Activity In Middle Frontal Gyrus Research Articles

The Intensity of Early Attentional Processing, but Not Conflict Monitoring, Determines the Size of Subliminal Response Conflicts.

Response conflicts hamper goal-directed behavior and may be evoked by both consciously and subliminally (unconsciously) processed information. Yet, not much is known about the mechanisms and brain regions driving the size of subliminally induced conflicts. We hence combined a response conflict paradigm featuring subliminal primes and conscious flankers with in-depth neurophysiological (EEG) analyses, including source localization in a sample of N = 243 healthy subjects. Intra-individual differences in the size of subliminal conflicts were reflected both during early attentional stimulus processing (prime-associated N1 and target-associated P1 and N1 amplitudes) and conflict monitoring (N2 amplitudes). On the neuroanatomical level, this was reflected by activity modulations in the TPJ (BA39, BA40) and V2 (BA18), which are known to be involved in attentional stimulus processing and task set maintenance. In addition to a “standard” analysis of event-related potentials, we also conducted a purely data-driven machine learning approach using support vector machines (SVM) in order to identify neurophysiological features which do not only reflect the size of subliminal conflict, but actually allow to classify/predict it. This showed that only extremely early information processing (about 65 ms after the onset of the prime) was predictive of subliminal conflict size. Importantly, this predictive feature occurred before target information could even be processed and was reflected by activity in the left middle frontal gyrus (BA6) and insula (BA13). We conclude that differences in task set maintenance and potentially also in subliminal attentional processing of task-relevant features, but not conflict monitoring, determine the size of subliminally induced response conflicts.

Resting-State Functional Connectivity of the Middle Frontal Gyrus Can Predict Language Lateralization in Patients with Brain Tumors.

A recent study using task-based fMRI demonstrated that the middle frontal gyrus is comparable with Broca's area in its ability to determine language laterality using a measure of verbal fluency. This study investigated whether the middle frontal gyrus can be used as an indicator for language-hemispheric dominance in patients with brain tumors using task-free resting-state fMRI. We hypothesized that no significant difference in language lateralization would occur between the middle frontal gyrus and Broca area and that the middle frontal gyrus can serve as a simple and reliable means of measuring language laterality. Using resting-state fMRI, we compared the middle frontal gyrus with the Broca area in 51 patients with glial neoplasms for voxel activation, the language laterality index, and the effect of tumor grade on the laterality index. The laterality index derived by resting-state fMRI and task-based fMRI was compared in a subset of 40 patients. Voxel activations in the left middle frontal gyrus and left Broca area were positively correlated (r = 0.47, P < .001). Positive correlations were seen between the laterality index of the Broca area and middle frontal gyrus regions (r = 0.56, P < .0005). Twenty-seven of 40 patients (67.5%) showed concordance of the laterality index based on the Broca area using resting-state fMRI and the laterality index based on a language task. Thirty of 40 patients (75%) showed concordance of the laterality index based on the middle frontal gyrus using resting-state fMRI and the laterality index based on a language task. The middle frontal gyrus is comparable with the Broca area in its ability to determine hemispheric dominance for language using resting-state fMRI. Our results suggest the addition of resting-state fMRI of the middle frontal gyrus to the list of noninvasive modalities that could be used in patients with gliomas to evaluate hemispheric dominance of language before tumor resection. In patients who cannot participate in traditional task-based fMRI, resting-state fMRI offers a task-free alternate to presurgically map the eloquent cortex.

The impulsive brain: Neural underpinnings of binge eating behavior in normal-weight adults

Converging evidence suggests that dysfunctional inhibitory control might be at the roots of overeating and binge eating disorder (BED). The majority of these results stems from studies on obese populations, however we hypothesized that potential prodromes might be evident also in non-clinical conditions, when binge eating episodes are present (without a diagnosis of BED) and a normal Body Mass Index is preserved.To explore this issue, brain activity of 42 normal weight individuals with and without binge eating episodes (21 binge eaters and 21 non-binge eaters, BE and non-BE respectively) was assessed by means of functional magnetic resonance imaging (fMRI) during response inhibition tasks. We adopted a food-modified version of a go/no-go (GNG) and stop signal task (SST): these tasks investigate different aspects of inhibitory control (action restraint and cancellation) that have been rarely studied in the same individuals but that are known to involve different neural networks. In addition, impulsivity traits were assessed with self-report instruments.Despite similar behavioral performances, the two groups differed in trait impulsivity and brain activity. The fMRI results revealed differential engagement of fronto-striatal regions between the groups during the tasks. The BE group, compared to non-BE, showed lower activation of the right middle frontal gyrus (MFG) and Putamen during the GNG task, and higher activation of the left MFG during the SST.These findings provide evidence of a dissociation of the neural underpinnings of action restraint and cancellation in impulsive individuals. Moreover, they add support to the hypothesis that impulsivity may be a possible hallmark of binge eating behavior (in the absence of weight or full-blown eating disorders) and yield new insights on the role of regions typically involved in response inhibition and selection as possible substrates of impulsive eating.

The Effect of Cognitive Reappraisal on Reactive Aggression: An fMRI Study.

A number of empirical researches have shown that reactive aggression, which is the behavior that is impulsive, thoughtless, driven by anger, and causes harm toward another individual, can lead to a series of negative effects. Cognitive reappraisal may have the potential to reduce reactive aggression, but evidence for this effect in healthy populations is lacking. We randomly assigned participants to a Reappraisal Group (n = 19) or Control Group (n = 20) in a functional magnetic resonance imaging (fMRI) version of the well-established Taylor Aggression Paradigm (TAP). TAP was employed to elicit and measure reactive aggression, during which participants were informed that they would play a competitive reaction time task against two opponents in turn and the winner would punish the loser. The TAP used in this study separates the decision-making (during which participants were asked to set a punishment level for the opponent) and affective processes (during which the punishment was applied or received) that underlie reactive aggression. Behavioral data showed that there was no difference between the Reappraisal Group and Control Group in the punishment level selections (i.e., reactive aggression). However, on the neural level, cognitive reappraisal reduced the activation of left insula, right cuneus, and right middle frontal gyrus (MFG) during the decision phase, independently of the level of provocation. In addition, cognitive reappraisal reduced the activation of the caudate under the provocative condition when making decisions about aggressive behavior. The results of the outcome phase showed that, after winning a competition, cognitive reappraisal increased the activation of the right orbital middle frontal gyrus (OMFG) under the provocative condition and reduced the activation of the bilateral supplementary motor area (SMA) under the non-provocative condition. The results suggest that cognitive reappraisal would be effective in modulating the neural activity of reactive aggression.

Latent variable analysis of negative affect and its contributions to neural responses during shock anticipation.

Negative affect is considered an important factor in the etiology of depression and anxiety, and is highly related to pain. However, negative affect is not a unitary construct. To identify specific targets for treatment development, we aimed to derive latent variables of negative affect and test their unique contributions to affective processing during anticipation of unpredictable, painful shock. Eighty-three subjects (43 with depression and anxiety spectrum disorders and 40 healthy controls) completed self-report measures of negative valence and underwent neuroimaging while exploring computer-simulated contexts with and without the threat of a painful, but tolerable, shock. Principal component analysis (PCA) extracted distinct components of general negative affect (GNA) and pain-related negative affect (PNA). While elevated GNA and PNA were both indicative of depression and anxiety disorders, greater PNA was more strongly related to task-specific anxious reactivity during shock anticipation. GNA was associated with increased precuneus and middle frontal gyrus activity, whereas PNA was related to increased bilateral anterior insula activity. Anterior insula activity mediated the relationship between PNA and task-specific anxious reactivity. In conclusion, GNA and PNA have distinct neural signatures and uniquely contribute to anxious anticipation. PNA, via insula activity, may relate to arousal in ways that could contribute to affective dysregulation, and thus may be an important treatment target.

Differences in Hearing Acuity among "Normal-Hearing" Young Adults Modulate the Neural Basis for Speech Comprehension.

In this paper, we investigate how subtle differences in hearing acuity affect the neural systems supporting speech processing in young adults. Auditory sentence comprehension requires perceiving a complex acoustic signal and performing linguistic operations to extract the correct meaning. We used functional MRI to monitor human brain activity while adults aged 18–41 years listened to spoken sentences. The sentences varied in their level of syntactic processing demands, containing either a subject-relative or object-relative center-embedded clause. All participants self-reported normal hearing, confirmed by audiometric testing, with some variation within a clinically normal range. We found that participants showed activity related to sentence processing in a left-lateralized frontotemporal network. Although accuracy was generally high, participants still made some errors, which were associated with increased activity in bilateral cingulo-opercular and frontoparietal attention networks. A whole-brain regression analysis revealed that activity in a right anterior middle frontal gyrus (aMFG) component of the frontoparietal attention network was related to individual differences in hearing acuity, such that listeners with poorer hearing showed greater recruitment of this region when successfully understanding a sentence. The activity in right aMFGs for listeners with poor hearing did not differ as a function of sentence type, suggesting a general mechanism that is independent of linguistic processing demands. Our results suggest that even modest variations in hearing ability impact the systems supporting auditory speech comprehension, and that auditory sentence comprehension entails the coordination of a left perisylvian network that is sensitive to linguistic variation with an executive attention network that responds to acoustic challenge.

Altered cortical activation and connectivity patterns for visual attention processing in young adults post-traumatic brain injury: A functional near infrared spectroscopy study.

This study aimed at understanding the neurobiological mechanisms associated with inattention induced by traumatic brain injury (TBI). To eliminate the potential confounding caused by the heterogeneity of TBI, we focused on young adults postsports-related concussion (SRC). Functional near-infrared spectroscopy (fNIRS) data were collected from 27 young adults post-SRC and 27 group-matched normal controls (NCs), while performing a visual sustained attention task. Task responsive cortical activation maps and pairwise functional connectivity among six regions of interest were constructed for each subject. Correlations among the brain imaging measures and clinical measures of attention were calculated in each group. Compared to the NCs, the SRC group showed significantly increased brain activation in left middle frontal gyrus (MFG) and increased functional connectivity between right inferior occipital cortex (IOC) bilateral calcarine gyri (CG). The left MFG activation magnitude was significantly negatively correlated with the hyperactive/impulsive symptom severity measure in the NCs, but not in the patients. The right hemisphere CG-IOC functional connectivity showed a significant positive correlation with the hyperactive/impulsive symptom severity measure in patients, but not in NCs. The current data suggest that abnormal left MFG activation and hyper-communications between right IOC and bilateral CG during visual attention processing may significantly contribute to behavioral manifestations of attention deficits in patients with TBI.

FUNCTIONAL NETWORK ACTIVITY MEDIATING THE SHIFT OF ATTENTIONAL RESOURCES DURING INATTENTIONAL DEAFNESS IN AN AVIATION PURSUIT TASK

FUNCTIONAL NETWORK ACTIVITY MEDIATING THE SHIFT OF ATTENTIONAL RESOURCES DURING INATTENTIONAL DEAFNESS IN AN AVIATION PURSUIT TASK

Cognitive control neuroimaging measures differentiate between those with and without future recurrence of depression

BackgroundMajor Depressive Disorder (MDD) is a prevalent, disruptive illness. A majority of those with MDD are at high risk for recurrence and increased risk for morbidity and mortality. This study examined whether multimodal baseline (and retest) Cognitive Control performance and neuroimaging markers (task activation and neural connectivity between key brain nodes) could differentiate between those with and without future recurrence of a major depressive (MD) episode within one year. We hypothesized that performance and neuroimaging measures of Cognitive Control would identify markers that differ between these two groups.MethodsA prospective cohort study of young adults (ages 18–23) with history (h) of early-onset MDD (N = 60), now remitted, and healthy young adults (N = 49). Baseline Cognitive Control measures of performance, task fMRI and resting state connectivity (and reliability retest 4–12 weeks later) were used to compare those with future recurrence of MDD (N = 21) relative to those without future recurrence of MDD (N = 34 with resilience). The measures tested were (1) Parametric Go/No-Go (PGNG) performance, and task activation for (2) PGNG Correct Rejections, (3) PGNG Commission errors, and (4 & 5), resting state connectivity analyses of Cognitive Control Network to and from subgenual anterior cingulate.ResultsRelative to other groups at baseline, the group with MDD Recurrence had less bilateral middle frontal gyrus activation during commission errors. MDD Recurrence exhibited greater connectivity of right middle frontal gyrus to subgenual anterior cingulate (SGAC). SGAC connectivity was also elevated in this group to numerous regions in the Cognitive Control Network. Moderate to strong ICCs were present from test to retest, and highest for rs-fMRI markers. There were modest, significant correlations between task, connectivity and behavioral markers that distinguished between groups.ConclusionMarkers of Cognitive Control function could identify those with early course MD who are at risk for depression recurrence. Those at high risk for recurrence would benefit from maintenance or preventative treatments. Future studies could test and validate these markers as potential predictors, accounting for sample selection and bias in feature detection.

Emotion processing in persons who respond vicariously towards others in pain: Disinhibited left-lateralized neural activity for threatening expressions

ABSTRACTWe investigated emotional processing in vicarious pain (VP) responders. VP responders report an explicit sensory and emotional feeling of pain when they witness another in pain, which is greater in magnitude than the empathic processing of pain in the general population. In Study 1, 31 participants completed a chimeric faces task, judging whether emotional chimera in the left, or right, visual field was more intense. VP responders took longer to judge emotionality than non-responders, and fixated more on the angry hemiface in the right visual field, whereas non-responder controls had no lateralized fixation bias. In Study 2, blood-oxygen level-dependent signals were recorded during an emotional face matching task. VP intensity was correlated with increased insula activity and reduced middle frontal gyrus activity for angry faces, and with reduced activity in the inferior and middle frontal gyri for sad faces. Together, these findings suggest that VP responders are more reactive to negative emotional expressions. Specifically, emotional judgements involved altered left-hemisphere activity in VP responders, and reduced engagement of regions involved in emotion regulation.

FUNCTIONAL MRI OF TABLET-BASED COMPUTERIZED PAIRED ASSOCIATE LEARNING (PAL) WITH IMPROVED ECOLOGICAL VALIDITY

Administered with a computerized touch-screen display, PAL assists in characterizing memory and learning deficits in patients with probable early Alzheimer's disease (AD) (Blackwell Dement-Geriatr-Cogn-Disord 2003). FMRI may clarify the relationship between PAL performance and brain activity, but ecological validity is a concern during complex motor tasks. Previously, we developed an fMRI-compatible tablet including visual feedback of hand position (VFHP) and an augmented reality display (Tam HBM-2011; Karimpoor Frontiers-2015) to address this issue for AD patients with impaired motor planning (Ghilardi BrainRes-2000). The purpose of the present work is to characterize brain activity for an ecologically valid fMRI computerized PAL test. Prior to testing AD patients, initial work involved young adults. The PAL test involves making associative judgements of an increasing number of patterns (1–6 patterns) and their locations on the screen (Fig.1). Each task is repeated twice in a mixed fMRI design interspersed with baseline visual fixation. Ten young healthy right-handed adults performed PAL at 3T. The PRONTO toolkit was used to optimize fMRI preprocessing pipelines (Churchill PloSone-2015), and obtain Z-scored maps of retrieval phase vs. baseline, using a uni-variate Gauss Naïve Base (GNB) model. Principal Component Analysis (PCA) was performed on the Z-scored activation maps to obtain brain patterns explaining maximum variance across the group. Fig 2.a shows group maps during retrieval of 3 patterns (3pat) vs. baseline. Fig 2.b shows 6 patterns (6pat) vs. baseline. Increased activity in medial temporal lobe and dorsolateral prefrontal cortex is observed during 6pat compared to 3pat, consistent with the different difficulty levels. Activation of left ventral premotor cortex is consistent with visually-guided hand actions. Extensive activation of the left middle frontal gyrus, superior parietal lobule, and basal ganglia is observed during 6pat, compared to 3pat; consistent with differences in complex motor planning and visuospatial understanding. Results suggest that the fMRI-compatible tablet with VFHP enables PAL tests with good ecological validity involving complex fine motor movements. These methods and findings are relevant to future fMRI studies of AD patients; involving batteries of tasks required to probe different cognitive domains during limited scan time. fMRI-compatible PAL test. The first principal component depicting brain activity for 10 subjects performing PAL. a) Retrieval 3 patterns vs. baseline. b) Retrieval 6 patterns vs. baseline.

Increased arithmetic complexity is associated with domain-general but not domain-specific magnitude processing in children: A simultaneous fNIRS-EEG study.

The investigation of the neural underpinnings of increased arithmetic complexity in children is essential for developing educational and therapeutic approaches and might provide novel measures to assess the effects of interventions. Although a few studies in adults and children have revealed the activation of bilateral brain regions during more complex calculations, little is known about children. We investigated 24 children undergoing one-digit and two-digit multiplication tasks while simultaneously recording functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) data. FNIRS data indicated that one-digit multiplication was associated with brain activity in the left superior parietal lobule (SPL) and intraparietal sulcus (IPS) extending to the left motor area, and two-digit multiplication was associated with activity in bilateral SPL, IPS, middle frontal gyrus (MFG), left inferior parietal lobule (IPL), and motor areas. Oscillatory EEG data indicated theta increase and alpha decrease in parieto-occipital sites for both one-digit and two-digit multiplication. The contrast of two-digit versus one-digit multiplication yielded greater activity in right MFG and greater theta increase in frontocentral sites. Activation in frontal areas and theta band data jointly indicate additional domain-general cognitive control and working memory demands for heightened arithmetic complexity in children. The similarity in parietal activation between conditions suggests that children rely on domain-specific magnitude processing not only for two-digit but-in contrast to adults-also for one-digit multiplication problem solving. We conclude that in children, increased arithmetic complexity tested in an ecologically valid setting is associated with domain-general processes but not with alteration of domain-specific magnitude processing.

Rethinking the function of brain regions for reading Chinese characters in a meta-analysis of fMRI studies

Abstract Neuroimaging studies have proposed specific brain regions for reading Chinese characters. For example, compared to alphabetic languages, Chinese reading has revealed more activation of the left Middle Frontal Gyrus (MFG) and null or deactivation at left posterior Superior Temporal Gyrus (pSTG). However, the model of specific regions for Chinese was contested by recent findings showing similar activities across languages under the same task demand. Thus, whether the engagement of the Chinese-specific regions was due to stimulus selectivity or to task demand was called into question. The current meta-analysis, using Activation Likelihood Estimation (ALE), summarized brain regions in previous fMRI studies from two types of contrast, stimulus contrasts (SC), in which more regions were activated for Chinese characters than for other visual stimuli (e.g., Korean words, faces) or for other types of characters (e.g., real > artificial characters), and task contrasts (TC), in which more regions were activated for one task than for another (e.g., lexical decision > symbol detection) in processing Chinese characters. ALE activation maps revealed a shared network for the two types of contrast, including the right Inferior Frontal Gyrus (IFG, BA47) and four clusters in the left hemisphere, the IFG (BA45/46), Superior Parietal Lobule, Superior Frontal Gyrus, and posterior Middle Temporal Gyrus (pMTG). The SC > TC comparison demonstrated the greater involvement of the left Angular Gyrus and left Fusiform Gyrus. The TC > SC comparison, in contrast, revealed the engagement of left-hemisphere regions in the IFG, MFG, pSTG, pMTG, and Medial Frontal Gyrus. These results suggest that the previously identified Chinese-specific areas (e.g., MFG, pSTG) might be task dependent rather than stimulus selective. This work shed light on the language-general neural network of visual word reading.

Altered effective brain connectivity at early response of antipsychotics in first-episode schizophrenia with auditory hallucinations.

This study aimed to examine the alterations of cortical connectivity in first-episode schizophrenia (FES) with auditory hallucinations at early response of antipsychotics. This was a nonexperimental control of medication study. We measured the cortical activity of 20 medicated patients with FES (medicated group), 19 nonmedicated patients with FES (nonmedicated group), and 22 healthy controls using electroencephalogram during eye-open resting state. Source reconstruction analysis was performed to determine the brain regions that showed significant group difference. A dynamic causal modelling (DCM) analysis was used to estimate the effective connectivity between sources. Both FES groups expressed increased activity in the right middle frontal gyrus (RMFG) and left/right superior temporal gyrus (L/RSTG) relative to that in the controls (p<0.05), and the nonmedicated group presented even higher activity than the medicated group (p<0.05). The effective connectivity from RMFG to LSTG was weaker in the nonmedicated group relative to that in the medicated group (p<0.01), although patients in the medicated group showed no difference with healthy controls in RMFG to L/RSTG connections. The Bayesian model selection analysis found modulatory lateralization in the nonmedicated group. The patients with FES showed frontotemporal hyperactivity and disconnectivity. The effective connections accompanied with modulation were improved when hallucination diminished at early response of routine medication. This study provided the first evidence of early drug response-related alterations in effective brain connectivity.

Trait and neurobiological underpinnings of negative emotion regulation in gambling disorder.

Gambling disorder is characterized by poor regulation of negative emotions and impulsive behaviours. This study aimed to (1) compare gambling disorder patients (GDPs) and healthy controls (HCs) in self-report and brain activation measures of emotion regulation; and (2) establish its relationship with negative emotion-driven impulsivity. Two cross-sectional case-control studies including GDPs and HCs. GDPs and HCs were recruited from specialized gambling clinics in Andalusia (Spain), where they were following out-patient treatment, and from the community, respectively. Study 1 included 41 GDPs and 45 HCs [All males; Mage =35.22, 33.22; standard deviation (SD)=11.16, 8.18; respectively]. Study 2 included 17 GDPs and 21 HCs (16/20 males; Mage =32.94, 31.00; SD=7.77, 4.60; respectively). In study 1, we compared both groups on suppression and re-appraisal emotion regulation strategies [Emotion Regulation Questionnaire (ERQ)]. In study 2, we compared GDPs with HCs on brain activation associated with down-regulation of negative emotions in a cognitive re-appraisal task, measured with functional magnetic resonance imaging (fMRI). In both studies, we correlated the measures of emotion regulation with mood-related impulsivity indicated by negative urgency (UPPS-P impulsive behaviour scale). GDPs relative to HCs showed higher levels of emotional suppression [F=4.525; P=0.036; means difference MHCs -MGDPs =-2.433, 95% confidence interval (CI)=-4.706, -0.159] and higher activation of the premotor cortex and middle frontal gyrus during negative emotion regulation in the fMRI task [P≤0.005, cluster size (CS)>50 voxels]. Negative urgency correlated positively with emotional suppression (r=0.399, 95% CI=0.104, 0.629, one-tailed P=0.005) and middle frontal gyrus activation during negative emotion regulation (P≤0.005, CS>50) in GDPs. Gambling disorder is associated with greater use of emotional suppression and stronger pre-motor cortex and middle frontal gyrus activation for regulating negative emotions, compared with healthy controls. Emotional suppression use and middle frontal gyrus activation during negative emotion regulation are linked with negative emotion-driven impulsivity in this disorder.

Neural bases of congenital amusia in tonal language speakers

Congenital amusia is a lifelong neurodevelopmental disorder of fine-grained pitch processing. In this fMRI study, we examined the neural bases of congenial amusia in speakers of a tonal language – Cantonese. Previous studies on non-tonal language speakers suggest that the neural deficits of congenital amusia lie in the music-selective neural circuitry in the right inferior frontal gyrus (IFG). However, it is unclear whether this finding can generalize to congenital amusics in tonal languages. Tonal language experience has been reported to shape the neural processing of pitch, which raises the question of how tonal language experience affects the neural bases of congenital amusia. To investigate this question, we examined the neural circuitries sub-serving the processing of relative pitch interval in pitch-matched Cantonese level tone and musical stimuli in 11 Cantonese-speaking amusics and 11 musically intact controls. Cantonese-speaking amusics exhibited abnormal brain activities in a widely distributed neural network during the processing of lexical tone and musical stimuli. Whereas the controls exhibited significant activation in the right superior temporal gyrus (STG) in the lexical tone condition and in the cerebellum regardless of the lexical tone and music conditions, no activation was found in the amusics in those regions, which likely reflects a dysfunctional neural mechanism of relative pitch processing in the amusics. Furthermore, the amusics showed abnormally strong activation of the right middle frontal gyrus and precuneus when the pitch stimuli were repeated, which presumably reflect deficits of attending to repeated pitch stimuli or encoding them into working memory. No significant group difference was found in the right IFG in either the whole-brain analysis or region-of-interest analysis. These findings imply that the neural deficits in tonal language speakers might differ from those in non-tonal language speakers, and overlap partly with the neural circuitries of lexical tone processing (e.g. right STG).

Brain function in patients with diarrhea type irritable bowel syndrome after rectal balloon distention

Objective To investigate the correlation between activated brain regions examined by functional magnetic resonance imaging (fMRI) after rectal balloon distention and intestinal symptoms, psychological status, and quality of life in patients with diarrhea type irritable bowel syndrome (IBS-D) at different stages of disease. Methods According to the symptoms status, patients with IBS-D were divided into onset group (seven patients), remission group (five patients) and persistence group (six patients), and six healthy individuals were selected as healthy controls at the same time. After stimulated with rectal balloon distention at first sensation thresholds, continual defecation thresholds or 80% of maximum tolerable thresholds, patients received fMRI examination. Analysis of variance and two-sample t test were used to compare the difference in activated brain areas between two groups. Pearson analysis was performed to analyze the correlations between activated brain areas and scores of irritable bowel syndrome (IBS) intestinal symptom, Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA) and irritable bowel syndrome special quality of life scale (IBS-QOL). Results There was no significant difference in first sensation thresholds, continual defecation thresholds or 80% of maximum tolerable thresholds between patients of different groups. After rectal balloon distention, there were differences in such brain areas: bilateral anterior cingulate cortex (ACC), left inferior parietal lobe, and left middle frontal gyrus. Compared with those of control group, the activation of ACC, inferior parietal lobe and middle frontal gyrus lowered in patients of onset group (both P<0.05). There was positive correlation between the activation of middle frontal gyrus and intestinal symptom scores in persistence group(r=0.823, P=0.048). There were negative correlations between the activation of inferior parietal lobe (r =-0.816, P=0.048), middle frontal gyrus(r=-0.860, P=0.028) of persistence group, activation of middle frontal gyrus (r=-0.892, P=0.042) of remission group and HAMD score. There were positive correlations between the activation of inferior parietal lobe (r =0.818, P=0.047), middle frontal gyrus(r = 0.907, P=0.013) of persistence group, activation of midfrontal gyrus (r = 0.914, P=0.030) of remission group and scores of IBS-QOL. Conclusion The brain regions were activated during the rectal balloon distention both in IBS-D patients and healthy controls, and there were differences in activated brain regions among different stages of IBS-D. Key words: Irritable bowel syndrome; diarrhea; Magnetic resonance imaging; Brain region activities; Rectal balloon distention

The neural bases of proactive and reactive control processes in normal aging

IntroductionResearch on cognitive control suggests an age-related decline in proactive control abilities (anticipatory control), whereas reactive control (following conflict detection) seems to remain intact. As proactive and reactive control abilities are associated with specific brain networks, this study investigated age-related effects on the neural substrates associated with each kind of control. MethodsIn an event-related fMRI study, a modified version of the Stroop task was administered to groups of 20 young and 20 older healthy adults. Based on the theory of dual mechanisms of control, the Stroop task has been built to induce proactive or reactive control depending on task context. ResultsBehavioral results (p<0.05) indicated faster processing of interfering items in the mostly incongruent (MI) than the mostly congruent (MC) context in both young and older participants. fMRI results showed that reactive control is associated with increased activity in left frontal areas for older participants. For proactive control, decreased activity in the bilateral anterior cingulate cortex was associated with more activity in the right middle frontal gyrus in the older than the younger group. ConclusionThese observations support the hypothesis that aging affects the neural networks associated with reactive and proactive cognitive control differentially. These age-related changes are very similar to those observed in young adults with low dopamine availability, suggesting that a general mechanism (prefrontal dopamine availability) may modulate brain networks associated with various kinds of cognitive control.

Cognitive and neural consequences of memory suppression in major depressive disorder

Negative biases in cognition have been documented consistently in major depressive disorder (MDD), including difficulties in the ability to control the processing of negative material. Although negative information-processing biases have been studied using both behavioral and neuroimaging paradigms, relatively little research has been conducted examining the difficulties of depressed persons with inhibiting the retrieval of negative information from long-term memory. In this study, we used the think/no-think paradigm and functional magnetic resonance imaging to assess the cognitive and neural consequences of memory suppression in individuals diagnosed with depression and in healthy controls. The participants showed typical behavioral forgetting effects, but contrary to our hypotheses, there were no differences between the depressed and nondepressed participants or between neutral and negative memories. Relative to controls, depressed individuals exhibited greater activity in right middle frontal gyrus during memory suppression, regardless of the valence of the suppressed stimuli, and differential activity in the amygdala and hippocampus during memory suppression involving negatively valenced stimuli. These findings indicate that depressed individuals are characterized by neural anomalies during the suppression of long-term memories, increasing our understanding of the brain bases of negative cognitive biases in MDD.

Increased Cognitive Control During Execution of Finger Tap Movement inPeople with Parkinson's Disease.

Previous studies employed demanding and complex hand tasks to study the brain activation in people with Parkinson's Disease (PD). There is inconsistent finding about the cerebellar activity during movement execution of this patient population. This study aimed to examine the brain activation patterns of PD individuals in the on-state and healthy control subjects in a simple finger tapping task. Twenty-seven patients with PD and 22 age-matched healthy subjects were recruited for the study. Subjects were instructed to perform simple finger tapping tasks under self- and cue-initiated conditions in separate runs while their brain activations were captured using fMRI. Healthy subjects had higher brain activity in contralateral precentral gyrus during the self-initiated task, and higher brain activity in the ipsilateral middle occipital gyrus during the cue-initiated task. PD patients had higher brain activity in the cerebellum Crus I (bilateral) and lobules VI (ipsilateral) during the self-initiated task and higher brain activity in the contralateral middle frontal gyrus during the cue-initiated task. When compared with healthy controls, PD patients had lower brain activity in the contralateral inferior parietal lobule during the self-initiated task, and lower brain activity in the ipsilateral cerebellum lobule VIII, lobule VIIB and vermis VIII, and thalamus during the cue-initiated task. Conjunction analysis indicated that both groups had activation in bilateral cerebellum and SMA and ipsilateral precentral gyrus and postcentral gyrus during both self- and cue-initiated movement. Individuals with PD exhibited higher brain activity in the executive zone (cerebellum Crus I and II) during self-initiated movement, and lower brain activity in the sensorimotor zone (i.e. lobule VIIb and VIII of the cerebellum) during cue-initiated movement. The findings suggest that individuals with PD may use more executive control when performing simple movements.