Delta Event-related Oscillations Research Articles

Age-Related Aspects of Sex Differences in Event-Related Brain Oscillatory Responses: A Turkish Study.

Earlier research has suggested gender differences in event-related potentials/oscillations (ERPs/EROs). Yet, the alteration in event-related oscillations (EROs) in the delta and theta frequency bands have not been explored between genders across the three age groups of adulthood, i.e., 18-50, 51-65, and >65 years. Data from 155 healthy elderly participants who underwent a neurological examination, comprehensive neuropsychological assessment (including attention, memory, executive function, language, and visuospatial skills), and magnetic resonance imaging (MRI) from past studies were used. The delta and theta ERO powers across the age groups and between genders were compared and correlational analyses among the ERO power, age, and neuropsychological tests were performed. The results indicated that females displayed higher theta ERO responses than males in the frontal, central, and parietal regions but not in the occipital location between 18 and 50 years of adulthood. The declining theta power of EROs in women reached that of men after the age of 50 while the theta ERO power was more stable across the age groups in men. Our results imply that the cohorts must be recruited at specified age ranges across genders, and clinical trials using neurophysiological biomarkers as an intervention endpoint should take gender into account in the future.

Tailoring transcranial alternating current stimulation based on endogenous event-related P3 to modulate premature responses: a feasibility study.

Transcranial alternating current stimulation (tACS) is a brain stimulation method for modulating ongoing endogenous oscillatory activity at specified frequency during sensory and cognitive processes. Given the overlap between event-related potentials (ERPs) and event-related oscillations (EROs), ERPs can be studied as putative biomarkers of the effects of tACS in the brain during cognitive/sensory task performance. This preliminary study aimed to test the feasibility of individually tailored tACS based on individual P3 (latency and frequency) elicited during a cued premature response task. Thus, tACS frequency was individually tailored to match target-P3 ERO for each participant. Likewise, the target onset in the task was adjusted to match the tACS phase and target-P3 latency. Twelve healthy volunteers underwent tACS in two separate sessions while performing a premature response task. Target-P3 latency and ERO were calculated in a baseline block during the first session to allow a posterior synchronization between the tACS and the endogenous oscillatory activity. The cue and target-P3 amplitudes, delta/theta ERO, and power spectral density (PSD) were evaluated pre and post-tACS blocks. Target-P3 amplitude significantly increased after activetACS, when compared to sham. Evoked-delta during cue-P3 was decreased after tACS. No effects were found for delta ERO during target-P3 nor for the PSD and behavioral outcomes. The present findings highlight the possible effect of phase synchronization between individualized tACS parameters and endogenous oscillatory activity, which may result in an enhancement of the underlying process (i.e., an increase of target-P3). However, an unsuccessful synchronization between tACS and EEG activity might also result in a decrease in the evoked-delta activity during cue-P3. Further studies are needed to optimize the parameters of endogenous activity and tACS synchronization. The implications of the current results for future studies, including clinical studies, are further discussed since transcranial alternating current stimulation can be individually tailored based on endogenous event-related P3 to modulate responses.

Event-related Oscillations to Emotional Faces are Related to a History of Internalizing Disorders.

Event-related oscillations (EROs) may represent sensitive biomarkers or endophenotypes for disorders that underlie risk behaviors such as suicidal thoughts and actions. In this study, young adults of American Indian (AI) (n = 821) and Mexican American (MA) (n = 721) ancestry (age 18-30 yrs) were clinically assessed for internalizing and externalizing disorders, and an internalizing scale was generated by extracting core diagnostic items from 6 lifetime DSM5-compatible diagnoses (social phobia, panic disorder, agoraphobia, obsessive compulsive disorder, post-traumatic stress disorder, major depressive episode) and symptoms of suicidality. EROs were generated to sad, happy and neutral faces, and energy and phase locking of delta ERO oscillations were assessed in frontal areas. An increase in delta ERO energy was found in the frontal lead (FZ) following presentation of the sad facial expressions in those with a history of 10 or more internalizing symptoms compared to those with no symptoms. Increases in delta ERO energy in FZ were also associated with a diagnosis of major depressive disorder (MDD), but not with anxiety disorders or antisocial personality disorder/conduct disorders (ASP). Major depression was also associated with increases in cross-cortical phase-locking (FZ-PZ). A decrease in the percentage of correctly identified neutral faces also was seen among those with 10 or more internalizing symptoms compared to those without internalizing symptoms, and in those with anxiety disorders, but not in those with ASP or MDD as compared to their controls. These findings suggest ERO measures may represent important potential biomarkers of depressive disorders as well as risk indicators for suicidal behaviors.

Event‐Related Delta Oscillations are Diminished in Parkinson’s Disease with Different Cognitive Status: A Longitudinal EEG Study

AbstractBackgroundThe neurophysiological differences between Parkinson’s disease mild cognitive impairment (PD‐MCI) and cognitively normal Parkinson’s disease (PD‐CN) have been poorly understood, covering limited electrophysiological interpretation. Delta event‐related oscillations (ERO) are recognized as a useful electrophysiological indicator of cognitive decline (Güntekin et al., 2018; Yener et al., 2019). The aim of the present study was to investigate baseline and follow‐up delta EROs of individuals with PD‐CN and PD‐MCI in comparison with healthy controls (HC).MethodsThirty one PD‐CN, 23 PD‐MCI, and 30 demographically‐matched HC were included. All examinations were applied to participants in a time period of 12.50±0.80 months. A comprehensive neuropsychological test battery was used for the PD‐MCI classification (Litvan et al., 2012). EEGs were recorded during visual oddball paradigm. The maximum peak‐to‐peak event‐related delta (0.5‐3.5 Hz) responses of the groups to the target stimulus were measured. Repeated measures ANOVA included Group (3 levels: HC, PD‐CN, PD‐MCI) as a between‐subject factor, Time (2 levels: baseline, follow‐up), and Anterior‐Posterior Electrode Location [AP (6 levels: frontal, central, temporal, temporoparietal, parietal, occipital)] as a within‐subject factor.ResultsThere was an interaction effect for Group x Time on event‐related delta responses [F(2,81)=3.650, p=0.030], indicating follow‐up delta EROs were reduced only in PD‐CN group (Figure 1). Further analyses revealed that there was an interaction effect for AP x Group on baseline delta responses [F(10,405)=11.629, p<0.001], and follow‐up delta [F(10,405)=9.569, p<0.001] responses. At baseline, PD‐MCI had reduced delta EROs in all electrode locations except occipital than both PD‐CN and HC, while PD‐CN had reduced delta responses than HC over frontal and central areas (for all; p<0.030) (Figure 2). At follow‐up, higher delta responses were detected in HC compared to both PD‐CN and PD‐MCI over all locations except occipital area (for all; p<0.001) (Figure3).ConclusionsThe current study revealed that longitudinal delta ERO reduction was apparent only in PD‐CN group. Individuals with PD‐MCI demonstrated decline at both baseline and follow‐up assessments. These findings may be interpreted as diminished delta EROs can be a successful indicator of subtle cognitive alterations in PD‐CN before neuropsychological assessments.

Alterations of Event-Related Oscillations in Patients With Parkinson’s Disease

The purpose of this study was to investigate changes in delta event-related oscillations (EROs) in younger and older healthy elderly subjects. We hypothesized that delta EROs were affected by age-related changes, which could be reflected in a visual oddball paradigm.The study included two groups of subjects, 17 younger healthy elderly (mean age: 63.1 ± 2.8 years) and 17 gender- and education-matched older healthy elderly (mean age: 79.6 ± 5.2 years), who performed a visual oddball paradigm. EEG was recorded from F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz and O2 locations. Peak-to-peak amplitudes of delta (0.5–3 Hz) target ERO responses during the post-stimulus 0–800 ms time window were measured. Repeated measures of ANOVA was used to analyze four locations (frontal, central, parietal, occipital), at three sagittal (left, midline, right) sites. Independent t-tests were applied for post-hoc analyses.The older healthy elderly group had 16–25% lower values for the maximum peak-to-peak amplitudes of delta ERO compared with the younger healthy elderly group over frontal (p < 0.003), central (p < 0.0001) and parietal (p < 0.007) locations [F3.96 = 4.396, p = 0.015]. Furthermore, there was a moderate negative correlation between age and Cz peak-to-peak amplitude of target delta responses [r = − 0.401, p < 0.02], indicating the notion that peak-to-peak amplitude of Cz decreases as age increases.In the present study younger healthy elderly showed significantly higher event-related delta responses than older healthy elderly at frontal, central and parietal locations. Moreover, delta ERO responses decreased in accordance with age.

Delta Event-Related Oscillations Are Related to a History of Extreme Binge Drinking in Adolescence and Lifetime Suicide Risk.

Alcohol exposure typically begins in adolescence, and heavy binge drinking is associated with health risk behaviors. Event-related oscillations (EROs) may represent sensitive biomarkers or endophenotypes for early alcohol exposure as well as other risk behaviors such as suicidal thoughts and actions. In this study, young adults (age 18–30 years) of American Indian (AI) (n = 479) and Mexican American (MA) (n = 705) ancestry were clinically assessed, and EROs were generated to happy, sad and neutral faces. Extreme adolescent binge drinking (10+ drinks) was common (20%) in this population of AI/MA and associated with a significantly increased risk of a lifetime history of suicidal acts (SA, suicide attempts, deaths) but not suicidal thoughts (ST, ideation, plans). ST were reported among MA participants, whereas SA were more common among AI young adults. Extreme adolescent binge drinking was also associated with errors in detection of sad and neutral faces, increases in delta ERO energy, and decreases in phase locking (PL), particularly in parietal areas. A lifetime history of ST was associated with increases in delta ERO energy and PL, whereas SA were associated with decreases in both. These studies suggest that ERO measures may represent important potential biomarkers of adolescent extreme binge drinking and risk for suicidal behaviors.

Evoked and induced EEG oscillations to visual targets reveal a differential pattern of change along the spectrum of cognitive decline in Alzheimer's Disease

In recent years, quantitative variables derived from the electroencephalogram (EEG) attract an increasing interest for the evaluation of neurodegenerative diseases, as EEG registers the neuro-electric activity with a high temporal resolution and provides a cost-effective and easily accessible, non-invasive method. Event-related oscillations (EROs) as oscillatory responses in the EEG to specific events further provide the possibility to track the cognitive decline in a task-specific manner. Current study in search for potential ERO biomarkers to distinguish different stages of cognitive decline along the Alzheimer's Disease (AD) continuum re-analyzed a combined set of data collected and analyzed in previous studies by Başar and coworkers. Target responses of a visual oddball experiment recorded from 33 AD patients, 46 Mild Cognitive Impairment (MCI) patients and 48 age, gender, and education matched normal elderly controls were analyzed for both evoked (phase-locked) and total (phase-locked + non-phase-locked) ERO powers in delta, theta, alpha, beta and gamma bands by applying continuous wavelet transform (WT) on averaged and single trial data, respectively. The cluster-based nonparametric permutation test implemented in the FieldTrip toolbox revealed significant differences among the three groups. While the total delta and theta responses already significantly declined in the MCI stage with further spatial expansion of the decline in AD, the evoked delta response reached a statistically significant reduction level in the AD stage. We obtained no significant difference among groups for alpha, beta and gamma frequency bands. These results suggest that total delta and theta EROs to oddball targets may be useful for early detection of the disease in MCI stage, while the evoked delta response allows detecting the conversion to AD.

Transcranial Alternating Current Stimulation (tACS) as a Tool to Modulate P300 Amplitude in Attention Deficit Hyperactivity Disorder (ADHD): Preliminary Findings

Studies examining event-related potentials (ERP) in patients affected by attention deficit/hyperactivity disorder (ADHD) have found considerable evidence of reduced target P300 amplitude across different perceptual modalities. P300 amplitude has been related to attention-driven context comparison and resource allocation processes. Altered P300 amplitude in ADHD can be reasonably assumed to be related to ADHD typical cognitive performance deficits. Transcranial alternating current stimulation (tACS) can increase the amplitude of endogenous brain oscillations. Because ERP components can be viewed as event-related oscillations (EROs), with P300 translating into the delta (0–4 Hz) and theta (4–8 Hz) frequency range, an increase of delta and theta ERO amplitudes by tACS should result in an increase of P300 amplitudes in ADHD patients. In this pilot study, 18 adult ADHD patients (7 female) performed three consecutive blocks of a visual oddball task while the electroencephalogram (EEG) was recorded. Patients received either 20 min of tACS or sham stimulation at a stimulation intensity of 1 mA. Individual stimulation frequency was determined using a time–frequency decomposition of the P300. Our preliminary results demonstrate a significant increase in P300 amplitude in the stimulation group which was accompanied by a decrease in omission errors pre-to-post tACS. However, studies including larger sample sizes are advised.

Decrease of Delta Oscillatory Responses in Cognitively Normal Parkinson's Disease.

Parkinson's disease (PD) is a common progressive neurodegenerative disorder. This study aims to compare sensory-evoked oscillations (SEOs) and event-related oscillations (EROs) of visual modality in cognitively normal PD patients and healthy controls. Sixteen PD and 16 age-, gender-, and education-matched healthy controls participated in the study. A simple flashlight was used for SEO and a classical visual oddball paradigm was used for target ERO. Oscillatory responses in the delta frequency range (0.5-3.5 Hz) were examined. Significantly lower delta ERO and SEO responses were found in PD patients than healthy controls. Delta ERO responses were decreased at all frontal, central and parietal locations, whereas delta SEO responses were decreased over mid and right central locations in PD. According to the notion that SEO reflects the activity of sensory networks and ERO reflects cognitive networks, these findings indicate that PD patients have impairments in both cognitive and sensory networks of visual modality. Decreased delta ERO responses indicate that the subliminal cognitive changes in PD can be detected by electrophysiological methods. These results demonstrate that brain oscillatory responses have the potential to be studied as a biomarker for visual cognitive and sensory networks in PD.

ID 114 – Progressive MCI proved with vMRI shows lower delta ERO than stable MCI at baseline: A longitudinal study

Objective Decreased delta event-related oscillations (ERO) have been reported in prior studies of Alzheimer’s disease (AD) and mild cognitive impairment (MCI); however no study has examined its utility in predicting disease progression. In this study, we examined the longitudinal changes in brain dynamics of MCI by using delta ERO and volumetric MRI (vMRI). Methods Twenty-two MCI and 23 matched control subjects were included. Peak-to-peak amplitudes of delta (0.5–3.5 Hz) auditory target ERO and vMRI were measured at baseline and a year later. The ERO and vMRI of stable and progressive MCI were compared. Results Decreased amplitudes of delta ERO were found in MCI for baseline and follow-up [F1.43 = 11.394, p = 0.002]. Progressive MCI had lower delta ERO than stable MCI at F3 electrode site at baseline. vMRI revealed that MCI had lower volumes at baseline in whole brain and left hippocampus, and at follow-up in whole brain, right and left hippocampi. Moreover, a moderate correlation was found between left hippocampus volumes and delta ERO at C4 electrode site. Conclusions These findings indicate that delta ERO may detect early changes in MCI and can be a useful tool to predict disease progression. Brain oscillatory responses have the potential to be used as biomarker in MCI.

ID 112 – Both sensory and cognitive networks are affected in Parkinson’s disease

Objective Parkinson’s disease (PD) is the second most common progressive neurodegenerative disorder which affects both motor and cognitive functioning. This study aims to investigate the sensory evoked oscillations (SEO) and event-related oscillations (ERO) of visual modality in cognitively normal PD patients and healthy controls. Methods Sixteen PD and 16 matched control subjects were participated to the study. Simple flashlight was used for SEO and a classical visual oddball paradigm was used for target ERO. Oscillatory responses in delta frequency range (0.5–3.0 Hz) were examined. Results Significant differences were found between groups on the maximum peak-to-peak amplitudes of both delta ERO and SEO responses [ F 1.27 = 8.573, p = 0.007; F 1.27 = 6.306, p = 0.018, respectively], indicating significantly lower delta responses in PD than healthy controls. Delta ERO responses were decreased in PD in frontal, central and parietal locations ( p Conclusions In this study, both target delta ERO and SEO responses were decreased in PD. According to the notion that the activity of sensory networks are reflected by SEO and cognitive networks by ERO, these findings indicate that PD patients have impairments in both networks of visual modality. Brain oscillatory responses have a potential to be searched as a biomarker for visual cognitive and sensory status of PD.

Delta, theta, and alpha event-related oscillations in alcoholics during Go/NoGo task: Neurocognitive deficits in execution, inhibition, and attention processing

Higher impulsivity observed in alcoholics is thought to be due to neurocognitive functional deficits involving impaired inhibition in several brain regions and/or neuronal circuits. Event-related oscillations (EROs) offer time-frequency measure of brain rhythms during perceptual and cognitive processing, which provide a detailed view of neuroelectric oscillatory responses to external/internal events. The present study examines evoked power (temporally locked to events) of oscillatory brain signals in alcoholics during an equal probability Go/NoGo task, assessing their functional relevance in execution and inhibition of a motor response. The current study hypothesized that increases in the power of slow frequency bands and their topographical distribution is associated with tasks that have increased cognitive demands, such as the execution and inhibition of a motor response. Therefore, it is hypothesized that alcoholics would show lower spectral power in their topographical densities compared to controls. The sample consisted of 20 right-handed abstinent alcoholic males and 20 age and gender-matched healthy controls. Evoked delta (1.0–3.5Hz; 200–600ms), theta (4.0–7.5Hz; 200–400ms), slow alpha (8.0–9.5Hz; 200–300ms), and fast alpha (10.0–12.5Hz; 100–200ms) ERO power were compared across group and task conditions. Compared to controls, alcoholics had higher impulsiveness scores on the Barrett Impulsiveness Scale (BIS-11) and made more errors on Go trials. Alcoholics showed significantly lower evoked delta, theta, and slow alpha power compared to controls for both Go and NoGo task conditions, and lower evoked fast alpha power compared to controls for only the NoGo condition. The results confirm previous findings and are suggestive of neurocognitive deficits while executing and suppressing a motor response. Based on findings in the alpha frequency ranges, it is further suggested that the inhibitory processing impairments in alcoholics may arise from inadequate early attentional processing with respect to the stimulus related aspects/semantic memory processes, which may be reflected in lower posterio-temporal evoked fast alpha power. It can thus be concluded that alcoholics show neurocognitive deficits in both execution and suppression of a motor response and inadequate early attentional processing with respect to the semantic memory/stimulus related aspects while suppressing a motor response.

Decrease of delta oscillatory responses is associated with increased age in healthy elderly

BackgroundThe purpose of this study was to investigate changes in delta event-related oscillations (EROs) in younger and older healthy elderly subjects. We hypothesized that delta EROs were affected by age-related changes, which could be reflected in a visual oddball paradigm. MethodThe study included two groups of subjects, 17 younger healthy elderly (mean age: 63.1±2.8years) and 17 gender- and education-matched older healthy elderly (mean age: 79.6±5.2years), who performed a visual oddball paradigm. EEG was recorded from F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz and O2 locations. Peak-to-peak amplitudes of delta (0.5–3Hz) target ERO responses during the post-stimulus 0–800ms time window were measured. Repeated measures of ANOVA was used to analyze four locations (frontal, central, parietal, occipital), at three sagittal (left, midline, right) sites. Independent t-tests were applied for post-hoc analyses. ResultsThe older healthy elderly group had 16–25% lower values for the maximum peak-to-peak amplitudes of delta ERO compared with the younger healthy elderly group over frontal (p<0.003), central (p<0.0001) and parietal (p<0.007) locations [F3.96=4.396, p=0.015]. Furthermore, there was a moderate negative correlation between age and Cz peak-to-peak amplitude of target delta responses [r=−0.401, p<0.02], indicating the notion that peak-to-peak amplitude of Cz decreases as age increases. ConclusionIn the present study younger healthy elderly showed significantly higher event-related delta responses than older healthy elderly at frontal, central and parietal locations. Moreover, delta ERO responses decreased in accordance with age.

Frontal delta event-related oscillations relate to frontal volume in mild cognitive impairment and healthy controls

Amnesic mild cognitive impairment (MCI) represents a risk of developing Alzheimer's disease (AD), but not all MCI subjects progress to dementia of AD type. Magnetic resonance imaging (MRI) of cortical and hippocampal atrophy supports early diagnosis of AD in MCI subjects, while frontal event-related oscillations (EROs) at delta frequencies (<4Hz) are appealing markers for this purpose, as they are both cost-effective and largely available. The present study tested the hypothesis that these EROs reflect cortical frontal neurodegeneration in the continuum between normal and amnesic MCI subjects.EROs and volumetric MRI data were recorded in 28 amnesic MCI and in 28 healthy elderly controls (HCs). EROs were collected during a standard visual oddball paradigm including frequent (66.6%) and rare (33.3%; targets to be mentally counted) stimuli. Peak-to-peak amplitude of delta target EROs (<4Hz) was measured. Volume of frontal cortex was estimated from MRIs.Frontal volume was lower in MCI compared to the HC group. Furthermore, widespread delta target EROs were lower in amplitude in the former than in the latter group. Finally, there was a positive correlation between frontal volume and frontal delta target EROs in MCI and HC subjects as a whole group. These results suggest that frontal delta EROs reflect frontal neurodegeneration in the continuum between normal and amnesic MCI subjects.

Age-related increases in within-person variability: Delta and theta oscillations indicate that the elderly are not always old

Behavioral and electrophysiological data related to performance in an auditory Go/NoGo task were analyzed in young and older adults in the present study. Especially, differences in within-person variability in behavior and neural activity between young and older adults and changes in topography of slow event-related oscillations (EROs) were of interest. Within-person variability in behavior was assessed by reaction time (RT) variability. Event-related delta and theta oscillations were analyzed using time–frequency transformation, which can give information on the time-course of single trial event-related EEG spectral power enhancement and intertrial phase-locking (ITC). In contrast to our previous visual Go/NoGo study, no under-recruitment of task-relevant brain regions was found for the auditory theta and delta EROs. Young did not differ from older adults in RT variability or in single trial delta/theta ITC. Altered recruitment of brain activity at advanced age was indicated, first, by stronger early theta phase-locking in older compared to young adults and, second, by a Go-specific lateralization of delta/theta activity. We conclude that within-person variability may increase with age, but the degree depends on performance level and the modality investigated.

Reciprocal dynamics of EEG alpha and delta oscillations during spontaneous blinking at rest: A survey on a default mode-based visuo-spatial awareness

By means of a narrowband wavelet analysis (0.5–6 Hz), EEG delta event-related oscillations (EROs), both time- and phase-locked to spontaneous blinking (delta blink-related oscillations or delta BROs), have recently been demonstrated. On the basis of their spatiotemporal characteristics, delta BROs have been proposed as being involved in an automatic mechanism of maintaining awareness in a visuo-spatial context. The aim of the present study was: a) to investigate whether spontaneous blinking was also able to modulate alpha oscillations and, if so, b) whether this modulation was consistent with delta BROs, in order c) to acquire additional information for a better understanding of the cognitive phenomena underlying blinking. Using a broadband (0.5–100 Hz) continuous wavelet transform (CWT), we analysed a total of 189 three-second EEG epochs time-locked to the blinks of seven healthy volunteers. The EEG signals were submitted both to band-pass filtered cross-trial averaging (to obtain frequency-specific BROs) and to alpha event-related synchronization/desynchronization (i.e., blink-related synchronization/desynchronization, BRS/BRD). The alpha oscillations showed: a) an early BRS; b) a BRD in the same temporal window of the delta BROs and, c) a late BRS. We postulate that: a) the early BRS represents the short-term memory maintenance of the last visually perceived trace of the surroundings; b) the alpha BRD is associated with the comparison between the newly perceived image of the environment and its mnestic representation, and, lastly, c) the late BRS is connected with neuronal recovery phenomena.

Auditory go/nogo processing in the aged brain: insights from delta and theta brain oscillations

Event Abstract Back to Event Auditory go/nogo processing in the aged brain: insights from delta and theta brain oscillations Christina Schmiedt-Fehr1*, Saskia Dühl1 and Canan Basar-Eroglu1 1 University of Bremen, Germany Increases in intraindividual variability (short-term trial-to-trial fluctuation) of behavior in later adulthood have been reported. Whether changes in trial-to-trial fluctuations are reflected on behavioral and neuronal level was in this study. Behavioral and electrophysiological data related to performance in an auditory Go/NoGo task were analyzed in young and older adults in the present study. Especially, differences in within-person variability in behavior and neural activity between young and older adults and changes in topography of slow event-related oscillations (EROs) were of interest. Within-person variability in behavior was assessed by reaction time (RT) variability. Event-related delta and theta oscillations were analyzed using time-frequency transformation, which provides information on the time-course of single trial event-related EEG spectral power enhancement and intertrial phase-locking (ITC). In contrast to our previous visual Go/NoGo study, neither under-recruitment of task-relevant brain regions nor larger ITC was found in older compared to young adults for the auditory theta and delta EROs. Young did not differ from older adults in RT variability or in single trial delta/theta ITC. Altered recruitment of brain activity at advanced age was indicated, first, by stronger early theta phase-locking older compared to young adults and, second, by a Go-specific lateralization of delta/theta activity. We conclude that within-person variability may increase with age, but the degree depends on performance level and the modality investigated. Funding: This research was supported by a grant of the University of Bremen, Germany (Zentrale Forschungsförderung: 11/854/05). Keywords: Aging, EROS Conference: XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011. Presentation Type: Poster Presentation Topic: Poster Sessions: Cognitive Aging Citation: Schmiedt-Fehr C, Dühl S and Basar-Eroglu C (2011). Auditory go/nogo processing in the aged brain: insights from delta and theta brain oscillations. Conference Abstract: XI International Conference on Cognitive Neuroscience (ICON XI). doi: 10.3389/conf.fnhum.2011.207.00619 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 15 Nov 2011; Published Online: 28 Nov 2011. * Correspondence: Dr. Christina Schmiedt-Fehr, University of Bremen, Bermen, Germany, schmiedtfehr@uni-bremen.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Christina Schmiedt-Fehr Saskia Dühl Canan Basar-Eroglu Google Christina Schmiedt-Fehr Saskia Dühl Canan Basar-Eroglu Google Scholar Christina Schmiedt-Fehr Saskia Dühl Canan Basar-Eroglu PubMed Christina Schmiedt-Fehr Saskia Dühl Canan Basar-Eroglu Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Effects of adolescent ethanol exposure on event-related oscillations (EROs) in the hippocampus of adult rats

Electrophysiological studies have shown that adolescent ethanol (EtOH) exposure can produce long-term changes in hippocampal EEG and ERP activity. Recently, evidence has emerged suggesting that event-related oscillations (EROs) may be good indices of alcoholism risk in humans, however, have not been evaluated for their ability to index the effects of EtOH exposure. The objective of the present study was to characterize EROs generated in hippocampus in adult rats exposed to EtOH during adolescence. Adolescent male Sprague–Dawley rats were exposed to EtOH vapor for 12 h/d for 10 days. A time–frequency representation method was used to determine delta, theta, alpha and beta ERO energy and the degree of phase variation in the hippocampus of adult rats exposed to EtOH and age-matched controls. The present results suggest that the decrease in P3 amplitudes, previously observed in adult rats exposed to EtOH during adolescence, is associated with increases in evoked theta ERO energy. These studies suggest that EROs are suitable for characterizing the long-term effects of adolescent EtOH exposure. Further studies are needed to determine the relationship between the mechanisms that regulate these neurophysiological endophenotypes and the consequences of adolescent EtOH exposure.

Event-related oscillations as risk markers in genetic mouse models of high alcohol preference

Mouse models have been developed to simulate several relevant human traits associated with alcohol use and dependence. However, the neurophysiological substrates regulating these traits remain to be completely elucidated. We have previously demonstrated that differences in the event-related potential (ERP) responses can be found that distinguish high-alcohol preferring from low alcohol preferring mice that resemble differences seen in human studies of individuals with high and low risk for alcohol dependence. Recently, evidence of genes that affect event-related oscillations (EROs) and the risk for alcohol dependence has emerged, however, to date EROs have not been evaluated in genetic mouse models of high and low alcohol preference. Therefore, the objective of the present study was to characterize EROs in mouse models of high (C57BL/6 [B6] and high alcohol preference 1 [HAP-1] mice) and low (DBA/2J [D2] and low alcohol preference-1 [LAP-1] mice) alcohol preference. A time-frequency representation method was used to determine delta, theta and alpha/beta ERO energy and the degree of phase variation in these mouse models. The present results suggest that the decrease in P3 amplitudes previously shown in B6 mice, compared to D2 mice, is related to reductions in evoked delta ERO energy and delta and theta phase locking. In contrast, the increase in P1 amplitudes reported in HAP-1 mice, compared to LAP-1 mice, is associated with increases in evoked theta ERO energy. These studies suggest that differences in delta and theta ERO measures in mice mirror changes observed between groups at high- and low-risk for alcoholism where changes in EROs were found to be more significant than group differences in P3 amplitudes, further suggesting that ERO measures are more stable endophenotypes in the study of alcohol dependence. Further studies are needed to determine the relationship between expression of these neurophysiological endophenotypes and the genetic profile of these mouse models.

Neurophysiological Endophenotypes, CNS Disinhibition, and Risk for Alcohol Dependence and Related Disorders

Biological endophenotypes are more proximal to gene function than psychiatric diagnosis, providing a powerful strategy in searching for genes in psychiatric disorders. These intermediate phenotypes identify both affected and unaffected members of an affected family, including offspring at risk, providing a more direct connection with underlying biological vulnerability. The Collaborative Study on the Genetics of Alcoholism (COGA) has employed heritable neurophysiological features (i.e., brain oscillations) as endophenotypes, making it possible to identify susceptibility genes that may be difficult to detect with diagnosis alone. We found significant linkage and association between brain oscillations and genes involved with inhibitory neural networks (e.g., GABRA2, CHRM2), including frontal networks that are deficient in individuals with alcohol dependence, impulsivity, and related disinhibitory disorders. We reported significant linkage and linkage disequilibrium for the beta frequency of the EEG and GABRA2, a GABAA receptor gene on chromosome 4, which we found is also associated with diagnosis of alcohol dependence and related disorders. More recently, we found significant linkage and association with GABRA2 and interhemispheric theta coherence. We also reported significant linkage and linkage disequilibrium between the theta and delta event-related oscillations underlying P3 to target stimuli and GABRA2, a cholinergic muscarinic receptor gene on chromosome 7, which we found is also associated with diagnosis of alcohol dependence and related disorders. Thus, the identification of genes important for the expression of the endophenotypes (brain oscillations) helps when identifying genes that increase the susceptibility for risk of alcohol dependence and related disorders. These findings underscore the utility of quantitative neurophysiological endophenotypes in the study of the genetics of complex disorders. We will present our recent genetic findings related to brain oscillations and Central Nervous System (CNS) disinhibition.