Individual Differences In Brain Responses Research Articles

Brain activity during reappraisal and associations with psychotherapy response in social anxiety and major depression: a randomized trial.

Cognitive behavioral therapy (CBT) is an effective treatment for patients with social anxiety disorder (SAD) or major depressive disorder (MDD), yet there is variability in clinical improvement. Though prior research suggests pre-treatment engagement of brain regions supporting cognitive reappraisal (e.g. dorsolateral prefrontal cortex [dlPFC]) foretells CBT response in SAD, it remains unknown if this extends to MDD or is specific to CBT. The current study examined associations between pre-treatment neural activity during reappraisal and clinical improvement in patients with SAD or MDD following a trial of CBT or supportive therapy (ST), a common-factors comparator arm. Participants were 75 treatment-seeking patients with SAD (n = 34) or MDD (n = 41) randomized to CBT (n = 40) or ST (n = 35). Before randomization, patients completed a cognitive reappraisal task during functional magnetic resonance imaging. Additionally, patients completed clinician-administered symptom measures and a self-report cognitive reappraisal measure before treatment and every 2 weeks throughout treatment. Results indicated that pre-treatment neural activity during reappraisal differentially predicted CBT and ST response. Specifically, greater trajectories of symptom improvement throughout treatment were associated with less ventrolateral prefrontal cortex (vlPFC) activity for CBT patients, but more vlPFC activity for ST patients. Also, less baseline dlPFC activity corresponded with greater trajectories of self-reported reappraisal improvement, regardless of treatment arm. If replicated, findings suggest individual differences in brain response during reappraisal may be transdiagnostically associated with treatment-dependent improvement in symptom severity, but improvement in subjective reappraisal following psychotherapy, more broadly.

Using MEG to assess the neural mechanisms of phonetic distributional learning and future language growth in 2- and 6-month-old infants

Infants are sensitive to the distributional characteristics of the speech they hear, and perception can be altered by the distributional properties of language input. Infants listening to languages with distinct distributional properties show altered perception at the age of 6 months based on learning from ambient language input. Perception can also be altered in the laboratory by manipulating the distributional characteristics of speech in a 2-min exposure. However, the brain mechanisms underlying this learning are not well understood. Here we used MEG to explore the neural processes involved in on-line distributional learning. We examined brain responses to ambiguous speech sounds that straddle a /ba-wa/ speech continuum. Infants were tested longitudinally at 2 and 6 months of age not only to assess whether effects of experience can be documented between 2 and 6 months, but also to determine whether individual differences in brain response can predict future language growth. Our results show that differences in the magnitude of the brain response to ambiguous speech sounds in brain regions involved in auditory speech processing, motor planning, and attention change from 2- to 6-months-of- age. Moreover, we found that individual differences in these regions predict language growth up to 27 months of age.

Using Clustering to Examine Inter-individual Variability in Topography of Auditory Event-Related Potentials in Autism and Typical Development.

Objective:Although prior studies have compared sensory ERP responses between groups of autistic and typically-developing participants, it is unclear how heterogeneity contributes to the results of these studies. The present study used examined individual differences in these responses.Method:130 autistic children and 81 typically-developing children, aged between 2–5 years, listened to tones at four identity levels while 61-channel electroencephalography was recorded. Hierarchical clustering was used to group participants based on rescaled event-related potential (ERP) topographies between 51–350ms.Results:The hierarchical clustering analysis revealed substantial heterogeneity. Some of the seven clusters defined in this analysis were characterized by prolonged fronto-central positivities and/or weak or absent N2 negativities. However, many other participants fell into clusters in which N2 responses were present at varying latencies.Conclusions:Atypical response morphologies such as absent N2 responses and/or prolonged positive-going responses found in some autistic participants may account for prior research findings of attenuated N2 amplitudes in autism. However, there was also considerable overlap between groups, with participants of both groups appearing in all clusters.Significance:These results emphasize the utility of using clustering to explore individual differences in brain responses, which can expand on and clarify the results of analyses of group mean differences.

Individual Differences in Brain Responses: New Opportunities for Tailoring Health Communication Campaigns.

Prevention neuroscience investigates the brain basis of attitude and behavior change. Over the years, an increasingly structurally and functionally resolved “persuasion network” has emerged. However, current studies have only identified a small handful of neural structures that are commonly recruited during persuasive message processing, and the extent to which these (and other) structures are sensitive to numerous individual difference factors remains largely unknown. In this project we apply a multi-dimensional similarity-based individual differences analysis to explore which individual factors—including characteristics of messages and target audiences—drive patterns of brain activity to be more or less similar across individuals encountering the same anti-drug public service announcements (PSAs). We demonstrate that several ensembles of brain regions show response patterns that are driven by a variety of unique factors. These results are discussed in terms of their implications for neural models of persuasion, prevention neuroscience and message tailoring, and methodological implications for future research.

Reliability map of individual differences reflected in inter-subject correlation in naturalistic imaging

Understanding individual differences in brain function is an essential aim of neuroscience. Naturalistic imaging links neural activity to real-life contexts and reflects individual differences in brain response. These unique features make it a promising tool for individualized psychiatry. An essential prerequisite for the extensive use of this paradigm is the reliable representation of inter-individual relationships. We used a test–retest approach to examine whether the naturalistic paradigm reliably represents inter-individual differences, which brain regions have the superior capability, and whether the ability alters with the contents of the stimuli. We quantified the reliability of the inter-subject relationships in repeated scans of two movie clips: a natural sight view and an emotion-evoking story. Besides statistical inference, we included resting-state scans, behavioral tests, and questionnaires as references for the comparison. The results showed that over one-third area of the brain could reliably characterize the inter-individual relationship, and the superior temporal lobe demonstrated comparable reliability representation with the State and Trait Anxiety Inventory. Furthermore, the temporal lobe regions could retain this capability across emotional movies with different contents. This study provides a base for pushing the naturalistic imaging paradigm towards clinical applications and proposes reliable target brain regions for future studies.

Network organization during probabilistic learning via taste outcomes

Reinforcement learning guides food decisions, yet how the brain learns from taste in humans is not fully understood. Existing research examines reinforcement learning from taste using passive condition paradigms, but response-dependent instrumental conditioning better reflects natural eating behavior. Here, we examined brain response during a taste-motivated reinforcement learning task and how measures of task-based network structure were related to behavioral outcomes. During a functional MRI scan, 85 participants completed a probabilistic selection task with feedback via sweet taste or bitter taste. Whole brain response and functional network topology measures, including identification of communities and community segregation, were examined during choice, sweet taste, and bitter taste conditions. Relative to the bitter taste, sweet taste was associated with increased whole brain response in the hippocampus, oral somatosensory cortex, and orbitofrontal cortex. Sweet taste was also related to differential community assignment of the ventromedial prefrontal cortex and ventrolateral prefrontal cortex compared to bitter taste. During choice, increasing segregation of a community containing the amygdala, hippocampus, and right fusiform gyrus was associated with increased sensitivity to punishment on the task's posttest. Further, normal BMI was associated with differential community structure compared to overweight and obese BMI, where high BMI reflected increased connectivity of visual regions. Together, results demonstrate that network topology of learning and memory regions during choice is related to avoiding a bitter taste, and that BMI is associated with increased connectivity of area involved in processing external stimuli. Network organization and topology provide unique insight into individual differences in brain response to instrumental conditioning via taste reinforcers.

Individual differences in feedback processing affect perceptual learning

The present study examines individual differences in brain responses to feedback stimuli as a complex perceptual task is gradually learned. Event-related potentials were recorded while subjects learned to categorize a visual stimulus that required integration of different physical dimensions. Feedback was provided following the subject's response. High learners achieved about 80% accuracy while low learners remained slightly above chance performance. A feedback-related negativity (FRN) peaking at about 340 ms became less negative-going as the study progressed. This FRN did not however differ between the two groups. On the other hand, the P300, peaking at about 400 was significantly larger following correct feedback for the high than low learners. Importantly, this P300 difference emerged early in learning and was predictive of future performance. The P300 following incorrect feedback increased in amplitude across the study for the high learners but did not change for low learners. A later positivity, peaking at about 625 ms following incorrect feedback was especially large for the high learners when it had a low probability of occurrence, after learning had occurred. The ERP group differences suggest a discrepancy in the utilization of feedback prior to and following learning.

Individual differences in verbal working memory underlie a tradeoff between semantic and structural processing difficulty during language comprehension: An ERP investigation.

This study investigated the processes reflected in the widely observed N400 and P600 event-related potential (ERP) effects and tested the hypothesis that the N400 and P600 effects are functionally linked in a tradeoff relationship, constrained in part by individual differences in cognitive ability. Sixty participants read sentences, and ERP effects of semantic anomaly, relative to plausible words, were calculated for each participant. Results suggested qualitatively different ERP patterns across participants: Some individuals generated N400-dominated effects, whereas others generated P600-dominated effects, for the same stimuli. To specify the sources of individual differences in brain responses, we also derived aggregate scores for verbal working memory (WM), nonverbal WM, and language experience/knowledge, based on 6 behavioral measures administered to each participant. Multiple regression analysis pitting these 3 constructs against each other showed that a larger verbal WM capacity was significantly associated with larger P600 and smaller N400 effect amplitudes across individuals, whereas the other constructs did not predict the ERP effects. The results suggest that N400 and P600 brain responses, which may be attributable to semantic integration difficulty and structural processing, respectively, vie for expression when comprehenders encounter semantically unexpected words and that which option wins out is constrained in part by each comprehender's verbal WM capacity. (PsycINFO Database Record

Event-related potentials index neural response to eye contact

Sensitivity to eye-contact is a foundation upon which social cognition is built. However, there are no known neural markers characterizing response to reciprocal gaze. Using co-registered EEG and eye-tracking, we measured brain activity while participants viewed faces that responded to their looking patterns. Contingent upon participant gaze, onscreen faces opened their eyes or mouths; in this way we measured brain response to reciprocal eye-contact. We identified two ERP components that were largest in response to reciprocal eye-contact: the N170 and the P300. The magnitude of the components’ differences between reciprocal eye-contact and mouth movement predicted self-reported social function. Individuals with greater brain response to reciprocal eye-contact reported more normative scores on measures of autistic traits. These results present the first neural markers of eye-contact, revealing that reciprocal eye-contact is identified in less than 500ms. Furthermore, individual differences in brain response to eye-contact predict meaningful variability in self-reports of social performance.

Individual Differences in Brain Responses to Dynamic Facial Expressions and their Relationship to Face Cognition Abilities

This EEG study (N=33) examined event-related potentials associated with conflict between activated responses in the Stroop task, in order to examine the conflict monitoring theory of cognitive control, which predicts the strength of exerted control to be proportional to the detected level of conflict. However, existing research manipulated the sole presence/absence of conflict, but not its exact level. Here, by using a modified color-word task that allowed multiple correct responses for target colors, as well as multiple incorrect responses for distractor words, we manipulated the level of conflict among activated responses (and not only its presence). We expected that a larger number of activated incorrect responses (i.e., a presumably higher conflict) would entail more pronounced conflict-related potentials. Indeed, two components of the N450 wave, parietal negativity and medial frontal negativity, were more negatively deflected when conflict was higher, than when it was lower, visibly responding to the level of conflict. Slow potential weakly responded to the sheer presence of conflict, but not to its level. These results can be plausibly explained by the conflict monitoring theory with a modified conflict evaluation formula, whereas they are at odds with several alternative theories of cognitive control.

Individual differences in brain responses to cigarette-related cues and pleasant stimuli in young smokers

BackgroundDecreased sensitivity to pleasant stimuli is associated with a higher vulnerability to nicotine dependence in youths and with difficulty quitting in adult smokers. Recently, we showed that smokers showing lower brain reactivity to non-cigarette-related pleasant images than to cigarette-related ones have lower chances of achieving long-term abstinence during a quit attempt. MethodsWe tested whether individual differences in brain responses to cigarette-related and pleasant stimuli require a long history of smoking to develop by measuring the late positive potential (LPP) to cigarette cues, emotional, and neutral stimuli in 45 young, light smokers (ages 18–25). k-means cluster analysis was used to partition smokers into two groups based on the magnitude of their LPPs. ResultsGroup 1 was characterized by larger LPPs to pleasant pictures than cigarette-related pictures whereas Group 2 showed the opposite pattern. ConclusionsOur results suggest that individual differences in brain responses to cigarette-related and pleasant cues do not require a long smoking history to develop.

Task-free MRI predicts individual differences in brain activity during task performance.

When asked to perform the same task, different individuals exhibit markedly different patterns of brain activity. This variability is often attributed to volatile factors, such as task strategy or compliance. We propose that individual differences in brain responses are, to a large degree, inherent to the brain and can be predicted from task-independent measurements collected at rest. Using a large set of task conditions, spanning several behavioral domains, we train a simple model that relates task-independent measurements to task activity and evaluate the model by predicting task activation maps for unseen subjects using magnetic resonance imaging. Our model can accurately predict individual differences in brain activity and highlights a coupling between brain connectivity and function that can be captured at the level of individual subjects.

Sensation seeking predicts brain responses in the old–new task: Converging multimodal neuroimaging evidence

Novel images and message content enhance visual attention and memory for high sensation seekers, but the neural mechanisms associated with this effect are unclear. To investigate the individual differences in brain responses to new and old (studied) visual stimuli, we utilized event-related potentials (ERP) and functional Magnetic Resonance Imaging (fMRI) measures to examine brain reactivity among high and low sensation seekers during a classic old–new memory recognition task. Twenty low and 20 high sensation seekers completed separate, but parallel, ERP and fMRI sessions. For each session, participants initially studied drawings of common images, and then performed an old–new recognition task during scanning. High sensation seekers showed greater ERP responses to new objects at the frontal N2 ERP component, compared to low sensation seekers. The ERP Novelty-N2 responses were correlated with fMRI responses in the orbitofrontal gyrus. Sensation seeking status also modulated the FN400 ERP component indexing familiarity and conceptual learning, along with fMRI responses in the caudate nucleus, which correlated with FN400 activity. No group differences were found in the late ERP positive components indexing classic old–new amplitude effects. Our combined ERP and fMRI results suggest that sensation-seeking personality affects the early brain responses to visual processing, but not the later stage of memory recognition.

The serotonin transporter gene polymorphism and the effect of baseline on amygdala response to emotional faces

Previous research has found that a common polymorphism in the serotonin transporter gene (5-HTTLPR) is an important mediator of individual differences in brain responses associated with emotional behaviour. In particular, relative to individuals homozygous for the l-allele, carriers of the s-allele display heightened amygdala activation to emotional compared to non-emotional stimuli. However, there is some debate as to whether this difference is driven by increased activation to emotional stimuli, resting baseline differences between the groups, or decreased activation to neutral stimuli. We performed functional imaging during an implicit facial expression processing task in which participants viewed angry, sad and neutral faces. In addition to neutral faces, we included two further baseline conditions, houses and fixation. We found increased amygdala activation in s-allele carriers relative to l-homozygotes in response to angry faces compared to neutral faces, houses and fixation. When comparing neutral faces to houses or fixation, we found no significant difference in amygdala response between the two groups. In addition, there was no significant difference between the groups in response to fixation when compared with a houses baseline. Overall, these results suggest that the increased amygdala response observed in s-allele carriers to emotional faces is primarily driven by an increased response to emotional faces rather than a decreased response to neutral faces or an increased resting baseline. The results are discussed in relation to the tonic and phasic hypotheses of 5-HTTLPR-mediated modulation of amygdala activity.

Additive effects of serotonin transporter and tryptophan hydroxylase-2 gene variation on neural correlates of affective processing

Individual differences in brain response to emotional stimuli have previously been associated with gene variations within the serotonin transporter ( 5-HTT) and tryptophan hydroxylase-2 ( TPH2) genes. We recently reported that these two genes exhibit an additive effect, based on recordings of event-related potentials (ERPs) from individuals viewing emotional scenes. The current study was designed to replicate and extent this initial report in an independent study sample, and use functional magnetic resonance imaging (fMRI) to identify specific neural loci that may mediate the 5-HTT– TPH2 additive effect. Furthermore, we sought to obtain convergent evidence for a gene–gene additive effect by collecting fMRI data from the same individuals engaged in two different cognitive-affective tasks, using emotional and neutral facial expressions and word stimuli. We found evidence for an additive effect of 5-HTT– TPH2 genotype, which was most robust in the putamen, a region rich in both 5-HTT and TPH2 protein, but was also observed in the amygdala at a less stringent threshold, and in other cortical regions. The additive effect was more robust effect for visuospatial than for verbal stimuli, and more robust for negatively than for positively valenced stimuli. These findings confirm and extend the additive effect of two critical genes in the serotonergic regulation of neural processing of affective stimuli, and identify the striatum as a critical site where is gene–gene regulation takes place.

Enhanced affective brain representations of chocolate in cravers vs. non‐cravers

To examine the neural circuitry involved in food craving, in making food particularly appetitive and thus in driving wanting and eating, we used fMRI to measure the response to the flavour of chocolate, the sight of chocolate and their combination in cravers vs. non-cravers. Statistical parametric mapping (SPM) analyses showed that the sight of chocolate produced more activation in chocolate cravers than non-cravers in the medial orbitofrontal cortex and ventral striatum. For cravers vs. non-cravers, a combination of a picture of chocolate with chocolate in the mouth produced a greater effect than the sum of the components (i.e. supralinearity) in the medial orbitofrontal cortex and pregenual cingulate cortex. Furthermore, the pleasantness ratings of the chocolate and chocolate-related stimuli had higher positive correlations with the fMRI blood oxygenation level-dependent signals in the pregenual cingulate cortex and medial orbitofrontal cortex in the cravers than in the non-cravers. To our knowledge, this is the first study to show that there are differences between cravers and non-cravers in their responses to the sensory components of a craved food in the orbitofrontal cortex, ventral striatum and pregenual cingulate cortex, and that in some of these regions the differences are related to the subjective pleasantness of the craved foods. Understanding individual differences in brain responses to very pleasant foods helps in the understanding of the mechanisms that drive the liking for specific foods and thus intake of those foods.