RELAX-Jr: An Automated Pre-Processing Pipeline for Developmental EEG Recordings.

Automated EEG pre-processing pipelines provide several key advantages over traditional manual data cleaning approaches; primarily, they are less time-intensive and remove potential experimenter error/bias. Automated pipelines also require fewer technical expertise as they remove the need for manual artefact identification. We recently developed the fully automated Reduction of Electroencephalographic Artefacts (RELAX) pipeline and demonstrated its performance in cleaning EEG data recorded from adult populations. Here, we introduce the RELAX-Jr pipeline, which was adapted from RELAX and designed specifically for pre-processing of data collected from children. RELAX-Jr implements multi-channel Wiener filtering (MWF) and/or wavelet-enhanced independent component analysis (wICA) combined with the adjusted-ADJUST automated independent component classification algorithm to identify and reduce all artefacts using algorithms adapted to optimally identify artefacts in EEG recordings taken from children. Using a dataset of resting-state EEG recordings (N = 136) from children spanning early-to-middle childhood (4-12 years), we assessed the cleaning performance of RELAX-Jr using a range of metrics including signal-to-error ratio, artefact-to-residue ratio, ability to reduce blink and muscle contamination, and differences in estimates of alpha power between eyes-open and eyes-closed recordings. We also compared the performance of RELAX-Jr against four publicly available automated cleaning pipelines. We demonstrate that RELAX-Jr provides strong cleaning performance across a range of metrics, supporting its use as an effective and fully automated cleaning pipeline for neurodevelopmental EEG data.

EEG During Dynamic Facial Emotion Processing Reveals Neural Activity Patterns Associated with Autistic Traits in Children.

Altered brain connectivity and atypical neural oscillations have been observed in autism, yet their relationship with autistic traits in non-clinical populations remains underexplored. Here, we employ electroencephalography (EEG) to examine functional connectivity, oscillatory power, and broadband aperiodic activity during a dynamic facial emotion processing (FEP) task in 101 typically developing children aged 4-12 years. We investigate associations between these electrophysiological measures of brain dynamics and autistic traits as assessed by the Social Responsiveness Scale, 2nd Edition (SRS-2). Our results revealed that increased FEP-related connectivity across theta (4-7 Hz) and beta (13-30 Hz) frequencies correlated positively with higher SRS-2 scores, predominantly in right-lateralized (theta) and bilateral (beta) cortical networks. Additionally, a steeper 1/f-like aperiodic slope (spectral exponent) across fronto-central electrodes was associated with higher SRS-2 scores. Greater aperiodic-adjusted theta and alpha oscillatory power further correlated with both higher SRS-2 scores and steeper aperiodic slopes. These findings underscore important links between FEP-related brain dynamics and autistic traits in typically developing children. Future work could extend these findings to assess these EEG-derived markers as potential mechanisms underlying behavioural difficulties in autism.

Procedural learning is associated with microstructure of basal ganglia-cerebellar circuitry in children.

In adults, individual differences in procedural learning (PL) are associated with white matter organization within the basal ganglia-cerebellar circuit. However, no research has examined whether this circuitry is related to individual differences in PL during childhood. Here, 28 children (Mage = 10.00 ± 2.31, 10 female) completed the serial reaction time (SRT) task to measure PL, and underwent structural magnetic resonance imaging (MRI). Fixel-Based Analysis was performed to extract specific measures of white matter fiber density (FD) and fiber cross-section (FC) from the superior cerebellar peduncles (SCP) and the striatal premotor tracts (STPMT), which underlie the fronto-basal ganglia-cerebellar system. These fixel metrics were correlated with the 'rebound effect' from the SRT task - a measure of PL proficiency which compares reaction times associated with generating a sequence, to random trials. While no significant associations were observed at the fixel level, a significant positive association was observed between average FD in the right SCP and the rebound effect, with a similar trend observed in the left SCP. No significant effects were detected in the STPMT. Our results indicate that, like in adults, microstructure of the basal ganglia-cerebellar circuit may explain individual differences in childhood PL.

Fear is more right lateralized than happiness and anger: Evidence for the motivational hypothesis of emotional face perception?

Facial emotion processing (FEP) tends to be right hemisphere lateralized. This right-hemispheric bias (RHB) for FEP varies within and between individuals. The aim of the present research was to examine evidence pertaining to the prominent theories of FEP hemispheric bias as measured by a half-emotional half-neutral (no emotion) chimeric faces task. FEP hemispheric bias was indexed using laterality quotients (LQs) calculated from a Chimeric Faces Task completed by 427 adults recruited from the general population aged 18-67 years. Participants indicated which of two identical (but mirrored) emotional-neutral chimeric faces were more emotive. While all investigated emotions (fear, anger, and happiness) were right lateralized, fear was significantly more right lateralized than anger and happiness. These results provide evidence for both the right hemisphere hypothesis and the motivational hypothesis of emotion perception.

The Neurophysiological Effects of Theta Burst Stimulation as Measured by Electroencephalography: A Systematic Review.

Theta burst stimulation (TBS) is a non-invasive brain stimulation technique that can modulate neural activity. The effect of TBS on regions beyond the motor cortex remains unclear. With increased interest in applying TBS to non-motor regions for research and clinical purposes, these effects must be understood and characterised. We synthesised the electrophysiological effects of a single session of TBS, as indexed by electroencephalography (EEG) and concurrent transcranial magnetic stimulation and EEG (TMS-EEG), in non-clinical participants. We reviewed 79 studies that administered either continuous TBS (cTBS) or intermittent TBS (iTBS) protocols. Broadly, cTBS suppressed and iTBS facilitated evoked response component amplitudes. Response to TBS as measured by spectral power and connectivity was much more variable. Variability increased in the presence of task stimuli. There was a large degree of heterogeneity in the research methodology across studies. Additionally, the effect of individual differences on TBS response is insufficiently investigated. Future research investigating the effects of TBS as measured by EEG must consider methodological and individual factors that may affect TBS outcomes.

White matter organisation of sensorimotor tracts is associated with motor imagery in childhood.

Despite the important role of motor imagery (MI) in motor development, our understanding of the contribution of white matter fibre properties to MI performance in childhood remains limited. To provide novel insight into the white matter correlates of MI performance, this study examined the association between white matter fibre properties and motor imagery performance in a sample of typically developing children. High angular diffusion weighted imaging data were collected from 22 typically developing children aged 6-14 years (12 female, MAge= 10.56). Implicit motor imagery performance was assessed using a mental hand rotation paradigm. The cerebellar peduncles and the superior longitudinal fasciculus were reconstructed using TractSeg, a semi-automated method. For each tract, white matter microstructure (fibre density, FD) and morphology (fibre bundle cross-section, FC) were estimated using Fixel-Based Analysis. Permutation-based inference testing and partial correlation analyses demonstrated that higher FC in the middle cerebellar peduncles was associated with better MI performance. Tract-based region of interest analyses showed that higher FC in the middle and superior cerebellar peduncles were associated with better MI performance. Results suggest that white matter connectivity along the cerebellar peduncles may facilitate MI performance in childhood. These findings advance our understanding of the neurobiological systems that underlie MI performance in childhood and provide early evidence for the relevance of white matter sensorimotor pathways to internal action representations.

Overlap of eating disorders and neurodivergence: the role of inhibitory control.

BACKGROUND: Difficulties with inhibitory control have been identified in eating disorders (EDs) and neurodevelopmental disorders (NDs; including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder), and there appear to be parallels between the expression of these impairments. It is theorised that impairments in inhibitory control within NDs may represent a unique vulnerability for eating disorders (EDs), and this same mechanism may contribute to poorer treatment outcomes. This review seeks to determine the state of the literature concerning the role of inhibitory control in the overlap of EDs and neurodivergence. METHOD: A scoping review was conducted to summarise extant research, and to identify gaps in the existing knowledge base. Scopus, Medline, PsycInfo, Embase, and ProQuest were systematically searched. Studies were included if the study measured traits of ADHD or autism, and symptoms of ED, and required participants to complete a performance task measure of inhibitory control. Where studies included a cohort with both an ND and ED, these results had to be reported separately from cohorts with a singular diagnosis. Studies were required to be published in English, within the last 10 years. RESULTS: No studies explored the relationship between autism and EDs using behavioural measures of inhibitory control. Four studies exploring the relationship between ADHD and EDs using behavioural measures of inhibitory control met selection criteria. These studies showed a multifaceted relationship between these conditions, with differences emerging between domains of inhibitory control. ADHD symptoms predicted poorer performance on measures of response inhibition in a non-clinical sample; this was not replicated in clinical samples, nor was there a significant association with EDs. Both ADHD and ED symptoms are associated with poor performance on attentional control measures; where these diagnoses were combined, performance was worse than for those with a singular diagnosis of ADHD. This was not replicated when compared to those with only ED diagnoses. CONCLUSION: Impairments in attentional control may represent a unique vulnerability for the development of an ED and contribute to poor treatment outcomes. Further research is needed to explore the role of inhibitory control in EDs, ADHD and autism, including the use of both self-report and behavioural measures to capture the domains of inhibitory control.

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.

A systematic review of visual processing in body dysmorphic disorder (BDD).

To understand the visual preponderance of perceived flaws in appearance in body dysmorphic disorder (BDD), the study of visual processing has been growing. Studies have focused on facial and other basic visual stimuli. The current literature does not provide evidence of consistent behavioural patterns, lacking an overarching body of work describing visual processing in BDD. This systematic review aims to characterise behavioural outcomes of visual processing anomalies and/or deficits in BDD. Articles were collected through online databases MEDLINE and PubMed, and were included if they comprised a clinical BDD group, and were published after 1990. Results indicate that individuals with BDD demonstrate deficits in emotional face processing, a possible overreliance on detail processing, aberrant eye-scanning behaviours, and a tendency to overvalue attractiveness. While findings consistently signal towards visual deficits in BDD, there is lack of clarity as to the type. This inconsistency may be attributed to heterogeneity within BDD samples and differences in experimental design (i.e., stimuli, tasks, conditions). There are difficulties distinguishing between BDD-associated deficits and those associated with OCD or eating disorders. A coherent framework, including sample characterisation and task design will seek to generate clear and consistent behavioural patterns to guide future treatments.

Cognitive and emotional empathy in acute and remitted anorexia nervosa: a systematic review.

Background: Impairments in empathy are well established in anorexia nervosa (AN). It is unclear, however, whether these deficits only occur in the acute phases of AN due to neurocognitive impacts of starvation (often referred to as context-dependent, or state-like), or if deficits remain once remission has been achieved (trait-like). This debate is commonly referred to as the 'state vs trait' debate. Objective: This systematic review aims to summarise existing literature regarding empathy in AN, and to investigate whether empathy deficits in AN are state- or trait-based. Method: A total of 1014 articles were identified, and seven articles remained after the screening process. These seven articles, comparing empathy across three groups (acute AN, remission of AN, and non-clinical controls), were evaluated and summarised in accordance with PRISMA guidelines. Articles were required to have included all three groups and report on either cognitive empathy and/or emotional empathy. Results: The majority of studies were of satisfactory quality. The results identified were inconsistent, with few articles lending some support to the 'state' hypothesis and others producing nonsignificant results. Conclusions: There is minimal literature comparing empathy in acute and remission phases of AN. While there were some inconsistencies in included articles, some data indicate that there may be slight improvements to emotional and cognitive empathy following recovery of AN. Further research is needed to better enrich knowledge regarding the role of state vs trait with regard to neurocognitive difficulties experienced by individuals with AN. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=335669, identifier CRD42022335669.

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.

Atypical alpha band microstates produced during eyes-closed resting state EEG in autism.

Electroencephalogram (EEG) microstates, which represent quasi-stable patterns of scalp topography, are a promising tool that has the temporal resolution to study atypical spatial and temporal networks in autism spectrum disorder (ASD). While current literature suggests microstates are atypical in ASD, their clinical utility, i.e., relationship with the core behavioural characteristics of ASD, is not fully understood. The aim of this study was to examine microstate parameters in ASD, and examine the relationship between these parameters and core behavioural characteristics in ASD. We compared duration, occurrence, coverage, global explained variance percentage, global field power and spatial correlation of EEG microstates between autistic and neurotypical (NT) adults. Modified k-means cluster analysis was used on eyes-closed, resting state EEG from 30 ASD (10 females, 28.97 ± 9.34 years) and 30 age-equated NT (13 females, 29.33 ± 8.88 years) adults. Five optimal microstates, A to E, were selected to best represent the data. Five microstate maps explaining 80.44% of the NT and 78.44% of the ASD data were found. The ASD group was found to have atypical parameters of microstate A, C, D, and E. Of note, all parameters of microstate C in the ASD group were found to be significantly less than NT. While parameters of microstate D, and E were also found to significantly correlate with subscales of the Ritvo Autism Asperger Diagnostic Scale - Revised (RAADS-R), these findings did not survive a Bonferroni Correction. These findings, in combination with previous findings, highlight the potential clinical utility of EEG microstates and indicate their potential value as a neurophysiologic marker that can be further studied.

Inhibitory dysfunction and social processing difficulties in autism: A comprehensive narrative review.

The primary inhibitory neurotransmitter γ-aminobutyric acid (GABA) has a prominent role in regulating neural development and function, with disruption to GABAergic signalling linked to behavioural phenotypes associated with neurodevelopmental disorders, particularly autism. Such neurochemical disruption, likely resulting from diverse genetic and molecular mechanisms, particularly during early development, can subsequently affect the cellular balance of excitation and inhibition in neuronal circuits, which may account for the social processing difficulties observed in autism and related conditions. This comprehensive narrative review integrates diverse streams of research from several disciplines, including molecular neurobiology, genetics, epigenetics, and systems neuroscience. In so doing it aims to elucidate the relevance of inhibitory dysfunction to autism, with specific focus on social processing difficulties that represent a core feature of this disorder. Many of the social processing difficulties experienced in autism have been linked to higher levels of the excitatory neurotransmitter glutamate and/or lower levels of inhibitory GABA. While current therapeutic options for social difficulties in autism are largely limited to behavioural interventions, this review highlights the psychopharmacological studies that explore the utility of GABA modulation in alleviating such difficulties.

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.

Exploring the role of autistic traits and eating disorder psychopathology on mentalising ability in the general population.

BACKGROUND: This study evaluated the role of overlapping traits and characteristics related to autism spectrum disorder (autism) and anorexia nervosa (AN) in the general population, and the impact of these traits on mentalising ability. METHODS: A sample of young adults (N = 306), aged 18-25 years, was recruited to complete an online study that consisted of 4 measures: the Autism-Spectrum Quotient, Eating Disorder Examination Questionnaire, the Mentalization Scale, and the Reading the Mind in the Eyes task. RESULTS: Higher levels of autistic traits, particularly difficulty with attention switching, were associated with increased eating disorder psychopathology. Overall, autistic traits and eating disorder psychopathology were related among females, but not males. Difficulty with attention switching, however, was related to eating disorder psychopathology among both females and males. Autistic traits also appear to have a greater role in mentalising ability than does eating disorder psychopathology. CONCLUSION: The role of attention switching in overlapping traits of autism and eating disorder psychopathology needs to be more comprehensively evaluated by future research, as does the role of biological sex. Expanded knowledge in this field will help to better understand and evaluate symptoms at presentation, leading to clearer diagnoses and potentially better treatment outcomes.

A systematic review of cannabidiol trials in neurodevelopmental disorders.

Cannabis-derived compounds, such as cannabidiol (CBD) and delta-9-trans-tetrahydrocannabinol (THC), are increasingly prescribed for a range of clinical indications. These phyto-cannabinoids have multiple biological targets, including the body's endocannabinoid system. There is growing scientific interest in the use of CBD, a non-intoxicating compound, to ameliorate symptoms associated with neurodevelopmental disorders. However, its suitability as a pharmaceutical intervention has not been reliably established in these clinical populations. This systematic review examines the nine published randomised controlled trials (RCTs) that have probed the safety and efficacy of CBD in individuals diagnosed with attention deficit hyperactivity disorder, autism spectrum disorder, intellectual disability, Tourette Syndrome, and complex motor disorders. Studies were identified systematically through searching four databases: Medline, CINAHL complete, PsycINFO, and EMBASE. Inclusion criteria were randomised controlled trials involving CBD and participants with neurodevelopmental disorders. No publication year or language restrictions were applied. Relevant data were extracted from the identified list of eligible articles. After extraction, data were cross-checked between the authors to ensure consistency. Several trials indicate potential efficacy, although this possibility is currently too inconsistent across RCTs to confidently guide clinical usage. Study characteristics, treatment properties, and outcomes varied greatly across the included trials. The material lack of comparable RCTs leaves CBD's suitability as a pharmacological treatment for neurodevelopmental disorders largely undetermined. A stronger evidence base is urgently required to establish safety and efficacy profiles and guide the ever-expanding clinical uptake of cannabis-derived compounds in neurodevelopmental disorders. Prospero registration number: CRD42021267839.

Father trait anger and associations with father-infant bonding and caregiving: The mediating role of mentalizing.

Trait anger reflects a tendency to feel irritation, annoyance, and rage, and involves a narrowing of cognition and attention. This narrowed scope may impact the capacity to understand the mental states of oneself and others (mentalizing), which for fathers of infants may compromise bonding and caregiving involvement. Here, we investigated the extent to which mentalizing mediated the relationship between father trait anger and both father-infant bonding and father involvement in infant caregiving. Data were from 168 fathers (M = 30.04 years of age, SD = 1.36) of 190 infants (M = 7.58 months of age, SD = 5.06) in the longitudinal Men and Parenting Pathways (MAPP) study. We assessed fathers' preconception trait anger at Wave 1 and their mentalizing 2 years later at Wave 3. At Waves 3, 4, and/or 5, we assessed father-infant bonding and father involvement in infant caregiving when men had an infant younger than 18 months of age. Associations were examined using path analysis. Poorer mentalizing fully mediated the relationship between preconception trait anger and father-infant bonding (total score), but not involvement in infant caregiving. Further, poorer mentalizing fully mediated the relationships between trait anger and each component of the father-infant bond (i.e., patience and tolerance, affection and pride, and pleasure in interactions). Findings suggest that for men high on trait anger, targeted interventions that facilitate mentalizing capacities may help to develop a foundation for a strong father-infant bond. Interventions may be offered on becoming a father (perinatal), or prior to becoming a father (preconception) to prevent future bonding problems.

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.

An Investigation of Age-related Neuropathophysiology in Autism Spectrum Disorder Using Fixel-based Analysis of Corpus Callosum White Matter Micro- and Macrostructure.

Fixel-based analysis was used to probe age-related changes in white matter micro- and macrostructure of the corpus callosum between participants with (N = 54) and without (N = 50) autism spectrum disorder (ASD). Data were obtained from the Autism Brain Imaging Data Exchange-II (ABIDE-II). Compared to age-matched controls, young adolescents with ASD (11.19 ± 7.54 years) showed reduced macroscopic fiber cross-section (logFC) and combined fiber-density and cross-section (FDC). Reduced fiber-density (FD) and FDC was noted in a marginally older (13.87 ± 3.15 years) ASD cohort. Among the oldest ASD cohort (17.07 ± 3.56 years), a non-significant trend indicative of reduced FD was noted. White matter aberration appears greatest and most widespread among younger ASD cohorts. This supports the suggestion that some early neuropathophysiological indicators in ASD may dissipate with age.

A systematic review of the neurobiological effects of theta-burst stimulation (TBS) as measured using functional magnetic resonance imaging (fMRI).

Theta burst stimulation (TBS) is associated with the modulation of a range of clinical, cognitive, and behavioural outcomes, but specific neurobiological effects remain somewhat unclear. This systematic literature review investigated resting-state and task-based functional magnetic resonance imaging (fMRI) outcomes post-TBS in healthy human adults. Fifty studies that applied either continuous-or intermittent-(c/i) TBS, and adopted a pretest-posttest or sham-controlled design, were included. For resting-state outcomes following stimulation applied to motor, temporal, parietal, occipital, or cerebellar regions, functional connectivity generally decreased in response to cTBS and increased in response to iTBS, though there were some exceptions to this pattern of response. These findings are mostly consistent with the assumed long-term depression (LTD)/long-term potentiation (LTP)-like plasticity effects of cTBS and iTBS, respectively. Task-related outcomes following TBS were more variable. TBS applied to the prefrontal cortex, irrespective of task or state, also produced more variable responses, with no consistent patterns emerging. Individual participant and methodological factors are likely to contribute to the variability in responses to TBS. Future studies assessing the effects of TBS via fMRI must account for factors known to affect the TBS outcomes, both at the level of individual participants and of research methodology.