Bilateral Dorsal Lateral Prefrontal Cortex Research Articles

Task switching involves working memory: Evidence from neural representation.

It is generally assumed that task switching involves working memory, yet some behavioral studies question the relationship between working memory and task switching ability. This debate can be resolved by directly comparing the brain activity pattern in task switching and working memory processes. If the task switching involves working memory, the neural activity patterns evoked by such two tasks would exhibit higher similarity. Here, we employed the task switching task and working memory to investigate the characteristic of the neural representation in such two cognitive processes. A conjunction analysis showed that the bilateral superior parietal lobule (SPL), bilateral insula, bilateral middle frontal gyrus (MFG), bilateral dorsal lateral prefrontal cortex (DLPFC) and pre-supplementary motor area (pre-SMA) were commonly and significantly activated in both task switching and working memory task. Critically, we found that task switching and working memory processing elicited similar activity patterns in bilateral SPL, right insula, left MFG, left DLPFC and pre-SMA, consistent with common neural processes for both tasks. These results not only suggest that the task switching process involves working memory from the perspective of neural representation, but also provide major new insights into the neurocognitive links between task switching and working memory.

Alteration of network connectivity in stroke patients with apraxia of speech after tDCS: A randomized controlled study.

ObjectiveThis study aimed to examine the changes in the functional connectivity of the cortical speech articulation network after anodal transcranial direct current stimulation (A-tDCS) over the left lip region of the primary motor cortex (M1) in subacute post-stroke patients with apraxia of speech (AoS), and the effect of A-tDCS on AoS.MethodsA total of 24 patients with post-stroke AoS were randomized into two groups and received A-tDCS over the left lip region of M1 (tDCS group)/ sham tDCS (control group) as well as speech and language therapy two times per day for 5 days. Before and after the treatment, the AoS assessments and electroencephalogram (EEG) were evaluated. The cortical interconnections were measured using the EEG non-linear index of cross approximate entropy (C-ApEn).ResultsThe analysis of EEG showed that, after the treatment, the activated connectivity was all in the left hemisphere, and not only regions in the speech articulation network but also in the dorsal lateral prefrontal cortex (DLPFC) in the domain-general network were activated in the tDCS group. In contrast, the connectivity was confined to the right hemisphere and between bilateral DLPFC and bilateral inferior frontal gyrus (IFG) in the control group. In AoS assessments, the tDCS group improved significantly more than the control group in four of the five subtests. The results of multivariate linear regression analyses showed that only the group was significantly associated with the improvement of word repetition (P = 0.002).ConclusionA-tDCS over the left lip region of M1 coupled with speech therapy could upregulate the connectivity of both speech-specific and domain-general networks in the left hemisphere. The improved articulation performance in patients with post-stroke AoS might be related to the enhanced connectivity of networks in the left hemisphere induced by tDCS.Clinical trial registrationChiCTR-TRC-14005072.

The Common and Different Neural Bases of Distraction and Reinterpretation: A Meta-Analysis of fMRI Studies.

Distraction and reinterpretation have been recognized as two different tactics of emotion regulation. As a tactic of attention deployment, distraction involves shifting attention to neutral information or performing a secondary task to distract attention from emotion stimuli of the primary task. Reinterpretation, a representative tactic of cognitive change, was defined as changing the meaning of a situation to enhance or reduce its emotional impact. Thus, there are significant differences between the two processes. We wondered if the neural mechanisms underlying distraction and reinterpretation are different. Even though their neural correlates have been widely studied with functional magnetic resonance imaging (fMRI), few studies were conducted to compare the two tactics directly. Here we conducted an activation likelihood estimation (ALE) meta-analyses to investigate the common or different neural bases of distraction and reinterpretation. Moreover, we also used the meta-analytic connectivity modeling (MACM) to identify the emotion regulation network of distraction and reinterpretation. Overall, we found that the left dorsal lateral prefrontal cortex (DLPFC) was consistently activated during distraction and reinterpretation, whereas the left amygdala and inferior frontal gyrus/ventrolateral prefrontal cortex (VLPFC) were specifically activated during reinterpretation alone. The results indicate that the neural basis of distraction and reinterpretation are similar but not identical. The MACM results showed that distraction and reinterpretation share a common emotion regulation network, including the bilateral DLPFC, the dorsal medial prefrontal cortex, the inferior parietal lobule, the insula, the left (pre) supplementary motor area, the left middle temporal gyrus, and the right superior temporal gyrus. However, that network may subserve different functions when adopting various emotion regulation strategies. In addition, we suggest that the emotion regulation network of the left VLPFC may be a specific regulatory network for reinterpretation.

Potential Locations for Non-Invasive Brain Stimulation in Treating Schizophrenia: A Resting-State Functional Connectivity Analysis.

Introduction: Non-invasive brain stimulation (NIBS) techniques have been widely used for the purpose of improving clinical symptoms of schizophrenia. However, the ambiguous stimulation targets may limit the efficacy of NIBS for schizophrenia. Exploring effective stimulation targets may improve the clinical efficacy of NIBS in schizophrenia.Methods: We first conducted a neurosynth-based meta-analysis of 715 functional magnetic resonance imaging studies to identify schizophrenia-related brain regions as regions of interest. Then, we performed the resting-state functional connectivity analysis in 32 patients with first-episode schizophrenia to find brain surface regions correlated with the regions of interest in three pipelines. Finally, the 10–20 system coordinates corresponding to the brain surface regions were considered as potential targets for NIBS.Results: We identified several potential targets of NIBS, including the bilateral dorsal lateral prefrontal cortex, supplementary motor area, bilateral inferior parietal lobule, temporal pole, medial prefrontal cortex, precuneus, superior and middle temporal gyrus, and superior and middle occipital gyrus. Notably, the 10-20 system location of the bilateral dorsal lateral prefrontal cortex was posterior to F3 (F4), not F3 (F4).Conclusion: Conclusively, our findings suggested that the stimulation locations corresponding to these potential targets might help clinicians optimize the application of NIBS therapy in individuals with schizophrenia.

Does Cardiorespiratory Fitness Influence the Effect of Acute Aerobic Exercise on Executive Function?

BackgroundThe beneficial effects of acute exercise on executive function have been well-documented, but the influence of cardiorespiratory fitness on this effect requires further investigations, especially using imaging technique. This study aimed to examine the effects of cardiorespiratory fitness on acute exercise-induced changes on behavioral performance and on functional brain activation.MethodBased on their cardiorespiratory fitness level, 62 participants ranked in the top and bottom of the maximum oxygen consumption (VO2 max) were finally selected and allocated to high-fit group or low-fit group. Both groups were asked to complete the Stroop task after 30 min of aerobic exercise and chair-seated rest (control session). Among them, 26 participants were randomly selected and asked to undergo the Functional Magnetic Resonance Imaging (fMRI).ResultsBehavioral results showed that individuals responded significantly faster after exercise than those in the control session. The fMRI results revealed a significant interaction effects of Group by Session in brain regions including anterior cingulate cortex (ACC) and bilateral dorsal lateral prefrontal cortex (DLPFC). For the ACC, activation in the high-fit group was significantly decreased after aerobic exercise compared to those in the control session; whereas an increased activation was noticed in the low-fit group. Regarding to the bilateral DLPFC, activation in high-fit group was significantly decreased after exercise compared to those in the control session, while no significant differences were found in the low-fit group. In addition, for the post-exercise session, a significant positive correlations between activation of the ACC and left DLPFC in the high-fit group was observed. There was a significant negative correlation between activation of the ACC and reaction time in the congruent condition after exercise in the low-fit group.ConclusionFindings further clarify the neurophysiological processes of acute exercise-induced changes in cognitive performance as they suggest that cardiorespiratory fitness is an important factor which influences changes in brain activation patterns in response to acute aerobic exercises.

Visual cortical regions show sufficient test-retest reliability while salience regions are unreliable during emotional face processing

Functional magnetic resonance imaging studies frequently use emotional face processing tasks to probe neural circuitry related to psychiatric disorders and treatments with an emphasis on regions within the salience network (e.g., amygdala). Findings across previous test-retest reliability studies of emotional face processing have shown high variability, potentially due to differences in data analytic approaches. The present study comprehensively examined the test-retest reliability of an emotional faces task utilizing multiple approaches to region of interest (ROI) analysis and by examining voxel-wise reliability across the entire brain for both neural activation and functional connectivity. Analyses included 42 healthy adult participants who completed an fMRI scan concurrent with an emotional faces task on two separate days with an average of 25.52 days between scans. Intraclass correlation coefficients (ICCs) were calculated for the ‘FACES-SHAPES’ and ‘FACES’ (compared to implicit baseline) contrasts across the following: anatomical ROIs identified from a publicly available brain atlas (i.e., Brainnetome), functional ROIs consisting of 5-mm spheres centered on peak voxels from a publicly available meta-analytic database (i.e., Neurosynth), and whole-brain, voxel-wise analysis. Whole-brain, voxel-wise analyses of functional connectivity were also conducted using both anatomical and functional seed ROIs. While group-averaged neural activation maps were consistent across time, only one anatomical ROI and two functional ROIs showed good or excellent individual-level reliability for neural activation. The anatomical ROI was the right medioventral fusiform gyrus for the FACES contrast (ICC ​= ​0.60). The functional ROIs were the left and the right fusiform face area (FFA) for both FACES-SHAPES and FACES (Left FFA ICCs ​= ​0.69 & 0.79; Right FFA ICCs ​= ​0.68 & 0.66). Poor reliability (ICCs ​< ​0.4) was identified for almost all other anatomical and functional ROIs, with some exceptions showing fair reliability (ICCs ​= ​0.4–0.59). Whole-brain voxel-wise analysis of neural activation identified voxels with good (ICCs ​= ​0.6–0.74) to excellent reliability (ICCs ​> ​0.75) that were primarily located in visual cortex, with several clusters in bilateral dorsal lateral prefrontal cortex (DLPFC). Whole-brain voxel-wise analyses of functional connectivity for amygdala and fusiform gyrus identified very few voxels with good to excellent reliability using both anatomical and functional seed ROIs. Exceptions included clusters in right cerebellum and right DLPFC that showed reliable connectivity with left amygdala (ICCs ​> ​0.6). In conclusion, results indicate that visual cortical regions demonstrate good reliability at the individual level for neural activation, but reliability is generally poor for salience regions often focused on within psychiatric research (e.g., amygdala). Given these findings, future clinical neuroimaging studies using emotional faces tasks to examine individual differences might instead focus on visual regions and their role in psychiatric disorders.

Different types of exercise relieve pain symptoms of knee osteoarthritis by modulating the cognitive control network

Knee osteoarthritis (KOA) is a common degenerative joint disease with unsatisfactory treatment. Recently, non-pharmacological therapies, such as physical exercise and mind-body exercises, have received considerable attention for their implications in pain management in KOA. However, the mechanisms underlying the efficacy of different exercises on pain improvement remain unclear. In this study, we investigate the effect and underlying mechanisms of mind-body exercises (Tai Chi Chuan and Baduanjin) and physical exercise (stationary cycling) in patients with knee osteoarthritis (KOA). One hundred and forty patients were randomized into Tai Chi Chuan, Baduanjin, stationary cycling, and health education control groups for 12 weeks. The Knee injury and Osteoarthritis Outcome Score (KOOS), resting-state functional connectivity (rsFC) of the cognitive control network (CCN), and blood markers [serum Protectin D1 (PD1) and brain derived neurotrophic factor (BDNF) levels] were measured at the beginning and end of the experiment. We also applied support vector machines regression to predict the effectiveness of different exercises on KOA patients based on rsFC of CCN. We found: –KOOS pain subscores and serum PD1 levels significantly increased in all three exercise groups compared to the control group, and there were no significant differences among the three exercise groups; –rsFC between the bilateral dorsal lateral prefrontal cortex (DLPFC) and bilateral supplementary motor area (SMA) and temporoparietal junction (TPJ) was significantly decreased in all exercise groups compared to control group, and the decreased DLPFC-SMA rsFC was significantly associated with improvements in knee pain and serum PD1 levels across all subjects at baseline; –baseline DLPFC-SMA rsFC can significantly predict the effect of exercise on pain improvement in KOA patients. Conclusion: Our findings demonstrate different exercises may achieve clinical improvements through shared pathways and highlight the potential of neuroimaging biomarkers for predicting the therapeutic effect of exercises on KOA pain.

Reduced Prefrontal Activation During the Tower of London and Verbal Fluency Task in Patients With Bipolar Depression: A Multi-Channel NIRS Study.

Background: The Tower of London (TOL) task is one of the most commonly used tests for evaluating executive functions, and can indicate planning and problem-solving abilities. The aim of this study was to evaluate hemodynamic changes between the task period and rest period in patients with bipolar depression during the TOL task and the verbal fluency task (VFT) using near-infrared spectroscopy (NIRS).Methods: Forty-three patients with bipolar depression and 32 healthy controls (HCs) matched for sex, age, handedness, and years of education were enrolled in this study. All participants were aged between 16 and 50. All patients in our study were taking medications such as antidepressants, antipsychotics and mood stabilizers at the time of measurement. Changes in oxygenated hemoglobin (oxy-Hb) levels in frontal areas during the TOL task and VFT were evaluated using a 41-channel NIRS system.Results: During the TOL task, the patients with bipolar depression exhibited significantly smaller changes in the bilateral dorsal-lateral prefrontal cortex (DLPFC) than the HCs. During the VFT task, the patients with bipolar depression exhibited significantly smaller changes in the right ventrolateral prefrontal cortex (VLPFC), the right DLPFC and both the right and left prefrontal cortex (PFC) than the HCs.Limitations: Our sample size was small, and the effects of medication cannot be excluded.Conclusions: These results indicate that planning and problem solving dysfunction is related to the impairment of the prefrontal cortex in patients with bipolar depression, and NIRS can be used to assess planning and problem solving abilities, which are essential to daily life in patients with bipolar disorder.

Compensatory increase of functional connectivity density in adolescents with internet gaming disorder.

Behavioral studies have demonstrated visual attention bias and working memory deficits in individuals with internet gaming disorder (IGD). Neuroimaging studies demonstrated that individuals with IGD presented abnormalities in brain structures and functions including resting-state functional connectivity (rsFC) disturbance. However, most previous studies investigated IGD-related rsFC alterations by using hypothesis-driven methods with priori selection of a region of interest, which cannot provide a full picture of the rsFC changes in IGD individuals. In this study, we recruited 27 male IGD adolescents and 35 demographically matched healthy controls (HCs) to investigate abnormal connective property of each voxel within whole brain of IGD adolescents using resting-state functional connectivity density (rsFCD) method, and further to evaluate the relationship between altered rsFCD and behavioral performances of visual attention and working memory. The results exhibited no significant intergroup difference in behavioral performance (visual working memory and attention). The IGD adolescents exhibited higher global/long-range rsFCD in the bilateral dorsal lateral prefrontal cortex (DLPFC) and the right inferior temporal cortex (ITC)/fusiform compared with the HCs. Although no significant correlation survived after Bonferroni correction, higher global/long-range rsFCD of the bilateral DLPFC was correlated with the Young's internet addiction test (IAT) score and/or behavioral performance in IGD adolescents using an uncorrected threshold of P<0.05. In conclusion, IGD adolescents demonstrated increased rsFCD in the brain regions involved in working memory, spatial orientation and attention processing, which indicated that increased rsFCD may reflect a compensatory mechanism for maintaining the normal behavioral performance in IGD adolescents compared with the HCs.

Neural correlates of 12-h abstinence-induced craving in young adult smokers: a resting-state study.

Studying the neural correlates of craving to smoke in young adulthood is of great importance to improve treatment outcomes in nicotine dependence. Previous nicotine dependence studies mainly focused on the neural substrates of craving elicited by smoking-related cues. More explicit attention to abstinence-induced craving during resting state in nicotine dependence has the potential to yield valuable information about craving, and characterizing this kind of craving is critical for developing effective interventions. Twenty-five young male smokers were enrolled in the present study. A within-subject experiment design was carried out to compare regional homogeneity (ReHo) between 12-h smoking abstinence and smoking satiety conditions during resting state in young adult smokers. Then, the ReHo changes associated with smoking abstinence (compared with satiety) were further examined for correlations with abstinence-induced changes in subjective craving. We found young adult smokers in abstinence state (compared with satiety) had higher ReHo in brain regions in fronto-striatal circuits including bilateral caudate, anterior cingulate cortex (ACC) and bilateral dorsal lateral prefrontal cortex (DLPFC), as well as brain regions in default mode network (DMN) including posterior cingulate cortex (PCC)/precuneus and angular gyrus. Additionally, we found the ReHo changes of the ACC and the bilateral caudate were positively correlated with the changes in craving induced by abstinence (i.e., abstinence minus satiety) in young adult smokers. The present findings improve the understanding of the effects of acute smoking abstinence on spontaneous brain activity and may contribute new insights into the neural mechanism of abstinence-induced craving in nicotine dependence.

Aberrant interhemispheric functional and structural connectivity in heroin-dependent individuals.

Models of heroin addiction emphasize the role of disrupted frontostriatal circuitry supporting cognitive control processes. However, heroin addiction-related alterations in functional and structural interactions among brain regions, especially between the cerebral hemispheres, are rarely examined directly. Resting-state functional magnetic resonance imaging (fMRI) approaches, which reveal patterns of coherent spontaneous fluctuations in the fMRI signal, offer a means to quantify directly functional interactions between the hemispheres. The corpus callosum (CC), which connects homologous regions of the cortex, is the major conduit for information transfer between the cerebral hemispheres and represents a structural connectivity index between hemispheres. We compared interhemispheric voxel-mirrored homotopic connectivity (VMHC) and CC volume between 45 heroin dependent-individuals (HDIs) and 35 non-addict individuals. We observed significant reduction of VMHC in a number of regions, particularly the striatum/limbic system regions, and significant decrease in splenium and genu sub-regions of CC in HDI. Importantly, within HDI, VMHC in the dorsal lateral prefrontal cortex (DLPFC) correlated with genu CC volume, VMHC in the putamen, VMHC in the DLPFC and genu CC volume and splenium CC volume were negatively correlated with heroin duration and impulsivity traits. Further analyses demonstrated that impairment of VMHC of bilateral DLPFC partially mediated the association between genu CC volumes decreased and increased impulsivity in HDI. Our results reveal a substantial impairment of interhemispheric coordination in the HDI. Further, interhemispheric connectivity correlated with the duration of heroin abuse and higher impulsivity behavior in HDI. Our findings provide insight into a heroin addicts' related pathophysiology and reinforce an integrative view of the interhemispheric cerebral functional and structural organization.

Relationship between the LHPP Gene Polymorphism and Resting-State Brain Activity in Major Depressive Disorder.

A single-nucleotide polymorphism at the LHPP gene (rs35936514) has been reported in genome-wide association studies to be associated with major depressive disorder (MDD). However, the neural system effects of rs35936514 that mediate the association are unknown. The present work explores whether the LHPP rs35936514 polymorphism moderates brain regional activity in MDD. A total of 160 subjects were studied: a CC group homozygous for the C allele (23 individuals with MDD and 57 controls) and a T-carrier group carrying the high risk T allele (CT/TT genotypes; 22 MDD and 58 controls). All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning. Brain activity was assessed using the amplitudes of low-frequency fluctuations (ALFF). MDD patients showed a significant increased ALFF in the left middle temporal gyrus and occipital cortex. The T-carrier group showed increased ALFF in the left superior temporal gyrus. Significant diagnosis × genotype interaction was noted in the bilateral lingual gyri, bilateral dorsal lateral prefrontal cortex (dlPFC), and left medial prefrontal cortex (mPFC) (P < 0.05, corrected). Results demonstrated that MDD patients with LHPP rs35936514 CT/TT genotype may influence the regional brain activity. These findings implicate the effects of the rs35936514 variation on the neural system in MDD.

Spontaneous regional brain activity links restrained eating to later weight gain among young women

Theory and prospective studies have linked restrained eating (RE) to risk for future weight gain and the onset of obesity, but little is known about resting state neural activity that may underlie this association. To address this gap, resting fMRI was used to test the extent to which spontaneous neural activity in regions associated with inhibitory control and food reward account for potential relations between baseline RE levels and changes in body weight among dieters over a one-year interval. Spontaneous regional activity patterns corresponding to RE were assessed among 50 young women using regional homogeneity (ReHo) analysis, which measured temporal synchronization of spontaneous fluctuations within a food deprivation condition. Analyses indicated higher baseline RE scores predicted more weight gain at a one-year follow-up. Furthermore, food-deprived dieting women with high dietary restraint scores exhibited more spontaneous local activity in brain regions associated with the expectation and valuation for food reward [i.e., orbitofrontal cortex (OFC)/ventromedial prefrontal cortex (VMPFC)] and reduced spontaneous local activity in inhibitory control regions [i.e., bilateral dorsal-lateral prefrontal cortex (DLPFC)] at baseline. Notably, the association between baseline RE and follow-up weight gain was mediated by decreased local synchronization of the right DLPFC in particular and, to a lesser degree, increased local synchronization of the right VMPFC. In conjunction with previous research, these findings highlight possible neural mechanisms underlying the relation between RE and risk for weight gain.

Altered resting-state connectivity in college students with nonclinical depressive symptoms.

BackgroundThe underlying brain basis of nonclinical depressive symptoms (nCDSs) is largely unknown. Recently, the seed-based functional connectivity (FC) approach for analyzing resting-state fMRI (rs-fMRI) data has been increasingly used to explore the neural basis of depressive disorders. Other than common seed-based FC method using an a priori seed region, we conducted FC analysis based on regions with altered spontaneous activity revealed by the fractional amplitude of low-frequency fluctuations (fALFF) approach. The aim of the present study was to provide novel insight in the underlying mechanism of nCDSs in college students.Methodology/Principal FindingsA total number of 1105 college students were recruited to participant in a survey for assessing depressive symptoms. Subsequently, 17 individuals with nCDSs and 20 healthy controls (HCs) were enrolled to perform MR studies. Alternations of fALFF were identified in the right superior parietal lobule (SPL) and left lingual gyrus, both of which were used as ROIs for further FC analysis. With right SPL, compare with HCs, subjects with nCDSs showed reduced FCs in the bilateral dorsal lateral prefrontal cortex (DLPFC), left inferior frontal gurus (IFG), left premotor cortex (PMC), DMN network [i.e., bilateral precuneus, posterior cingulate cortex (PCC), right supramarginal gyrus (SMG), right parahippocampal gyrus (PHG), bilateral inferior temporal gurus (ITG)] and left cerebellum posterior lobe (CPL). In addition, increased FCs were observed between the left lingual gyrus and right fusiform gyrus as well as in the left precuneus.Conclusion/SignificanceOur results indicate the abnormalities of spontaneous activity in the right SPL and left lingual gyrus and their corresponding dysfunction of the brain circuits might be related to the pathophysiology of nCDSs.

Changes in cerebral morphometry and amplitude of low-frequency fluctuations of BOLD signals during healthy aging: correlation with inhibitory control

Aging is known to be associated with changes in cerebral morphometry and in regional activations during resting or cognitive challenges. Here, we investigated the effects of age on cerebral gray matter (GM) volumes and fractional amplitude of low-frequency fluctuation (fALFF) of blood oxygenation level-dependent signals in 111 healthy adults, 18-72years of age. GM volumes were computed using voxel-based morphometry as implemented in Statistical Parametric Mapping, and fALFF maps were computed for task-residuals as described in Zhang and Li (Neuroimage 49:1911-1918, 2010) for individual participants. Across participants, a simple regression against age was performed for GM volumes and fALFF, respectively, with quantity of recent alcohol use as a covariate. At cluster level p<0.05, corrected for family-wise error of multiple comparisons, GM volumes declined with age in prefrontal/frontal regions, bilateral insula, and left inferior parietal lobule (IPL), suggesting structural vulnerability of these areas to aging. FALFF was negatively correlated with age in the supplementary motor area (SMA), pre-SMA, anterior cingulate cortex, bilateral dorsal lateral prefrontal cortex (DLPFC), right IPL, and posterior cingulate cortex, indicating that spontaneous neural activities in these areas during cognitive performance decrease with age. Notably, these age-related changes overlapped in the prefrontal/frontal regions including the pre-SMA, SMA, and DLPFC. Furthermore, GM volumes and fALFF of the pre-SMA/SMA were negatively correlated with the stop signal reaction time, in accord with our earlier work. Together, these results describe anatomical and functional changes in prefrontal/frontal regions and how these changes are associated with declining inhibitory control during aging.

The impulsivity behavior is correlated with prefrontal cortex gray matter volume reduction in heroin-dependent individuals

PurposeChronic exposure to heroin induced cerebral structural abnormalities may underlie heroin-related behaviors. The aim of this study was to: (1) identify cerebral structural abnormalities in heroin-dependent individuals (HDIs) by an automated and unbiased morphometric technique. (2) Define the correlation between these cerebral structural abnormalities and the impulsivity characteristic in HDIs. Methods24 HDIs and 24 control subjects were completed with (1) high resolution structural magnetic resonance imaging scanning and analysis of gray matter volume using voxel-based morphometry implemented in Statistical Parametric Mapping and (2) a Chinese translation Barratt Impulsiveness Scale-11 questionnaire survey. Differences in regional gray matter volume were tested using an analysis of covariance model, co-varying for global gray matter and age. Statistical maps were set at p<0.05, corrected for multiple comparisons. The abnormal brain regions were correlated with the duration of heroin use and impulsivity scores. ResultsAfter adjusting for effects of age and total gray matter volume, cortical gray matter volume in the bilateral medial prefrontal cortex, bilateral dorsal lateral prefrontal cortex, and right fusiform cortex were significantly reduced in HDIs. Moreover, the gray matter volume in prefrontal cortex that showed group differences was negatively correlated with the duration of heroin use and negatively correlated with the impulsivity characteristic in HDIs. ConclusionThese findings reveal the prefrontal cortex was impaired in HDIs, meanwhile, indicate the changes in gray matter volume are relating to the duration of heroin use and the impulsivity characteristic of the HDIs.

Ventral medial prefrontal functional connectivity and emotion regulation in chronic schizophrenia: A pilot study

People with schizophrenia exhibit impaired social cognitive functions, particularly emotion regulation. Abnormal activations of the ventral medial prefrontal cortex (vMPFC) during emotional tasks have been demonstrated in schizophrenia, suggesting its important role in emotion processing in patients. We used the resting-state functional connectivity approach, setting a functionally relevant region, the vMPFC, as a seed region to examine the intrinsic functional interactions and communication between the vMPFC and other brain regions in schizophrenic patients. We found hypo-connectivity between the vMPFC and the medial frontal cortex, right middle temporal lobe (MTL), right hippocampus, parahippocampal cortex (PHC) and amygdala. Further, there was a decreased strength of the negative connectivity (or anticorrelation) between the vMPFC and the bilateral dorsal lateral prefrontal cortex (DLPFC) and pre-supplementary motor areas. Among these connectivity alterations, reduced vMPFC-DLPFC connectivity was positively correlated with positive symptoms on the Positive and Negative Syndrome Scale, while vMPFC-right MTL/PHC/amygdala functional connectivity was positively correlated with the performance of emotional regulation in patients. These findings imply that communication and coordination throughout the brain networks are disrupted in schizophrenia. The emotional correlates of vMPFC connectivity suggest a role of the hypo-connectivity between these regions in the neuropathology of abnormal social cognition in chronic schizophrenia.

Frontal-Amygdala Connectivity Alterations During Emotion Downregulation in Bipolar I Disorder

The symptoms of bipolar disorder suggest dysfunction of emotion regulatory networks. In healthy control populations, downregulation of emotional responses activates the ventral lateral prefrontal cortex (vlPFC) and dampens amygdala activation. This study investigated frontal and limbic function and connectivity during emotion downregulation in euthymic subjects with bipolar I disorder (BPI) and healthy control subjects. Thirty BPI and 26 control subjects underwent functional magnetic resonance imaging scanning while performing an emotion processing task with passive viewing and emotion downregulation conditions. Contrasts were made for each group comparing the downregulation and passive viewing conditions, and these were entered into a between-group random effects analysis to assess group differences in activation. Psychophysiological interaction analyses were conducted to test for significant group differences in functional connectivity between the amygdala and inhibitory frontal regions (i.e., vlPFC). Control subjects showed the expected robust bilateral activation of frontal and limbic regions during passive viewing and emotion downregulation tasks. Between-group analyses revealed similar activation of BPI and control subjects during passive viewing but significantly decreased activation in bilateral vlPFC, bilateral anterior and posterior cingulate, medial frontal gyrus, and bilateral dorsal lateral prefrontal cortex during emotion downregulation in subjects with BPI. Connectivity analysis demonstrated that control subjects had significantly greater negative functional connectivity between the left amygdala and bilateral vlPFC compared with subjects with BPI. This study provides evidence that dysfunction in the neural networks responsible for emotion regulation, including the prefrontal cortex, cingulate, and subcortical structures, are present in BPI subjects, even while euthymic.

Detection of PCC functional connectivity characteristics in resting-state fMRI in mild Alzheimer’s disease

Resting-state networks dissociate in the early stage of Alzheimer’s disease (AD). The posterior cingulate cortex (PCC) in AD brain is vulnerable to isolation from the rest of brain. However, it remains unclear how this functional connectivity is related to PCC changes. We employed resting-state functional MRI (fMRI) to examine brain regions with a functional connection to PCC in a mild AD group compared with matched control subjects. PCC connectivity was gathered by investigating synchronic low frequency fMRI signal fluctuations with a temporal correlation method. We found asymmetric PCC-left hippocampus, right dorsal–lateral prefrontal cortex and right thalamus connectivity disruption. In addition, some other regions such as the bilateral visual cortex, the infero-temporal cortex, the posterior orbital frontal cortex, the ventral medial prefrontal cortex and the precuneus showed decreased functional connectivity to the PCC. There were also some regions, primarily in the left frontal–parietal cortices, that showed increased connectivity. These regions included the medial prefrontal cortex, bilateral dorsal–lateral prefrontal cortex, the left basal ganglia and the left primary motor cortex. Impairments to memory, high vision-related functions and olfaction in AD can be explained by a disruption to the functional connection of resting-state networks. The results of increased connectivity may support the compensatory-recruitment hypothesis. Our findings suggest that the characteristics of resting-state functional connectivity could plausibly provide an early imaging biomarker for AD.