Changes In Neural Responses Research Articles

Longitudinal changes in neural responses to fearful faces in adolescents with anorexia nervosa – A fMRI study

ObjectiveAlthough proven neuronal changes are correlated with anorexia nervosa (AN), where these changes occur and how they change during the course of this disease are often unclear; this is especially true regarding emotion processing, e.g., of anxiety, despite a growing body of literature on its importance for the pathophysiology and clinical course of patients with AN. MethodsTwenty-two female adolescent patients with AN were scanned during acute starvation and after short-term weight recovery and were compared to 27 healthy controls. A well-established face-matching paradigm involving individuals with different emotions was used during fMRI. ResultsPatients with AN selectively showed significantly increasing neural activation in the somatomotor cortex when viewing fearful faces following short-term weight recovery. No differences were found compared to healthy controls or for neutral, angry or surprised faces. Neural activation in response to fearful faces during acute starvation was associated with lower BMI-SDS and greater illness burden. ConclusionHigher somatomotor activity could represent anxiety-induced preparations for motor reactions (e.g., fight or flight) that are more pronounced in more affected patients. These results align with recent models of AN that increasingly incorporate anxiety into the pathophysiological and prognostic model of AN and help elucidate its underlying neurological mechanisms.

Neural Responses to Auditory Food Stimuli Following Cognitive Behavioral Therapy for Binge-Eating Disorder.

Adults with binge-eating disorder (BED), compared with those without BED, demonstrate higher blood-oxygen-level-dependent (BOLD) response to food cues in reward-related regions of the brain. It is not known whether cognitive behavioral therapy (CBT) can reverse this reward system hyperactivation. This randomized controlled trial (RCT) assessed changes in BOLD response to binge-eating cues following CBT versus wait-list control (WLC). Females with BED (N = 40) were randomized to CBT or WLC. Participants completed assessments at baseline and 16 weeks including measures of eating and appetite and functional magnetic resonance imaging (fMRI) to measure BOLD response while listening to personalized scripts of binge-eating and neutral-relaxing cues. Data were analyzed using general linear models with mixed effects. Overall retention rate was 87.5%. CBT achieved significantly greater reductions in binge-eating episodes than WLC (mean ± standard error decline of 14.6 ± 2.7 vs. 5.7 ± 2.8 episodes in the past 28 days, respectively; p = 0.03). CBT and WLC did not differ significantly in changes in neural responses to binge-eating stimuli during the fMRI sessions. Compared with WLC, CBT had significantly greater improvements in reward-based eating drive, disinhibition, and hunger as assessed by questionnaires (ps < 0.05). CBT was effective in reducing binge eating, but, contrary to our hypothesis, CBT did not improve BOLD response to auditory binge-eating stimuli in reward regions of the brain. Further studies are needed to assess mechanisms underlying improvements with CBT for BED. ClinicalTrials.gov identifier: NCT03604172.

Investigating the effectiveness of music therapy combined with binaural beats on chronic tinnitus: A randomized controlled trial

BackgroundBinaural beat stimulation (BBS) involve presenting two sinusoidal waves with specific frequency differences to induce neural changes in the brain, often used for mental state induction and symptom reduction. However, there are limited studies on its effectiveness for tinnitus. This study aimed to assess the effectiveness of combining binaural beats with music containing nature sounds for chronic tinnitus. MethodsA total of 30 men, aged 45.87 on average (SD = 8.09), who had chronic tinnitus and symmetrical mild to moderate hearing loss, were included in this study. The participants were randomly assigned to two groups: MT group (Music therapy; n = 15), which received relaxing music containing the sound of sea waves, and MT + BBS group (Music therapy plus binaural beats; n = 15), which received the same music combined with alpha frequency (8 Hz) binaural beats. The therapy sessions were conducted twice a day for 15 min, over a period of 4 weeks. Outcome measures, including the Tinnitus Handicap Inventory (THI), Tinnitus Functional Index (TFI), Hospital Anxiety and Depression Scale (HADS), Visual Analog Scale (VAS) and the pitch and loudness of tinnitus were administered before, immediately after, and during the three-month follow-up period. ResultsThe findings revealed improvements in loudness and annoyance VAS, as well as THI total and all subscale scores in both groups (p < 0.001). Additionally, TFI total score showed improvement in both groups (MT: p = 0.001; MT + BBS: p < 0.001) except for the sense of control subscale in both groups and the cognitive subscale in the MT group after the treatment and during the three-month follow-up period. Furthermore, both groups exhibited a decrease in scores for both subscales of HADS. However, there were no significant differences between the two groups in any of the measurement outcomes (p > 0.05), except for the emotional subscale scores of TFI (p = 0.049) and the functional subscale scores of THI (p = 0.034). In other words, during the follow-up period, the MT + BBS group exhibited lower scores in these two subscales compared to the MT group. ConclusionAlthough our study failed to demonstrate the superiority of combining binaural beats with music, both groups experienced significant improvements. This suggest that there are potential benefits to be gained from these types of stimuli. Given the sustained effect of both methods and the even greater improvements in follow-up observed in the binaural beats group for some scales, it seems that the changes in neural response and brain waves caused by our stimulations are persistent. This necessitates further research involving brain mapping, especially with longer follow-up durations.

Social Isolation, Brain Food Cue Processing, Eating Behaviors, and Mental Health Symptoms

Perceived social isolation is associated with negative health outcomes, including increased risk for altered eating behaviors, obesity, and psychological symptoms. However, the underlying neural mechanisms of these pathways are unknown. To investigate the association of perceived social isolation with brain reactivity to food cues, altered eating behaviors, obesity, and mental health symptoms. This cross-sectional, single-center study recruited healthy, premenopausal female participants from the Los Angeles, California, community from September 7, 2021, through February 27, 2023. Participants underwent functional magnetic resonance imaging while performing a food cue viewing task. The main outcomes included brain reactivity to food cues, body composition, self-reported eating behaviors (food cravings, reward-based eating, food addiction, and maladaptive eating behaviors), and mental health symptoms (anxiety, depression, positive and negative affect, and psychological resilience). The study included 93 participants (mean [SD] age, 25.38 [7.07] years). Participants with higher perceived social isolation reported higher fat mass percentage, lower diet quality, increased maladaptive eating behaviors (cravings, reward-based eating, uncontrolled eating, and food addiction), and poor mental health (anxiety, depression, and psychological resilience). In whole-brain comparisons, the higher social isolation group showed altered brain reactivity to food cues in regions of the default mode, executive control, and visual attention networks. Isolation-related neural changes in response to sweet foods correlated with various altered eating behaviors and psychological symptoms. These altered brain responses mediated the connection between social isolation and maladaptive eating behaviors (β for indirect effect, 0.111; 95% CI, 0.013-0.210; P = .03), increased body fat composition (β, -0.141; 95% CI, -0.260 to -0.021; P = .02), and diminished positive affect (β, -0.089; 95% CI, -0.188 to 0.011; P = .09). These findings suggest that social isolation is associated with altered neural reactivity to food cues within specific brain regions responsible for processing internal appetite-related states and compromised executive control and attentional bias and motivation toward external food cues. These neural responses toward specific foods were associated with an increased risk for higher body fat composition, worsened maladaptive eating behaviors, and compromised mental health. These findings underscore the need for holistic mind-body-directed interventions that may mitigate the adverse health consequences of social isolation.

Reduced body-image disturbance by body-image interventions is associated with neural-response changes in visual and social processing regions: a preliminary study.

Body-image disturbance is a major factor in the development of eating disorders, especially among young women. There are two main components: perceptual disturbance, characterized by a discrepancy between perceived and actual body size, and affective disturbance, characterized by a discrepancy between perceived and ideal body size. Interventions targeting body-image disturbance ask individuals to describe their own body without using negative expressions when either viewing it in a mirror or imagining it. Despite the importance of reducing body-image disturbance, its neural mechanisms remain unclear. Here we investigated the changes in neural responses before and after an intervention. We hypothesized that neuralresponses correlated with the degree of body-image disturbance would also be related to its reduction, i.e., a reduction in perceptual and affective disturbances would be related to changes in attentional and socio-cognitive processing, respectively. Twenty-eight young adult women without known psychiatric disorders underwent a single 40-min intervention. Participants completed tasks before and after the intervention, in which they estimated their perceived and ideal body sizes using distorted silhouette images to measure body-image disturbance. We analyzed the behavioral and neural responses of participants during the tasks. The intervention did not significantly reduce body-image disturbance. Analysis of individual differences showed distinct changes in neural responses for each type of disturbance. A decrease in perceptual disturbance was associated with bodily visuospatial processing: increased activation in the left superior parietal lobule, bilateral occipital gyri, and right cuneus. Reduced affective disturbance was associated with socio-cognitive processing; decreased activation in the right temporoparietal junction, and increased functional connectivity between the left extrastriate body area and the right precuneus. We identified distinct neural mechanisms (bodily visuospatial and socio-cognitive processing) associated with the reduction in each component of body-image disturbance. Our results imply that different neural mechanisms are related to reduced perceptual disturbance and the expression thereof, whereas similar neural mechanisms are related to the reduction and expression of affective disturbance. Considering the small sample size of this study, our results should be regarded as preliminary.

Study on Improving the Modulatory Effect of Rhythmic Oscillations by Transcranial Magneto-Acoustic Stimulation.

In hippocampus, synaptic plasticity and rhythmic oscillations reflect the cytological basis and the intermediate level of cognition, respectively. Transcranial ultrasound stimulation (TUS) has demonstrated the ability to elicit changes in neural response. However, the modulatory effect of TUS on synaptic plasticity and rhythmic oscillations was insufficient in the present studies, which may be attributed to the fact that TUS acts mainly through mechanical forces. To enhance the modulatory effect on synaptic plasticity and rhythmic oscillations, transcranial magneto-acoustic stimulation (TMAS) which induced a coupled electric field together with TUS's ultrasound field was applied. The modulatory effect of TMAS and TUS with a pulse repetition frequency of 100 Hz were compared. TMAS/TUS were performed on C57 mice for 7 days at two different ultrasound intensities (3 W/cm2 and 5 W/cm [Formula: see text]. Behavioral tests, long-term potential (LTP) and local field potentials in vivo were performed to evaluate TUS/TMAS modulatory effect on cognition, synaptic plasticity and rhythmic oscillations. Protein expression based on western blotting were used to investigate the under- lying mechanisms of these beneficial effects. At 5 W/cm2, TMAS-induced LTP were 113.4% compared to the sham group and 110.5% compared to TUS. Moreover, the relative power of high gamma oscillations (50-100Hz) in the TMAS group ( 1.060±0.155 %) was markedly higher than that in the TUS group ( 0.560±0.114 %) and sham group ( 0.570±0.088 %). TMAS significantly enhanced the synchronization of theta and gamma oscillations as well as theta-gamma cross-frequency coupling. Whereas, TUS did not show relative enhancements. TMAS provides enhanced effect for modulating the synaptic plasticity and rhythmic oscillations in hippocampus.

Age-related changes in neural responses to sensory stimulation in autism: a cross-sectional study

BackgroundSensory over-responsivity (SOR) is an impairing sensory processing challenge in autism spectrum disorder (ASD) which shows heterogenous developmental trajectories and appears to improve into adulthood in some but not all autistic individuals. However, the neural mechanisms underlying interindividual differences in these trajectories are currently unknown.MethodsHere, we used functional magnetic resonance imaging (fMRI) to investigate the association between age and neural activity linearly and nonlinearly in response to mildly aversive sensory stimulation as well as how SOR severity moderates this association. Participants included 52 ASD (14F) and 41 (13F) typically developing (TD) youth, aged 8.6–18.0 years.ResultsWe found that in pre-teens, ASD children showed widespread activation differences in sensorimotor, frontal and cerebellar regions compared to TD children, while there were fewer differences between ASD and TD teens. In TD youth, older age was associated with less activation in the prefrontal cortex. In contrast, in ASD youth, older age was associated with more engagement of sensory integration and emotion regulation regions. In particular, orbitofrontal and medial prefrontal cortices showed a nonlinear relationship with age in ASD, with an especially steep increase in sensory-evoked neural activity during the mid-to-late teen years. There was also an interaction between age and SOR severity in ASD youth such that these age-related trends were more apparent in youth with higher SOR.LimitationsThe cross-sectional design limits causal interpretations of the data. Future longitudinal studies will be instrumental in determining how prefrontal engagement and SOR co-develop across adolescence. ConclusionsOur results suggest that enhanced recruitment of prefrontal regions may underlie age-related decreases in SOR for a subgroup of ASD youth.

Representations in human primary visual cortex drift over time

Primary sensory regions are believed to instantiate stable neural representations, yet a number of recent rodent studies suggest instead that representations drift over time. To test whether sensory representations are stable in human visual cortex, we analyzed a large longitudinal dataset of fMRI responses to images of natural scenes. We fit the fMRI responses using an image-computable encoding model and tested how well the model generalized across sessions. We found systematic changes in model fits that exhibited cumulative drift over many months. Convergent analyses pinpoint changes in neural responsivity as the source of the drift, while population-level representational dissimilarities between visual stimuli were unchanged. These observations suggest that downstream cortical areas may read-out a stable representation, even as representations within V1 exhibit drift.

Changes in neural responses during affective and non-affective tasks and improvement of posttraumatic stress disorder symptoms following trauma-focused psychotherapy

At least one-third posttraumatic stress disorder (PTSD) patients do not respond to trauma-focused psychotherapy (TF-psychotherapy), which is the treatment of choice for PTSD. To clarify the change mechanisms that may be associated with treatment response, this study examined changes in neural activations during affective and non-affective processing that occur with improvement of symptoms after TF-psychotherapy. This study assessed PTSD treatment-seeking patients (n = 27) prior to and after TF-psychotherapy using functional magnetic resonance imaging when they completed three tasks: (a) passive viewing of affective faces, (b) cognitive reappraisal of negative images, and (c) non-affective response inhibition. Patients then underwent 9 sessions of TF-psychotherapy, and were assessed on the Clinician-Administered PTSD Scale following treatment. Changes in neural responses in affect and cognitive processing regions-of-interest for each task were correlated with reduction of PTSD severity from pretreatment to posttreatment in the PTSD cohort. Data from 21 healthy controls was used for comparison. Improvement of symptoms in PTSD were associated with increased activation of left anterior insula, reductions in the left hippocampus and right posterior insula during viewing of supraliminally presented affective images, and reduced connectivity between the left hippocampus with the left amygdala and rostral anterior cingulate. Treatment response was also associated with reduced activation in the left dorsolateral prefrontal cortex during reappraisal of negative images. There were no associations between response and activation change during response inhibition. This pattern of findings indicates that improvement of PTSD symptoms following TF-psychotherapy is associated with changes in affective rather than non-affective processes. These findings accord with prevailing models that TF-psychotherapy promotes engagement and mastery of affective stimuli.Clinical Trials Registration: Trial Registration: Prospectively registered at Australian and New Zealand Clinical Trials Registry, ACTRN12612000185864 and ACTRN12609000324213. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=83857

Sustained responses and neural synchronization to amplitude and frequency modulation in sound change with age

Perception of speech requires sensitivity to features, such as amplitude and frequency modulations, that are often temporally regular. Previous work suggests age-related changes in neural responses to temporally regular features, but little work has focused on age differences for different types of modulations. We recorded magnetoencephalography in younger (21–33 years) and older adults (53–73 years) to investigate age differences in neural responses to slow (2–6 Hz sinusoidal and non-sinusoidal) modulations in amplitude, frequency, or combined amplitude and frequency. Audiometric pure-tone average thresholds were elevated in older compared to younger adults, indicating subclinical hearing impairment in the recruited older-adult sample. Neural responses to sound onset (independent of temporal modulations) were increased in magnitude in older compared to younger adults, suggesting hyperresponsivity and a loss of inhibition in the aged auditory system. Analyses of neural activity to modulations revealed greater neural synchronization with amplitude, frequency, and combined amplitude-frequency modulations for older compared to younger adults. This potentiated response generalized across different degrees of temporal regularity (sinusoidal and non-sinusoidal), although neural synchronization was generally lower for non-sinusoidal modulation. Despite greater synchronization, sustained neural activity was reduced in older compared to younger adults for sounds modulated both sinusoidally and non-sinusoidally in frequency. Our results suggest age differences in the sensitivity of the auditory system to features present in speech and other natural sounds.

The Common Effects of Sleep Deprivation on Human Long-Term Memory and Cognitive Control Processes.

Sleep deprivation is known to have adverse effects on various cognitive abilities. In particular, a lack of sleep has been reported to disrupt memory consolidation and cognitive control functions. Here, focusing on long-term memory and cognitive control processes, we review the consistency and reliability of the results of previous studies of sleep deprivation effects on behavioral performance with variations in the types of stimuli and tasks. Moreover, we examine neural response changes related to these behavioral changes induced by sleep deprivation based on human fMRI studies to determine the brain regions in which neural responses increase or decrease as a consequence of sleep deprivation. Additionally, we discuss about the possibility that light as an environmentally influential factor affects our sleep cycles and related cognitive processes.

Transcranial direct current stimulation to modulate brain reactivity to food cues in overweight and obese adults: study protocol for a randomized controlled trial with fMRI (NeuroStim-Obesity)

BackgroundWith increasing obese populations worldwide, developing interventions to modulate food-related brain processes and functions is particularly important. Evidence suggests that transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) may modulate the reward–control balance towards facilitation of cognitive control and possible suppression of reward-related mechanisms that drive food cue-induced craving. This protocol describes a clinical trial that investigates the neurocognitive mechanisms of action for tDCS to modulate food cue-reactivity and cravings in people with obesity.MethodThe NeuroStim-Obesity trial is a prospective, randomized, sham-controlled, double-blind single-session tDCS trial targeting food craving in those with obesity or overweighed. Once randomized, 64 adults with obesity or overweighed complete one session in which they receive either active or sham tDCS over the DLPFC (anode F4 and cathode F3, 2 mA intensity for 20 min). The primary outcome is change in neural response to the food cue-reactivity task in the ventral striatum after a single-session bilateral tDCS compared to sham stimulation. Secondary outcomes include changes in food craving evaluated by the Food Craving Questionnaire-State (FCQ-S). We will also explore the predictive role of brain structure and functional networks assessed by structural and functional magnetic resonance imaging (MRI) during both task performance and the resting-state that are acquired pre- and post-intervention to predict response to tDCS.DiscussionThe results will provide novel insight into neuroscience for the efficacy of tDCS and will advance the field towards precision medicine for obesity. Exploratory results will examine the potential predictive biomarkers for tDCS response and eventually provide personalized intervention for the treatment of obesity.Trial registrationIranian Registry of Clinical Trials (IRCT) IRCT20121020011172N4. Retrospectively registered on 4 June 2020

The effect of mental schema evolution on mental workload measurement: an EEG study with simulated quadrotor UAV operation

Objective. Mental workload is the result of the interactions between the demands of an operation task, the environment in which the task is performed, and the skills, behavior and perception of the performer. Working under a high mental workload can significantly affect an operator’s ability to choose optimal decisions, judgments and motor actions while operating an unmanned aerial vehicle (UAV). However, the effect of mental schema, which reflects the level of expertise of an operator, on mental workload remains unclear. Here, we propose a theoretical framework for describing how the evolution of mental schema affects mental workload from the perspective of cognitive processing. Approach. We recruited 51 students to participate in a 10-day simulated quadrotor UAV flight training exercise. The EEG power spectral density (PSD)-based metrics were used to investigate the changes in neural responses caused by variations in the mental workload at different stages of mental schema evolution. Main results. It was found that the mental schema evolution influenced the direction and change trends of the frontal theta PSD, parietal alpha PSD, and central beta PSD, which are EEG indicators of mental workload. Initially, before the mental schema was formed, only the frontal theta PSD increased with increasing task difficulty; when the mental schema was initially being developed, the frontal theta PSD and the parietal alpha PSD decreased with increasing task difficulty, while the central beta PSD increased with increasing task difficulty. Finally, as the mental schema gradually matured, the trend of the three indicators did not change with increasing task difficulty. However, differences in the frontal PSD became more pronounced across task difficulty levels, while differences in the parietal PSD narrowed. Significance. Our results describe the relationship between the EEG PSD and the mental workload of UAV operators as the mental schema evolved. This suggests that EEG activity can be used to identify the mental schema and mental workload experienced by operators while performing a task, which can not only provide more accurate measurements of mental workload but also provide insights into the development of an operator’s skill level.

Age-Related Changes in Functional Connectivity during the Sensorimotor Integration Detected by Artificial Neural Network.

Large-scale functional connectivity is an important indicator of the brain’s normal functioning. The abnormalities in the connectivity pattern can be used as a diagnostic tool to detect various neurological disorders. The present paper describes the functional connectivity assessment based on artificial intelligence to reveal age-related changes in neural response in a simple motor execution task. Twenty subjects of two age groups performed repetitive motor tasks on command, while the whole-scalp EEG was recorded. We applied the model based on the feed-forward multilayer perceptron to detect functional relationships between five groups of sensors located over the frontal, parietal, left, right, and middle motor cortex. Functional dependence was evaluated with the predicted and original time series coefficient of determination. Then, we applied statistical analysis to highlight the significant features of the functional connectivity network assessed by our model. Our findings revealed the connectivity pattern is consistent with modern ideas of the healthy aging effect on neural activation. Elderly adults demonstrate a pronounced activation of the whole-brain theta-band network and decreased activation of frontal–parietal and motor areas of the mu-band. Between-subject analysis revealed a strengthening of inter-areal task-relevant links in elderly adults. These findings can be interpreted as an increased cognitive demand in elderly adults to perform simple motor tasks with the dominant hand, induced by age-related working memory decline.

Changes in functional connectivity associated with facial expression processing over the working adult lifespan

The recognition of negative emotions from facial expressions is shown to decline across the adult lifespan, with some evidence that this decline begins around middle age. While some studies have suggested ageing may be associated with changes in neural response to emotional expressions, it is not known whether ageing is associated with changes in the network connectivity associated with processing emotional expressions. In this study, we examined the effect of participant age on whole-brain connectivity to various brain regions that show connectivity during emotion processing, namely, the left and right amygdalae, medial prefrontal cortex (mPFC), and right posterior superior temporal sulcus (rpSTS). The study involved healthy participants aged 20–65 years who completed an implicit affect processing task involving facial expressions displaying anger, fear, happiness, and neutral expressions during functional magnetic resonance imaging (fMRI). Participants were also tested on recognition accuracy during an emotion labelling task. We found that participant age was negatively associated with connectivity between the left amygdala and voxels in the left occipital pole; between the rpSTS and voxels in the orbitofrontal cortex; and between the mPFC and cingulate cortex and left insular cortex. Furthermore, these effects were due to a greater age-related decline in brain connectivity for negative expressions compared to happy and neutral expressions. There was, however, no significant relationship between age and emotion recognition accuracy (though in the expected direction), and between connectivity strength and emotion recognition accuracy. Together, these results provide evidence for a specific age-related decline in the neural processing of negative emotions, and could suggest that changes in underlying network connectivity over the working adult lifespan might occur before any marked decline in the recognition of the emotion.

Longitudinal change in neural response to vocal emotion in adolescence.

Adolescence is associated with maturation of function within neural networks supporting the processing of social information. Previous longitudinal studies have established developmental influences on youth’s neural response to facial displays of emotion. Given the increasing recognition of the importance of non-facial cues to social communication, we build on existing work by examining longitudinal change in neural response to vocal expressions of emotion in 8- to 19-year-old youth. Participants completed a vocal emotion recognition task at two timepoints (1 year apart) while undergoing functional magnetic resonance imaging. The right inferior frontal gyrus, right dorsal striatum and right precentral gyrus showed decreases in activation to emotional voices across timepoints, which may reflect focalization of response in these areas. Activation in the dorsomedial prefrontal cortex was positively associated with age but was stable across timepoints. In addition, the slope of change across visits varied as a function of participants’ age in the right temporo-parietal junction (TPJ): this pattern of activation across timepoints and age may reflect ongoing specialization of function across childhood and adolescence. Decreased activation in the striatum and TPJ across timepoints was associated with better emotion recognition accuracy. Findings suggest that specialization of function in social cognitive networks may support the growth of vocal emotion recognition skills across adolescence.

Testing the adolescent social reorientation model during self and other evaluation using hierarchical growth curve modeling with parcellated fMRI data

Adolescence is characterized as a period when relationships and experiences shift toward peers. The social reorientation model of adolescence posits this shift is driven by neurobiological changes that increase the salience of social information related to peer integration and acceptance. Although influential, this model has rarely been subjected to tests that could falsify it, or studied in longitudinal samples assessing within-person development. We focused on two phenomena that are highly salient and dynamic during adolescence—social status and self-perception—and examined longitudinal changes in neural responses during a self/other evaluation task. We expected status-related social information to uniquely increase across adolescence in social brain regions. Despite using hierarchical growth curve modeling with parcellated whole-brain data to increase power to detect developmental effects, we didn’t find evidence in support of this hypothesis. Social brain regions showed increased responsivity across adolescence, but this trajectory was not unique to status-related information. Additionally, brain regions associated with self-focused cognition showed heightened responses during self-evaluation in the transition to mid-adolescence, especially for status-related information. These results qualify existing models of adolescent social reorientation and highlight the multifaceted changes in self and social development that could be leveraged in novel ways to support adolescent health and well-being.

Transcranial focused ultrasound induces sustained synaptic plasticity in rat hippocampus

Transcranial focused ultrasound (tFUS) neuromodulation provides a promising emerging non-invasive therapy for the treatment of neurological disorders. Many studies have demonstrated the ability of tFUS to elicit transient changes in neural responses. However, the ability of tFUS to induce sustained changes need to be carefully examined. In this study, we use the long-term potentiation/long term depression (LTP/LTD) model in the rat hippocampus, the medial perforant path (mPP) to dentate gyrus (DG) pathway, to explore whether tFUS is capable of encoding frequency specific information to induce plasticity. Single-element focused transducers were used for tFUS stimulation with ultrasound fundamental frequency of 0.5 MHz and nominal focal distance of 38 mm tFUS stimulation is directed to mPP. Measurement of synaptic connectivity is achieved through the slope of field excitatory post synaptic potentials (fEPSPs), which are elicited using bipolar electrical stimulation electrodes and recorded at DG using extracellular electrodes to quantify degree of plasticity. We applied pulsed tFUS stimulation with total duration of 5 min, with 5 levels of pulse repetition frequencies each administered at 50 Hz sonication frequency at the mPP. Baseline fEPSP is recorded 10 min prior, and 30+ minutes after tFUS administration. In N = 16 adult wildtype rats, we observed sustained depression of fEPSP slope after 5 min of tFUS focused at the presynaptic field mPP. Across all PRFs, no significant difference in maximum fEPSP slope change was observed, average tFUS induced depression level was observed at 19.6%. When compared to low frequency electrical stimulation (LFS) of 1 Hz delivered to the mPP, the sustained changes induced by tFUS stimulation show no statistical difference to LFS for up to 24 min after tFUS stimulation. When both the maximum depression effects and the duration of sustained effects are both taken into account, PRF 3 kHz can induce significantly larger effects than other PRFs tested. tFUS stimulation is measured with a spatial-peak pressure amplitude of 99 kPa, translating to an estimation of 0.43 °C temperature increase when assuming no loss of heat. The results suggest the ability of tFUS to encode sustained changes in synaptic connectivity through mechanism which are unlikely to involve thermal changes.

Neural Responses to Novel and Existing Words in Children with Autism Spectrum and Developmental Language Disorder.

The formation of new phonological representations is key in establishing items in the mental lexicon. Phonological forms become stable with repetition, time and sleep. Atypicality in the establishment of new word forms is characteristic of children with developmental language disorder (DLD) and autism spectrum disorder (ASD), yet neural changes in response to novel word forms over time have not yet been directly compared in these groups.This study measured habituation of event-related-potentials (ERPs) to novel and known words within and between two sessions spaced 24 hours apart in typically developing (TD) children, and their peers with DLD or ASD. We hypothesised that modulation of the auditory N400 amplitude would mark real-time changes in lexical processing with habituation evident within and across sessions in the TD group, while the DLD group would show attenuated habituation within sessions, and the ASD group attenuated habituation between sessions.Twenty-one typically developing children, 19 children with ASD, and 16 children with DLD listened passively to known and novel words on two consecutive days, while ERPs were recorded using dry electrodes. Counter to our hypotheses, no habituation effect emerged within sessions. However, responses did habituate between sessions, with this effect being reduced in the DLD group, indicating less pre-activation of lexical representations in response to words encountered the previous day. No differences in change over time were observed between the TD and ASD groups. These data are in keeping with theories stressing the importance of sleep-related consolidation in word learning.

Differential neural sensitivity to social inclusion and exclusion in adolescents in foster care

ObjectivesAdolescents in foster care may exhibit differential patterns of brain functioning that contribute to their pervasive socioemotional challenges. However, there has been limited investigation of implicated neural processes, particularly in the social domain. Thus, the current study investigated neural responses to exclusionary and inclusionary peer interactions in adolescents in foster-care. MethodsParticipants comprised adolescents aged 11–18 years in foster care (N = 69) and a community sample (N = 69). They completed an fMRI adaptation of Cyberball, a virtual ball-throwing paradigm, that included periods of exclusion and over-inclusion. To investigate neural sensitivity to peer social experiences, we quantified neural responses that scaled with consecutive inclusionary and exclusionary interactions (using parametric modulators). ResultsRelative to the community sample, adolescents in foster care exhibited increasing response to consecutive exclusionary events in lateral prefrontal regions and decreasing response to consecutive inclusionary events in the intraparietal sulcus and temporo-occipital cortex. Further, exploratory analyses revealed that dorsolateral prefrontal activation to exclusion was related to externalizing problems, particularly in the foster care sample. ConclusionsFindings highlight greater neural sensitivity to exclusionary, and lesser sensitivity to inclusionary, peer interactions in adolescents in foster care. Engagement of prefrontal clusters may reflect greater salience and emotion regulatory processes during exclusion, while parietal and temporal clusters may reflect reduced attention and behavioural engagement during inclusion. Thus foster care involvement is associated with broad changes in neural responses during peer interactions, and further these potentially relate to externalizing problems that have been identified in this vulnerable population.