Prefrontal Areas Research Articles

When the brain says “No!”: An MRI study on the neural correlates of resistance to immoral orders

Abstract Milgram’s studies explored psychological and contextual factors influencing (dis)obedience to immoral orders, but the mechanisms preventing individuals from being coerced into causing pain to others remained largely unknown. Our fMRI study investigated the neural correlates of disobedience to such orders, focusing on three phases of the decision-making process: order processing (predecision), action (decision), and outcome and effect processing (postdecision). Within these phases we targeted three sociocognitive (cognitive conflict, sense of agency—SoA, and theory of mind—ToM) and two socioaffective (empathy and guilt) processes. Our findings revealed that participants who engaged the angular gyrus and temporoparietal junction, particularly in the left hemisphere, as well as median prefrontal areas before obeying the command to send a shock—possibly to mitigate cognitive conflict between self and other and to enhance their SoA—were more likely to disobey the experimenter’s instructions to administer a shock to a victim. Additionally, we found involvement of social brain regions during the postdecision phase (encompassing ToM, empathy, and guilt areas), especially in response to shock events, to process the victim’s pain. Higher activity in these regions when obeying orders was associated with a higher rate of prosocial disobedience. This study sheds light on the mechanisms that lead individuals to resist immoral actions under authoritative pressure in an experimental context.

Differences in the Lateralization of Theta and Alpha Power During n-Back Task Performance Between Older and Young Adults in the Context of the Hemispheric Asymmetry Reduction in Older Adults (HAROLD) Model

Hemispheric Asymmetry Reduction in Old Adults (HAROLD) is one of the most well-known models of compensatory brain involvement in older adults. Most evidence supports its occurrence from the perspective of PET and fMRI studies, with a deficiency in electroencephalographic research in this domain. Therefore, we aimed to investigate the possibility of identifying the HAROLD pattern in older adults’ power of theta and alpha. The study sample comprised 50 older adults and 60 young adults performing n-back tasks while recording EEG signals. The level of cognitive performance and the theta and alpha power for pairs of symmetrical electrodes in the prefrontal, frontal, and parietal areas were analyzed. Older adults exhibited inferior cognitive performance compared to young adults and heightened theta power in the right hemisphere within the prefrontal and parietal areas. However, they also demonstrated increased alpha power in the right frontal pole, which contradicts the compensatory effects of theta power. Moreover, the two indicated phenomena of lateralization of theta and alpha power in older adults were unrelated to individual cognitive performance. The results make it challenging to discern whether the revealed age-related differences in theta and alpha power lateralization denote compensation, dedifferentiation, or nonselective recruitment as neutral features of brain activity in old adults.

Brain activation patterns in normal hearing adults: An fNIRS Study using an adapted clinical speech comprehension task

ObjectivesUnderstanding brain processing of auditory and visual speech is essential for advancing speech perception research and improving clinical interventions for individuals with hearing impairment. Functional near-infrared spectroscopy (fNIRS) is deemed to be highly suitable for measuring brain activity during language tasks. However, accurate data interpretation also requires validated stimuli and behavioral measures. DesignTwenty-six adults with normal hearing listened to sentences from the Oldenburg Sentence Test (OLSA), and brain activation in the temporal, occipital, and prefrontal areas was measured by fNIRS. The sentences were presented in one of the four different modalities: speech-in-quiet, speech-in-noise, audiovisual speech or visual speech (i.e., lipreading). To support the interpretation of our fNIRS data, and to obtain a more comprehensive understanding of the study population, we performed hearing tests (pure tone and speech audiometry) and collected behavioral data using validated questionnaires, in-task comprehension questions, and listening effort ratings. ResultsIn the auditory conditions (i.e., speech-in-quiet and speech-in-noise), we observed cortical activity in the temporal regions bilaterally. During the visual speech condition, we measured significant activation in the occipital area. Following the audiovisual condition, cortical activation was observed in both regions. Furthermore, we established a baseline for how individuals with normal hearing process visual cues during lipreading, and we found higher activity in the prefrontal cortex in noise conditions compared to quiet conditions, linked to higher listening effort. ConclusionsWe demonstrated the applicability of a clinically inspired audiovisual speech-comprehension task in participants with normal hearing. The measured brain activation patterns were supported and complemented by objective and behavioral parameters.

NCOG-06. FACTORS ASSOCIATED WITH SOCIAL DISABILITY IN THE CHRONIC POSTOPERATIVE PERIOD IN PATIENTS WITH GLIOMAS

Abstract BACKGROUND Patients with low-grade gliomas may have no obvious problems during hospitalization or their initial return to social life; however, social life difficulties may gradually become more apparent long after the surgery. We investigated factors associated with social disabilities in patients with low-grade gliomas in the postoperative chronic phase. METHODS The study included 114 patients with WHO grade 2 or 3 gliomas who underwent surgery (mean age, 44.3±13.2 years). Seventy-six patients underwent an initial surgery and 38 underwent a second surgery. All patients underwent various brain functional assessments and interviews about their social lives over 1 year after the surgery (median, 23 months). Factors associated with social disabilities were determined using logistic multiple regression analysis and chi-square tests. Voxel-based lesion symptom mapping was used to examine the brain regions associated with social disabilities. RESULTS Social disabilities were observed in 12.3% of the patients. Factors associated with social disabilities were the number of surgeries (first vs. second, p=0.0052) and tumor location (left vs. right, p=0.0091). Patients with recurrence and right cerebral hemispheric lesions had a higher probability of social disability (42.1%, p<0.0001) than that of other patients. The reasons for social disability after right hemispheric recurrence were social behavior disorder (62.5%) and neuropsychological dysfunctions (37.5%). Social behavioral disorders include interpersonal problems, such as job switching owing to problems with others, poor interpersonal relationships, and sexually deviant behavior. No other apparent neuropsychological abnormalities were found in patients with social behavior disorders. Surgical resection of the deep part of the right prefrontal area is associated with social behavior disorders and right supplementary motor cortex resection is associated with neuropsychological disorders. CONCLUSION In lower grade glioma, patients with right hemispheric recurrence were more likely to develop social disabilities in the chronic phase, which was caused by social behavioral disorders and neuropsychological dysfunctions.

Volumetric Integrated Classification Index: An Integrated Voxel-Based Morphometry and Machine Learning Interpretable Biomarker for Post-Traumatic Stress Disorder.

PTSD is a complex mental health condition triggered by individuals' traumatic experiences, with long-term and broad impacts on sufferers' psychological health and quality of life. Despite decades of research providing partial understanding of the pathobiological aspects of PTSD, precise neurobiological markers and imaging indicators remain challenging to pinpoint. This study employed VBM analysis and machine learning algorithms to investigate structural brain changes in PTSD patients. Data were sourced ADNI-DoD database for PTSD cases and from the ADNI database for healthy controls. Various machine learning models, including SVM, RF, and LR, were utilized for classification. Additionally, the VICI was proposed to enhance model interpretability, incorporating SHAP analysis. The association between PTSD risk genes and VICI values was also explored through gene expression data analysis. Among the tested machine learning algorithms, RF emerged as the top performer, achieving high accuracy in classifying PTSD patients. Structural brain abnormalities in PTSD patients were predominantly observed in prefrontal areas compared to healthy controls. The proposed VICI demonstrated classification efficacy comparable to the optimized RF model, indicating its potential as a simplified diagnostic tool. Analysis of gene expression data revealed significant associations between PTSD risk genes and VICI values, implicating synaptic integrity and neural development regulation. This study reveals neuroimaging and genetic characteristics of PTSD, highlighting the potential of VBM analysis and machine learning models in diagnosis and prognosis. The VICI offers a promising approach to enhance model interpretability and guide clinical decision-making. These findings contribute to a better understanding of the pathophysiological mechanisms of PTSD and provide new avenues for future diagnosis and treatment.

Frontoparietal Structural Network Disconnections Correlate With Outcome After a Severe Stroke.

Structural disconnectome analyses have provided valuable insights into how a stroke lesion results in widespread network disturbances and how these relate to deficits, recovery patterns, and outcomes. Previous analyses have primarily focused on patients with relatively mild to moderate deficits. However, outcomes vary among survivors of severe strokes, and the mechanisms of recovery remain poorly understood. This study assesses the association between lesion-induced network disconnection and outcome after severe stroke. Thirty-eight ischaemic stroke patients underwent MRI brain imaging early after stroke and longitudinal clinical follow-up. Lesion information was integrated with normative connectome data to infer individual disconnectome profiles on a localized regional and region-to-region pathway level. Ordinal logistic regressions were computed to link disconnectome information to the modified Rankin Scale after 3-6 months. Disconnections of ipsilesional frontal, parietal, and temporal cortical brain areas were significantly associated with a worse motor outcome after a severe stroke, adjusted for the initial deficit, lesion volume, and age. The analysis of the underlying pathways mediating this association revealed location-specific results: For frontal, prefrontal, and temporal brain areas, the association was primarily driven by relatively sparse intrahemispheric disconnections. In contrast, the ipsilesional primary motor cortex, the dorsal premotor cortex, and various parietal brain regions showed a remarkable involvement of either frontoparietal intrahemispheric or additionally interhemispheric disconnections. These results indicate that localized disconnection of multiple regions embedded in the structural frontoparietal network correlates with worse outcomes after severe stroke. Specifically, primary motor and parietal cortices might gain particular importance as they structurally link frontoparietal networks of both hemispheres. These data shed novel light on the significance of distinct brain networks for recovery after a severe stroke.

The Impact of Task Difficulty on Neural Modulation Throughout A Visuomotor Multi-day Practice Training

The effectiveness of rehabilitation is contingent upon the motor recovery process which typically involves long-term motor skill re-acquisition. Given that the learning process can be modulated by task difficulty, elucidating the underlying neural mechanism is essential for optimizing rehabilitation prescription to suit different patient conditions. This study aimed to investigate the impact of task difficulty on cortical response during force-control training via electroencephalography (EEG). An 8-day visuomotor force-tracking training experiment was conducted. Healthy right-handed participants (N=33) were recruited and randomly assigned to 3 groups, and each group was tasked with a different level of difficulty. The task difficulty was manipulated by variation in force-production complexity and execution sequence assignments, with real-time visual feedback provided to participants for self-output adjustment. Behavioral performance was quantitatively assessed using a pre-defined score metric related to performance accuracy. The EEG signals were collected, and corresponding event-related desynchronization (ERD) and relative functional connectivity (FC) during the task execution were analyzed within the alpha- (8-13Hz) and beta- (15-30Hz) bands. A post-training experiment was also performed to evaluate the near-transfer capability of learning. Results showed all the behavioral performances improved during practice, while higher task difficulty level was affiliated with better post-training near-transfer ability. The dynamic neural response to training could be mediated by changes in difficulty level, where increased task complexity corresponded with the heightened activities in the beta-band priorly within the right dorsolateral prefrontal area. Additionally, stronger alpha-band functional connectivity was observed to be predominantly associated with the left motor area (LMA) during challenging tasks, and the intensification in connectivity persisted selectively post-training which appeared to be acritical factor for skill transfer performance improvement. These findings illustrated the dynamic neural mechanism through which task difficulty affects behavioral performance during long-term motor training with accurate force-control purpose. The selectively strengthened functional connectivity may contribute to facilitating new task execution after training interventions. Therefore, beneficial neural modulation can be expected to be feasible by well-designed task difficulty strategies for effective motor rehabilitation.

Correspondence between Morphometric MRI and Metabolism Profile in Self-limited Epilepsy with Centrotemporal Spikes

Abstract Self-limited epilepsy with centrotemporal spikes (SeLECTS) is a common pediatric epilepsy, and this age-dependent subtype usually incidents in the golden period of brain development. The integration of multi-scale and cross-modal brain image data can help to analyze the neural mechanism of brain development. In this study, we aimed to test whether macroscale brain morphometric features were altered in children with SeLECTS, and how the differences were related to clinical phenotypes and brain metabolism profiles. We extracted five cortical morphometric features to construct morphometric similarity (MS) connectome. The study revealed significant case-control differences in the MS in children with SeLECTS, mainly involved in left prefrontal area, right precuneus, left supramarginal gyrus and medial temporal gyrus. The MS in supramarginal gyrus was negatively correlated with general intelligence measurements. And the global changes of the MS showed correlations between metabolism profiles of dopamine D2, glutamate and vesicular acetylcholine transporter distributions.

Otak Bilingual: Sinergi Dwibahasa dalam Meningkatkan Fungsi Eksekutif

Amidst the growing demand for proficiency in more than one language in today's global society, it is crucial to understand how bilingual abilities engage in various cognitive processes, particularly in executive functions from a neuropsychological perspective. The ability to acquire and use two languages affects high-level cognitive functions described through a tripartite model, including inhibitory control, working memory, and cognitive flexibility. Through a critical analysis of the literature, it is found that bilingual individuals often have an advantage in tasks requiring self-control and the management of complex information. This advantage is attributed to the need to manage and shift attention between two language systems, which intensively trains executive functions. This study also examines the neuropsychological implications of bilingual abilities, including structural and functional changes in the brain, particularly in the prefrontal cortex area. In conclusion, bilingualism not only affects linguistic abilities but also supports cognitive development. This research underscores the potential significance of bilingualism in education and personal development as a tool to enhance critical thinking skills and mental flexibility, which are valuable for learning and adapting to ever-changing environments.

Age-related cerebral changes during different n-back tasks: a functional near-infrared spectroscopy study.

The n-back task is a widely used paradigm to assess working memory and is commonly applied in research on age-related cognitive decline. However, studies utilizing functional near-infrared spectroscopy (fNIRS) to explore this area are limited. This study aims to investigate age-related differences in brain activation during the n-back task using fNIRS. fNIRS data were collected from 18 elderly and 19 young participants while performing different n-back tasks. Brain activation patterns and peripheral performance were compared between the two groups. Significant differences in brain activation patterns were observed between elderly and young participants. Under the 3-back condition, the older group exhibited reduced activation in brain regions adjacent to prefrontal cognitive areas compared to the younger group. Additionally, the older group's performance plateaued at the 2-back level, along with a decline in prefrontal activation. These findings may suggest potential markers for cognitive decline, providing a new target for future screening.

Distinct Roles of Medial Prefrontal Cortex Subregions in the Consolidation and Recall of Remote Spatial Memories.

It is a common belief that memories, over time, become progressively independent of the hippocampus and are gradually stored in cortical areas. This view is mainly based on evidence showing that prefrontal cortex (PFC) manipulations impair the retrieval of remote memories, while hippocampal inhibition does not. More controversial is whether activity in the medial PFC is required immediately after learning to initiate consolidation. Another question concerns functional differences among PFC subregions in forming and storing remote memories. To address these issues, we directly contrasted the effects of loss-of-function manipulations of the anterior cingulate cortex (aCC) and the ventromedial PFC, which includes the infralimbic (IL) and prelimbic (PL) cortices, before testing and immediately after training on the ability of CD1 mice to recall the hidden platform location in the Morris water maze. We injected an AAV carrying the hM4Di receptor into the PL-IL or aCC. Interestingly, pretest administrations of clozapine-N-oxide (CNO; 3 mg/kg) revealed that the aCC, but not the PL-IL, was necessary to recall remote spatial information. Furthermore, systemic post-training administration of CNO impaired memory recall at remote, but not recent, time points in both groups. These findings revealed a functional dissociation between the two prefrontal areas, demonstrating that both the PL-IL and the aCC are involved in early consolidation of remote spatial memories, but only the aCC is engaged in their recall.

Cognitive Impact of β-Amyloid Load in the Rapid Eye Movement Sleep Behavior Disorder-Lewy Body Disease Continuum.

Rapid eye movement sleep behavior disorder (RBD) is linked to the diffuse-malignant subtype and higher cognitive burden in Lewy body disease (LBD). This study explores brain β-amyloid deposition and its association with cognitive decline across the RBD-LBD continuum. Patients with isolated RBD (iRBD), Parkinson's disease with probable RBD (PDRBD), and dementia with Lewy bodies with probable RBD (DLBRBD) underwent 18F-florbetaben positron emission tomography, 3T magnetic resonance imaging scans, and comprehensive neuropsychological assessments. Subjects were categorized as cognitively normal (NC), mild cognitive impairment (MCI), or dementia. Global and regional standardized uptake value ratios (SUVR) were estimated in predefined cognitive volumes of interest (VOI) derived from voxel-wise comparison analysis among the cognitive groups, namely the prefrontal, parietal, precentral cortices, lingual gyrus, and supplementary motor area. Generalized linear models assessed the relationship between 18F-florbetaben SUVRs and neuropsychological testing, adjusting for age and sex. Subgroup analysis focused on the polysomnography-confirmed iRBD-continuum subset (n = 41) encompassing phenoconverters and nonconverters in our prospective iRBD cohort. Eighty-six subjects were classified as follows: 14 NC, 54 MCI, and 18 dementia. The proportion of positive β-amyloid scans increased with advanced cognitive stages (P = 0.038). β-Amyloid signals in cognitive VOIs were elevated in subgroups showing impairment in Trail-Making Test B (TMT-B). A linear association between TMT-B z score and global cortical β-amyloid levels was observed in the iRBD-continuum subset (P = 0.013). Cortical β-amyloid accumulates with declines in executive function within the RBD-LBD continuum. TMT-B performance may be a useful marker associating with β-amyloid load, particularly in the iRBD population. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Neural Correlates of Reactive Inhibition in Gambling Disorder: An FMRI Study with Transcranial Magnetic Stimulation (TMS)

Gambling Disorder (GD) is a condition characterized by a persistent and recurrent pattern of problematic gambling behavior. Despite significant advances in understanding the neurobiological correlates of Gambling Disorder phenomenological manifestation, there are still several unanswered questions regarding the pathophysiological mechanisms underlying GD. There is substantial evidence from fMRI studies on the role of pre-SMA stimulation in psychiatric conditions with impairments in response inhibition such as behavioral addictions on enhancing the activity of the brain circuitry involving the right inferior (IFG) and middle frontal gyrus (MFG) (two cortical areas are differentially associated with two distinct aspects of control inhibition). In this study we utilized task-related functional Magnetic Resonance Imaging (fMRI) to explore the impact of continuous Theta-Burst Stimulation (cTBS) on the pre-Supplementary Motor Area (pre-SMA) in patients with Gambling Disorder (GD). Four GD patients underwent cTBS on bilateral pre-SMA, administered with the MagVenture MagPro R30 stimulator with add-on theta-burst option (MagVenture INC.) using a Cool D-B80 figure-of-eight coil. cTBS consists of bursts of 3 pulses separated by 20 ms (i.e., 50 Hz) delivered repeatedly at theta frequency on the pre-SMA bilaterally. Changes in Functional Connectivity (FC) were assessed before and after Real or Sham treatment using CONN functional connectivity toolbox and Statistical Parametric Mapping (SPM). The study aimed to determine whether cTBS influences the functional connectivity between pre-SMA and right prefrontal areas, specifically the right Inferior Frontal Gyrus (rIFG) and right Middle Frontal Gyrus (rMFG), and whether these changes correlate with treatment outcomes. Results indicated that real cTBS treatment increased functional connectivity between pre-SMA and both rIFG and rMFG, suggesting enhanced control inhibition. This was associated with a reduction in Gambling Disorder symptom severity, assessed with the Pathological Gambling version of the Yale-Brown Obsessive-Compulsive Scale (PG-YBOCS) and the Gambling Urges Questionnaire (GUQ), indicating a treatment response. Conversely, sham cTBS did not elicit the same positive FC changes in the reactive control inhibition network, aligning with behavioral measures. The study highlighted the potential of cTBS on pre-SMA in modulating inhibitory control circuit. Overall, this preliminary investigation provides a foundation for future investigations into the neurobiological mechanisms underlying GD and the potential efficacy of TMS interventions.

Resting-state functional connectivity in anxiety disorders: a multicenter fMRI study.

Anxiety disorders (AD) are associated with altered connectivity in large-scale intrinsic brain networks. It remains uncertain how much these signatures overlap across different phenotypes due to a lack of well-powered cross-disorder comparisons. We used resting-state functional magnetic resonance imaging (rsfMRI) to investigate differences in functional connectivity (FC) in a cross-disorder sample of AD patients and healthy controls (HC). Before treatment, 439 patients from two German multicenter clinical trials at eight different sites fulfilling a primary diagnosis of panic disorder and/or agoraphobia (PD/AG, N = 154), social anxiety disorder (SAD, N = 95), or specific phobia (SP, N = 190) and 105 HC underwent an 8 min rsfMRI assessment. We performed categorical and dimensional regions of interest (ROI)-to-ROI analyses focusing on connectivity between regions of the defensive system and prefrontal regulation areas. AD patients showed increased connectivity between the insula and the thalamus compared to controls. This was mainly driven by PD/AG patients who showed increased (insula/hippocampus/amygdala-thalamus) and decreased (dorsomedial prefrontal cortex/periaqueductal gray-anterior cingulate cortex) positive connectivity between subcortical and cortical areas. In contrast, SAD patients showed decreased negative connectivity exclusively in cortical areas (insula-orbitofrontal cortex), whereas no differences were found in SP patients. State anxiety associated with the scanner environment did not explain the FC between these regions. Only PD/AG patients showed pronounced connectivity changes along a widespread subcortical-cortical network, including the midbrain. Dimensional analyses yielded no significant results. The results highlighting categorical differences between ADs at a systems neuroscience level are discussed within the context of personalized neuroscience-informed treatments. PROTECT-AD's registration at NIMH Protocol Registration System: 01EE1402A and German Register of Clinical Studies: DRKS00008743. SpiderVR's registration at ClinicalTrials.gov: NCT03208400.

Characteristic Changes of Prefrontal and Motor Areas in Patients with Type 2 Diabetes and Major Depressive Disorder During a Motor Task of Tai Chi Chuan: A Functional Near-Infrared Spectroscopy Study.

This cross-sectional study aims to identify the characteristic changes of prefrontal and motor areas during a tai chi chuan task in patients with Type 2 diabetes mellitus (T2DM) and major depressive disorder (MDD) using wearable functional near-infrared spectroscopy (fNIRS). Three parallel groups (T2DM with DD group, T2DM group, and healthy group) were recruited from December 10, 2022, to May 31, 2023. Participants in three groups conducted a motor task of tai chi chuan designed by Eprime 3.0, and fNIRS was used to monitor the brain activation, functional connectivity (FC), and lateralization of prefrontal and motor areas. Correlation analyses were performed to examine the relationship between depressive symptoms and the function of prefrontal and motor areas. Ninety elder adults (aged ≥ 60), including 30 patients with T2DM and MDD, 30 patients with T2DM, and 30 healthy subjects, were enrolled. In contrast with the patients with T2DM and healthy subjects, the patients with T2DM and MDD had decreased activation and abnormal lateralization in prefrontal and motor areas and decreased FC among supplementary motor area, motor area, and dorsolateral prefrontal cortex (DLPFC). Furthermore, the oxyhemoglobin (HbO2) concentration value of DLPFC in patients with T2DM and MDD was negatively associated with scores of Hamilton Depression Scale-24 (HAMD-24). Patients with T2DM and MDD had characteristic functional changes in prefrontal and motor areas. DLPFC may be a potential target of diagnosis and intervention for patients with T2DM and MDD.

High-resolution awake mouse fMRI at 14 Tesla.

High-resolution awake mouse fMRI remains challenging despite extensive efforts to address motion-induced artifacts and stress. This study introduces an implantable radiofrequency (RF) surface coil design that minimizes image distortion caused by the air/tissue interface of mouse brains while simultaneously serving as a headpost for fixation during scanning. Furthermore, this study provides a thorough acclimation method used to accustom animals to the MRI environment minimizing motion induced artifacts. Using a 14T scanner, high-resolution fMRI enabled brain-wide functional mapping of visual and vibrissa stimulation at 100×100×200μm resolution with a 2s per frame sampling rate. Besides activated ascending visual and vibrissa pathways, robust BOLD responses were detected in the anterior cingulate cortex upon visual stimulation and spread through the ventral retrosplenial area (VRA) with vibrissa air-puff stimulation, demonstrating higher-order sensory processing in association cortices of awake mice. In particular, the rapid hemodynamic responses in VRA upon vibrissa stimulation showed a strong correlation with the hippocampus, thalamus, and prefrontal cortical areas. Cross-correlation analysis with designated VRA responses revealed early positive BOLD signals at the contralateral barrel cortex (BC) occurring 2 seconds prior to the air-puff in awake mice with repetitive stimulation, which was not detected using a randomized stimulation paradigm. This early BC activation indicated a learned anticipation through the vibrissa system and association cortices in awake mice under continuous training of repetitive air-puff stimulation. This work establishes a high-resolution awake mouse fMRI platform, enabling brain-wide functional mapping of sensory signal processing in higher association cortical areas.

Disrupted functional connectivity of bilateral nucleus accumbens in major depressive disorder with and without melancholic features.

Our study aims to explore the differences in functional connectivity in the nucleus accumbens (NAc) between patients with melancholic depression and non-melancholic depression (NMD) and their relation to melancholic depression's pathogenesis. We recruited 60 melancholic depression, 58 NMD, and 80 healthy controls, all matched for gender, age, and education. Functional connectivity analysis focused on bilateral NAc as the region of interest, comparing it with the whole brain and correlating significant differences with clinical scores. Melancholic depression patients showed reduced functional connectivity between the left NAc and anterior brain regions, and between the right NAc and temporal and frontal areas, compared to healthy controls. In contrast, NMD patients displayed reduced functional connectivity only between the left NAc and the posterior cingulate cortex. Melancholic depression patients also exhibited increased functional connectivity between the right NAc and the middle frontal gyrus, unlike NMD patients. The findings suggest that melancholic depression patients exhibit unique NAc functional connectivity patterns, particularly with the default mode network and prefrontal areas, suggesting atypical reward-circuitry interactions. The right NAc's connection to the prefrontal gyrus may distinguish melancholic depression from NMD.

Neurophysiological response to social feedback in stressful situations.

The relationship between external feedback and cognitive and neurophysiological performance has been extensively investigated in social neuroscience. However, few studies have considered the role of positive and negative external social feedback on electroencephalographic (EEG) and moderate stress response. Twenty-six healthy adults underwent a moderately stressful job interview consisting of a modified version of the Trier Social Stress Test. After each preparation, feedback was provided by an external committee, ranging from positive to negative with increasing impact on subjects. Stress response was measured by analysing response times (RTs) during the speech phase, while cognitive performance was assessed using a Stroop-like task before and after the test. Results indicate that RTs used to deliver the final speeches with negative feedback were significantly lower compared with those used for the initial speech with positive feedback. Moreover, a generalized improvement in Stroop-like task performance was observed in the post-SST compared with the pre-SST. Consistent with behavioural results, EEG data indicated greater delta, theta, and alpha band responses in right prefrontal and left central areas, and for delta and theta bands, also in parietal areas in response to positive feedback compared with aversive-neutral feedback, highlighting greater cognitive effort required by the former. Conversely, an increase in these bands in right and left temporal and left occipital areas was observed following negative and aversive feedback, indicative of an adaptive response to stress and emotion-regulatory processes. These findings suggest that negative social feedback in moderately stressful and noncritical conditions could contribute to improving individual cognitive performance.

Sex-specific gene expression differences in the prefrontal cortex of major depressive disorder individuals

Major depressive disorder (MDD) is a leading global cause of disability, being more prevalent in females, possibly due to molecular and neuronal pathway differences between females and males. However, the connection between transcriptional changes and MDD remains unclear. We identified transcriptionally altered genes (TAGs) in MDD through gene and transcript expression analyses, focusing on sex-specific differences. Analyzing 263 brain samples from both sexes, we conducted differential gene expression, differential transcript expression, and differential transcript usage analyses, revealing 1169 unique TAGs, primarily in the prefrontal areas, with nearly half exhibiting transcript-level alterations. Females showed notable RNA splicing and export process disruptions in the orbitofrontal cortex, alongside altered DDX39B gene expression in five of the six brain regions in both sexes. Our findings suggest that disruptions in RNA processing pathways may play a vital role in MDD.

Multivariate pattern analysis of cooperation and competition in constructive action

The neural underpinning of cooperative and competitive constructive activity has been investigated using mass-univariate approaches. In this study, we sought to compare the results of these approaches with the results of multivariate pattern analysis (MVPA). In particular, we wanted to test whether MVPA supports the claim made in previous studies that cooperation is associated with the activity of reward-related brain circuits. Participants were required to construct a pattern on the screen either individually or in cooperation or competition with another person during an fMRI scan. Both the MVPA classification methods and the representational similarity analysis indicated the involvement of orbitofrontal and ventromedial prefrontal areas in processes that distinguish between cooperation and competition, and activation analysis showed that these areas are more active during cooperation than during competition. However, a single trial analysis showed that the effect was reversed when only winning trials were considered. In these trials, activation of reward-related areas was higher during competition than during cooperation. Moreover, the contrast between won and lost trials in terms of reward circuits involvement was sharper under competition than under cooperation. Thus, although cooperation can be generally more rewarding than competition, it is associated with smaller difference between trials lost and trials won in terms of reward circuits activation. One may speculate that in cooperation, victory and defeat are shared with the partner and, contrary to competition, are not experienced as personal achievement or failure.