Connectivity Of Subregions Research Articles

Functional connectivity of paired default mode network subregions in patients with eye trauma.

To study functional brain abnormalities in patients with eye trauma (ET) and to discuss the pathophysiological mechanisms of ET. Totally 31 ET patients and 31 healthy controls (HCs) were recruited. The age, gender, and educational background characteristics of the two groups were similar. After functional magnetic resonance imaging (fMRI) scanning, the subjects' spontaneous brain activity was evaluated with the functional connectivity (FC) method. Receiver operating characteristic (ROC) curve analysis was used to classify the data. Pearson's correlation analysis was used to explore the relationship between FC values in specific brain regions and clinical behaviors in patients with ET. Significantly increased FC between several regions was identified including the medial prefrontal cortex (MPFC) and left hippocampus formations (HF), the MPFC and left inferior parietal lobule (IPL), the left IPL and left medial temporal lobe (MTL), the left IPL and right MTL, and the right IPL and left MTL. No decreased region-to-region connectivity was detected in default mode network (DMN) sub-regions in patients with ET. Compared with HCs, ET patients exhibited significantly increased FC between several paired DMN regions, as follows: posterior cingulate cortex (PCC) and right HF (HF.R, t=2.196, P=0.032), right inferior parietal cortices (IPC.R) and left MTL (MTL.L, t=2.243, P=0.029), and right MTL (MTL.R) and HF.R (t=2.236, P=0.029). FC values in multiple brain regions of ET patients are abnormal, suggesting that these brain regions in ET patients may be dysfunctional, which may help to reveal the pathophysiological mechanisms of ET.

The altered resting-state functional connectivity of thalamic subregions in patients with globus pharyngeus.

Globus Pharyngeus (GP) is a somatic symptom that accompanies mood distress. Although the etiology of GP remains unclear, its specific symptom of a false lump sensation in the throat without physical obstruction raises the possibility of alterations in brain networks responsible for somatosensory and emotion processing in patients with GP. To address this possibility, we investigated resting-state functional connectivity (rsFC) in 31 patients with GP and 24 healthy individuals using resting-state functional magnetic resonance imaging. Considering its significance in somatosensory and emotional functions, we focused on rsFC in the subregions of the thalamus. We found significantly decreased rsFC between the right caudal temporal thalamus (rcTtha) and the midcingulate cortex (MCC) as well as significantly decreased rsFC between the right rostral temporal thalamus (rrTtha) and the left cerebellum in the patients with GP. Additionally, within the patient group, the abnormalities in rsFC between the rcTtha and the MCC were correlated with the severity of somatization symptoms but not with depression and anxiety. These findings suggest alterations in the rsFC of thalamic subregions in patients with GP, shedding light on the pathogenesis of GP and potentially leading to improved diagnosis and treatment approaches for the condition.

Intrinsic functional connectivity of right dorsolateral prefrontal cortex and hippocampus subregions relates to emotional and sensory-perceptual properties of intrusive trauma memories.

Trauma-related intrusive memories (TR-IMs), unwanted and vivid, are core symptoms of posttraumatic stress disorder (PTSD). Prior research links voluntary TR-IM suppression to inhibitory control of the right dorsolateral prefrontal cortex (dlPFC) over the hippocampus (HPC). However, the potential relevance of tonic resting-state inhibition has not been examined, nor has the functional differentiation of the anterior and posterior hippocampus (aHPC/HPC). This study examined relationships of TR-IM frequency and properties with resting-state negative coupling between the right dlPFC and right aHPC/pHPC in trauma-exposed individuals with PTSD symptoms. Participants (N=109; 88 female) completed two weeks of ecological momentary assessments capturing TR-IM frequency and properties (intrusiveness, emotional intensity, vividness, visual properties, and reliving). Using 3T resting-state magnetic resonance imaging, participant-specific 4-mm spheres were placed at the right dlPFC voxel most anticorrelated with the right aHPC and pHPC. Quasi-Poisson and linear mixed-effects models assessed relationships of TR-IM frequency and properties with right dlPFC-right aHPC and pHPC anticorrelation. TR-IM emotional intensity was positively associated with right dlPFC-aHPC connectivity, while vividness and visual properties were linked to right dlPFC-pHPC connectivity. No significant associations were found between TR-IM frequency, intrusiveness, or reliving, and anticorrelation with either HPC subregion. This study provides novel insights into the neural correlates of TR-IMs, highlighting the relevance of intrinsic negative coupling between the right dlPFC and aHPC/pHPC to their emotional impact and perceptual properties. Further research on inhibitory mechanisms in this circuit could improve understanding of component processes of intrusive reexperiencing, a severe and treatment-refractory PTSD symptom.

Abnormal resting-state functional connectivity of hippocampal subregions in type 2 diabetes mellitus-associated cognitive decline.

Type 2 diabetes mellitus (T2DM) over time predisposes to inflammatory responses and abnormalities in functional brain networks that damage learning, memory, or executive function. The hippocampus is a key region often reporting connectivity abnormalities in memory disorders. Here, we investigated peripheral inflammatory responses and resting-state functional connectivity (RSFC) changes characterized of hippocampal subregions in type 2 diabetes-associated cognitive decline (T2DACD). The study included 16 patients with T2DM, 16 patients with T2DACD and 25 healthy controls (HCs). Subjects were assessed for cognitive performance, tested for the expression of inflammatory factors IL-6, IL-10 and TNF-α in peripheral serum, underwent resting-state functional magnetic resonance imaging scans, and analyzed for RSFC using the hippocampal subregions as seeds. We also calculated the correlation between cognitive performance and RSFC of hippocampal subregion, and analyzed the significantly altered RSFC values of T2DACD for Receiver Operating Characteristic (ROC) analysis. T2DACD patients showed a decline in their ability to complete cognitive assessment scales and experimental paradigms, and T2DM did not show abnormal cognitive performance. IL-6 expression was increased in peripheral serum in both T2DACD and T2DM. Compared with HCs, T2DACD showed abnormalities RSFC of the left anterior hippocampus with left precentral gyrus and left angular gyrus. T2DM showed abnormalities RSFC of the left middle hippocampus with right medial frontal gyrus, right anterior and middle hippocampus with left precuneus, left anterior hippocampus with right precuneus and right posterior middle temporal gyrus. Compared with T2DM, T2DACD showed abnormalities RSFC of the left posterior hippocampus and right middle hippocampus with left precuneus. In addition, RSFC in the left posterior hippocampus with left precuneus of T2DACD was positively correlated with Flanker conflict response time (r=0.766, P=0.001). In the ROC analysis, the significantly altered RSFC values of T2DACD achieved significant performance. T2DACD showed a significant decrease in attentional inhibition and working memory, peripheral pro-inflammatory response increased, and abnormalities RSFC of the hippocampal subregions with default mode network and sensory-motor network. T2DM did not show a significant cognitive decline, but peripheral pro-inflammatory response increased and abnormalities RSFC of the hippocampus subregions occurred in the brain. In addition, the left precuneus may be a key brain region in the conversion of T2DM to T2DACD. The results of this study may provide a basis for the preliminary diagnosis of T2DACD.

Aberrant functional connectivity of amygdala subregions in temporal lobe epilepsy with ictal panic.

The amygdala joins the model of fear neurocircuitry for its subregional roles in processing and mediating panic. This study aims to explore the underlying neuromechanisms of temporal lobe epilepsy (TLE) patients with ictal panic (IP) by investigating the amygdala subregions functional connectivity (FC) alteration. 18 TLE patients with IP (TLE-IP group), 23 TLE patients without IP (TLE-none-IP group) and 22 age- and sex- matched healthy controls (HC) were enrolled and required to take resting-state functional magnetic resonance imaging (rs-fMRI) scanning. The basolateral (BLA), centromedial (CMA), and superficial(SFA) amygdala subregions were extracted from Juelich histological atlas. The amygdala subregions-based FC was computed and compared among three groups. The TLE-IP group demonstrated stronger FC between the left BLA and right middle frontal gyrus (MFG) than the TLE-none-IP group and HC. Compared with the TLE-none-IP group and HC, the TLE-IP group showed increased FC between the right BLA and right postcentral gyrus. The FC between the left BLA/SFA and the orbital part of right MFG increased in the TLE-IP group. Furthermore, the TLE-IP group exhibited decreased FC between the left CMA and pons. Further analysis indicated altered FC between the amygdala subregions and the pons, precuneus and thalamus in the left-sided TLE-IP group, but the MFG, inferior parietal gyrus, supplementary motor area and cerebellum in the right-sided TLE-IP group. The present study revealed aberrant amygdala subregions-based FC in TLE patients with IP. These findings offer unique insights into the understanding of fear neurocircuitry in TLE patients with IP.

Altered dynamic functional connectivity of nucleus accumbens subregions in major depressive disorder: the interactive effect of childhood trauma and diagnosis.

Major depressive disorder (MDD) with childhood trauma represents a heterogeneous clinical subtype of depression. Previous research has observed alterations in the reward circuitry centered around the nucleus accumbens (NAc) in MDD patients. However, limited investigations have focused on aberrant functional connectivity (FC) within NAc subregions among MDD with childhood trauma. Thus, this study adopts analyses of both static FC (sFC) and dynamic FC (dFC) to examine neurobiological changes in MDD with childhood trauma. The bilateral nucleus accumbens shell (NAc-shell) and nucleus accumbens core (NAc-core) were selected as the seeds. Four participant groups were included: MDD with childhood trauma (n = 48), MDD without childhood trauma (n = 30), healthy controls (HCs) with childhood trauma (n = 57), and HCs without childhood trauma (n = 46). Our findings revealed both abnormal sFC and dFC between NAc-shell and NAc-core and regions including the middle occipital gyrus (MOG), anterior cingulate cortex, and inferior frontal gyrus in MDD with childhood trauma. Furthermore, a significant correlation was identified between the dFC of the left NAc-shell and the right MOG in relation to childhood trauma. Additionally, abnormal dFC moderated the link between childhood abuse and depression severity. These outcomes shed light on the neurobiological underpinnings of MDD with childhood trauma.

Abnormal resting-state functional connectivity in subregions of amygdala in adults and adolescents with major depressive disorder

BackgroundThe different symptoms of major depressive disorder (MDD) in adolescents compared to adults suggested there may be differences in the pathophysiology between adolescents and adults with MDD. However, despite the amygdala being considered critical in the pathophysiology, there was limited knowledge about the commonalities and differences in the resting-state functional connectivity (rsFC) of amygdala subregions in MDD patients of different age groups.MethodsIn the current study, 65 adolescents (46 with MDD and 19 controls) and 91 adults (35 with MDD and 56 controls) were included. A seed-based functional connectivity analysis was performed for each of the amygdala subregions. A 2 × 2 ANOVA was used to analyze the main effect of age, diagnosis, and their interaction on the rsFC of each subregion.ResultsA significant main effect of age was revealed in the rsFC of bilateral centromedial (CM) subregions and right laterobasal (LB) subregion with several brain regions in the limbic system and frontoparietal network. The significant main effect of diagnosis showed MDD patients of different ages showed higher connectivity than controls between the right LB and left middle frontal gyrus (MFG).ConclusionsThe rsFC of specific amygdala subregions with brain regions in the limbic system and frontoparietal network is affected by age, indicating a distinct amygdala connectivity profile in adolescents. The decreased rsFC between the right LB and the left MFG in adolescents and adults with MDD could serve as a diagnostic biomarker and a target of nonpharmacological treatment for MDD.

Altered Functional Connectivity of the Thalamus Subregions Associated with Impaired Attention After Sleep Deprivation.

The thalamus plays a critical role in attentional maintenance. Previous studies have revealed the dysfunction of the thalamus in attention decline after acute sleep deprivation (SD). However, the functional connectivity (FC) between the thalamus subregions and cortical regions underlying attentional impairment after acute SD remains unclear. Here, we aimed to probe the relationship between attentional function and the altered thalamocortical FC after acute SD. In this study, 25 healthy participants with regular sleep conducted an attentional network test and received a resting-state fMRI scan before and after 24 hours of SD. Then, we analyzed the FC between the thalamus and cerebrum and relationships with attentional function in the enrolled subjects. Our results showed that the participants showed a significantly lower alerting effect, a higher executive effect, and lower accuracy after acute SD. Compared to the rested wakefulness state, we observed decreased FCs between the "somatosensory" thalamic seed and left frontal pole, right frontal pole, left middle temporal gyrus (posterior division), and right middle temporal gyrus (posterior division). Furthermore, the reduced FC between the right middle temporal gyrus and "somatosensory" thalamic seed was negatively associated with the change in orienting effect of the participants. Our findings reveal that the disrupted FC between thalamus subregions and cortical regions may contribute to impaired attention after SD.

Striatal Functional Alterations Link to Distinct Symptomatology Across Mood States in Bipolar Disorder

BackgroundAs a central hub in cognitive and emotional brain circuits, the striatum is considered likely to be integrally involved in the psychopathology of bipolar disorder (BD). However, it remains unclear how alterations in striatal function contribute to distinct symptomatology of BD during different mood states. MethodsBehavioral assessment (i.e., emotional symptoms and cognitive performance) and neuroimaging data were collected from 125 participants comprising 31 (hypo)manic, 31 depressive, and 31 euthymic patients with BD, and 32 healthy control participants. We compared the functional connectivity (FC) of striatal subregions across BD mood states with healthy control participants and then used a multivariate data-driven approach to explore dimensional associations between striatal connectivity and behavioral performance. Finally, we compared the FC and behavioral composite scores, which reflect the individual weighted representation of the associations, among different mood states. ResultsPatients in all mood states exhibited increased FC between the bilateral ventral rostral putamen and ventrolateral thalamus. Bipolar (hypo)mania uniquely exhibited increased ventral rostral putamen connectivity and superior ventral striatum connectivity. One latent component was identified, whereby increased FCs of striatal subregions were associated with distinct psychopathological symptomatology (more manic symptoms, elevated positive mood, less depressive symptoms, and worse cognitive performance). Patients with bipolar (hypo)mania had the highest FC and behavioral composite scores while bipolar patients with depression had the lowest scores. ConclusionsOur data demonstrated both trait features of BD and state features specific to bipolar (hypo)mania. The findings underscored the fundamental role of the striatum in the pathophysiological processes underlying specific symptomatology across all mood states.

Altered functional connectivity of cerebellar subregions in male patients with obstructive sleep apnea: A resting-state fMRI study.

Previous studies have demonstrated impaired cerebellar function in patients with obstructive sleep apnea (OSA), which is associated with impaired cognition. However, the effects of OSA on resting-state functional connectivity (FC) in the cerebellum has not been determined. The purpose of this study was to investigate resting-state FC of the cerebellar subregions and its relevance to clinical symptoms in patients with OSA. Sixty-eight patients with OSA and seventy-two healthy controls (HCs) were included in the study. Eight subregions of the cerebellum were selected as regions of interest, and the FC values were calculated for each subregion with other voxels. A correlation analysis was performed to examine the relationship between clinical and cognitive data. Patients with OSA showed higher FC in specific regions, including the right lobule VI with the right posterior middle temporal gyrus and right angular gyrus, the right Crus I with the bilateral precuneus/left superior parietal lobule, and the right Crus II with the precuneus/right posterior cingulate cortex. Furthermore, the oxygen depletion index was negatively correlated with aberrant FC between the right Crus II and the bilateral precuneus / right posterior cingulate cortex in OSA patients (p = 0.004). The cerebellum is functionally lateralized and closely linked to the posterior default mode network. Higher FC is related to cognition, emotion, language, and sleep in OSA. Abnormal FC may offer new neuroimaging evidence and insights for a deeper comprehension of OSA-related alterations.

The association between gray matter volume in the hippocampal subfield and antidepressant efficacy mediated by abnormal dynamic functional connectivity

An abnormality of structures and functions in the hippocampus may have a key role in the pathophysiology of major depressive disorder (MDD). However, it is unclear whether structure factors of the hippocampus effectively impact antidepressant responses by hippocampal functional activity in MDD patients. We collected longitudinal data from 36 MDD patients before and after a 3-month course of antidepressant pharmacotherapy. Additionally, we obtained baseline data from 43 healthy controls matched for sex and age. Using resting-state functional magnetic resonance imaging (rs-fMRI), we estimated the dynamic functional connectivity (dFC) of the hippocampal subregions using a sliding-window method. The gray matter volume was calculated using voxel-based morphometry (VBM). The results indicated that patients with MDD exhibited significantly lower dFC of the left rostral hippocampus (rHipp.L) with the right precentral gyrus, left superior temporal gyrus and left postcentral gyrus compared to healthy controls at baseline. In MDD patients, the dFC of the rHipp.L with right precentral gyrus at baseline was correlated with both the rHipp.L volume and HAMD remission rate, and also mediated the effects of the rHipp.L volume on antidepressant performance. Our findings suggested that the interaction between hippocampal structure and functional activity might affect antidepressant performance, which provided a novel insight into the hippocampus-related neurobiological mechanism of MDD.

Resting-state functional connectivity of amygdala subregions predicts treatment outcome for cognitive behavioral therapy in obsessive-compulsive disorder at a 4-month follow-up

BackgroundCognitive behavioral therapy (CBT) is considered as the first-line treatment for obsessive-compulsive disorder (OCD). However, the underlying neural mechanisms through which CBT exerts its effects in OCD remain unclear. This study aims to investigate whether the improvement of clinical symptoms in OCD patients after CBT treatment is associated with changes in resting-state functional connectivity (FC) of the amygdala subregion, and whether these changes can be served as potential predictors of four-months treatment efficacy. MethodsWe collected resting-state functional magnetic resonance imaging (rs-fMRI) data from 57 OCD patients and 50 healthy subjects at baseline. In the patient group, rs-fMRI was also obtained after completion of an 8-week CBT treatment and 4 months post-treatment. A whole-brain rsFC analysis was conducted using the amygdala subregion as the seed point. We analyzed the FC patterns in relation to 4 months clinical outcomes to elucidate the long-term efficacy of CBT in OCD patients. ResultsTreatment responseat at pre-treatment was found to be associated with reduced rsFC between the left basolateral amygdala(BLA)and left superior temporal gyrus(STG) at baseline. Lower pre-treatment FC were negatively correlated with the severity of OCD symptoms as measured by the Yale-Brown Obsessive Compulsive Severity Scale (Y-BOCS). Moreover, the area under the receiver operating characteristic (ROC) curve for the FC between the left BLA and STG at the end of treatment was 73.0% and 70.4% for the effective-ineffective and remitted or unremitted groups, respectively. At the 4-month follow-up, the area under the ROC curve for the effective-ineffective and remitted or unremitted groups was 83.9% and 76.5%, respectively. ConclusionThese findings suggest that brain functional activity in patients with OCD can predict treatment response to CBT, and longitudinal changes in relevant brain functional activity following CBT treatment are associated with treatment response in OCD.

Functional connectome hierarchy of thalamus impacts fatigue in acute stroke patients.

This study aimed to explore the topographic features of thalamic subregions, functional connectomes and hierarchical organizations between thalamus and cortex in poststroke fatigue patients. We consecutively recruited 121 acute ischemic stroke patients (mean age: 59years) and 46 healthy controls matched for age, sex, and educational level. The mean age was 59years (range 19-80) and 38% of acute stroke patients were females. Resting-state functional and structural magnetic resonance imaging were conducted on all participants. The fatigue symptoms were measured using the Fatigue Severity Scale. The thalamic functional subdivisions corresponding to the canonical functional network were defined using the winner-take-all parcellation method. Thalamic functional gradients were derived using the diffusion embedding analysis. The results suggested abnormal functional connectivity of thalamic subregions primarily located in the temporal lobe, posterior cingulate gyrus, parietal lobe, and precuneus. The thalamus showed a gradual increase from the medial to the lateral in all groups, but the right thalamus shifted more laterally in poststroke fatigue patients than in non- poststroke fatigue patients. Poststroke fatigue patients also had higher gradient scores in the somatomotor network and the right medial prefrontal and premotor thalamic regions, but lower values in the right lateral prefrontal thalamus. The findings suggested that poststroke fatigue patients had altered functional connectivity and thalamocortical hierarchical organizations, providing new insights into the neural mechanisms of the thalamus.

Altered functional connectivity of insular subregions in subjective cognitive decline.

Recent research has highlighted the insula as a critical hub in human brain networks and the most susceptible region to subjective cognitive decline (SCD). However, the changes in functional connectivity of insular subregions in SCD patients remain poorly understood. The present study aims to clarify the altered functional connectivity patterns within insular subregions in individuals with SCD using resting-state functional magnetic resonance imaging (rs-fMRI). In this study, we collected rs-fMRI data from 30 patients with SCD and 28 healthy controls (HCs). By defining three subregions of the insula, we mapped whole-brain resting-state functional connectivity (RSFC). We identified several distinct RSFC patterns of the insular subregions. Specifically, for positive connectivity, three cognitive-related RSFC patterns were identified within the insula, suggesting anterior-to-posterior functional subdivisions: (1) a dorsal anterior zone of the insula that shows RSFC with the executive control network (ECN); (2) a ventral anterior zone of the insula that shows functional connectivity with the salience network (SN); and (3) a posterior zone along the insula that shows functional connectivity with the sensorimotor network (SMN). Compared to the controls, patients with SCD exhibited increased positive RSFC to the sub-region of the insula, demonstrating compensatory plasticity. Furthermore, these abnormal insular subregion RSFCs are closely correlated with cognitive performance in the SCD patients. Our findings suggest that different insular subregions exhibit distinct patterns of RSFC with various functional networks, which are affected differently in patients with SCD.

Functional connectivity of the amygdala subregions and the antidepressant effects of repeated ketamine infusions in major depressive disorder.

Amygdala subregion-based network dysfunction has been determined to be centrally implicated in major depressive disorder (MDD). Little is known about whether ketamine modulates amygdala subarea-related networks. We aimed to investigate the relationships between changes in the resting-state functional connectivity (RSFC) of amygdala subregions and ketamine treatment and to identify important neuroimaging predictors of treatment outcomes. Thirty-nine MDD patients received six doses of ketamine (0.5mg/kg). Depressive symptoms were assessed, and magnetic resonance imaging (MRI) scans were performed before and after treatment. Forty-five healthy controls underwent one MRI scan. Seed-to-voxel RSFC analyses were performed on the amygdala subregions, including the centromedial amygdala (CMA), laterobasal amygdala (LBA), and superficial amygdala subregions. Abnormal RSFC between the left LBA and the left precuneus in MDD patients is related to the therapeutic efficacy of ketamine. There were significant differences in changes in bilateral CMA RSFC with the left orbital part superior frontal gyrus and in changes in the left LBA with the right middle frontal gyrus between responders and nonresponders following ketamine treatment. Moreover, there was a difference in the RSFC of left LBA and the right superior temporal gyrus/middle temporal gyrus (STG/MTG) between responders and nonresponders at baseline, which could predict the antidepressant effect of ketamine on Day 13. The mechanism by which ketamine improves depressive symptoms may be related to its regulation of RSFC in the amygdala subregion. The RSFC between the left LBA and right STG/MTG may predict the response to the antidepressant effect of ketamine.

Altered connectivity patterns of medial and lateral orbitofrontal cortex underlie the severity of bulimic symptoms

ObjectiveCompared to clinical bulimia nervosa, sub-threshold bulimic symptoms are becoming more prevalent in non-clinical or general population, which is repeatedly linked with the connectivity in orbitofrontal cortex (OFC), including functionally heterogeneous the medial and lateral OFC (mOFC; lOFC). However, the specific connectivity patterns of the mOFC and lOFC in individuals with severe or mild bulimic symptoms (SB; MB) remain poorly understood. MethodsWe first utilized resting-state functional connectivity (FC) and spectral dynamic causal modeling (spDCM) to investigate abnormal functional and effective connectivity (EC) of OFC subregions in adults with different severity of bulimic. The SB group (n = 21), MB group (n = 114), and healthy controls (HC, n = 91) underwent rs-fMRI scans. A generalized linear model was applied to determine the OFC-seeded whole-brain FC across the three groups. Subsequently, spDCM was used to estimate differences in EC among the three groups based on the FC results. ResultsWe observed a shared neural basis for SB and MB groups (i.e., weaker lOFC-superior parietal lobule connectivity), which may support the role of dysfunctional inhibitory control in general bulimic symptomatology. Whereas, SB group displayed greater lOFC-occipital pole connectivity than MB group, suggesting the specificity of the neural correlates of full-threshold/severe bulimia. The directional links from the mOFC to lOFC and amygdala could further explain the aberrant interactions of reward sensitivity with inhibitory control and homeostatic energy in sub-threshold/mild condition. ConclusionThe current study provides novel evidence that divergent connectivity patterns of the lOFC and mOFC may contribute to different severities of bulimia, which will expands our understanding of the neurobiological substrates underlying bulimia across a spectrum from healthy to unhealthy.

Disorganized Functional Connectivity of Anterior Insular Subnetworks in Adults with Executive Dysfunction after Trauma Exposure

There is increasing evidence that major trauma can adversely affect the brain and cognition. In some cases, trauma may lead to deficits in executive function (EF). The anterior insula may be a causal outflow hub acting to coordinate EF-related brain networks. To clarify the neural underpinnings of EF deficits (EFD) after trauma, we performed a resting-state functional magnetic resonance imaging (rs-fMRI) study of anterior insular subnetworks in adults who have lost their only child. A total of 167 participants completed various psychological and cognitive assessments to assess EF-related deficits. Correlations were computed between abnormal connectivity and cognitive/post-traumatic stress symptoms. The results showed abnormal anterior insular subregion connectivity in the default mode network (DMN), prefrontal lobe, and cerebellum lobe in participants with EFD. No correlation was found between abnormal connectivity and cognitive/post-traumatic stress symptoms in participants with EFD. These results suggest that excessive connections between the insula and DMN could contribute to EFD after trauma. Overall, this study provides novel references into the neural mechanisms of EF status after trauma exposure.

Microstructural integrity and structural connectivity of medial temporal lobe subregions is related to Alzheimer’s pathology

AbstractBackgroundThe earliest effects of Alzheimer’s disease pathology on medial temporal lobe (MTL) gray matter microstructure and white matter connectivity are still unknown. Here, we applied ultra‐high‐resolution diffusion MRI to characterize microstructural integrity and structural connectivity of the MTL, and tested associations with Alzheimer’s pathology and memory performance in cognitively normal older adults.Method83 participants (M = 71.7yrs, 66% female) received structural and ultra‐high‐resolution diffusion MRI (0.67×0.67×3mm). Subsamples received [18F]‐florbetapir (FBP) to measure Aß (n = 77; global summary SUVR), [18F]‐MK6240 to measure tau (n = 23; entorhinal SUVR), and performed an object mnemonic discrimination task (n = 74). Structural MRI was processed with ASHS to obtain MTL ROIs (Fig1). Diffusion MRI was processed with FSL DTIfit to calculate mean diffusivity (MD), an index of cellular integrity. Tractography was performed with DSI Studio. ROI‐to‐ROI streamlines were calculated (Fig3A) and used for structural connectivity graph analyses of the MTL network. Analyses controlled for age and sex, with scan interval and education in relevant models.ResultEntorhinal MK6240 SUVR was associated with increased MD in transentorhinal cortex (BA35; r = 0.72, p<0.001), entorhinal cortex (EC; r = 0.61, p = 0.004), and dentate gyrus (DG; r = 0.46, p = 0.04; Fig2A), while global FBP SUVR was associated with higher MD in EC (r = 0.25, p = 0.03). Worse mnemonic discrimination performance was associated with increased MD in DG (r = ‐0.29, p = 0.01), with trends in EC (r = ‐0.23, p = 0.06) and CA3 (r = ‐0.20, p = 0.09; Fig2B). The number of streamlines between EC and DG was not significantly associated with entorhinal MK6240 SUVR (r = ‐0.32, p = 0.17), FBP SUVR, or mnemonic discrimination (ps>0.37). Lower global efficiency of the MTL network was associated with increased entorhinal MK6240 SUVR (r = ‐0.50, p = 0.025) yet better mnemonic discrimination performance (r = ‐0.28, p = 0.02; Fig3B).ConclusionEntorhinal tau pathology and memory performance are closely related to microstructural integrity and structural connectivity of the MTL, suggesting tau‐related MTL neurodegeneration may drive early memory decline.

Microstructural integrity and structural connectivity of medial temporal lobe subregions is related to Alzheimer’s pathology

AbstractBackgroundThe earliest effects of Alzheimer’s disease pathology on medial temporal lobe (MTL) gray matter microstructure and white matter connectivity are still unknown. Here, we applied ultra‐high‐resolution diffusion MRI to characterize microstructural integrity and structural connectivity of the MTL, and tested associations with Alzheimer’s pathology and memory performance in cognitively normal older adults.Method83 participants (M = 71.7yrs, 66% female) received structural and ultra‐high‐resolution diffusion MRI (0.67×0.67×3mm). Subsamples received [18F]‐florbetapir (FBP) to measure Aβ (n = 77; global summary SUVR), [18F]‐MK6240 to measure tau (n = 23; entorhinal SUVR), and performed an object mnemonic discrimination task (n = 74). Structural MRI was processed with ASHS to obtain MTL ROIs (Fig1). Diffusion MRI was processed with FSL DTIfit to calculate mean diffusivity (MD), an index of cellular integrity. Tractography was performed with DSI Studio. ROI‐to‐ROI streamlines were calculated (Fig3A) and used for structural connectivity graph analyses of the MTL network. Analyses controlled for age and sex, with scan interval and education in relevant models.ResultEntorhinal MK6240 SUVR was associated with increased MD in transentorhinal cortex (BA35; r = 0.72, p<0.001), entorhinal cortex (EC; r = 0.61, p = 0.004), and dentate gyrus (DG; r = 0.46, p = 0.04; Fig2A), while global FBP SUVR was associated with higher MD in EC (r = 0.25, p = 0.03). Worse mnemonic discrimination performance was associated with increased MD in DG (r = ‐0.29, p = 0.01), with trends in EC (r = ‐0.23, p = 0.06) and CA3 (r = ‐0.20, p = 0.09; Fig2B). The number of streamlines between EC and DG was not significantly associated with entorhinal MK6240 SUVR (r = ‐0.32, p = 0.17), FBP SUVR, or mnemonic discrimination (ps>0.37). Lower global efficiency of the MTL network was associated with increased entorhinal MK6240 SUVR (r = ‐0.50, p = 0.025) yet better mnemonic discrimination performance (r = ‐0.28, p = 0.02; Fig3B).ConclusionEntorhinal tau pathology and memory performance are closely related to microstructural integrity and structural connectivity of the MTL, suggesting tau‐related MTL neurodegeneration may drive early memory decline.

The modulation effects of the mind-body and physical exercises on the basolateral amygdala-temporal pole pathway on individuals with knee osteoarthritis

Background/ObjectiveTo investigate the modulatory effects of different physical exercise modalities on connectivity of amygdala subregions and its association with pain symptoms in patients with knee osteoarthritis (KOA). Methods140 patients with KOA were randomly allocated either to the Tai Chi, Baduanjin, Stationary cycling, or health education group and conducted a 12 week-long intervention in one of the four groups. The behavioral, magnetic resonance imaging (MRI), and blood data were collected at baseline and the end of the study. ResultsCompared to the control group, all physical exercise modalities lead to significant increases in Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score (pain relief) and serum Programmed Death-1 (PD-1) levels. Additionally, all physical exercise modalities resulted in decreased resting state functional connectivity (rsFC) of the basolateral amygdala (BA)-temporal pole and BA-medial prefrontal cortex (mPFC). The overlapping BA-temporal pole rsFC observed in both Tai Chi and Baduanjin groups was significantly associated with pain relief, while the BA-mPFC rsFC was significantly associated with PD-1 levels. In addition, we found increased fractional anisotropy (FA) values, a measurement of water diffusion anisotropy of tissue that responded to changes in brain microstructure, within the mind-body exercise groups' BA-temporal pole pathway. The average FA value of this pathway was positively correlated with KOOS pain score at baseline across all subjects. ConclusionsOur findings suggest that physical exercise has the potential to modulate both functional and anatomical connectivity of the amygdala subregions, indicating a possible shared pathway for various physical exercise modalities.