Activity In Superior Frontal Gyrus Research Articles

The Longitudinal Relationship Between the Symptoms of Depression and Perceived Stress Among Chinese University Students.

Depression is one of the most common mental disorders. Perceived stress is a significant trigger and has adverse effects on depression. The complex longitudinal relationship between perceived stress and depression at the symptom level has significant implications for clinical intervention but is understudied. In our study, 823 students (67% female, median age 20.38, IQR 19.42-21.43) from a university in Tianjin were randomly sampled and completed measures of PHQ-9 and PSS-10, while 393 (65% female, median age 20.42, IQR 19.46-21.45) were followed up at three points, six months apart. The longitudinal relationships were estimated using cross-lagged modelling and cross-lagged panel network modelling. Among them, 49 students (59% female, median age 19.48, IQR 18.76-20.12) participated in resting-state functional magnetic resonance imaging (fMRI) scans. Cross-lagged analyses showed that depression and perceived stress predicted each other at the global level. At the dimensional level, depression and perceived helplessness were mutually predictive, while depression and perceived coping did not. In the cross-lagged panel network analyses, we identified symptoms in the top 20% of Bridge Expected Influence as bridging symptoms, specifically 'Guilt' (PHQ6) and 'Felt nervous and stressed' (PSS3). Notably, 'guilt' consistently demonstrated the highest Bridge Expected Influence across all time points and showed the strongest predictive power for perceived stress. We found that fALFF in the left superior frontal gyrus (SFG) mediated the association between "guilt" and perceived stress. Our findings elucidate the bidirectional relationship between symptoms of depression and perceived stress, identifying guilt is the most critical symptom of depression for the followed perceived stress, with SFG activity mediating this association.

Exploring the impact of immersive virtual reality on depression knowledge and stigma reduction: a cross-over RCT fMRI study

The stigma of mental illness is a form of negative judgmental knowledge and is a barrier to individual seeking treatment. Contact-based educational interventions with first-person perspective (1PP) combined with immersive virtual reality (IVR) is promising as an anti-stigma intervention. This study aims to investigate the effectiveness of 1PP anti-stigma IVR intervention compared to video in enhancing depression knowledge and reducing stigma, as well as to examine the corresponding depression knowledge brain activity change using functional magnetic resonance imaging (fMRI). Participants engaged in a 1PP anti-stigma intervention using both IVR and conventional video, focusing on the daily life and recovery of a patient with mild depression. The change in depression knowledge, stigma-related behavioral, and brain activity using fMRI were measured at pre- and post-interventions. Depression knowledge improved for both interventions; however, only the IVR intervention reduced stigma. In the IVR intervention, depression knowledge score was positively associated with neural response in the right superior frontal gyrus activation, indicative of empathic concern. Conversely, the video intervention correlated with increased activity in the right anterior insula, suggesting a distress-related response. The findings demonstrate that the immersive nature of IVR can reduce stigma more effectively than video intervention. This effectiveness is underpinned by the change in depression knowledge on neural activity, with IVR fostering empathy-related behavioral responses. The results highlight the potential of IVR in enhancing empathic understanding and reducing stigma towards mental illness, emphasizing the need for further exploration into immersive technologies for mental health education.

Social intelligence mediates the protective role of resting-state brain activity in the social cognition network against social anxiety.

Social intelligence refers to an important psychosocial skill set encompassing an array of abilities, including effective self-expression, understanding of social contexts, and acting wisely in social interactions. While there is ample evidence of its importance in various mental health outcomes, particularly social anxiety, little is known on the brain correlates underlying social intelligence and how it can mitigate social anxiety. This research aims to investigate the functional neural markers of social intelligence and their relations to social anxiety. Data of resting-state functional magnetic resonance imaging and behavioral measures were collected from 231 normal students aged 16 to 20 years (48% male). Whole-brain voxel-wise correlation analysis was conducted to detect the functional brain clusters related to social intelligence. Correlation and mediation analyses explored the potential role of social intelligence in the linkage of resting-state brain activities to social anxiety. Social intelligence was correlated with neural activities (assessed as the fractional amplitude of low-frequency fluctuations, fALFF) among two key brain clusters in the social cognition networks: negatively correlated in left superior frontal gyrus (SFG) and positively correlated in right middle temporal gyrus. Further, the left SFG fALFF was positively correlated with social anxiety; brain-personality-symptom analysis revealed that this relationship was mediated by social intelligence. These results indicate that resting-state activities in the social cognition networks might influence a person's social anxiety via social intelligence: lower left SFG activity → higher social intelligence → lower social anxiety. These may have implication for developing neurobehavioral interventions to mitigate social anxiety.

'I am afraid you will see the stain onmy soul': Direct gaze neural processing inindividuals with PTSD after moral injury recall.

Direct eye contact is essential to understanding others' thoughts and feelings in social interactions. However, those with post-traumatic stress disorder (PTSD) and exposure to moral injury (MI) may exhibit altered theory-of-mind (ToM)/mentalizing processes and experience shame which precludes one's capacity for direct eye contact. We investigated blood oxygenation level-dependent (BOLD) responses associated with direct vs averted gaze using a virtual reality paradigm in individuals with PTSD (n = 28) relative to healthy controls (n = 18) following recall of a MI vs a neutral memory. Associations between BOLD responses and clinical symptomatology were also assessed. After MI recall, individuals with PTSD showed greater activation in the right temporoparietal junction as compared to controls (T = 4.83; pFDR < 0.001; k = 237) during direct gaze. No significant activation occurred during direct gaze after neutral memory recall. Further, a significant positive correlation was found between feelings of distress and right medial superior frontal gyrus activation in individuals with PTSD (T = 5.03; pFDR = 0.049; k = 123). These findings suggest that direct gaze after MI recall prompts compensatory ToM/mentalizing processing. Implications for future interventions aimed at mitigating the effects of PTSD on social functioning are discussed.

Neural correlates of PTSD in women with childhood sexual abuse with and without PTSD and response to paroxetine treatment: A placebo-controlled, double-blind trial

ObjectiveChildhood sexual abuse is the leading cause of posttraumatic stress disorder (PTSD) in women, and is a prominent cause of morbidity and loss of function for which limited treatments are available. Understanding the neurobiology of treatment response is important for developing new treatments. The purpose of this study was to assess neural correlates of personalized traumatic memories in women with childhood sexual abuse with and without PTSD, and to assess response to treatment. MethodsWomen with childhood sexual abuse with (N = 28) and without (N = 17) PTSD underwent brain imaging with High-Resolution Positron Emission Tomography scanning with radiolabeled water for brain blood flow measurements during exposure to personalized traumatic scripts and memory encoding tasks. Women with PTSD were randomized to paroxetine or placebo followed by three months of double-blind treatment and repeat imaging with the same protocol. ResultsWomen with PTSD showed decreases in areas involved in the Default Mode Network (DMN), a network of brain areas usually active when the brain is at rest, hippocampus and visual processing areas with exposure to traumatic scripts at baseline while women without PTSD showed increased activation in superior frontal gyrus and other areas (p < 0.005). Treatment of women with PTSD with paroxetine resulted in increased anterior cingulate activation and brain areas involved in the DMN and visual processing with scripts compared to placebo (p < 0.005). ConclusionPTSD related to childhood sexual abuse in women is associated with alterations in brain areas involved in memory and the stress response and treatment with paroxetine results in modulation of these areas.

EEG Oscillatory Networks in Peri-Ictal Period of Absence Epilepsy.

ObjectiveTo investigate the dynamical brain network changes before and after an absence seizure episode in absence epilepsy (AE).Methods21 AE patients with a current high frequency of seizures and 21 sex- and age-matched health control (HC) who reported no history of neurological or psychiatric disorders and visited the hospital for routine physical examinations were included. Each included subject underwent a 2-h and 19-channel video EEG examination. For AE patients, five epochs of 10-s EEG data in inter-ictal, pre-ictal, and post-ictal states were collected. For the HC group, five 10-s resting-state EEG epochs were extracted. Functional independent components analysis (ICA) was carried out using the LORETA KEY tool.ResultsCompared with the resting-state EEG data of the HC group, the EEG data from AE patients during inter-ictal periods showed decreased alpha oscillations in regions involving the superior frontal gyrus (SFG) (BA11). From inter-ictal to pre-ictal, SFG (BA10) showed maximum decreased delta oscillations. Additionally, from pre-ictal to post-ictal, superior temporal gyrus (STG) (BA 22) presented maximum increased neural activity in the alpha band. Moreover, compared with inter-ictal EEG, post-ictal EEG showed significantly decreased theta activity in SFG (BA8).ConclusionThe changes in SFG alpha oscillations are the key brain network differences between inter-ictal EEG of AE patients and resting-state EEG of HCs. The brain networks of EEG oscillatory during peri-ictal episodes are mainly involving SFG and STG. Our study suggests that altered EEG brain networks dynamics exist between inter-ictal EEG of AE patients and resting-state EEG of HCs and between pre- and post-ictal EEG in AE patients.

The neural mechanisms underlying the modulation of attentional deployment on emotional stability.

Emotional stability, the change of emotion response among situations, was associated with mental illness, such as depression. The current study aimed to explore the modulation of attentional deployment on emotional stability by combining functional magnetic resonance imaging (fMRI) and a sequential risk-taking task. During the task, participants were asked to open a series of boxes consecutively and decided when to stop. Each box contained a reward, except one containing a devil to zero reward in the trial. When participants stopped, both collected gains and missed chances were revealed. The attentional deployment was manipulated during the outcome feedback, i.e., inducing participants to focus on the good part (GF context) or the bad part (MF context) of the decision outcome. Besides, the Control context was also set, in which the attentional deployment was not manipulated. The behavioral results showed that the emotional stability was stronger in GF context relative to MF and Control contexts. At the neural level, with outcomes getting better, activations of ventral striatum (VS) and superior frontal gyrus (SFG) increased faster in GF context than that in MF and Control contexts. In addition, in GF context, the changing of SFG activation with outcomes getting better was associated with emotional stability. The current study highlighted that focusing on the good part of decision outcomes could enhance emotional stability effectively and SFG played a vital role in this process.

Altered neural responses to missed chance contribute to the risk-taking behaviour in individuals with Internet gaming disorder.

Missed chance is a powerful factor in shaping risk-taking behaviour. The abnormal risk-taking behaviour is an obvious feature of individuals with Internet gaming disorder (IGD). However, the relationship between the neural responses to missed chance and risk-taking behaviour in IGD individuals remains unclear. In the current fMRI study, 28 IGD subjects (12 female, 23.04 ± 2.43 years old) and 26 healthy control (HC) subjects (13 female, 23.58 ± 2.67 years old) participated in fMRI scanning during performance of a sequential risk-taking task. The general linear model and the psycho-physiological interaction analyses were conducted to explore the difference in neural responses between the two groups. The results showed that IGD subjects reported more regret for the large missed chance and took more risk than HC subjects. Moreover, compared with HC subjects, IGD subjects exhibited greater activations in brain regions like ventral striatum (VS) and superior frontal gyrus (SFG), and stronger VS-thalamus functional connectivity for the large missed chance. Additionally, among IGD subjects, the SFG activation for the large missed chance was positively correlated with the risk-taking behaviour. Together, the results revealed the altered neural responses to missed chance contributed to the risk-taking behaviour in IGD individuals. The findings could help to clearly understand why IGD individuals continue playing online games despite the risks of widely known and could provide a new perspective for the intervention of IGD.

Neural mechanism for dynamic distractor processing during video target detection: Insights from time-varying networks in the cerebral cortex

In dynamic video target detection tasks, distractors may suddenly appear due to the dynamicity of the visual scene and the uncertainty of the visual information, strongly influencing participants’ attention and target detection performance. Moreover, the neural mechanism that accounts for dynamic distractor processing remains unknown, which makes it difficult to compensate for in EEG-based video target detection. Here, cortical activities with high spatiotemporal resolution were reconstructed using the source localization method. The time-varying networks among important brain regions in different cognitive phases, including information integration, decision-making, and execution, were identified to investigate the neural mechanism of dynamic distractor processing. The experimental results indicated that dynamic distractors could induce a P3-like component. In addition, there was obvious asymmetry between the two hemispheres during video target detection. Specifically, the brain responses induced by dynamic distractors were weak and more concentrated in the left hemisphere during the information integration phase; left superior frontal gyrus activity related to preparation for the presence of distractors was critical, while the attention network and primary visual network, especially in the left visual pathway, were more active for dynamic targets during the decision-making phase. These findings provide guidance for designing an effective EEG-based model for dynamic video target detection.

Brain Mechanisms Underlying Reading the Mind from Eyes, Voice, and Actions

Evidence from cognitive and social neuroscience research suggests that Theory of Mind (ToM), the ability to attribute mental states to others, is mediated by a group of brain regions collectively known as the ToM network. Nevertheless, there is significant variability in the functional activation of regions within this network across tasks. The goal of the present functional magnetic resonance imaging (fMRI) study was to examine the common and differential neural mechanisms of two aspects of ToM processing (emotion/mental-state recognition and intentional attribution) using three distinct, but complementary ToM tasks (Reading the Mind in the Eyes (RMIE), Reading the Mind in the Voice (RMIV), and Intentional Causal Attribution) in healthy adults. Participant accuracy was significantly worse in the ToM compared to the control condition across all tasks. Brain activation analyses replicated previously reported activation in inferior frontal gyrus (IFG) and middle temporal gyrus extending to posterior superior temporal sulcus (pSTS) in RMIE. Activation in the fusiform gyrus and bilateral middle temporal gyrus extending to temporo-parietal junction (TPJ) was unique to causality task. A region-of-interest analysis revealed shared activation in left IFG for RMIE and RMIV as well as TPJ recruitment specific to the causality task. The role of right TPJ in the causality task was further supported by a percent signal change analysis. A conjunction analysis revealed overlap in left IFG, left precentral gyrus, and left superior frontal gyrus activity across all tasks. These findings highlight common and differential recruitment of ToM regions according to task demand.

The regulation of positive and negative emotions through instructed causal attributions in lifetime depression - A functional magnetic resonance imaging study.

Adequate emotional control is essential for mental health. Deficiencies in emotion regulation are evident in many psychiatric disorders, including depression. Patients with depression show, for instance, disrupted neural emotion regulation in cognitive regulation regions such as lateral and medial prefrontal cortices. Since depressed individuals tend to attribute positive events to external circumstances and negative events to themselves, modifying this non-self-serving attributional style may represent a promising regulation strategy. Spontaneous causal attributions are generally processed in medial brain structures, particularly the precuneus. However, so far no study has investigated neural correlates of instructed causal attributions (e.g. instructing a person to intentionally relate positive events to the self) and their potential to regulate emotions. The current study therefore aimed to examine how instructed causal attributions of positive and negative events affect the emotional experience of depressed individuals as well as its neural bases. For this purpose pictures of sad and happy faces were presented to 26 patients with a lifetime major depression (MDD) and 26 healthy controls (HC) during fMRI. Participants should respond naturally (“view”) or imagine that the person on the picture was sad/happy because of them (“internal attribution”) or because something else happened (“external attribution”). Trait attributional style and depressive symptoms were assessed with questionnaires to examine potential influential factors on emotion regulation ability.Results revealed that patients compared to controls show a non-self-serving trait attributional style (i.e. more external attributions of positive events and more internal attributions of negative events). Intriguingly, when instructed to apply specific causal attributions during the emotion regulation task, patients and controls were similarly able to regulate positive and negative emotions. Regulating emotions through instructed attributions (internal/external attribution>view) generally engaged the precuneus, which was correlated with patients' trait attributional style (i.e. more precuneus activation during external>view was linked to a general tendency to relate positive events to external sources). Up-regulating happiness through internal (compared to external) attributions recruited the parahippocampal gyrus only in controls. The down-regulation of sadness (external>internal attribution), in contrast, engaged the superior frontal gyrus only in patients. Superior frontal gyrus activation thereby correlated with depression severity, which implies a greater need of cognitive resources for a successful regulation in more severely depressed. Patients and controls did not differ in activation in brain regions related to cognitive emotion regulation or attribution. However, results point to a disturbed processing of positive emotions in depression. Interestingly, increased precuneus resting-state connectivity with emotion regulation brain regions (inferior parietal lobule, middle frontal gyrus) was linked to healthier attributions (i.e. external attributions of negative events) in patients and controls. Adequate neural communication between these regions therefore seem to facilitate an adaptive trait attributional style. Findings of this study emphasize that despite patients' dysfunctional trait attributional style, explicitly applying causal attributions effectively regulates emotions. Future research should examine the efficacy of instructed attributions in reducing negative affect and anhedonia in depressed patients, for instance by means of attribution trainings during psychotherapy.

Acute Affective Reactivity and Quality of Life in Older Adults with Amnestic Mild Cognitive Impairment: A Functional MRI Study

Poor quality of life (QoL) is a major concern among older adults with amnestic mild cognitive impairment (MCI). Maladaptive affective regulation and its relevant frontal dysfunction that are often observed in older adults with MCI may provide an insight into the understanding of their QoL. In this case-controlled study, participants (MCI patients, N = 18; healthy comparisons [HC], N = 21) completed cognitive tasks, and underwent resting-state functional magnetic resonance imaging (rs-fMRI) immediately before and after the tasks. The amplitude of low-frequency fluctuations (ALFF) of rs-fMRI signals was calculated to examine the brain's spontaneous activity. The change in valence from the Self-Assessment Manikin indexed affective reactivity. QoL was assessed using Quality of Life-AD measure. Multiple mediator model was used to examine the mediating effect of frontal regions' ALFF reactivity between the affective reactivity and QoL. The MCI group had significantly worse QoL and more negative affective reactivity than HC group. Less negative affective reactivity was significantly associated with better QoL in MCI not HC. ALFF in the anterior cingulate cortex, medial prefrontal cortex (MPFC), and superior frontal gyrus (SFG) increased significantly less after cognitive tasks in MCI than HC. For the entire sample, greater increases of ALFF in MPFC and SFG were significantly associated with better QoL, and SFG alone significantly mediated the association between affective reactivity and QoL. Enhancing SFG activation, especially among those with MCI, may provide a therapeutic target for addressing the negative impact of maladaptive affective regulation on QoL.

Effects of Alcohol Dependence Severity on Neural Correlates of Delay Discounting.

The current study examines the relationship between alcohol dependence severity and delay discounting neural activation. Participants (N = 17; 6 female) completed measures of alcohol use and severity and a functional magnetic resonance imaging version of a delay discounting task. Alcohol dependence severity was negatively associated with activation in superior frontal gyrus during impulsive relative to delayed decisions, and positively associated with activation in paracingulate gyrus and frontal pole in delayed relative to impulsive decisions. These results indicate that alcohol dependence severity tracks closely with dysregulations in cognitive control and reward evaluation areas during impulsive and delayed decisions, respectively. Delay discounting may be a useful construct in capturing these cognitive dysregulations as alcohol use disorders become more severe. Among alcohol-dependent individuals, alcohol dependence severity is associated with overactivation of ventromedial prefrontal areas during delayed and underactivation of dorsolateral prefrontal regions during impulsive reward decisions.

The Right Superior Frontal Gyrus and Individual Variation in Proactive Control of Impulsive Response.

Individuals vary in impulse control. However, the neural bases underlying individual variation in proactive control of impulsive responses remain unknown. Here, in a large sample of young adults, we showed that activation of the right superior frontal gyrus (SFG) during conflict anticipation is positively correlated with the capacity of inhibitory control and negatively with motor urgency in the stop signal task. Importantly, activity of the right SFG mediates the counteracting processes of inhibitory control and motor urgency across subjects. The results support a unique role of the right SFG in individual variation in cognitive control.

Increased superior frontal gyrus activation during working memory processing in psychosis: Significant relation to cumulative antipsychotic medication and to negative symptoms

ObjectivesImpairment in working memory (WM) is a core symptom in schizophrenia. However, little is known about how clinical features influence functional brain activity specific to WM processing during the development of first-episode psychosis (FEP) to schizophrenia (SZ). We compared functional WM-specific brain activity in FEP and SZ patients, including the effects of the duration of illness, psychopathological factors and antipsychotic medication. MethodsCross-sectional study of male FEP (n=22) and SZ (n=20) patients performing an n-back task when undergoing functional magnetic resonance imaging (fMRI). Clinical features were collected by semi-structured interviews and medical records. ResultsThe SZ group performed significantly worse than the FEP group in the 2-back condition. The SZ group also showed significantly higher activation in the left superior frontal gyrus in the 2-back versus 0-back condition (2-back>0-back). This frontal activation correlated positively with negative symptoms and with cumulative antipsychotic medication during the year before the fMRI examination. There were no significant correlations between activation and duration of illness. ConclusionThere was greater frontal neural activation in SZ than in FEP. This indicated differences in WM processing, and was significantly related to cumulative antipsychotic exposure and negative symptoms, but not to the duration of illness.

Neural correlates of improved executive function following erythropoietin treatment in mood disorders.

Cognitive dysfunction in depression and bipolar disorder (BD) is insufficiently targeted by available treatments. Erythropoietin (EPO) increases neuroplasticity and may improve cognition in mood disorders, but the neuronal mechanisms of these effects are unknown. This functional magnetic resonance imaging (fMRI) study investigated the effects of EPO on neural circuitry activity during working memory (WM) performance. Patients with treatment-resistant major depression, who were moderately depressed, or with BD in partial remission, were randomized to eight weekly infusions of EPO (40 000 IU) (N = 30) or saline (N = 26) in a double-blind, parallel-group design. Patients underwent fMRI, mood ratings and blood tests at baseline and week 14. During fMRI patients performed an n-back WM task. EPO improved WM accuracy compared with saline (p = 0.045). Whole-brain analyses revealed that EPO increased WM load-related activity in the right superior frontal gyrus (SFG) compared with saline (p = 0.01). There was also enhanced WM load-related deactivation of the left hippocampus in EPO-treated compared to saline-treated patients (p = 0.03). Across the entire sample, baseline to follow-up changes in WM performance correlated positively with changes in WM-related SFG activity and negatively with hippocampal response (r = 0.28-0.30, p < 0.05). The effects of EPO were not associated with changes in mood or red blood cells (p ⩾0.08). The present findings associate changes in WM-load related activity in the right SFG and left hippocampus with improved executive function in EPO-treated patients. clinicaltrials.gov: NCT00916552.

An fMRI study in patients with active mania using Verbal N-Back test

Introduction There is a lack of consensus on the dysfunctional brain areas underlying mania. Aims and objectives The study was carried out to understand the various brain networks implicated in active mania. Methods After obtaining ethical clearance from the Institute Review Board, we recruited 30 subjects with active mania and 15 healthy controls using purposive sampling, and applying SCID. A computerized cognitive test (Verbal N-Back) was used. Results Mania group took significantly longer time while making correct responses. They (Fig. 1C) showed activation in bilateral frontal lobe, and bilateral superior temporal gyrus during verbal 1-Back task, whereas, the control group (Fig. 1A) showed left middle frontal gyrus, and right superior frontal gyrus activation. On verbal 2-Back task, the mania group (Fig. 1D) had bilateral frontal lobe, and bilateral superior temporal gyrus activation, whereas the control group (Fig. 1B) had activation in the bilateral frontal lobe. Conclusions It was clearly visible that the mania group was significantly slower in giving correct responses on N-Back task as compared to the controls. On the 2-Back task, there was under-activation in left frontal lobe in the mania group with respect to the control group (Fig. 1E). This implies that the mania group may have deficits in information processing speed.

An Event Related Potentials Study of the Effects of Age, Load and Maintenance Duration on Working Memory Recognition.

Age-related decline in cognitive capacities has been attributed to a generalized slowing of processing speed and a reduction in working memory (WM) capacity. Nevertheless, it is unclear how age affects visuospatial WM recognition and its underlying brain electrical activity. Whether age modulates the effects of memory load or information maintenance duration, which determine the limits of WM, remains also elusive. In this exploratory study, performance in a delayed match to sample task declined with age, particularly in conditions with high memory load. Event related potentials analysis revealed longer N2 and P300 latencies in old than in young adults during WM recognition, which may reflect slowing of stimulus evaluation and classification processes, respectively. Although there were no differences between groups in N2 or P300 amplitudes, the latter was more homogeneously distributed in old than in young adults, which may indicate an age-related increased reliance in frontal vs parietal resources during WM recognition. This was further supported by an age-related reduced posterior cingulate activation and increased superior frontal gyrus activation revealed through standardized low resolution electromagnetic tomography. Memory load and maintenance duration effects on brain activity were similar in both age groups. These behavioral and electrophysiological results add evidence in support of age-related decline in WM recognition theories, with a slowing of processing speed that may be limited to stimulus evaluation and categorization processes -with no effects on perceptual processes- and a posterior to anterior shift in the recruitment of neural resources.

Hyperactivation to pleasant interoceptive stimuli characterizes the transition to stimulant addiction

AimsAltered interoception, how the brain processes afferents from the body, may contribute to the urge to take drugs, and subsequently, the development of addiction. Although chronic stimulant dependent individuals exhibit attenuated brain responses to pleasant interoceptive stimuli, it is unclear whether this deficit exists early-on in the process of transition to stimulant addiction. MethodsTo this end, we compared problem stimulant users (PSU; n=18), desisted stimulant users (DSU; n=15), and stimulant naïve comparison subjects (CTL; n=15) during functional magnetic resonance imaging (fMRI) while they anticipated and experienced pleasant soft touch (slow brushstroke to the palm and forearm). ResultsGroups did not differ in behavioral performance or visual analog scale ratings of soft touch stimuli. fMRI results indicated that PSU exhibited greater right anterior insula, left inferior frontal gyrus, and right superior frontal gyrus activation than DSU and CTL during the anticipation and experience of soft touch. Moreover, during the experience of soft touch, PSU demonstrated higher bilateral precentral gyrus/middle insula and right posterior temporal gyrus activation than DSU and CTL. ConclusionsIn contrast to chronic stimulant dependence, individuals who have recently developed stimulant use disorders show exaggerated neural processing of pleasant interoceptive stimuli. Thus, increased processing of body-relevant information signaling pleasant touch in those individuals who develop problem use may be a predictive interoceptive biomarker. However, future investigations will need to determine whether the combination of probing pleasant interoception using neuroimaging is sufficiently sensitive and specific to help identify individuals at high risk for future problem use.

Altered brain activation patterns under different working memory loads in patients with type 2 diabetes.

Type 2 diabetes mellitus (T2DM) has important effects on cognition and the risk for Alzheimer disease (AD). Working memory (WM) is a susceptible cognitive domain of mild cognitive impairment and AD. Thus, the identification of brain activation patterns under different WM loads can potentially enhance our understanding of the mechanisms underlying cognitive dysfunction in T2DM. The current study assessed the effects of T2DM on cognitive performance and explored the related neuronal damage through a visual n-back task and functional magnetic resonance imaging. We found that patients with T2DM exhibited worse executive and memory abilities than control subjects. Furthermore, the patterns of brain activation changed under different WM loads in the T2DM patients, who exhibited reduced activation in the left inferior frontal gyrus under low loads and reduced activation in the left middle frontal gyrus and superior frontal gyrus (SFG) under high loads. Thus, more regions of diminished activation were seen in the frontal cortex with increasing task difficulty. Furthermore, we found that lower SFG activation was associated with worse cognitive function. The findings demonstrate deficient WM in patients with T2DM and the relation between cognitive function and degree of neuronal activity and their relevance to AD risk. Further longitudinal studies are needed to replicate these results and to evaluate the clinical value of brain imaging methods in the prediction of disease progress in these patients.