Exploring aperiodic activity in first episode schizophrenia spectrum psychosis: A resting-state EEG analysis.

Abnormalities in brain oscillatory patterns have long been observed in schizophrenia and psychotic disorders more broadly. However, far less is known about aperiodic neural activity in these disorders, which has been linked to excitation/inhibition balance and neuronal population spiking within the brain. Here, we analysed resting-state electroencephalographic (EEG) recordings from 43 first episode schizophrenia spectrum psychosis (FESSP) patients and 28 healthy controls to examine whether aperiodic activity is disrupted in FESSP. We further assessed potential associations between aperiodic activity in FESSP and clinical symptom severity using the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Negative Symptoms (SANS), and the Scale for the Assessment of Positive Symptoms (SAPS). We found no significant differences in either the 1/f-like aperiodic exponent or the broadband aperiodic offset between the FESSP and healthy control groups when analysing the global neural signal averaged across all EEG electrodes. Bayesian analyses further supported these non-significant findings. However, additional non-parametric cluster-based permutation analyses did identify reduced aperiodic offset in the FESSP group, relative to controls across broad central, temporal, parietal and select frontal regions. No associations were found between either exponent or offset and clinical symptom severity when examining all FESSP participants, irrespective of antipsychotic medication status. However, offset was shown to predict BPRS and SANS scores in medication naive patients. In sum, this research presents an initial analysis of aperiodic neural activity in FESSP, offering preliminary evidence of altered aperiodic offset in this disorder. This contributes to a broader understanding of disrupted neural dynamics in early psychosis.

Pupillometry reveals resting state alpha power correlates with individual differences in adult auditory language comprehension.

Although individual differences in adult language processing are well-documented, the neural basis of this variability remains largely unexplored. The current study addressed this gap in the literature by examining the relationship between resting state alpha activity and individual differences in auditory language comprehension. Alpha oscillations modulate cortical excitability, facilitating efficient information processing in the brain. While resting state alpha oscillations have been tied to individual differences in cognitive performance, their association with auditory language comprehension is less clear. Participants in the study were 80 healthy adults with a mean age of 25.8 years (SD = 7.2 years). Resting state alpha activity was acquired using electroencephalography while participants looked at a benign stimulus for 3 min. Participants then completed a language comprehension task that involved listening to 'syntactically simple' subject-relative clause sentences and 'syntactically complex' object-relative clause sentences. Pupillometry measured real-time processing demand changes, with larger pupil dilation indicating increased processing loads. Replicating past research, comprehending object relative clauses, compared to subject relative clauses, was associated with lower accuracy, slower reaction times, and larger pupil dilation. Resting state alpha power was found to be positively correlated with the pupillometry data. That is, participants with higher resting state alpha activity evidenced larger dilation during sentence comprehension. This effect was more pronounced for the 'complex' object sentences compared to the 'simple' subject sentences. These findings suggest the brain's capacity to generate a robust resting alpha rhythm contributes to variability in processing demands associated with auditory language comprehension, especially when faced with challenging syntactic structures. More generally, the study demonstrates that the intrinsic functional architecture of the brain likely influences individual differences in language comprehension.

Atypical procedural learning in children with developmental coordination disorder: A combined behavioral and neuroimaging study.

While procedural learning (PL) has been implicated in delayed motor skill observed in developmental coordination disorder (DCD), few studies have considered the impact of co-occurring attentional problems. Furthermore, the neurostructural basis of PL in children remains unclear. We investigated PL in children with DCD while controlling for inattention symptoms, and examined the role of fronto-basal ganglia-cerebellar morphology in PL. Fifty-nine children (6-14 years; nDCD = 19, ncontrol = 40) completed the serial reaction time (SRT) task to measure PL. The Attention-Deficit Hyperactivity Disorder Rating Scale-IV was administered to measure inattention symptoms. Structural T1 images were acquired for a subset of participants (nDCD = 10, ncontrol = 28), and processed using FreeSurfer. Volume was extracted for the cerebellum, basal ganglia, and frontal regions. After controlling for inattention symptoms, the reaction time profile of controls was consistent with learning on the SRT task. This was not the case for those with DCD. SRT task performance was positively correlated with cerebellar cortical volume, and children with DCD trended towards lower cerebellar volume compared to controls. Children with DCD may not engage in PL during the SRT task in the same manner as controls, with this differential performance being associated with atypical cerebellar morphology.

EEG microstates in early-to-middle childhood show associations with age, biological sex, and alpha power.

Electroencephalographic (EEG) microstates can provide a unique window into the temporal dynamics of large-scale brain networks across brief (millisecond) timescales. Here, we analysed fundamental temporal features of microstates extracted from the broadband EEG signal in a large (N = 139) cohort of children spanning early-to-middle childhood (4-12 years of age). Linear regression models were used to examine if participants' age and biological sex could predict the temporal parameters GEV, duration, coverage, and occurrence, for five microstate classes (A-E) across both eyes-closed and eyes-open resting-state recordings. We further explored associations between these microstate parameters and posterior alpha power after removal of the 1/f-like aperiodic signal. The microstates obtained from our neurodevelopmental EEG recordings broadly replicated the four canonical microstate classes (A to D) frequently reported in adults, with the addition of the more recently established microstate class E. Biological sex served as a significant predictor in the regression models for four of the five microstate classes (A, C, D, and E). In addition, duration and occurrence for microstate E were both found to be positively associated with age for the eyes-open recordings, while the temporal parameters of microstates C and E both exhibited associations with alpha band spectral power. Together, these findings highlight the influence of age and sex on large-scale functional brain networks during early-to-middle childhood, extending understanding of neural dynamics across this important period for brain development.

Resting state electroencephalography power correlates with individual differences in implicit sequence learning.

Neuroimaging resting state paradigms have revealed synchronised oscillatory activity is present even in the absence of completing a task or mental operation. One function of this neural activity is likely to optimise the brain's sensitivity to forthcoming information that, in turn, likely promotes subsequent learning and memory outcomes. The current study investigated whether this extends to implicit forms of learning. A total of 85 healthy adults participated in the study. Resting state electroencephalography was first acquired from participants before they completed a serial reaction time task. On this task, participants implicitly learnt a visuospatial-motor sequence. Permutation testing revealed a negative correlation between implicit sequence learning and resting state power in the upper theta band (6-7 Hz). That is, lower levels of resting state power in this frequency range were associated with superior levels of implicit sequence learning. This association was observed at midline-frontal, right-frontal and left-posterior electrodes. Oscillatory activity in the upper theta band supports a range of top-down processes including attention, inhibitory control and working memory, perhaps just for visuospatial information. Our results may be indicating that disengaging theta-supported top-down attentional processes improves implicit learning of visuospatial-motor information that is embedded in sensory input. This may occur because the brain's sensitivity to this type of information is optimally achieved when learning is driven by bottom-up processes. Moreover, the results of this study further demonstrate that resting state synchronised brain activity influences subsequent learning and memory.

Individual differences in procedural learning are associated with fiber specific white matter microstructure of the superior cerebellar peduncles in healthy adults.

Functional neuroimaging has consistently implicated the fronto-basal ganglia-cerebellar circuit in procedural learning-defined as the incidental acquisition of sequence information through repetition. Limited work has probed the role of white matter fiber pathways that connect the regions in this network, such as the superior cerebellar peduncles (SCP) and the striatal premotor tracts (STPMT), in explaining individual differences in procedural learning. High angular diffusion weighted imaging was acquired from 20 healthy adults aged 18-45 years. Fixel-based analysis was performed to extract specific measures of white matter microstructure (fiber density; FD) and macrostructure (fiber cross-section; FC), from the SCP and STPMT. These fixel metrics were correlated with performance on the serial reaction time (SRT) task, and sensitivity to the sequence was indexed by the difference in reaction time between the final block of sequence trials and the randomized block (namely, the 'rebound effect'). Analyses revealed a significant positive relationship between FD and the rebound effect in segments of both the left and right SCP (pFWE < .05). That is, increased FD in these tracts was associated with greater sensitivity to the sequence on the SRT task. No significant associations were detected between fixel metrics in the STPMT and the rebound effect. Our results support the likely role of white matter organization in the basal ganglia-cerebellar circuit in explaining individual differences in procedural learning.

Neural basis of implicit motor sequence learning: Modulation of cortical power.

Implicit sequence learning describes the acquisition of serially ordered movements and sequentially structured cognitive information, that occurs without awareness. Theta, alpha and beta cortical oscillations are present during implicit motor sequence learning, but their role in this process is unclear. The current study addressed this gap in the literature. A total of 50 healthy adults aged between 19 and 37 years participated in the study. Implicit motor sequence learning was examined using the Serial Reaction Time task where participants unknowingly repeat a sequence of finger movements in response to a visual stimulus. Sequence learning was examined by comparing reaction times and oscillatory power between sequence trials and a set of control trials comprising random stimulus presentations. Electroencephalography was recorded as participants completed the task. Analyses of the behavioral data revealed participants learnt the sequence. Analyses of oscillatory activity, using permutation testing, revealed sequence learning was associated with a decrease in theta band (4-7 Hz) power recorded over frontal and central electrode sites. Sequence learning effects were not observed in the alpha (7-12 Hz) or beta bands (12-20 Hz). Even though alpha and beta power modulations have long been associated with executing a motor response, it seems theta power is a correlate of sequence learning in the manual domain. Theta power modulations on the serial reaction time task may reflect disengagement of attentional resources, either promoting or occurring as a consequence of implicit motor sequence learning.

Right anterior theta connectivity predicts autistic social traits in typically developing children.

Growing evidence supports functional network alterations in autism spectrum disorder, however much less is known about the neural mechanisms underlying autistic traits in typically developing children. Using resting-state electroencephalographic (EEG) recordings, we examined whether functional connectivity could predict autistic trait expression in 127 children aged between 4 and 12 years. Regression models showed that right anterior theta connectivity was a significant predictor of autistic traits (p = 0.013), with increased connectivity in this region associated with greater autistic trait expression. These results corroborate similar recent findings in adults, extending this observation to a cohort of children spanning early-to-middle childhood. These findings further highlight EEG-derived functional connectivity as a sensitive physiological correlate of autistic trait expression in typically developing children.

Moral content influences facial emotion processing development during early-to-middle childhood.

Facial emotions are often processed in light of moral information, which can assist in predicting and interpreting the intentions of another. Neurophysiological measures of facial emotion processing (FEP) may be sensitive to moral content. Relatively little is known, however, about the relationship between moral content and FEP during early-to-middle childhood, and how this relationship may change across development. Eighty-four children aged 4-12 years completed a task assessing whether child faces primed within the moral harm/care domain influenced face sensitive event-related potentials (ERPs; N170 and LPP). Results demonstrated that N170 amplitude decreased with age for faces primed with positive moral content, whilst LPP amplitude decreased with age for faces primed with negative moral content. Collectively, this suggests that morally relevant content within the harm/care domain is integrated during the early stages of FEP in early-to-middle childhood. Moreover, stronger language ability was positively correlated with the LPP for fearful faces primed with negative moral content. Overall, findings provide novel evidence to suggest that FEP development may be modulated by moral content, and emotion-specific results may be influenced by language. Findings from this research highlight the complex relationship between broader social cognitive skills during child development.

Enlarged Interior Built Environment Scale Modulates High-Frequency EEG Oscillations.

There is currently no robust method to evaluate how built environment design affects our emotion. Understanding emotion is significant, as it influences cognitive processes, behavior, and wellbeing, and is linked to the functioning of physiological systems. As mental health problems are becoming more prevalent, and exposure to indoor environments is increasing, it is important we develop rigorous methods to understand whether design elements in our environment affect emotion. This study examines whether the scale of interior built environments modulate neural networks involved in emotion regulation. Using a Cave Automatic Virtual Environment (CAVE) and controlling for indoor environmental quality (IEQ), 66 adults (31 female, aged 18-55) were exposed to context-neutral enclosed indoor room scenes to understand whether built environment scale affected self-report, autonomic nervous system, and central nervous system correlates of emotion. Our results revealed enlarged scale increased electroencephalography (EEG) power in the ß bandwidth. Frontal midline low-γ and high-γ power were also found to increase with enlarged scale, but contrary to our hypothesis, scale did not modulate frontal midline power or lateralization in the θ or α bandwidths. We did not detect an effect of scale on autonomic indicators or self-reported emotion. However, we did find increased range in skin conductance response (SCR) and heart rate variability (HRV) to the built environment conditions. This study provides a rigorous empirical framework for assessing the environmental impact of a design characteristic on human emotion and suggests that measures of high-frequency oscillations may provide a useful marker of the response to built environment.

Built environment color modulates autonomic and EEG indices of emotional response.

Understanding built environment exposure as a component of environmental enrichment has significant implications for mental health, but little is known about the effects design characteristics have on our emotions and associated neurophysiology. Using a Cave Automatic Virtual Environment while monitoring indoor environmental quality (IEQ), 18 participants were exposed to a resting state (black), and two room scenes, control (white) and condition (blue), to understand if the color of the virtual walls affected self-report, autonomic nervous system, and central nervous system correlates of emotion. Our findings showed that exposure to the chromatic color condition (blue) compared to the achromatic control (white) and resting-state (black, no built environment) significantly increased the range in respiration and skin conductance response. We also detected a significant increase in alpha frontal midline power and frontal hemispheric lateralization relative to blue condition, and increased power spectral density across all electrodes in the blue condition for theta, alpha, and beta bandwidths. The ability for built environment design to modulate emotional response has the potential to deliver significant public health, economic, and social benefits to the entire community. The findings show that blue coloring of the built environment increases autonomic range and is associated with modulations of brain activity linked to emotional processing.

Resting state electroencephalography (EEG) correlates with children's language skills: Evidence from sentence repetition.

Spontaneous neural oscillatory activity reflects the brain's functional architecture and has previously been shown to correlate with perceptual, motor and executive skills. The current study used resting state electroencephalography to examine the relationship between spontaneous neural oscillatory activity and children's language skills. Participants in the study were 52 English-speaking children aged around 10-years. Language was assessed using a sentence repetition task. The main analysis revealed resting state theta power negatively correlated with this task. No significant correlations were found in the other studied frequency bands (delta, alpha, beta, gamma). As part of typical brain development, spontaneous theta power declines across childhood and adolescence. The negative correlation observed in this study may therefore be indicating children's language skills are related to the maturation of theta oscillations. More generally, the study provides further evidence that oscillatory activity in the developing brain, even at rest, is reliably associated with children's language skills.

Periodic and aperiodic neural activity displays age-dependent changes across early-to-middle childhood.

The neurodevelopmental period spanning early-to-middle childhood represents a time of significant growth and reorganisation throughout the cortex. Such changes are critical for the emergence and maturation of a range of social and cognitive processes. Here, we utilised both eyes open and eyes closed resting-state electroencephalography (EEG) to examine maturational changes in both oscillatory (i.e., periodic) and non-oscillatory (aperiodic, '1/f-like') activity in a large cohort of participants ranging from 4-to-12 years of age (N = 139, average age=9.41 years, SD=1.95). The EEG signal was parameterised into aperiodic and periodic components, and linear regression models were used to evaluate if chronological age could predict aperiodic exponent and offset, as well as well as peak frequency and power within the alpha and beta ranges. Exponent and offset were found to both decrease with age, while aperiodic-adjusted alpha peak frequency increased with age; however, there was no association between age and peak frequency for the beta band. Age was also unrelated to aperiodic-adjusted spectral power within either the alpha or beta bands, despite both frequency ranges being correlated with the aperiodic signal. Overall, these results highlight the capacity for both periodic and aperiodic features of the EEG to elucidate age-related functional changes within the developing brain.

Implicit manual and oculomotor sequence learning in developmental language disorder.

Procedural memory functioning in developmental language disorder (DLD) has largely been investigated by examining implicit sequence learning by the manual motor system. This study examined whether poor sequence learning in DLD is present in the oculomotor domain. Twenty children with DLD and 20 age-matched typically developing (TD) children were presented with a serial reaction time (SRT) task. On the task, a visual stimulus repeatedly appears in different positions on a computer display which prompts a manual response. The children were unaware that on the first three blocks and final block of trials, the visual stimulus followed a sequence. On the fourth block, the stimulus appeared in random positions. Manual reaction times (RT) and saccadic amplitudes were recorded, which assessed sequence learning in the manual and oculomotor domains, respectively. Manual RT were sensitive to sequence learning for the TD group, but not the DLD group. For the TD group, manual RT increased when the random block was presented. This was not the case for the DLD group. In the oculomotor domain, sequence learning was present in both groups. Specifically, sequence learning was found to modulate saccadic amplitudes resulting in both DLD and TD children being able to anticipate the location of the visual stimulus. Overall, the study indicates that not all aspects of the procedural memory system are equally impaired in DLD.

Is vegetation cover in key behaviour settings important for early childhood socioemotional function? A preregistered, cross-sectional study.

The environmental influences on early childhood development are understudied. The association between vegetation cover (i.e., trees, shrubs, grassed areas) in four key behaviour settings and socioemotional functioning was investigated in 1196 young children (2-5 years). Emotional difficulties were inversely associated with vegetation cover in the home yard (OR: 0.81 [0.69-0.96]) and neighbourhood (OR: 0.79 [0.67-0.94]), but not in early childhood education and care (ECEC) centre outdoor areas or the ECEC neighbourhood. The higher odds of emotional difficulties associated with lower levels of maternal education was reduced with higher percentages of home yard vegetation cover. There was no evidence of mediation of the relationship between emotional difficulties and vegetation cover by time spent playing outside the home, day or nighttime sleep duration, or physical activity. We found no associations between vegetation cover and conduct, hyperactivity and inattention, peer difficulties, or prosocial behaviours. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=J3HeEiIjVZc.

Facial emotion processing and language during early-to-middle childhood development: An event related potential study.

Facial emotion processing (FEP) is critical to social cognitive ability. Developmentally, FEP rapidly improves in early childhood and continues to be fine-tuned throughout middle childhood and into adolescence. Previous research has suggested that language plays a role in the development of social cognitive skills, including non-verbal emotion recognition tasks. Here we investigated whether language is associated with specific neurophysiological indicators of FEP. One hundred and fourteen children (4-12 years) completed a language assessment and a FEP task including stimuli depicting anger, happiness, fear, and neutrality. EEG was used to record key event related potentials (ERPs; P100, N170, LPP at occipital and parietal sites separately) previously shown to be sensitive to faces and facial emotion. While there were no main effects of language, the P100 latency to negative expressions appeared to increase with language, while LPP amplitude increased with language for negative and neutral expressions. These findings suggest that language is linked to some early physiological indicators of FEP, but this is dependent on the facial expression. Future studies should explore the role of language in later stages of neural processing, with a focus on processes localised to ventromedial prefrontal regions.

A Daytime Nap Does Not Enhance the Retention of a First-Order or Second-Order Motor Sequence.

This study examined the effects of a daytime nap on the retention of implicitly learnt "first-order conditional" (FOC) and "second-order conditional" (SOC) motor sequences. The implicit learning and retention of a motor sequence has been linked to the neural processes undertaken by the basal ganglia and primary motor cortex (i.e., procedural memory system). There is evidence, however, suggesting that SOC learning may further rely on the hippocampus-supported declarative memory system. Sleep appears to benefit the retention of information processed by the declarative memory system, but not the procedural memory system. Thus, it was hypothesized that sleep would benefit the retention of a SOC motor sequence but not a FOC sequence. The implicit learning and retention of these sequences was examined using the Serial Reaction Time Task. In this study, healthy adults implicitly learnt either a FOC (n = 20) or a SOC sequence (n = 20). Retention of both sequences was assessed following a daytime nap and period of wakefulness. Sleep was not found to improve the retention of the SOC sequence. There were no significant differences in the retention of a FOC or a SOC sequence following a nap or period of wakefulness. The study questions whether the declarative memory system is involved in the retention of implicitly learnt SOC sequences.

The development of neural responses to emotional faces: A review of evidence from event-related potentials during early and middle childhood.

Facial emotion processing (FEP) develops throughout childhood and provides crucial social information necessary for the interpretation and prediction of others' behaviour. This systematic review, which includes a meta-regression component, sought to explore the development of FEP event-related potentials (P100, N170, and late positive potential [LPP]) in children aged three to twelve years. Thirty-four studies, representing data from 1511 children, were included in the review. The combination of meta-regression and systematic review suggest that P100 amplitude decreases with increasing age in response to emotional facial stimuli. P100 latency may show a gradual decrease around the age of ten. In terms of the N170, it is suggested that amplitude follows a non-linear trend with age, and latency may decrease in early childhood before plateauing during middle childhood. Of note, review of the literature indicates that substantial methodological differences and high levels of heterogeneity exist. We suggest future research considers these results within the context of emotion-specific development, whilst also acknowledging how this may relate to individual social functioning skills across early-to-middle childhood.

The mediating effect of language on the development of cognitive and affective theory of mind.

Theory of mind (ToM) development is critical to effective social functioning and appears to depend on complementary language abilities. The current study explored the mediating influence of language on the development of both cognitive and affective ToM. A total of 151 children aged 5-12 years completed ToM (cognitive and affective) and language assessments, and parents provided ratings of their children's empathic ability. Results showed that language mediated the relationship between age and both cognitive and affective ToM but not parent-reported cognitive empathy. Examination of younger and older subgroups revealed that language mediated cognitive and affective ToM differently across developmental periods. Findings highlight the dynamic role that language plays in the development of both cognitive and affective ToM throughout early and middle childhood.

Continuous theta-burst stimulation modulates language-related inhibitory processes in bilinguals: evidence from event-related potentials.

The dorsolateral prefrontal cortex (DLPFC) is activated when bilinguals switch between languages. Language switching can also elicit the N2 event-related potential (ERP). This ERP component appears to capture the cognitive control processes related to conflict monitoring, response selection and response inhibition. In the present study, continuous theta-burst stimulation (cTBS) was used to examine the role of the left DLPFC in bilingual language switching, using a picture-naming task. Participants in the study were 17 Afrikaans-English bilinguals. The picture-naming task consisted of non-switch and switch trials. On non-switch trials, participants named two consecutive pictures in the same language. On switch trials, participants named consecutive pictures in different languages (e.g., Afrikaans and then English). The participants completed three testing sessions. In each session, participants received either cTBS to the left DLPFC or the vertex, or sham stimulation, and then completed the picture-naming task. The results showed that following DLPFC stimulation, the N2 ERP was attenuated on switch trials compared to non-switch trials. Vertex or sham stimulation did not modulate the N2 ERP. cTBS did not affect language switching at the behavioural level. These results provide support for the role of the left DLPFC in the cognitive control processes underlying bilingual language switching. Furthermore, the study demonstrates that these processes can be modulated via non-invasive brain stimulation and the effects detected at the neural level.