Differences In Neural Connectivity Research Articles

Electroencephalography complexity in resting and task states in adults with attention-deficit/hyperactivity disorder.

Analysing EEG complexity could provide insight into neural connectivity underlying attention-deficit/hyperactivity disorder symptoms. EEG complexity was calculated through multiscale entropy and compared between adults with attention-deficit/hyperactivity disorder and their peers during resting and go/nogo task states. Multiscale entropy change from the resting state to the task state was also examined as an index of the brain’s ability to change from a resting to an active state. Thirty unmedicated adults with attention-deficit/hyperactivity disorder were compared with 30 match-paired healthy peers on the multiscale entropy in the resting and task states as well as their multiscale entropy change. Results showed differences in multiscale entropy between individuals with attention-deficit/hyperactivity disorder and their peers during the resting state as well as the task state. The multiscale entropy measured from the comparison group was larger than that from the attention-deficit/hyperactivity disorder group in the resting state, whereas the reverse pattern was found during the task state. Our most robust finding showed that the multiscale entropy change from individuals with attention-deficit/hyperactivity disorder was smaller than that from their peers, specifically at frontal sites. Interestingly, individuals without attention-deficit/hyperactivity disorder performed better with decreasing multiscale entropy changes, demonstrating higher accuracy, faster reaction time and less variability in their reaction times. These data suggest that multiscale entropy could not only provide insight into neural connectivity differences between adults with attention-deficit/hyperactivity disorder and their peers but also into their behavioural performance.

24.3 NEURAL TARGET GENES OF ESTROGEN RECEPTOR ALPHA SPECIFY SEX DIFFERENCES IN THE BRAIN

The “female protective effect” (FPE) theory suggests that females with loss-of-function mutations in autism spectrum disorder (ASD)-associated genes are resistant to developing ASD symptoms. However, it has been challenging to identify candidate pathways that could promote an FPE, as there is minimal information on sex differences in neurodevelopmental trajectories. In rodents, estrogen receptor alpha (ERα) is necessary and sufficient for sex differences in neural connectivity and behavior, but the neural genes regulated by this transcription factor had not been described. We employed CUT&RUN sequencing to identify direct ERα genomic binding sites in the brains of female and male mice. We performed RNA-seq and ATAC-seq specifically within ERα+ neurons within the bed nucleus of the stria terminalis (BNST), a sexually dimorphic brain region that regulates social and motivated behaviors, to associate ERα binding with gene regulation. We assessed snRNA-seq data from the BNST of both sexes to identify sex differences both in transcripts within a cell type and in cell types and correlated these findings with ERα occupancy. ERα directly binds neurodevelopmental genes, including several strong ASD candidate loci. Sex differences in gene expression in the brain occur exclusively in cells that express ERα. ERα regulates a male-biased gene expression program that initiates in early life and cooperates with the transcription factor Nfix to specify identity of a male-biased inhibitory neuronal population. We identify an estrogen-driven transcriptional strategy for brain masculinization. We anticipate that ERα target genes and loci contribute to susceptibility or resilience to developing ASD and that other genetic or environmental factors can intersect with mutations in these loci to produce sex-specific outcomes.

Interactive relations between maternal prenatal stress, fetal brain connectivity, and gestational age at delivery

Studies reporting significant associations between maternal prenatal stress and child outcomes are frequently confounded by correlates of prenatal stress that influence the postnatal rearing environment. The major objective of this study is to identify whether maternal prenatal stress is associated with variation in human brain functional connectivity prior to birth. We utilized fetal fMRI in 118 fetuses [48 female; mean age 32.9 weeks (SD = 3.87)] to evaluate this association and further addressed whether fetal neural differences were related to maternal health behaviors, social support, or birth outcomes. Community detection was used to empirically define networks and enrichment was used to isolate differential within- or between-network connectivity effects. Significance for χ2 enrichment was determined by randomly permuting the subject pairing of fetal brain connectivity and maternal stress values 10,000 times. Mixtures modelling was used to test whether fetal neural differences were related to maternal health behaviors, social support, or birth outcomes. Increased maternal prenatal negative affect/stress was associated with alterations in fetal frontoparietal, striatal, and temporoparietal connectivity (β = 0.82, p < 0.001). Follow-up analysis demonstrated that these associations were stronger in women with better health behaviors, more positive interpersonal support, and lower overall stress (β = 0.16, p = 0.02). Additionally, magnitude of stress-related differences in neural connectivity was marginally correlated with younger gestational age at delivery (β = −0.18, p = 0.05). This is the first evidence that negative affect/stress during pregnancy is reflected in functional network differences in the human brain in utero, and also provides information about how positive interpersonal and health behaviors could mitigate prenatal brain programming.

Developmental differences in neural connectivity for semantic processing in youths with autism.

Youths with autism spectrum disorder (ASD) rely more on lower-level visual processing as revealed by greater occipital activation, yet less effectively engage higher-level processing of modality-independent semantic knowledge as indicated by reduced frontal activation, compared to typically developing (TD) youths. However, little is known about age-dependent differences in neural connectivity during semantic processing in youths with ASD as compared to TD youths. Four groups were recruited: 31 ASD children (mean age=10.5years old), 33 TD children (mean age=10.4), 30 ASD adolescents (mean age=14.9), and 34 TD adolescents (mean age=15.1). We explored their differences in neural connectivity by using functional magnetic resonance imaging (fMRI) with psychophysiological interaction (PPI) during semantic judgments. In comparison with TD children, children with ASD showed greater activation in the left cuneus and weaker connectivity between the left cuneus and left middle temporal gyrus (MTG). In comparison with TD adolescents, adolescents with ASD showed less activation in the left inferior frontal gyrus (IFG) and weaker functional connectivity between the left IFG and left MTG. Children with ASD may rely more on visual processes in the occipital cortex that are disconnected from modality-independent semantics in the temporal cortex. However, adolescents with ASD may less effectively engage frontal mechanisms involved in the top-down control of modality-independent semantic knowledge in the temporal cortex. Our findings provide evidence of developmental differences in the neural substrates of the alterations in semantic processing in youths with ASD compared to TD youths.

Sex Differences in Neural Connectivity in Obesity

Variability in behavioral illness between sexes cuts across diagnoses and may elucidate underlying pathophysiology. In order to elucidate neurocircuitry underlying this and other differences in hedonic behavior associated with addiction, mood disorders and schizophrenia we analyzed sex differences in functional connectivity associated with obesity using seed regions of interest drawn from psychiatric literature.

Neural Correlates of Workload Transition in Multitasking: An ACT-R Model of Hysteresis Effect.

This study investigated the effect of task demand transitions at multiple levels of analysis including behavioral performance, subjective rating, and brain effective connectivity, while comparing human data to Adaptive Control of Thought-Rational (ACT-R) simulated data. Three stages of task demand were designed and performed sequentially (Low-High-Low) during AF-MATB tasks, and the differences in neural connectivity during workload transition were identified. The NASA Task Load Index (NASA-TLX) and the Instantaneous Self-Assessment (ISA) were used to measure the subjective mental workload that accompanies the hysteresis effect in the task demand transitions. The results found significant hysteresis effects on performance and various brain network measures such as outflow of the prefrontal cortex and connectivity magnitude. These findings would assist in clarifying the direction and strength of the Granger Causality under demand transitions. As a result, these findings involving the neural mechanisms of hysteresis effects in multitasking environments may be utilized in applications of neuroergonomics research. The ability to compare data derived from human participants to data gathered by the ACT-R model allows researchers to better account for hysteresis effects in neuro-cognitive models in the future.

Brain Activity on Observation of Another Person's Action: A Magnetoencephalographic Study.

Brain activity was recorded using a whole-head magnetoencephalography system followed by coherence analysis to assess neural connectivity in 10 healthy right-handed adults to clarify differences in neural connectivity in brain regions during action observation from several perspectives. The subjects were instructed to observe and memorize or imitate the hand action from a first-person or second-person visual perspective. The brain activity in coherence was modified among frontal and central, sensorimotor, and mirror neuron system-related regions based on the visual perspectives of finger movements. The regional activity in coherence changed similarly under the imitation and observation tasks compared with the condition of observing static hand figures. The information from different visual perspectives of body movements was processed in the frontal-central regions related to sensorimotor processes and partially in mirror neuron system.

Abstract TP57: Altered Functional Connectivity in Transient Ischemic Attack Patients

Introduction: The pathophysiology and sequelae of transient ischaemic attacks (TIA) merit further study,. Particular challenges arise from the on-going debate on diagnostic criteria and the fact that few studies use the modern tissue-based definition. Differences in functional connectivity have previously been identified in a number of conditions, including stroke, have been implicated in the symptom profile and are known to vary during recovery. In this pilot study we investigate whether there were functional connectivity differences between TIA patients and healthy controls. Methods: Patients were referred for a standard clinical magnetic resonance imaging (MRI) neurovascular protocol, with the addition of a resting state functional MRI (fMRI) sequence. Eight patients diagnosed with a TIA (4 women, 57±9) were recruited, along with eight healthy controls (4 women, 30±5). Independent component analysis was used to isolate the networks before performing non-parametric two-sample t-test using both threshold-free cluster enhancement (TFCE) and voxel-wise statistics. Results: Significant differences (p&lt;0.05, FWE-corrected) emerged using TFCE, in particular increased connectivity was noted in the mid-cingulate area with contrasting decreases in the cerebellum within the sensorimotor network. Additionally clusters of decreased connectivity were noted in the right insula in an attentional component, the pre-cuneus within the default mode network and the supplementary motor area in a visual component. No significant differences between the TIA and control group were above the threshold using voxel-wise statistics. Conclusion: In line with previous research in groups of stroke patients, this study has identified evidence of differences in neural connectivity associated with TIA, which cannot be explained by age. Differences in the sensorimotor network may be linked to the symptoms experienced by patients, with the mid-cingluate area being implicated in memory and learning. Alterations in functional connectivity may be relevant for recovery, including the on-going cognitive deficits reported in TIA patients. These findings suggest an important area for further research with a larger cohort.

Modeling the effective connectivity of the visual network in healthy and photosensitive, epileptic baboons.

The baboon provides a model of photosensitive, generalized epilepsy. This study compares cerebral blood flow responses during intermittent light stimulation (ILS) between photosensitive (PS) and healthy control (CTL) baboons using H 2 (15) O-PET. We examined effective connectivity associated with visual stimulation in both groups using structural equation modeling (SEM). Eight PS and six CTL baboons, matched for age, gender and weight, were classified on the basis of scalp EEG findings performed during the neuroimaging studies. Five H 2 (15) O-PET studies were acquired alternating between resting and activation (ILS at 25Hz) scans. PET images were acquired in 3D mode and co-registered with MRI. SEM demonstrated differences in neural connectivity between PS and CTL groups during ILS that were not previously identified using traditional activation analyses. First-level pathways consisted of similar posterior-to-anterior projections in both groups. While second-level pathways were mainly lateralized to the left hemisphere in the CTL group, they consisted of bilateral anterior-to-posterior projections in the PS baboons. Third- and fourth-level pathways were only evident in PS baboons. This is the first functional neuroimaging study used to model the photoparoxysmal response (PPR) using a primate model of photosensitive, generalized epilepsy. Evidence of increased interhemispheric connectivity and bidirectional feedback loops in the PS baboons represents electrophysiological synchronization associated with the generation of epileptic discharges. PS baboons demonstrated decreased model stability compared to controls, which may be attributed to greater variability in the driving response or PPRs, or to the influence of regions not included in the model.

Differences in neural connectivity between the substantia nigra and ventral tegmental area in the human brain

Objectives: Many animal and a few human studies have reported on the neural connectivity of the substantia nigra (SN) and the ventral tegmental area (VTA). However, it has not been clearly elucidated so far. We attempted to investigate any differences in neural connectivity of the SN/VTA in the human brain, using diffusion tensor imaging (DTI).Methods: Sixty-three healthy subjects were recruited for this study. DTIs were acquired using a sensitivity-encoding head coil at 1. 5T. Connectivity was defined as the incidence of connection between the SN/VTA and each brain regions in the brain.Results: The connectivity of SN was higher than that of the VTA. This included in the primary motor cortex, primary somatosensory cortex, premotor cortex, prefrontal cortex, caudate nucleus, globus pallidus, putamen, nucleus accumbens, temporal lobe, amygdala, pontine basis, occipital lobe, anterior and posterior lobe of cerebellum, corpus callosum, and external capsule (p < 0.05). However, no significant differences were observed in the red nucleus, thalamus, pontine tegmentum, and medial temporal lobe between the SN and VTA (p > 0.05).Conclusions: We found the differences in neural connectivity of the SN/VTA in the human brain. The method and results of this study can provide useful information for clinicians and researchers in neuroscience, especially who work for Parkinson’s disease and patients with brain injury.

Cognitive processes associated with compulsive buying behaviours and related EEG coherence

The behavioural and cognitive phenomena associated with Compulsive Buying (CB) have been investigated previously but the underlying neurophysiological cognitive process has received less attention. This study specifically investigated the electrophysiology of CB associated with executive processing and cue-reactivity in order to reveal differences in neural connectivity (EEG Coherence) and distinguish it from characteristics of addiction or mood disorder. Participants (N=24, M=25.38yrs, S.D.=7.02yrs) completed the Sensitivity to Punishment Sensitivity to Reward Questionnaire and a visual memory task associated with shopping items. Sensitivities to reward and punishment were examined with EEG coherence measures for preferred and non-preferred items and compared to CB psychometrics. Widespread EEG coherence differences were found in numerous regions, with an apparent left shifted lateralisation for preferred and right shifted lateralisation for non-preferred items. Different neurophysiological networks presented with CB phenomena, reflecting cue reactivity and episodic memory, from increased arousal and attachment to items.

Changes in long term neural connectivity following psychological trauma

Neural connectivity differences between adults reporting childhood, adulthood or no history of trauma were examined. A total of 39 participants completed the Post-traumatic Stress Diagnostic Scale (PDS; Foa EB. Post-traumatic Stress Diagnostic Scale (PDS) Manual. Minneapolis, MN: National Computer Systems, 1995), a Word Memory Task (WMT; [McNally RJ, Metzger LJ, Lasko NB, Clancy SA, Pitman RK. Directed forgetting of trauma cues in adult survivors of childhood sexual abuse with and without post-traumatic stress disorder. J Abnorm Psychol 1998;107:596-601]) and EEG analysis. Intelligence was not assessed during the study. As predicted, those with childhood trauma had significantly higher EEG coherence than those with either adulthood trauma or no past trauma. Significant differences were observed over frontal, central, temporal and parietal areas. Evidence was found suggesting that childhood psychological trauma may have a lasting impact on neuronal connectivity. This is the first study to demonstrate the suspected long term effect of trauma over central, temporal and parietal areas. Long term neural correlates of childhood and adult trauma appear to suggest information processing differences--differences that may, eventually, lead to better interventions following trauma.

Preterm birth and the developing brain

Preterm birth and the developing brain