Regular recreational Cannabis users exhibit altered neural oscillatory dynamics during attention reorientation

BACKGROUND

Cannabis is the most widely used illicit drug in the United States and is often associated with changes in attention function, which may ultimately impact numerous other cognitive faculties (e.g. memory, executive function). Importantly, despite the increasing rates of cannabis use and widespread legalization in the United States, the neural mechanisms underlying attentional dysfunction in chronic users are poorly understood.

METHODS

We used magnetoencephalography (MEG) and a modified Posner cueing task in 21 regular cannabis users and 32 demographically matched non-user controls. MEG data were imaged in the time-frequency domain using a beamformer and peak voxel time series were extracted to quantify the oscillatory dynamics underlying use-related aberrations in attentional reorienting, as well as the impact on spontaneous neural activity immediately preceding stimulus onset.

RESULTS

Behavioral performance on the task (e.g. reaction time) was similar between regular cannabis users and non-user controls. However, the neural data indicated robust theta-band synchronizations across a distributed network during attentional reorienting, with activity in the bilateral inferior frontal gyri being markedly stronger in users relative to controls (p's < 0.036). Additionally, we observed significantly reduced spontaneous theta activity across this distributed network during the pre-stimulus baseline in cannabis users relative to controls (p's < 0.020).

CONCLUSIONS

Despite similar performance on the task, we observed specific alterations in the neural dynamics serving attentional reorienting in regular cannabis users compared to controls. These data suggest that regular cannabis users may employ compensatory processing in the prefrontal cortices to efficiently reorient their attention relative to non-user controls.

The development of sensorimotor cortical oscillations is mediated by pubertal testosterone

Puberty is a period of substantial hormonal fluctuations, and pubertal hormones can modulate structural and functional changes in the developing brain. Many previous studies have characterized the neural oscillatory responses serving movement, which include a beta event-related desynchronization (ERD) preceding movement onset, gamma and theta responses coinciding with movement execution, and a post-movement beta-rebound (PMBR) response following movement offset. While a few studies have investigated the developmental trajectories of these neural oscillations serving motor control, the impact of pubertal hormone levels on the maturation of these dynamics has not yet been examined. Since the timing and tempo of puberty varies greatly between individuals, pubertal hormones may uniquely impact the maturation of motor cortical oscillations distinct from other developmental metrics, such as age. In the current study we quantified these oscillations using magnetoencephalography (MEG) and utilized chronological age and measures of endogenous testosterone as indices of development during the transition from childhood to adolescence in 69 youths. Mediation analyses revealed complex maturation patterns for the beta ERD, in which testosterone predicted both spontaneous baseline and ERD power through direct and indirect effects. Age, but not pubertal hormones, predicted motor-related theta, and no relationships between oscillatory responses and developmental metrics were found for gamma or PMBR responses. These findings provide novel insight into how pubertal hormones affect motor-related oscillations, and highlight the continued development of motor cortical dynamics throughout the pubertal period.

Impacts of adrenarcheal DHEA levels on spontaneous cortical activity during development

Dehydroepiandrosterone (DHEA) production is closely associated with the first pubertal hormonal event, adrenarche. Few studies have documented the relationships between DHEA and functional brain development, with even fewer examining the associations between DHEA and spontaneous cortical activity during the resting-state. Thus, whether DHEA levels are associated with the known developmental shifts in the brain's idling cortical rhythms remains poorly understood. Herein, we examined spontaneous cortical activity in 71 typically-developing youth (9-16 years; 32 male) using magnetoencephalography (MEG). MEG data were source imaged and the power within five canonical frequency bands (delta, theta, alpha, beta, gamma) was computed to identify spatially- and spectrally-specific effects of salivary DHEA and DHEA-by-sex interactions using vertex-wise ANCOVAs. Our results indicated robust increases in power with increasing DHEA within parieto-occipital cortices in all frequency bands except alpha, which decreased with increasing DHEA. In the delta band, DHEA and sex interacted within frontal and temporal cortices such that with increasing DHEA, males exhibited increasing power while females showed decreasing power. These data suggest that spontaneous cortical activity changes with endogenous DHEA levels during the transition from childhood to adolescence, particularly in sensory and attentional processing regions. Sexually-divergent trajectories were only observed in later-developing frontal cortical areas.

Increases in Circulating Cortisol during the COVID-19 Pandemic are Associated with Changes in Perceived Positive and Negative Affect among Adolescents

The Coronavirus Disease 2019 (COVID-19) pandemic has spread across the world and resulted in over 5 million deaths to date, as well as countless lockdowns, disruptions to daily life, and extended period of social distancing and isolation. The impacts on youth in particular are astounding, with shifts in learning platforms, limited social outlets, and prolonged uncertainty about the future. Surveys have shown that mental health among youth has severely suffered during the pandemic. However, limited research to date has reported on physiological indices of stress surrounding the pandemic, such as cortisol. Cortisol is a stress hormone that typically increases during stressful situations and can have deleterious effects on mental and physical health when chronically heightened. The present study leveraged hair cortisol concentration measurements, which allowed the retrospectiveinvestigation of circulating cortisol prior to- versus after pandemic-related local lockdowns during the first wave of the pandemic. A final sample of 44 youth ages 10- to 18-years-old provided hair samples and reported on their perceived affective well-being and level of concern regarding pandemic-related stressors between May and June of 2020. We found significant levels of concern and decreases in affective well-being following local lockdowns. Moreover, we saw that cortisol robustly increased following local lockdowns, and those increases were predictive of changes in affect. These findings provide critical insights into the underlying neuroendocrinology of stress during the pandemic and support the need for resources to support youths’ mental health and well-being during this globally significant event.

Reliability of the NIH toolbox cognitive battery in children and adolescents: a 3-year longitudinal examination

BACKGROUND

The Cognitive Battery of the National Institutes of Health Toolbox (NIH-TB) is a collection of assessments that have been adapted and normed for administration across the lifespan and is increasingly used in large-scale population-level research. However, despite increasing adoption in longitudinal investigations of neurocognitive development, and growing recommendations that the Toolbox be used in clinical applications, little is known about the long-term temporal stability of the NIH-TB, particularly in youth.

METHODS

The present study examined the long-term temporal reliability of the NIH-TB in a large cohort of youth (9-15 years-old) recruited across two data collection sites. Participants were invited to complete testing annually for 3 years.

RESULTS

Reliability was generally low-to-moderate, with intraclass correlation coefficients ranging between 0.31 and 0.76 for the full sample. There were multiple significant differences between sites, with one site generally exhibiting stronger temporal stability than the other.

CONCLUSIONS

Reliability of the NIH-TB Cognitive Battery was lower than expected given early work examining shorter test-retest intervals. Moreover, there were very few instances of tests meeting stability requirements for use in research; none of the tests exhibited adequate reliability for use in clinical applications. Reliability is paramount to establishing the validity of the tool, thus the constructs assessed by the NIH-TB may vary over time in youth. We recommend further refinement of the NIH-TB Cognitive Battery and its norming procedures for children before further adoption as a neuropsychological assessment. We also urge researchers who have already employed the NIH-TB in their studies to interpret their results with caution.

The impact of pubertal DHEA on the development of visuospatial oscillatory dynamics

The adolescent brain undergoes tremendous structural and functional changes throughout puberty. Previous research has demonstrated that pubertal hormones can modulate sexually dimorphic changes in cortical development, as well as age-related maturation of the neural activity underlying cognitive processes. However, the precise impact of pubertal hormones on these functional changes in the developing human brain remains poorly understood. In the current study, we quantified the neural oscillatory activity serving visuospatial processing using magnetoencephalography, and utilized measures of dehydroepiandrosterone (DHEA) as an index of development during the transition from childhood to adolescence (i.e., puberty). Within a sample of typically developing youth (ages 9-15), a novel association between pubertal DHEA and theta oscillatory activity indicated that less mature children exhibited stronger neural responses in higher-order prefrontal cortices during the visuospatial task. Theta coherence between bilateral prefrontal regions also increased with increasing DHEA, such that network-level theta activity became more distributed with more maturity. Additionally, significant DHEA-by-sex interactions in the gamma range were centered on cortical regions relevant for attention processing. These findings suggest that pubertal DHEA may modulate the development of neural oscillatory activity serving visuospatial processing and attention functions during the pubertal period.

Left amygdala structure mediates longitudinal associations between exposure to threat and long-term psychiatric symptomatology in youth

Traumatic experiences during childhood can have profound effects on stress sensitive brain structures (e.g., amygdala and hippocampus) and the emergence of psychiatric symptoms. Recent theoretical and empirical work has delineated dimensions of trauma (i.e., threat and deprivation) as having distinct neural and behavioral effects, although there are few longitudinal examinations. A sample of 243 children and adolescents were followed for three time points, with each assessment approximately 1 year apart (ages 9–15 years at Time 1; 120 males). Participants or their caregiver reported on youths' threat exposure, perceived stress (Time 1), underwent a T1‐weighted structural high‐resolution MRI scan (Time 2), and documented their subsequent psychiatric symptoms later in development (Time 3). The primary findings indicate that left amygdala volume, in particular, mediated the longitudinal association between threat exposure and subsequent internalizing and externalizing symptomatology. Greater threat exposure related to reduced left amygdala volume, which in turn differentially predicted internalizing and externalizing symptoms. Decreased bilateral hippocampal volume was related to subsequently elevated internalizing symptoms. These findings suggest that the left amygdala is highly threat‐sensitive and that stress‐related alterations may partially explain elevated psychopathology in stress‐exposed adolescents. Uncovering potential subclinical and/or preclinical predictive biomarkers is essential to understanding the emergence, progression, and eventual targeted treatment of psychopathology following trauma exposure.

Auditory experience modulates frontoparietal theta activity serving fluid intelligence

Children who are hard of hearing are at risk for developmental language and academic delays compared with children with normal hearing. Some work suggests that high-order cognitive function, including fluid intelligence, may relate to language and academic outcomes in children with hearing loss, but findings in these studies have been mixed and to date, there have been no studies of the whole-brain neural dynamics serving fluid intelligence in the context of hearing loss. To this end, this study sought to identify the impact of hearing loss and subsequent hearing aid use on the neural dynamics serving abstract reasoning in children who are hard of hearing relative to children with normal hearing using magnetoencephalography. We found significant elevations in occipital and parietal theta activity during early stimulus evaluation in children who are hard of hearing relative to normal-hearing peers. In addition, we found that greater hearing aid use was significantly related to reduced activity throughout the fronto-parietal network. Notably, there were no differences in alpha dynamics between groups during later-stage processing nor did alpha activity correlate with hearing aid use. These cross-sectional data suggest that differences in auditory experience lead to widespread alterations in the neural dynamics serving initial stimulus processing in fluid intelligence in children.

Longitudinal changes in the neural oscillatory dynamics underlying abstract reasoning in children and adolescents

Fluid reasoning is the ability to problem solve in the absence of prior knowledge and is commonly conceptualized as “non-verbal” intelligence. Importantly, fluid reasoning abilities rapidly develop throughout childhood and adolescence. Although numerous studies have characterized the neural underpinnings of fluid reasoning in adults, there is a paucity of research detailing the developmental trajectory of this neural processing. Herein, we examine longitudinal changes in the neural oscillatory dynamics underlying fluid intelligence in a sample of typically developing youths. A total of 34 participants age 10 to 16 years-old completed an abstract reasoning task during magnetoencephalography (MEG) on two occasions set one year apart. We found robust longitudinal optimization in theta, beta, and gamma oscillatory activity across years of the study across a distributed network commonly implicated in fluid reasoning abilities. More specifically, activity tended to decrease longitudinally in additional, compensatory areas such as the right lateral prefrontal cortex and increase in areas commonly utilized in mature adult samples (e.g., left frontal and parietal cortices). Importantly, shifts in neural activity were associated with improvements in task performance from one year to the next. Overall, the data suggest a longitudinal shift in performance that is accompanied by a reconfiguration of the functional oscillatory dynamics serving fluid reasoning during this important period of development.

Cortisol changes in healthy children and adolescents during the COVID-19 pandemic

The Coronavirus Disease 2019 (COVID-19) pandemic has caused massive disruptions to daily life in the United States, closing schools and businesses and increasing physical and social isolation, leading to deteriorations in mental health and well-being in people of all ages. Many studies have linked chronic stress with long-term changes in cortisol secretion, which has been implicated in many stress-related physical and mental health problems that commonly emerge in adolescence. However, the physiological consequences of the pandemic in youth remain understudied. Using hair cortisol concentrations (HCC), we quantified average longitudinal changes in cortisol secretion across a four-month period capturing before, during, and after the transition to pandemic-lockdown conditions in a sample of healthy youth (n = 49). Longitudinal changes in HCC were analyzed using linear mixed-effects models. Perceived levels of pandemic-related stress were measured and compared to the physiological changes in HCC. In children and adolescents, cortisol levels significantly increased across the course of the pandemic. These youth reported a multitude of stressors during this time, although changes in HCC were not associated with self-reported levels of COVID-19-related distress. We provide evidence that youth are experiencing significant physiological changes in cortisol activity across the COVID-19 pandemic, yet these biological responses are not associated with perceived stress levels. Youth may be especially vulnerable to the deleterious impacts of chronic cortisol exposure due to their current status in the sensitive periods for development, and the incongruency between biological and psychological stress responses may further complicate these developmental problems.

Individual differences in amygdala volumes predict changes in functional connectivity between subcortical and cognitive control networks throughout adolescence

Adolescence is a critical period of structural and functional neural maturation among regions serving the cognitive control of emotion. Evidence suggests that this process is guided by developmental changes in amygdala and striatum structure and shifts in functional connectivity between subcortical (SC) and cognitive control (CC) networks. Herein, we investigate the extent to which such developmental shifts in structure and function reciprocally predict one another over time. 179 youth (9–15 years-old) completed annual MRI scans for three years. Amygdala and striatum volumes and connectivity within and between SC and CC resting state networks were measured for each year. We tested for reciprocal predictability of within-person and between-person changes in structure and function using random-intercept cross-lagged panel models. Within-person shifts in amygdala volumes in a given year significantly and specifically predicted deviations in SC-CC connectivity in the following year, such that an increase in volume was associated with decreased SC-CC connectivity the following year. Deviations in connectivity did not predict changes in amygdala volumes over time. Conversely, broader group-level shifts in SC-CC connectivity were predictive of subsequent deviations in striatal volumes. We did not see any cross-predictability among amygdala or striatum volumes and within-network connectivity measures. Within-person shifts in amygdala structure year-to-year robustly predicted weaker SC-CC connectivity in subsequent years, whereas broader increases in SC-CC connectivity predicted smaller striatal volumes over time. These specific structure function relationships may contribute to the development of emotional control across adolescence.

Altered amygdala-cortical connectivity in individuals with Cannabis use disorder

BACKGROUND

Cannabis is one of the most commonly used substances in the United States. Prior literature using task-based functional magnetic resonance imaging (fMRI) has identified that individuals with Cannabis use disorder (CUD) show impairments in emotion processing circuitry. However, whether the functional networks involving these regions are also altered in CUD remains poorly understood.

AIMS

Investigate changes in resting-state functional connectivity (rsFC) in regions related to emotional processing in CUD.

METHODS

Sixty-two participants completed resting-state fMRI, including 21 with CUD, 20 with histories of illicit substance use but no current CUD diagnosis, and 21 with no history of illicit substance use. Whole-brain seed-based connectivity analyses were performed and one-way analyses of covariance (ANCOVAs) were conducted to detect group differences in the bilateral amygdalae, hippocampi, and the anterior and posterior cingulate cortices.

RESULTS

The CUD group exhibited significant reductions in rsFC between the amygdala and the cuneus, paracentral lobule, and supplementary motor area, and between the cingulate cortices and the occipital and temporal lobes. There were no significant group differences in hippocampal functional connectivity. In addition, CUD symptom counts based on the Structured Clinical Interview for DSM-5 (SCID) and the Cannabis Use Disorders Identification Test (CUDIT) significantly correlated with multiple connectivity metrics.

CONCLUSION

These data expand on emerging literature indicating that CUD is associated with dysfunction in the neural circuits underlying emotion processing. Dysfunction in emotion processing circuits may play a role in the behavioral impairments seen in emotion processing tasks in individuals with CUD, and the severity of CUD symptoms appears to be directly related to the degree of dysfunction in these circuits.

Subclinical Anxiety and Posttraumatic Stress Influence Cortical Thinning During Adolescence

OBJECTIVE

Adolescence is a sensitive period for the development and emergence of anxiety and mood disorders. Research suggests that symptoms ranging from subclinical to clinical levels are associated with pathological developmental changes in the neocortex. However, much of this research has been cross-sectional, limiting the field's ability to identify the neurodevelopmental impacts of these symptoms. The present study examined how early reported symptoms predict baseline cortical thickness and surface area, and trajectories of change in these measures during adolescence.

METHOD

A total of 205 typically developing individuals 9 to 15 years of age (103 male and 102 female participants) completed 3T structural magnetic resonance imaging annually for 3 years. From these, we extracted mean cortical thickness and total surface area for each year. Youth self-reported their anxiety, depressive, and posttraumatic stress symptoms during their first visit. We used latent growth curve modeling to determine how these symptoms along with sex interactions predicted baseline thickness and surface area, and rates of change in these measures over the 3-year period.

RESULTS

Higher anxiety was associated with lower baseline thickness and slowed cortical thinning over time. Conversely, greater posttraumatic stress predicted higher baseline thickness and accelerated thinning over time. Sex interactions suggested that the effects were dampened among female compared to male participants. Depressive symptoms were not related to cortical thickness or surface area.

CONCLUSION

Female adolescents may express more regionally specific effects of symptoms sets on cortical thickness, although this requires further investigation. Cortical thickness in male adolescents appears to be preferentially susceptible to anxiety and posttraumatic stress symptoms, exhibiting global changes across multiple years.

Increases in Stressors Prior to-Versus During the COVID-19 Pandemic in the United States Are Associated With Depression Among Middle-Aged Mothers

Working parents in are struggling to balance the demands of their occupation with those of childcare and homeschooling during the COVID-19 pandemic. Moreover, studies show that women are shouldering more of the burden and reporting greater levels of psychological distress, anxiety, and depression relative to men. However, research has yet to show that increases in psychological symptoms are linked to changes in stress during the pandemic. Herein, we conduct a small-N study to explore the associations between stress and psychological symptoms during the pandemic among mothers using structural equation modeling, namely latent change score models. Thirty-three mothers completed questionnaires reporting current anxious and depressive symptoms (Beck Anxiety and Depression Index, respectively), as well as stressful life experiences prior to-versus during the pandemic (Social Readjustment Rating Scale). Women endorsed significantly more stressful events during the pandemic, relative to the pre-pandemic period. Additionally, 58% of mothers scored as moderate-to-high risk for developing a stress-related physical illness in the near future because of their pandemic-level stress. Depressive symptoms were associated with the degree of change in life stress, whereas anxiety symptoms were more related to pre-pandemic levels of stress. The present study preliminarily sheds light on the nuanced antecedents to mothers’ experiences of anxious and depressive symptoms during the COVID-19 pandemic. Although further work is needed in larger, more diverse samples of mothers, this study highlights the potential need for appropriate policies, and prevention and intervention programs to ameliorate the effects of pandemics on mothers’ mental health.

Sexually dimorphic development in the cortical oscillatory dynamics serving early visual processing

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Visual processing dynamics continue to develop throughout childhood and adolescence.

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Visual alpha response power differed between males and females.

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Sex and age interacted to modulate visual gamma responses.

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Peak frequency predicted response power above and beyond the effects of age and sex.

Successful interaction with one’s visual environment is paramount to developing and performing many basic and complex mental functions. Although major aspects of visual development are completed at an early age, other structural and functional components of visual processing appear to be dynamically changing across a much more protracted period extending into late childhood and adolescence. However, the underlying neurophysiological changes and cortical oscillatory dynamics that support maturation of the visual system during this developmental period remain poorly understood. The present study utilized magnetoencephalography (MEG) to investigate maturational changes in the neural dynamics serving basic visual processing during childhood and adolescence (ages 9–15, n = 69). Our key results included robust sex differences in alpha oscillatory activity within the left posterior parietal cortex, and sex-by-age interactions in gamma activity in the right lingual gyrus and superior parietal lobule. Hierarchical regression revealed that the peak frequency of both the alpha and gamma responses predicted response power in parietal regions above and beyond the noted effects of age and sex. These findings affirm the view that neural oscillations supporting visual processing develop over a much more protracted period, and illustrate that these maturational trajectories are influenced by numerous elements, including age, sex, and individual variation.

Resting-state functional connectivity of the human hippocampus in periadolescent children: Associations with age and memory performance

The hippocampus is necessary for declarative (relational) memory, and the ability to form hippocampal‐dependent memories develops through late adolescence. This developmental trajectory of hippocampal‐dependent memory could reflect maturation of intrinsic functional brain networks, but resting‐state functional connectivity (rs‐FC) of the human hippocampus is not well‐characterized for periadolescent children. Measuring hippocampal rs‐FC in periadolescence would thus fill a gap, and testing covariance of hippocampal rs‐FC with age and memory could inform theories of cognitive development. Here, we studied hippocampal rs‐FC in a cross‐sectional sample of healthy children (N = 96; 59 F; age 9–15 years) using a seed‐based approach, and linked these data with NIH Toolbox measures, the Picture‐Sequence Memory Test (PSMT) and the List Sorting Working Memory Test (LSWMT). The PSMT was expected to rely more on hippocampal‐dependent memory than the LSWMT. We observed hippocampal rs‐FC with an extensive brain network including temporal, parietal, and frontal regions. This pattern was consistent with prior work measuring hippocampal rs‐FC in younger and older samples. We also observed novel, regionally specific variation in hippocampal rs‐FC with age and hippocampal‐dependent memory but not working memory. Evidence consistent with these findings was observed in a second, validation dataset of similar‐age healthy children drawn from the Philadelphia Neurodevelopment Cohort. Further, a cross‐dataset analysis suggested generalizable properties of hippocampal rs‐FC and covariance with age and memory. Our findings connect prior work by describing hippocampal rs‐FC and covariance with age and memory in typically developing periadolescent children, and our observations suggest a developmental trajectory for brain networks that support hippocampal‐dependent memory.

Neural oscillations underlying selective attention follow sexually divergent developmental trajectories during adolescence

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A cohort of 9- to 16-year-olds completed a classic flanker task during MEG.

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There were developmentally-sensitive interference effects in key attention regions.

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Youth showed sexually-divergent patterns of age-related interference activity.

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Maturational differences among males supported improved task behavior.

Selective attention processes are critical to everyday functioning and are known to develop through at least young adulthood. Although numerous investigations have studied the maturation of attention systems in the brain, these studies have largely focused on the spatial configuration of these systems; there is a paucity of research on the neural oscillatory dynamics serving selective attention, particularly among youth. Herein, we examined the developmental trajectory of neural oscillatory activity serving selective attention in 53 typically developing youth age 9-to-16 years-old. Participants completed the classic arrow-based flanker task during magnetoencephalography, and the resulting data were imaged in the time-frequency domain. Flanker interference significantly modulated theta and alpha/beta oscillations within prefrontal, mid-cingulate, cuneus, and occipital regions. Interference-related neural activity also increased with age in the temporoparietal junction and the rostral anterior cingulate. Sex-specific effects indicated that females had greater theta interference activity in the anterior insula, whereas males showed differential effects in theta and alpha/beta oscillations across frontoparietal regions. Finally, males showed age-related changes in alpha/beta interference in the cuneus and middle frontal gyrus, which predicted improved behavioral performance. Taken together, these data suggest sexually-divergent developmental trajectories underlying selective attention in youth.

Altered fronto-occipital connectivity during visual selective attention in regular cannabis users

RATIONALE AND OBJECTIVES

Cognitive processing impairments have been associated with acute cannabis use, but there is mixed evidence regarding the cognitive effects of chronic cannabis use. Several neuroimaging studies have noted selective-attention processing differences in those who chronically use cannabis, but the neural dynamics governing the altered processing is unclear.

METHODS

Twenty-four adults reporting at least weekly cannabis use in the past 6 months on the Cannabis Use Disorder Identification Test - Revised were compared to 24 demographically matched controls who reported no prior cannabis use. All participants completed a visual selective attention processing task while undergoing magnetoencephalography. Time-frequency windows of interest were identified using a data-driven method, and spectrally specific neural activity was imaged using a beamforming approach.

RESULTS

All participants performed within normal range on the cognitive task. Regular cannabis users displayed an aberrant cognitive interference effect in the theta (4-8 Hz) frequency range shortly after stimulus onset (i.e., 0-250 ms) in the right occipital cortex. Cannabis users also exhibited altered functional connectivity between the right prefrontal cortex and right occipital cortices in comparison to controls.

CONCLUSIONS

Individuals with a history of regular cannabis use exhibited abnormal theta interference activity in the occipital cortices, as well as altered prefrontal-occipital functional connectivity in the theta range during a visual selective attention task. Such differences may reflect compensatory processing, as these participants performed within normal range on the task. Understanding the neural dynamics in chronic, regular cannabis users may provide insight on how long-term and/or frequent use may affect neural networks underlying cognitive processes.

The impact of mild-to-severe hearing loss on the neural dynamics serving verbal working memory processing in children

Children with hearing loss (CHL) exhibit delays in language function relative to children with normal hearing (CNH). However, evidence on whether these delays extend into other cognitive domains such as working memory is mixed, with some studies showing decrements in CHL and others showing CHL performing at the level of CNH. Despite the growing literature investigating the impact of hearing loss on cognitive and language development, studies of the neural dynamics that underlie these cognitive processes are notably absent. This study sought to identify the oscillatory neural responses serving verbal working memory processing in CHL compared to CNH. To this end, participants with and without hearing loss performed a verbal working memory task during magnetoencephalography. Neural oscillatory responses associated with working memory encoding and maintenance were imaged separately, and these responses were statistically evaluated between CHL and CNH. While CHL performed as well on the task as CNH, CHL exhibited significantly elevated alpha-beta activity in the right frontal and precentral cortices during encoding relative to CNH. In contrast, CHL showed elevated alpha maintenance-related activity in the right precentral and parieto-occipital cortices. Crucially, right superior frontal encoding activity and right parieto-occipital maintenance activity correlated with language ability across groups. These data suggest that CHL may utilize compensatory right-hemispheric activity to achieve verbal working memory function at the level of CNH. Neural behavior in these regions may impact language function during crucial developmental ages.

The Developmental Chronnecto-Genomics (Dev-CoG) study: A multimodal study on the developing brain

Brain development has largely been studied through unimodal analysis of neuroimaging data, providing independent results for structural and functional data. However, structure clearly impacts function and vice versa, pointing to the need for performing multimodal data collection and analysis to improve our understanding of brain development, and to further inform models of typical and atypical brain development across the lifespan. Ultimately, such models should also incorporate genetic and epigenetic mechanisms underlying brain structure and function, although currently this area is poorly specified. To this end, we are reporting here a multi-site, multi-modal dataset that captures cognitive function, brain structure and function, and genetic and epigenetic measures to better quantify the factors that influence brain development in children originally aged 9-14 years. Data collection for the Developmental Chronnecto-Genomics (Dev-CoG) study (http://devcog.mrn.org/) includes cognitive, emotional, and social performance scales, structural and functional MRI, diffusion MRI, magnetoencephalography (MEG), and saliva collection for DNA analysis of single nucleotide polymorphisms (SNPs) and DNA methylation patterns. Across two sites (The Mind Research Network and the University of Nebraska Medical Center), data from over 200 participants were collected and these children were re-tested annually for at least 3 years. The data collection protocol, sample demographics, and data quality measures for the dataset are presented here. The sample will be made freely available through the collaborative informatics and neuroimaging suite (COINS) database at the conclusion of the study.

Development and sex modulate visuospatial oscillatory dynamics in typically-developing children and adolescents

Visuospatial processing is a cognitive function that is critical to navigating one's surroundings and begins to develop during infancy. Extensive research has examined visuospatial processing in adults, but far less work has investigated how visuospatial processing and the underlying neurophysiology changes from childhood to early adolescence, which is a critical period of human development that is marked by the onset of puberty. In the current study, we examined behavioral performance and the oscillatory dynamics serving visuospatial processing using magnetoencephalography (MEG) in a cohort of 70 children and young adolescents aged 8-15 years. All participants performed a visuospatial processing task during MEG, and the resulting oscillatory responses were imaged using a beamformer and probed for developmental and sex-related differences. Our findings indicated that reaction time on the task was negatively correlated with age, and that the amplitude of theta oscillations in the medial occipital cortices increased with age. Significant sex-by-age interactions were also detected, with female participants exhibiting increased theta oscillatory activity in the right prefrontal cortex with increasing age, while male participants exhibited theta increases in the left parietal lobe/left precuneus and left supplementary motor area with increasing age. These data indicate that different nodes of the visuospatial processing network develop earlier in males compared to females (and vice versa) in this age range, which may have major implications for the developmental trajectory of behavioral performance and executive function more generally during the transition through puberty.

Pubertal Testosterone Tracks the Developmental Trajectory of Neural Oscillatory Activity Serving Visuospatial Processing

Puberty is a period of substantial hormonal fluctuations that induce dramatic physical, neurological, and behavioral changes. Previous research has demonstrated that pubertal hormones modulate cortical development, as well as sex- and age-specific patterns of cognitive development during childhood and adolescence. However, the influence of pubertal hormones on the brain's functional development, specifically neural oscillatory dynamics, has yet to be fully examined. Thus, in the current study, we used magnetoencephalography to investigate the oscillatory dynamics serving visuospatial perception and attention, and testosterone levels and chronological age as measures of development. Within a sample of typically developing youth, age was associated with changes in alpha, theta, and gamma oscillatory activity. Novel testosterone-by-sex interactions in the gamma range were identified in critical areas of the visual and attention networks. Females had increased gamma activity with increasing testosterone in the right temporal-parietal junction and occipital cortices, while males showed increased gamma activity in the right insula with increasing testosterone. These findings reveal robust developmental alterations in the oscillatory dynamics serving visuospatial processing during childhood and adolescence and provide novel insight into the hormonal basis of sexually dimorphic patterns of functional brain development during the pubertal transition that is at least partially mediated by endogenous testosterone.

Neural oscillatory dynamics serving abstract reasoning reveal robust sex differences in typically-developing children and adolescents

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A cohort of 10–16 year-olds completed an abstract reasoning task during MEG.

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Performance on the abstract reasoning task correlated with fluid intelligence.

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The task was associated with increased cortical dynamics in frontoparietal areas.

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Youth showed sexually divergent patterns of distributed cortical activity with age.

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Specific frontoparietal activity differentially predicted aspects of task behavior.

Fluid intelligence, the ability to problem-solve in novel situations, is linked to higher-order cognitive abilities, and to academic achievement in youth. Previous research has demonstrated that fluid intelligence and the underlying neural circuitry continues to develop throughout adolescence. Neuroimaging studies have predominantly focused on identifying the spatial distribution of brain regions associated with fluid intelligence, with only a few studies examining the temporally-sensitive cortical oscillatory dynamics underlying reasoning abilities. The present study collected magnetoencephalography (MEG) during an abstract reasoning task to examine these spatiotemporal dynamics in a sample of 10-to-16 year-old youth. We found increased cortical activity across a distributed frontoparietal network. Specifically, our key results showed: (1) age was associated with increased theta activity in occipital and cerebellar regions, (2) robust sex differences were distributed across frontoparietal regions, and (3) that specific frontoparietal regions differentially predicted abstract reasoning performance among males versus females despite similar mean performance. Among males, increased theta activity mediated the relationship between age and faster reaction times; conversely, among females, decreased theta mediated the relationship between age and improved accuracy. These findings may suggest that males and females engage in distinct neurocognitive strategies across development to achieve similar behavioral outcomes during fluid reasoning tasks.