, p ​< ​0.0001). ConclusionOur findings indicate that spontaneous frontal EEG beta and alpha activity were significantly affected by the intrahippocampal injection of Aβ1-42. However, the results suggest that the power ratios of these bands are more sensitive to the hippocampal amyloid pathology. As such, it is proposed that the rFBA may be a more effective biomarker for diagnosing hippocampal pathology induced by Aβ1-42.

The association between working memory precision and the nonlinear dynamics of frontal and parieto-occipital EEG activity

Electrophysiological working memory (WM) research shows brain areas communicate via macroscopic oscillations across frequency bands, generating nonlinear amplitude modulation (AM) in the signal. Traditionally, AM is expressed as the coupling strength between the signal and a prespecified modulator at a lower frequency. Therefore, the idea of AM and coupling cannot be studied separately. In this study, 33 participants completed a color recall task while their brain activity was recorded through EEG. The AM of the EEG data was extracted using the Holo-Hilbert spectral analysis (HHSA), an adaptive method based on the Hilbert-Huang transforms. The results showed that WM load modulated parieto-occipital alpha/beta power suppression. Furthermore, individuals with higher frontal theta power and lower parieto-occipital alpha/beta power exhibited superior WM precision. In addition, the AM of parieto-occipital alpha/beta power predicted WM precision after presenting a target-defining probe array. The phase-amplitude coupling (PAC) between the frontal theta phase and parieto-occipital alpha/beta AM increased with WM load while processing incoming stimuli, but the PAC itself did not predict the subsequent recall performance. These results suggest frontal and parieto-occipital regions communicate through theta-alpha/beta PAC. However, the overall recall precision depends on the alpha/beta AM following the onset of the retro cue.

A Pilot Investigation Evaluating Relative Changes in Fronto-Occipital Alpha and Beta Spectral Power as Measurement of Anesthesia Hypnotic Depth.

Other than clinical observation of a patient's vegetative response to nociception, monitoring the hypnotic component of general anesthesia (GA) and unconsciousness relies on electroencephalography (EEG)-based indices. These indices exclusively based on frontal EEG activity neglect an important observation. One of the main hallmarks of transitions from wakefulness to GA is a shift in alpha oscillations (7.5-12.5 Hz activity) from occipital brain regions toward anterior brain regions ("alpha anteriorization"). Monitoring the degree of this alpha anteriorization may help to guide induction and maintenance of hypnotic depth and prevent intraoperative awareness. However, the occipital region of the brain is completely disregarded and occipital alpha as characteristic of wakefulness and its posterior-to-anterior shift during induction are missed. Here, we propose an application of Narcotrend's reduced power alpha beta (RPAB) index, originally developed to monitor differences in hemispheric perfusion, for determining the ratio of alpha and beta activity in the anterior-posterior axis. Perioperative EEG data of 32 patients undergoing GA in the ophthalmic surgery department of Bern University Hospital were retrospectively analyzed. EEG was recorded with the Narcotrend® monitor using a frontal (Fp1-Fp2) and a posterior (T9-Oz) bipolar derivation with reference electrode over A2. The RPAB index was computed between both bipolar signals, defining the fronto-occipital RPAB (FO-RPAB). FO-RPAB was analyzed during wakefulness, GA maintenance, and emergence, as well as before and after the intraoperative administration of a ketamine bolus. FO-RPAB was compared with a classical quantitative EEG measure-the spectral edge frequency 95% (SEF-95). A significant shift of the FO-RPAB was observed during both induction of and emergence from GA ( P < .001). Interestingly, the additional administration of ketamine during GA did not lead to a significant change in FO-RPAB ( P = 0.81). In contrast, a significant increase in the SEF-95 in the frontal channel was observed during the 10-minute period after ketamine administration ( P < .001). FO-RPAB appears to qualify as a marker of unconsciousness, reflecting physiological fronto-occipital activity differences during GA. In contrast to frontal SEF-95, it is not disturbed by additional administration of ketamine for analgesia.

Automatic Discrimination of Task Difficulty Predicted by Frontal EEG Activity During Working Memory Tasks in Young and Elderly Drivers

It is desirable to prevent traffic accidents by focusing on elderly people’s brain characteristics. The attention level during driving depends on the amount of information-processing resources. This study first aimed at investigating the effects of the change in attention levels on the electroencephalogram (EEG) waves during the graded working memory tasks for a traffic situation. With the increase in memory loads, reaction times were delayed in the elderly than the young group. The difficult tasks activated the induced [Formula: see text] and [Formula: see text] powers in the frontal midline area primarily in the elderly, during the selective task for a target. The elderly could retain the attention level because of the activated slow EEG responses, regardless of the task performance, although the increased [Formula: see text] wave may reflect drowsiness. Because the assistance system based on drivers’ brain signals can prevent car accidents, this study also aimed at evaluating the analytical method to automatically discriminate the different attentional tasks from the EEG signals. Compared with [Formula: see text]-nearest neighbors and artificial neural networks, support vector machines more accurately classified attention levels (i.e., task difficulty) during working memory tasks reflecting a change in the induced [Formula: see text] and [Formula: see text] waves. This result can be related to a brain-computer interface system to judge the task difficulty during driving and alert a driver to danger. The experimental tasks for this study were limited because they involved simulations only in which participants recognized guided boards and removed irrelevant information. Real-time judgments should be investigated using EEG data to improve systems that can alert drivers to oncoming dangers.

Brain rhythms: How control gets into working memory

New research suggests that frontal midline theta EEG activity in humans controls activity in parietal cortex associated with memory maintenance. In turn, the speed of this frontal theta is modulated by the number of items to be handled, potentially indicating strong bidirectional communication within a fronto-parietal network.

Slow-Wave EEG Activity Correlates with Impaired Inhibitory Control in Internet Addiction Disorder.

Impaired inhibitory control is a core feature of internet addiction disorder (IAD). It is therefore of interest to determine the neurophysiological markers associated with it. The present study aimed to find such biomarkers with a resting-state electroencephalogram (EEG). We specifically used scores on the Chinese Internet Addiction Scale revised edition (CIAS-R) to divide 46 participants into two groups: the IAD group (>53, n = 23) and control group (<46, n = 23). Both behavioral aspects (Go/NoGo responses and impulsivity) and EEG were measured in the lab. The results suggest that the IAD group presented a decreased slow-wave (1–8 Hz) absolute power across the whole brain. The slow-wave activities in the frontal areas were also correlated with the commission error rate in the Go/NoGo task in the IAD group. These results imply that the frontal slow-wave EEG activity may serve as a neurophysiological marker of IAD, helping to understand the underlying neural mechanisms of inhibitory control deficits in IAD and point to possible interventions.

Individual differences in error-related frontal midline theta activity during visuomotor adaptation

Post-feedback frontal midline EEG activity has been found to correlate with error magnitude during motor adaptation. However, the role of this neuronal activity remains to be elucidated. It has been hypothesized that post-feedback frontal midline activity may represent a prediction error, which in turn may be directly related to the adaptation process or to an unspecific orienting response. To address these hypotheses, we replicated a previous visuomotor adaptation experiment with very small perturbations, likely to invoke implicit adaptation, in a new group of 60 participants and combined it with EEG recordings. We found error-related peaks in the frontal midline electrodes in the time domain. However, these were best understood as modulations of frontal midline theta activity (FMT, 4–8 Hz). Trial-level differences in FMT correlated with error magnitude. This correlation was robust even for very small errors as well as in the absence of imposed perturbations, indicating that FMT does not depend on explicit or strategic re-aiming. Within participants, trial-level differences in FMT were not related to between-trial error corrections. Between participants, individual differences in FMT-error-sensitivity did not predict differences in adaptation rate. Taken together, these results imply that FMT does not drive implicit motor adaptation. Finally, individual differences in FMT-error-sensitivity negatively correlate to motor execution noise. This suggests that FMT reflects saliency: larger execution noise means a larger standard deviation of errors so that a fixed error magnitude is less salient. In conclusion, this study suggests that frontal midline theta activity represents a saliency signal and does not directly drive motor adaptation.

The relationship between habitual use and real-time emotion regulation strategies in adolescents: Evidence from frontal EEG asymmetry

Past research on emotion regulation has shown that cognitive reappraisal is a healthier and more effective emotion regulation strategy than expressive suppression. However, there are few studies in this field that combine real-time emotion regulation with the use of habitual emotion regulation strategies to observe the patterns of brain activity, and fewer studies focusing on adolescents. Frontal electroencephalography (EEG) asymmetry reflects the difference between brain activation in left and right frontal areas and is widely viewed as an effective biomarker of emotional reactivity and regulation. The present study investigated the asymmetry of the frontal EEG activity during adolescents' emotional regulation, and explored its relationship with adolescents’ habitual use of emotional regulation strategies. Habitual use of cognitive reappraisal and expressive suppression was measured with the emotion regulation questionnaire (ERQ). EEG was recorded from 54 adolescents (24 boys & 30 girls, Mage = 12.59), during the Reactivity and Regulation-Image Task. Results showed that adolescents who used cognitive reappraisal strategies more habitually exhibited greater left frontal asymmetry during real-time enhancement or reduction of negative emotions. In contrast, no significant correlation was found between habitual use of suppression and frontal alpha asymmetry. The results provide neurological evidence that, for adolescents, the use of habitual emotion regulation strategies may affect real-time emotion regulation, adolescents who use cognitive reappraisal more frequently are more capable or more prone to recruit appropriate brain regions in situations that need to regulate negative emotions. This reinforces the importance of the formation and use of correct emotion regulation habits for adolescents.

Longitudinal investigation of shyness and physiological vulnerability: Moderating influences of attention biases to threat and safety.

Shyness has long been identified as a vulnerability factor to developing psychosocial problems, but there is heterogeneity in these observed outcomes. One potential factor underlying these relations is individual differences in threat sensitivity. Using a longitudinal design, we examined whether attentional biases toward social threat and safety measured during adulthood moderated the association between shyness measured in emerging adulthood (N = 83, nfemale = 48; Mage = 23.56 years, SDage = 1.09 years) and frontal electroencephalogram (EEG) asymmetry at rest, a physiological index of vulnerability to psychopathology, measured nearly a decade later in adulthood (Mage = 31.68 years, SDage = 2.27 years). We found that only biases to threat moderated the association between shyness and resting frontal EEG asymmetry longitudinally. In individuals who displayed relative vigilance to social threat, shyness was associated with greater relative right frontal EEG activity at rest (i.e., increased physiological vulnerability). These findings suggest that attentional biases to threat may play a role in understanding the relation between shyness and some known physiological vulnerabilities to psychopathology in adults.

Affectionate Touch in the Context of Breastfeeding and Maternal Depression Influences Infant Neurodevelopmental and Temperamental Substrates

Background: While numerous studies have demonstrated maternal depression’s influence on infant brain development, few studies have examined the changes that occur as a consequence of co-occurring experiential factors that affect quality of mother and infant affectionate touch as well as infant temperament and neurophysiological systems. The aim of the study was to examine the interactive effects of maternal depression and breastfeeding on mother and infant affectionate touch and infant temperament and cortical maturation patterns across early development. Methods: 113 mothers and their infants participated when infants were 1 and 3 months of age. Questionnaires to assess maternal depressive symptoms, feeding, and temperament were completed. Tonic EEG patterns (asymmetry and left and right activity) were collected and the dyads were video-recorded during feeding to assess mother and infant affectionate touch patterns. Results: Data analysis showed that EEG activity and mother-infant affectionate touch differed as a function of mood and feeding method. Notably, only infants of depressed mothers that bottle-fed showed right frontal EEG asymmetry and attenuated change in the left frontal region across 3 months. Breastfeeding positively impacted affectionate touch behaviors and was associated with increased left and decreased right frontal EEG activation even for depressed groups. Furthermore, a model incorporating physiology, maternal depression, touch, temperament, and feeding indicated significant prediction for infant affectionate touch (with breastfeeding and affectively positive temperament demonstrating the strongest prediction). Con­clusion: The findings suggest that breastfeeding and the infant’s positive temperament influence mother-infant affectionate touch patterns and result in neuroprotective outcomes for infants, even those exposed to maternal depression within early development.

Intolerant of being tolerant? Examining the impact of intergroup toleration on relative left frontal activity and outgroup attitudes

Increases in cultural and religious diversity have led to calls for toleration of differences, although it is unclear how calling for toleration impacts people’s affective and attitudinal responses. The present research conducted in a small western nation examines if calling for toleration of Muslim minority practices elicits an aggressive backlash against the group amongst those relatively conservative, using relative left frontal EEG activity to examine the motivational processes involved. Non-Muslim participants from New Zealand (N = 172) self-reported their political orientation before being randomly assigned to a toleration or control condition involving writing and reflection tasks about Muslims. Participants then evaluated various groups including Muslims while EEG was recorded. Results revealed that among those relatively conservative, toleration produced higher levels of relative left frontal activity, which in turn led to more negative evaluations of Muslims (relative to control participants). However, for those relatively liberals, toleration had no impact on neuropsychological or attitudinal responses relative to controls. Collectively, these findings suggest that intergroup toleration may backfire amongst those relatively conservative, undermining its intended purpose.

Transacting brains: testing an actor-partner model of frontal EEG activity in mother-infant dyads.

Studies have long observed the bidirectional nature of mother-infant relationships. While behavioral studies have shown that mothers high in social avoidance tendencies can influence the development of these traits in their offspring, the neurophysiological mechanisms underlying this phenomenon, and the role that the infants play, are not well understood. Here we acquired frontal electroencephalogram asymmetry (FA) data simultaneously in 40 mother-infant dyads (Mage mother = 31.6 years; Mage infant = 9 months). Using an actor-partner interdependence model, we examined whether mother (or infant) resting-state FA predicted infant (or mother) FA during two subsequent emotion-eliciting conditions (happy and fear). Maternal social approach versus avoidance traits were assessed as moderators to examine the impact of maternal characteristics on these mother-infant FA relations. In dyads led by mothers with high social avoidance/low social approach characteristics, maternal resting-state FA predicted infant FA during both emotion-eliciting conditions. We did not observe any effects of infant FA on mothers. Therefore, we speculate that individual differences in FA patterns might be a putative brain mechanism through which socially avoidant mothers transfer affective/behavioral information to their infants.

Frontal electroencephalogram activity during emergence from general anaesthesia in children with and without emergence delirium

BackgroundEmergence delirium (ED) in children after general anaesthesia causes significant distress in patients, their family members, and clinicians; however, electroencephalogram (EEG) markers predicting ED have not been fully investigated. MethodsThis prospective, single-centre observational study enrolled children aged 2–10 yr old under sevoflurane anaesthesia. ED was assessed according to Diagnostic and Statistical Manual of Mental Disorders (DSM) IV or 5 criteria. The relative power of low-frequency (delta and theta) and high-frequency (alpha and beta) EEG waves during the emergence period was compared between the children with and without ED. The linear relationships between the relative power and peak Paediatric Assessment of Emergence Delirium (PAED) score were investigated. ResultsAmong the 60 patients, 22 developed ED (ED group), whereas the other 38 did not (non-ED group). The relative power of the delta wave was higher (mean [standard deviation], 0.579 [0.083] vs 0.453 [0.090], respectively, P<0.001) in the ED group, whereas that of the alpha and beta waves was lower in the ED group, than in the non-ED group (0.155 [0.063] vs 0.218 [0.088], P=0.005 and 0.114 [0.069] vs 0.186 [0.070], P<0.001, respectively). The areas under the receiver operating characteristic curves of the relative power of the delta wave, low-to-high frequency power ratio, and delta-to-alpha ratio were 0.837 (95% confidence interval, 0.737–0.938), 0.835 (0.735–0.934), and 0.768 (0.649–0.887), respectively. The relative power of the delta wave and the two ratios had a positive linear relationship with the peak PAED scores. ConclusionsPaediatric patients developing ED have increased low-frequency (delta) frontal EEG activity with reduced high-frequency (alpha and beta) activity during emergence from general anaesthesia. Clinical trial registrationNCT03797274.

Development of Frontal EEG Differences Between Eyes-Closed and Eyes-Open Resting Conditions in Children: Data From a Single-Channel Dry-Sensor Portable Device.

Changes in EEG when moving from an eyes-closed to an eyes-open resting condition result from bottom-up sensory processing and have been referred to as activation. In children, activation is characterized by a global reduction in alpha, frontally present reductions for delta and theta, and a frontal increase for beta. The present study aimed to replicate frontal EEG activation effects using single-channel, dry-sensor EEG, and to extend current understanding by examining developmental change in children. Frontal EEG was recorded using a single-channel, dry-sensor EEG device while 182 children aged 7 to 12 years completed eyes-closed resting (EC), eyes-open resting (EO), and focus (FO) tasks. Results indicated that frontal delta, theta, and alpha power were reduced, and frontal beta power was increased, in the EO compared with the EC condition. Exploratory analysis of a form of top-down activation showed that frontal beta power was increased in the FO compared with to the EO condition, with no differences for other bands. The activation effects were robust at the individual level. The bottom-up activation effects reduced with age for frontal delta and theta, increased for frontal alpha, with no developmental change for top-down or bottom-up frontal beta activation. These findings contribute further to validation of the single-channel, dry-sensor, frontal EEG and provide support for use in a range of medical, therapeutic, and clinical domains.

Plasma nitrite as an indicator of cerebral ischemia during extracranial/intracranial bypass surgery in moyamoya patients

Background and PurposeNitric oxide (NO) plays a key role in ischemia and shows potential as a biomarker for ischemia. We measured mixed venous nitrite (NO2-) as a proxy for NO, during controlled cerebral ischemia in patients with moyamoya disease (MMD) during direct extracranial/intracranial (EC/IC) bypass surgery with temporary occlusion of the M4 branch of the middle cerebral artery (MCA) to permit anastomosis with the superficial temporal artery (STA). This small, focal ischemic event is not reliably detected using cerebral oximetry, somatosensory evoked potentials (SSEPs) or electroencephalography (EEG). MethodsWe enrolled nine adult MMD patients (n=8 female, n=1 male) undergoing direct EC/IC bypass surgery. Nitrite was measured at least one hour prior to MCA occlusion, and before, during and after anastomosis. Cortical function was monitored using either multi-lead EEG and SSEPs, or frontal EEG activity. ResultsMixed venous NO2- was significantly elevated (p<0.05) within 12 min following arterial occlusion vs. baseline. An M4 branch of the MCA was cross clamped for a median duration of 18 (IQR = 5) minutes during anastomosis. One patient with elevated NO2- showed a transient neurologic deficit that resolved 3 days post-operatively. ConclusionsMixed venous NO2- was significantly elevated shortly following cerebral artery occlusion vs. baseline in a majority of the study subjects, suggesting that NO2- is a potential biomarker for ischemia. Since all patients received identical burst suppression anesthesia and vasopressors, the fact that NO2- was not elevated during cross-clamp in all patients supports the conclusion that the NO2- elevation is likely due to ischemia.

Right frontal brain activity at rest in the early 20s predicts threat-related bias ten years later among extremely low birth weight survivors

Exposure to early adversity is known to shape brain-behavior relations, which in turn can lead to hypersensitivity to threat and an increased risk of developing a range of psychopathologies. To date, much of the work in this area has considered exposure to negative post-natal events (e.g., maltreatment) in shaping these relations in humans. Here we examined the influence of prenatal adversity in the form of a suboptimal intra-uterine environment (i.e., being born at extremely low birth weight; [ELBW i.e., < 1000 g]). ELBW babies are the tiniest and most at-risk infants and are known to be at risk for internalizing problems (e.g., depression and anxiety) from childhood through early adulthood. However, we know relatively little about the mechanism(s) underlying this risk. Using the oldest known prospectively followed cohort of ELBW survivors, we examined associations among birth weight status, individual differences in frontal brain electrical activity (EEG) at rest (a marker of affective style) at age 22−26 years, and threat-related biases to angry faces (using the dot probe task) at 30−35 years of age. We found that among ELBW adults, those displaying greater relative right frontal EEG activity at rest exhibited greater vigilance to angry faces than those exhibiting greater relative left frontal EEG activity (n = 34, r = -0.40, p = .02). This pattern was not observed among normal birth weight (NBW) control participants (n = 47, r = .08, p > .05). As well, the relation between frontal EEG asymmetry and vigilance to angry faces was stronger for the ELBW group versus the NBW group (z = -2.21, p = .03). These findings suggest that exposure to significant prenatal adversity may have long-term programming effects on biological and cognitive systems associated with emotion regulatory processes in the fourth decade of life. We speculate that these vulnerabilities may contribute to making some ELBW survivors susceptible to psychopathology.

Exploratory Analysis of Behavioral Impulsivity, Pro-inflammatory Cytokines, and Resting-State Frontal EEG Activity Associated With Non-suicidal Self-Injury in Patients With Mood Disorder.

Introduction: Non-suicidal self-injury (NSSI) is a rapidly increasing mental health problem that requires more clinical attention. In this study, we aimed to explore the biobehavioral markers of NSSI in participants with mood disorders.Methods: A total of 45 participants with mood disorders (bipolar I, II, and major depressive disorder) were included in the study. Behavioral impulsivity was measured using the immediate memory task (IMT)/delayed memory task (DMT) and the go-no-go (GNG) tests. Plasma levels of tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1 β), and interleukin 6 (IL-6) and resting-state quantitative electroencephalography (qEEG) were measured.Results: The NSSI group had shorter GNG reaction time (GNG-RT) and higher TNF-α levels compared to the non-NSSI group. TNF-α was positively correlated with frontal theta power. In addition, GNG-RT showed a significant positive association with frontal alpha activity.Conclusion: NSSI in mood disorders was associated with increased behavioral impulsivity and greater inflammation. Increased pro-inflammatory cytokines were associated with frontal theta power. Increased inflammation might change major neurotransmitter metabolism, which eventually affects frontal function and decreases response inhibition. Further studies to explore their causal relationship are warranted.

학업스트레스 수준에 따른 향기흡입이 인지과제 수행동안 전두엽 뇌파활성도에 미치는 영향

이 연구는 학업스트레스 수준에 따른 향기 흡입이 인지과제 수행 동안 어떤 차이를 보이는지 알아보고자 하였다. 이를 위하여 여자 중학생 140명을 대상으로 학업스트레스를 검사한 후, 학업스트레스가 높은 20명과 낮은 20명으로 집단을 구분하였다. 그런 다음 향기 흡입 전과 후에 인지과제를 각각 5분 10초간 수행하여 전두엽 뇌파 활성도에 어떠한 차이가 있는지를 알아봄으로써 학업스트레스 수준에 따른 향기의 활용방안을 모색해보고자 하였다. 분석결과는 다음과 같다. 첫 번째, 전두엽 뇌파 활성도의 변화를 살펴보면, 우측 전두엽에서 집단 간 차이를 보였다. 낮은 난이도에서 향기 흡입 후에 학업스트레스가 낮은 집단은 Alpha파가 증가하고, Low-Beta파는 감소하였으며, 높은 집단에서는 상반되게 나타났다. 높은 난이도에서는 학업스트레스가 낮은 집단이 정신적 스트레스를 반영하는 High-Beta/Alpha 비율이 감소되었으며, 낮은 집단은 증가되었다. 이러한 결과는 학업스트레스가 낮은 상태일 때 향기흡입이 정신적 스트레스 감소시켜 학습 효율성을 향상시키는데 더 효과적임을 의미한다. 두 번째, 좌·우 비대칭 변화를 살펴보면, 학업스트레스가 높은 집단보다 낮은 집단의 Theta, Mid-Beta, High-Beta에서 향기 흡입 후에 좌뇌가 활성화되었다. 이러한 향기 흡입으로 유도된 좌뇌의 비대칭적 활성은 인지과제의 적응력과 효율성을 높여주는 방향으로 향기흡입의 효과가 유도될 수 있음을 의미하였다.

Altered Causal Coupling Pathways within the Central-Autonomic-Network in Patients Suffering from Schizophrenia.

The multivariate analysis of coupling pathways within physiological (sub)systems focusing on identifying healthy and diseased conditions. In this study, we investigated a part of the central-autonomic-network (CAN) in 17 patients suffering from schizophrenia (SZO) compared to 17 age–gender matched healthy controls (CON) applying linear and nonlinear causal coupling approaches (normalized short time partial directed coherence, multivariate transfer entropy). Therefore, from all subjects continuous heart rate (successive beat-to-beat intervals, BBI), synchronized maximum successive systolic blood pressure amplitudes (SYS), synchronized calibrated respiratory inductive plethysmography signal (respiratory frequency, RESP), and the power PEEG of frontal EEG activity were investigated for 15 min under resting conditions. The CAN revealed a bidirectional coupling structure, with central driving towards blood pressure (SYS), and respiratory driving towards PEEG. The central-cardiac, central-vascular, and central-respiratory couplings are more dominated by linear regulatory mechanisms than nonlinear ones. The CAN showed significantly weaker nonlinear central-cardiovascular and central-cardiorespiratory coupling pathways, and significantly stronger linear central influence on the vascular system, and on the other hand significantly stronger linear respiratory and cardiac influences on central activity in SZO compared to CON, and thus, providing better understanding of the interrelationship of central and autonomic regulatory mechanisms in schizophrenia might be useful as a biomarker of this disease.

Nasal skin temperature reveals changes in arousal levels due to time on task: An experimental thermal infrared imaging study

Infrared thermography, thanks to technological developments and lowering prices, is now getting considerable attention as a potential arousal monitor in the safety industry. Nasal skin temperature might be a valid index to track physiological variations due to reduced arousal levels, and its use could prevent a drowsiness-related deterioration of performance. However, the few studies that have investigated nasal skin temperature in applied settings have had inconsistent results. Here, we assessed the validity of nasal skin temperature to monitor changes in arousal levels (from alertness to drowsiness). The participants performed a 2-h simulated driving task while we simultaneously recorded their nasal skin temperature, brain activity (we used frontal delta electroencephalographic [EEG] activity as the reference index of alertness), and driving performance (speeding time). For those variables, we calculated growth curve models. We also collected subjective ratings of alertness and fatigue before and after the driving session. We found that the nasal skin temperature showed a cubic trajectory (it increased for the first 75 min, and then it began to decrease, but such deceleration gradually diminished over time). As expected, frontal delta EEG activity showed an inverted U-shaped quadratic trend (EEG power increased for the first hour and half, and gradually decreased during the last thirty minutes). The speeding time exhibited a similar pattern of change. Subjective sleepiness and fatigue increased after the task. Overall, our results suggest that nasal skin temperature seems to be a valid measure of arousal variations while performing a complex and dynamic everyday task.