Inferior Parietal Lobule Research Articles

Neural correlates of thought–action fusion and their associations with rumination in patients with major depressive disorder

Thought-action fusion (TAF) is the metacognitive belief that the power of thoughts can have real-life consequences, often inducing unpleasant inner experiences and recruiting coping strategies such as rumination. Therefore, this study aimed to investigate the neural correlates of TAF and their associations with rumination in depression. A total of 37 patients with major depressive disorder (MDD) and 37 healthy controls (HCs) underwent functional magnetic resonance imaging with a TAF induction task and psychological assessments. In the TAF induction task, participants were asked to read the name of a close person (CP) or neutral person (NP) in association with negative (Neg) TAF and neutral (Neu) control statements. In this study, our TAF induction task activated brain regions, including the salient and default-mode networks, in the MDD and HC groups. However, along with higher likelihood TAF and rumination, behavioral data showed less negative feelings and longer reaction times under the NegCP condition in the MDD group compared with the HC group. Furthermore, in the MDD group, significantly higher activation in the bilateral caudate nuclei, left inferior frontal gyrus/anterior insula, putamen, and inferior parietal lobule under the NegCP condition was positively correlated with TAF and reflection. These findings suggest that during the TAF task, patients with MDD may activate different brain areas associated with the maintenance of high stimulus saliency and habit formation, which are important neural correlates linking TAF and rumination in depression.

Speech motor impairment in ALS is associated with multiregional cortical thinning beyond primary motor cortex.

Cortical thinning is well-documented in individuals with amyotrophic lateral sclerosis (ALS), yet its association with speech deterioration remains understudied. This study characterizes anatomical changes in the brain within the context of speech impairment patterns in individuals with ALS, providing insight into the disease's multiregional spread and biology. To evaluate patterns of cortical thickness in speakers with ALS with and without functional speech changes compared to healthy controls (HCs) using whole-brain and region of interest (ROI) analyses. Forty individuals with ALS and 22 HCs underwent a T1-weighted 3-Tesla magnetic resonance imaging (MRI). Individuals with ALS were divided into two groups based on the preserved speech [ps-ALS] (n = 18) or deteriorated speech [ds-ALS] (n = 22) as measured by the ALSFRSF-R speech subscore (=4 or <4 points, respectively). Sixteen a priori-defined and automatically segmented cortical and subcortical brain ROIs were selected based on their previously documented roles in speech production. Two cortical thickness analyses were performed: (1) group-level whole-brain surface-based analyses and (2) group-level ROI analyses. A case study of 6 ALS individuals examined the cortical thickness, and their speech was characterized using quantitative and qualitative measures. Based on the group-level whole-brain surface-based analyses, the ds-ALS group demonstrated significant cortical thinning compared to HCs in the left primary motor and somatosensory cortices and the right inferior parietal lobe with its adjacent lateral occipital cortical regions. The ps-ALS group demonstrated no significant cortical thinning compared to HCs. Based on the group-level ROI analyses, the ds-ALS group demonstrated significant cortical thinning compared to HCs in bilateral middle motor cortices, right posterior dorsal premotor cortex, and left anterior cingulate cortex. The case study analysis revealed that ALS speakers with speech features characteristic of spastic dysarthria exhibited cortical thinning, while those with speech features characteristic of flaccid dysarthria did not. Individuals with ALS have anatomical changes involving multiregional neocortical areas beyond the primary motor cortex that may manifest as subjective (i.e., clinical judgment) and objective (i.e., speaking rate) changes in speech production. Further longitudinal work in ALS is needed to better understand the link between MRI cortical thickness changes and bulbar dysfunction.

Transformation but not generation of motor images is disrupted following stimulation over the left inferior parietal lobe

Motor imagery (MI) involves the generation, maintenance, and transformation of motor images; yet, the neural underpinnings of each stage are not well understood. Here, we investigated the role of the left inferior parietal lobe (IPL) in the stages of MI. Healthy participants (N=20) engaged in a MI task (making judgments about hands presented on a screen; hand laterality judgment task) over two days. Past literature demonstrates the mental rotation of hands in this task involves implicit MI (i.e., where MI occurs spontaneously in the absence of explicit instructions). During the task, active (Day A; 120% resting motor threshold) or sham (Day B; placebo) neuronavigated transcranial magnetic stimulation (TMS) was applied to the left IPL (location determined from past neuroimaging work) on 50% of trials at 250, 500, or 750ms post-stimulus onset, corresponding to different stages of MI. A/B days were randomized across participants. Linear mixed effects (LME) modelling conducted on reaction time and accuracy revealed that longer reaction times were observed when TMS was delivered at 750ms after trial onset, and more greatly for active vs. sham stimulation. This effect was exacerbated for palm- vs. back-view stimuli and for left vs. right hands. Accuracy overall was decreased for active vs. sham stimulation, and to a greater extent for palm- vs. back-view stimuli. Findings suggest that the left IPL is involved in image transformation. Overall this work informs on the neural underpinnings of the stages of MI.

Contribution of resting-state functional connectivity of the subgenual anterior cingulate to prediction of antidepressant efficacy in patients with major depressive disorder

This study investigated how resting-state functional connectivity (rsFC) of the subgenual anterior cingulate cortex (sgACC) predicts antidepressant response in patients with major depressive disorder (MDD). Eighty-seven medication-free MDD patients underwent baseline resting-state functional MRI scans. After 12 weeks of escitalopram treatment, patients were classified into remission depression (RD, n = 42) and nonremission depression (NRD, n = 45) groups. We conducted two analyses: a voxel-wise rsFC analysis using sgACC as a seed to identify group differences, and a prediction model based on the sgACC rsFC map to predict treatment efficacy. Haufe transformation was used to interpret the predictive rsFC features. The RD group showed significantly higher rsFC between the sgACC and regions in the fronto-parietal network (FPN), including the bilateral dorsolateral prefrontal cortex (DLPFC) and bilateral inferior parietal lobule (IPL), compared to the NRD group. These sgACC rsFC measures correlated positively with symptom improvement. Baseline sgACC rsFC also significantly predicted treatment response after 12 weeks, with a mean accuracy of 72.64% (p < 0.001), mean area under the curve of 0.74 (p < 0.001), mean specificity of 0.82, and mean sensitivity of 0.70 in 10-fold cross-validation. The predictive voxels were mainly within the FPN. The rsFC between the sgACC and FPN is a valuable predictor of antidepressant response in MDD patients. These findings enhance our understanding of the neurobiological mechanisms underlying treatment response and could help inform personalized treatment strategies for MDD.

Non-Alzheimer's amnestic mild cognitive impairment with medial temporal hypometabolism.

The increasing use of Alzheimer's disease (AD) biomarkers has led to the recognition of a subgroup of non-AD amnestic mild cognitive impairment (aMCI) patients who have medial temporal hypometabolism on fluorodeoxyglucose-positron emission tomography (FDG-PET). In this academic memory-clinic-based consecutive series, 16 non-AD aMCI patients and 28 AD controls matched for sex, age, and baseline Mini-Mental State Examination (MMSE) were followed for a median duration of 4.5 years. Our primary outcome was the MMSE decline rate over the subsequent years. We also determined the final diagnosis over time. FDG-PET showed more pronounced medial temporal hypometabolism in non-AD cases and more inferior parietal lobule hypometabolism in AD controls. MMSE decline was slower in non-AD (β=-0.51) than in AD (β=-2.00) patients. Five non-AD cases developed frontotemporal dementia years after symptom onset, and one developed dementia with Lewy bodies. Non-AD aMCI patients with medial temporal hypometabolism show slower cognitive decline. Non-AD aMCI with medial temporal hypometabolism shows slower cognitive decline than AD.FDG-PET revealed distinct metabolic patterns between non-AD aMCI and AD patients.Approximately one-third of non-AD aMCI cases developed frontotemporal dementia.Comprehensive diagnostic biomarkers are crucial for non-AD aMCI characterization.

Neural mechanisms associated with sleep-dependent enhancement of motor learning after brain injury.

This study aimed to examine the improvement in performance and functional magnetic resonance imaging correlates of motor learning after a daytime nap versus a period of resting wakefulness among individuals with traumatic brain injury. A sample of 32 individuals with traumatic brain injury was randomly assigned to a Sleep (N = 17) or Wake (N = 15) group after a period of training on a motor sequential learning task. A 45-min nap opportunity was provided for the Sleep group, while the Wake group watched a documentary for 45 min. Performance at the end of training was compared with their performance after the nap or wake intervention. Before and after the intervention, the motor sequential learning task was completed in the magnetic resonance imaging scanner to examine the relationship between change in performance and neural activation. Participants in the Sleep group showed significant gains from the end of training to after the intervention, whereas the Wake group did not. The functional magnetic resonance imaging results showed that relative to the Wake group, the Sleep group showed significantly decreased activation post-intervention in the anterior cingulate/paracingulate, cerebellum, cuneus/precuneus, and inferior parietal lobule including angular and supramarginal gyri. Importantly, across both groups, increased task performance at post-intervention was associated with decreased activation in the anterior cingulate/paracingulate and cerebellum. This study demonstrated the enhancing effect of a nap on motor learning performance in a sample of individuals with traumatic brain injury, with patterns of neural activation suggesting that the sequence was more automatized in the Sleep group. Strategic placement of a nap after an intense period of motor learning in the medical rehabilitation setting may have important implications for maximizing recovery after traumatic brain injury.

Structural and functional brain alterations in laryngeal dystonia: A coordinate-based activation likelihood estimation meta-analysis.

Laryngeal dystonia (LD) is an isolated, task-specific, focal dystonia characterized by intermittent spasms of laryngeal muscles impairing speech production. Although recent studies have demonstrated neural alterations in LD, the consistency of findings across studies is not well-established, limiting their translational applicability. We conducted a systematic literature search to identify studies reporting stereotactic coordinates of peak structural and functional abnormalities in LD patients compared to healthy controls, followed by a coordinate-based activation likelihood estimation meta-analysis. A total of 21 functional and structural neuroimaging studies, including 31 experiments in 521 LD patients and 448 healthy controls, met the study inclusion criteria. The multimodal meta-analysis of these studies identified abnormalities in the bilateral primary motor cortices, the left inferior parietal lobule and striatum, the right insula, and the supplementary motor area in LD patients compared to healthy controls. The meta-analytical findings reinforce the current view of dystonia as a neural network disorder and consolidate evidence for future investigations probing these targets with new therapies.

Correlation Between Swallowing and Cognitive Brain Networks in Older Adults via Functional MRI.

Clinical evidence supports that swallowing function is correlated with cognition, but the neurobiological mechanism associated with cognitive impairment and dysphagia remains unclear. To compare the brain activation patterns of the swallowing and the cognitive tasks and explore neural associations between swallowing and cognitive function via task-related functional magnetic resonance imaging (fMRI). A total of 13 healthy older adults (aged > 60 years) were recruited. Participants underwent the clinical dementia rating (CDR) test and the Montreal Cognitive Assessment (MoCA). A block-designed task-related fMRI study was conducted where each participant completed both swallowing and cognitive tasks within a single session. During the swallowing task, participants swallowed 2 mL of thickened water, while the Stroop Colour Word Test (SCWT) served as the cognitive task. First-level analysis of swallowing time-series images utilised the general linear model (GLM) with Statistical Parametric Mapping (SPM), applying a voxel threshold of p < 0.001 for significance. Common activations in brain regions during swallowing and cognitive tasks were extracted at the group level, with significance set at p < 0.05, corrected for multiple comparisons using the false discovery rate (FDR), with a minimum cluster size of 20 voxels. Correlation analysis between behavioural measurements and imaging signals was also conducted. Some regions were commonly activated in both task networks; these regions were the bilateral occipital lobe, cerebellum, lingual gyrus, fusiform, middle frontal gyrus, precentral and postcentral gyrus, right supramarginal and inferior parietal lobe. Most importantly, the average beta value of cognitive and swallowing tasks in these areas are both significantly negative related to the MoCA score. Furthermore, opposite signal changes were seen in the bilateral prefrontal lobes during the swallowing task, while positive activation in the bilateral prefrontal lobes was observed during the SCWT. Postcentral gyrus activation was more extensive than precentral gyrus activation in the swallowing task. The common activation of swallowing and cognitive tasks had multiple foci. The activity of cognitive and swallowing task in these areas is significantly negative correlated with the MoCA score. These findings may help to illustrate the association between dysphagia and cognitive impairment due to the common brain regions involved in cognition and swallowing and may provide a reference for further rehabilitation of dysphagia. Clinical Trial: (Chinese Clinical Trial Registry): ChiCTR1900021795.

Cognitive State Classification Using Convolutional Neural Networks on Gamma-Band EEG Signals

This study introduces a novel methodology for classifying cognitive states using convolutional neural networks (CNNs) on electroencephalography (EEG) data of 41 students, aimed at streamlining the traditionally labor-intensive analysis procedures utilized in EEGLAB. Concentrating on the 30–40 Hz frequency range within the gamma band, we developed a CNN model to analyze EEG signals recorded from the inferior parietal lobule during various cognitive tasks. The model demonstrated substantial efficacy, achieving an accuracy of 91.42%, precision of 71.41%, and recall of 72.51%, effectively distinguishing between high and low gamma activity states. This performance surpasses traditional machine learning methods for EEG analysis, such as support vector machines and random forests, which typically achieve accuracies between 70–85% for similar tasks. Our approach offers significant time savings over manual EEGLAB methods. The integration of event-related spectral perturbation (ERSP) analysis with a novel CNN architecture enables capture of both fine-grained and broad spectral EEG features, advancing the field of computational neuroscience. This research has implications for brain-computer interfaces, clinical diagnostics, and cognitive monitoring, offering a more efficient and accurate alternative to current EEG analysis methods.

Self-control enhances vigilance performance in temporally irregular tasks: an fNIRS frontoparietal investigation.

The present study investigated whether trait self-control impacted operators' behavior and associated neural resource strategies during a temporally irregular vigilance task. Functional near-infrared spectroscopy (fNIRS) readings of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (HbR) from 29 participants were recorded fromthe prefrontal and parietal cortices. Self-control was associated with better perceptual sensitivity (A') in the task with the irregular event schedule. A left-lateralized effect of HbO2 was found for temporal irregularity within the dorsomedial prefrontal cortex, in accordance with functional transcranial doppler (fTCD) studies. Self-control increased HbR (decreasing activation) at right superior parietal lobule (rSPL; supporting vigilance utilization) and right inferior parietal lobule (rIPL; supporting resource reallocation). However, only rSPL was associated with the vigilance decrement-where decreases in activation led to better perceptual sensitivity in the temporally irregular task. Additionally, short stress-state measures suggest decreases in task engagement in individuals with higher self-control in the irregular task. The authors suggest a trait-state-brain-behavior relationship for self-control during difficult vigilance tasks. Implications for the study include steps toward rectifying the resource utilization vs. allocation debate in vigilance-as well as validating HbO2 and HbR as effective constructs for predicting operators' mental resources through fNIRS.

Assessing social anhedonia in a transdiagnostic sample: Insights from a computational psychiatry lens.

Anhedonia, a reduced ability to experience positive affect and seek rewards, is present across many psychiatric disorders, notably among individuals who experienced trauma. Within the social domain, anhedonia manifests as an altered sense of belonging and social isolation and is associated with poorer clinical outcomes. Yet, mechanistic operationalizations of social anhedonia are lacking, limiting our understanding of the relationship between these mechanisms and affective symptoms. To address these questions, we developed a social reward exploration task which was administered to a transdiagnostic sample of trauma-exposed Veterans (N = 33) while they underwent functional magnetic resonance imaging. The goal was to maximize compliments from two unknown partners, as participants were told these partners selected compliments based on seeing their picture. A Bayesian reinforcement learning modeling approach was used to extract cognitive and neural markers of compliment (reward) exploration. To address these questions, we developed a social reward exploration task which was administered to a transdiagnostic sample of trauma-exposed Veterans (N = 33) while they underwent functional magnetic resonance imaging. The goal was to maximize compliments from two unknown partners, as participants were told these partners selected compliments based on seeing their picture. A Bayesian reinforcement learning modeling approach was used to extract cognitive and neural markers of compliment (reward) exploration. Higher social connectedness (β = 0.51; 95 % CI=[0.11,0.94]) and anxiety (β = 0.57; 95 % CI=[0.13,1.00]) were independently associated with more model-based choices of the partner they anticipated to be most complimenting. In the dorsal anterior cingulate cortex (ACC; z = 3.89, p .001) and left inferior parietal lobule (z = 3.96, p .001), neural responses to reward prediction errors (RPE) were more positive in response to compliment relative to non-compliment outcomes. Greater positive RPE ACC activation was associated with lower anxiety (β = −0.51; 95 % CI=[−0.99,−0.10]. Computational approaches to social reinforcement learning can help identify important neurocognitive differences in social reward sensitivity among individuals with complex affective profiles, such as trauma-exposed individuals. Understanding these differences may help develop new prediction and treatment tools for social anhedonia.

The Lifespan Trajectories of Brain Activities Related to Cognitive Control.

Cognitive control plays a pivotal role in guiding human goal-directed behavior. While existing studies have documented an inverted U-shaped trajectory of cognitive control both behaviorally and anatomically, little is known about the corresponding changes in functional brain activation with age. To bridge this gap, we conducted a comprehensive meta-analysis of 129 neuroimaging studies using conflict tasks, encompassing 3,388 participants aged from 5 to 85 years old. We have three major findings: 1) The inverted U-shaped trajectory is the predominant pattern; 2) Cognitive control-related brain regions exhibit heterogeneous lifespan trajectories: the frontoparietal control network follows inverted U-shaped trajectories, peaking between 24 and 40 years, while the dorsal attention network demonstrates no clear trajectories; 3) Both the youth and the elderly show weaker brain activities and greater left laterality than young to middle-aged adults. These results reveal the lifespan trajectories of cognitive control, highlighting heterogeneous fluctuations in brain networks with age.

Correlation Between the Fractional Amplitude of Low-Frequency Fluctuation and Cognitive Defects in Alzheimer's Disease.

The fractional amplitude of low-frequency fluctuations (fALFFs) can detect spontaneous brain activity. However, the association between abnormal brain activity and cognitive function, amyloid protein (Aβ), and emotion in Alzheimer's disease (AD) patients remains unclear. This study aimed to survey alterations in fALFF in different frequency bands and the relationship between abnormal brain activity, depressive mood, and cognitive function to determine the potential mechanism of AD. We enrolled 34 AD patients and 32 healthy controls (HC). All the participants underwent resting-state magnetic resonance imaging, and slow-4 and slow-5 fALFF values were measured. Subsequently, the study determined the correlation of abnormal brain activity with mood and cognitive function scores. AD patients revealed altered mfALFF values in the slow-5 and slow-4 bands. In the slow-4 band, the altered mfALFF regions were the right cerebellar crus I, right inferior frontal orbital gyrus (IFOG), right supramarginal gyrus, right precuneus, angular gyrus, and left middle cingulate gyrus. Elevated mfALFF values in the right IFOG were negatively associated with Montreal Cognitive Assessment scores, Boston Naming Test, and Aβ1-42 levels. The mfALFF value of the AD group was lower than the HC group in the slow-5 band, primarily within the right inferior parietal lobule and right precuneus. Altered mfALFF values in AD patients are linked with cognitive dysfunction. Compared with HCs, Aβ1-42 levels in AD patients are related to abnormal IFOG activity. Therefore, mfALFF could be a potential biomarker of AD.

Functional connectivity of the amygdala in relation to high stress and low mindfulness

BackgroundHigh psychological stress has been associated with several brain functional changes, including functional connectivity (FC) alterations in regions such as the prefrontal cortex and the amygdala. This study explored FC alterations associated with high perceived stress, and also investigated whether these neuroimaging features were correlated with low levels of mindfulness. MethodsThis study included 29 adults (12 males and 17 females; mean age: 27.6 ± 3.2) who complained of moderate or higher perceived stress and 31 adults (17 males and 14 females; mean age: 29.2 ± 7.2) who complained of low-level stress on the questionnaire scale. Seed-based resting-state FC analysis was conducted to compare between high and low stress groups. The dorsolateral prefrontal cortex (DLPFC), the ventromedial prefrontal cortex (VMPFC) and the amygdala were selected as seeds. ResultsHigh stress group showed weaker left amygdala-based FC in the left cerebellum crus II and the left orbitofrontal cortex compared with low stress group. High stress group had weaker FC between the left DLPFC and the left inferior parietal lobule. On the contrary, high stress group had stronger FC between the left VMPFC and the left caudate compared with low stress group. Weaker FC between the amygdala and the cerebellum crus II was correlated with lower level of awareness facet of mindfulness. ConclusionsThose with high perceived stress showed low levels of mindfulness and several FC alterations centered on the prefrontal cortex and amygdala. Our findings also suggest that weak amygdala-based FC alterations associated with high psychological stress are related to low-level awareness facet of mindfulness.

Cortical and subcortical substrates of working memory in the right hemisphere: A connectome-based lesion-symptom mapping study

Working Memory (WM) is a cognitive system whose crucial role is to temporarily hold and manipulate information. Early studies suggest that verbal WM is typically associated with left hemisphere (LH) brain regions, while the processing of visuospatial information in WM more specifically depends on the right hemisphere (RH). However, recent evidence suggests a more complex network involving both hemispheres' prefrontal and posterior parietal cortices in these processes. Unfortunately, previous lesion studies often examined only one modality (either verbal, or visuospatial) or one hemisphere, which limits the possible conclusions regarding non-lateralized hemispheric involvement. Using connectome-based lesion-symptom mapping on a large sample of patients with left (LBD) and right (RBD) focal brain damage, we examined whether gray matter damage and white matter disconnections predict deficits of WM updating in an N-back task. Patients were examined with two WM tasks that differed regarding modality (verbal, spatial) and cognitive load (1-back, 2-back). Behavioral outcomes indicated that RBD patients showed significant deficits in WM updating, regardless of task modality or load. This observation was supported by whole-brain voxel-based analysis, revealing associations between WM deficits and gray matter clusters in the RH. Specifically, damage to the right lateral frontal cortex including the brain region homologous to Broca's area was associated with verbal WM deficits, while damage to the right inferior parietal lobe and posterior temporal cortex predicted spatial WM deficits. Additionally, white matter analyses identified severely impacted tracts in the RH, predicting deficits in both verbal and spatial WM. Our findings suggest that the mental manipulation of both verbal and visuospatial information in WM updating relies on the integrity of the RH, irrespective of the specific type of information held in mind.

Reward system neurodynamics during menstrual pain modulated by COMT Val158Met polymorphisms.

Primary dysmenorrhea (PDM), characterized by cyclic pain, may involve pain modulation within the reward system (RS). The Catechol-O-methyltransferase (COMT) Val158Met polymorphism, which significantly influences dopamine activity, is linked to the regulation of both acute and chronic pain. This study examines the differential neurodynamic modulation in the RS associated with COMT Val158Met polymorphisms during menstrual pain among PDM subjects. Ninety-one PDM subjects underwent resting-state fMRI during menstruation and were genotyped for COMT Val158Met polymorphisms. The amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) analyses were used to assess the RS response. Psychological evaluations included the McGill Pain Questionnaire, Pain Catastrophizing Scale, Beck Anxiety Inventory, and Beck Depression Inventory. Val/Val homozygotes (n = 50) and Met carriers (n = 41) showed no significant differences in McGill Pain Questionnaire, Beck Anxiety Inventory, and Beck Depression Inventory. However, Met carriers exhibited lower scores on the Pain Catastrophizing Scale. Distinct FC patterns was observed between Val/Val homozygotes and Met carriers, specifically between the nucleus accumbens (NAc) and prefrontal cortex, NAc and inferior parietal lobe, ventral tegmental area (VTA) and prefrontal cortex, VTA and precentral gyrus, and VTA and superior parietal lobe. Only Met carriers showed significant correlations between ALFF and FC values of the NAc and VTA with pain-related metrics (McGill Pain Questionnaire and Pain Catastrophizing Scale scores). NAc ALFF and NAc-prefrontal cortex FC values positively correlated with pain-related metrics, while VTA ALFF and VTA-prefrontal cortex and VTA-superior parietal lobe FC values negatively correlated with pain-related metrics. This study reveals that the COMT Val158Met polymorphism results in genotype-specific functional changes in the brain's RS during menstrual pain. In Met carriers, engagement of these regions is potentially linked to motivational reward-seeking and top-down modulation. This polymorphism likely influences the RS's responses, significantly contributing to individual differences in pain regulation.

Progressive gray matter atrophy in parkinsonian variant of multiple system atrophy assessed by using causal structural covariance network.

Multiple system atrophy (MSA), a rare neurodegenerative disease, is usually accompanied by brain morphological alterations. However, the causal relationships between progressive gray matter atrophy in MSA parkinsonian (MSA-P) subtype remain unknown. In total, thirty-five MSA-P patients and thirty-five healthy controls (HC) underwent three-dimensional high-resolution T1-weighted structural imaging and voxel-based morphometry analysis. The causal structural covariance network (CaSCN) of gray matter was assessed to explore the causal relationships in MSA-P. With greater illness duration, the reduction of gray matter was originated from right cerebellum and progressed to bilateral cerebellum, fusiform gyrus, insula, putamen, caudate nucleus, frontal lobe, right angular gyrus, right precuneus, left middle occipital lobe and left inferior temporal lobe, then expanded to midbrain, bilateral para-hippocampus, thalamus, temporal lobe, inferior parietal lobule (IPL), precentral gyrus, postcentral gyrus and middle cingulate cortex. The right cerebellum was revealed to be the core node of the directional network and projected positive causal effects to bilateral cerebellum, caudate nucleus and left IPL. MSA-P patients showed progression of gray matter atrophy over time, with the right cerebellum probably as a primary hub. Furthermore, the early structural vulnerability of cerebellum in MSA-P may play a pivotal role in the modulation of motor and non-motor circuits at the structural level.

Physical activity and frontoparietal network connectivity in traumatic brain injury.

Prolonged changes to functional network connectivity as a result of a traumatic brain injury (TBI) may relate to long-term cognitive complaints reported by TBI survivors. No interventions have proven to be effective at treating long-term cognitive complaints after TBI but physical activity has been shown to promote cognitive function and modulate functional network connectivity in non-injured adults. Therefore, the objective of this study was to test if physical activity engagement was associated with functional connectivity of the cognitively relevant frontoparietal control network (FPCN) in adults with a TBI history. In a case-control study design, resting state function magnetic resonance imaging and physical activity data from a subset of participants (18-81 years old) from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) study was analyzed. Fifty-seven participants reported a prior head injury with loss of consciousness and 57 age and sex matched controls were selected. Seed-based functional connectivity analyses were performed using seeds in the dorsolateral prefrontal cortex and the inferior parietal lobule, to test for differences in functional connectivity between groups, associations between physical activity and functional connectivity within TBI as well as differential associations between physical activity and functional connectivity between TBI and controls. Seed-based connectivity analyses from the dorsolateral prefrontal cortex showed that those with a history of TBI had decreased positive connectivity between dorsolateral prefrontal cortex and intracalcarine cortex, lingual gyrus, and cerebellum, and increased positive connectivity between dorsolateral prefrontal cortex and cingulate gyrus and frontal pole in the TBI group. Results showed that higher physical activity was positively associated with increased connectivity between the dorsolateral prefrontal cortex and inferior temporal gyrus. Differential associations were observed between groups whereby the strength of the physical activity-functional connectivity association was different between the inferior parietal lobule and inferior temporal gyrus in TBI compared to controls. Individuals with a history of TBI show functional connectivity alterations of the FPCN. Moreover, engagement in physical activity is associated with functional network connectivity of the FPCN in those with a TBI. These findings are consistent with the evidence that physical activity affects FPCN connectivity in non-injured adults; however, this effect presents differently in those with a history of TBI.

Abstract 56: High Blood Pressure Is Associated with Lower Brain Volume and Cortical Thickness in Healthy Young Adults

Background: High blood pressure (BP) in middle-aged and older adults is associated with lower brain volume and cortical thickness assessed with structural MRI. However, little evidence is available in young adults. Objective: We investigated the associations of high BP with brain volumes and cortical thickness in healthy young adults. We hypothesized that high BP is associated with lower brain volume and cortical thickness in young adults. Methods: This cross-sectional study included 1095 young adults (54% women, 22-37 years) from the Human Connectome Project (HCP) who self-reported not having a history of hypertension or taking antihypertensive medications. Brachial systolic (SBP) and diastolic BP (DBP) were measured with semi-automatic or manual sphygmomanometer during study visits. Structural MRI was used to measure gray matter (GM) and white matter (WM) volume and mean cortical thickness. Associations of BP and hypertension stage with total and regional brain volumes and cortical thickness were analyzed using linear regression and analysis of covariance (ANCOVA) after adjusting for age, sex, education years, body mass index (BMI), smoking, alcohol consumption history, zygosity, and total intracranial volume. Results: SBP and DBP were (mean ± SD) 123.6 ± 14.2 and 76.5 ± 10.6 mmHg, respectively (n = 1095). High DBP was associated with lower total GM ( p = 0.012), cortical GM ( p = 0.004), subcortical GM ( p = 0.012), and total WM volumes ( p = 0.031). There were no associations of SBP and hypertension stage with total brain volume and cortical thickness. High SBP and DBP were associated with lower regional cortical thickness in the parietal lobe and lingual gyrus, and lower regional cortical volume in the postcentral gyrus, inferior parietal lobe, lateral occipital gyrus, and middle temporal gyrus. Conclusion: Associations of high BP, particularly DBP, with lower total and regional brain volume and cortical thickness were observed in healthy young adults. These findings suggest the importance of prevention or control of high BP early in life for brain health.

Action Segmentation in the Brain: The Role of Object-Action Associations.

Motion information has been argued to be central to the subjective segmentation of observed actions. Concerning object-directed actions, object-associated action information might as well inform efficient action segmentation and prediction. The present study compared the segmentation and neural processing of object manipulations and equivalent dough ball manipulations to elucidate the effect of object-action associations. Behavioral data corroborated that objective relational changes in the form of (un-)touchings of objects, hand, and ground represent meaningful anchor points in subjective action segmentation rendering them objective marks of meaningful event boundaries. As expected, segmentation behavior became even more systematic for the weakly informative dough. fMRI data were modeled by critical subjective, and computer-vision-derived objective event boundaries. Whole-brain as well as planned ROI analyses showed that object information had significant effects on how the brain processes these boundaries. This was especially pronounced at untouchings, that is, events that announced the beginning of the upcoming action and might be the point where competing predictions are aligned with perceptual input to update the current action model. As expected, weak object-action associations at untouching events were accompanied by increased biological motion processing, whereas strong object-action associations came with an increased contextual associative information processing, as indicated by increased parahippocampal activity. Interestingly, anterior inferior parietal lobule activity increased for weak object-action associations at untouching events, presumably because of an unrestricted number of candidate actions for dough manipulation. Our findings offer new insights into the significance of objects for the segmentation of action.