Voxel-based Morphometry Analysis Research Articles

Reduced Sulcal Depth in Central Sulcus of Major Depressive Disorder.

Major depressive disorder (MDD) is one of the most common psychiatric disorders, and present various symptoms such as the dysregulation of mood, cognition, and behavior. The purpose of the present study was to investigate the morphometric change in MDD patients by voxel-based morphometry (VBM) and sulcal depth analyses. Forty-six MDD patients (mean age, SD; 36.07±14.34), and 23 age- and sex-matched normal controls (NML) (mean age, SD; 36.78±14.42) were included. Coronal 3D T1 magnetic resonance imaging (MRI) was obtained with the resolution of isotropic 1.0 mm. To check morphological changes of brain, T1 MRIs were objectively processed by VBM and sulcal depth methods. In sulcal depth analysis, depressed patients showed reduced sulcal depth in the areas of left posterior ramus of the lateral sulcus, superior frontal sulcus, supramarginal gyrus, central sulcus (Rolando's fissure), and Heschl's gyrus. And right posterior ramus of the lateral sulcus, temporal plane of the superior temporal gyrus, anterior transverse collateral sulcus, and central sulcus (Rolando's fissure) were also reduced compared to NML. But, VBM analyses did not showed significant finding. Reduced sulcal depth in the motor and emotion related areas were found in patients with MDD. Especially reduced sulcal depth in bilateral central sulci which are connecting between primary motor cortex and primary sensory cortex seems to be related with social and physical anhedonia in MDD.

Meta-analytical evidence of functional and structural abnormalities associated with pain processing in migraine patients: An activation likelihood estimation.

Migraine is a primary headache disorder that causes debilitating throbbing pain. Several functional MRI (fMRI) and voxel-based morphometry (VBM) studies have been used to investigate the structural and functional alteration in migraine. Here, we aim to study the converged brain regions of functional and structural abnormalities in gray matter volume (GMV) associated with pain processing and management in migraineurs and healthy controls (HC). A systematic search through PubMed and Sleuth was carried out for peer-reviewed functional and structural neuroimaging studies on migraine patients and HC yielded a total of 1136 studies. We performed an activation likelihood estimation (ALE) meta-analysis on VBM and pain stimulation task-based fMRI studies to investigate the converged areas of GMV and functional abnormalities between migraineurs and HC. We performed two subgroup analyses between migraine with aura (MwA) and migraine without aura (MwoA) relative to HC, and between chronic migraine (CM) and episodic migraine (EM) compared to HC. The total sample included 16 fMRI and 22 VBM studies, consisting of 1295 migraine patients, compared to 995 HC. In fMRI analysis, ALE maps for pain stimulation tasks revealed hyperactivation in migraineurs in the substantia nigra compared to HC, whereas hypoactivation was seen in the cerebellum. For the VBM analysis, ALE clusters of increased GMV in migraineurs were observed in the parahippocampus and putamen nucleus. Whereas clusters of reduced GMV in migraineurs were seen in the frontal gyri. Compared to HC, MwoA patients showed a GMV reduction in the insula, and anterior cingulate, whereas MwA patients showed GMV reduction in the cerebellum, cingulate gyrus, and insula. CM patients showed decreased GMV in the precentral gyrus, whereas EM patients showed decreased GMV in the parahippocampus, and inferior frontal gyrus when compared to HC. Our findings represent a potential biomarker for the diagnosis and management of migraine, by showing clustered brain regions of abnormal patterns of activation and GMV changes between migraineurs and HC which might be associated with hyposensitivity to pain in migraineurs. Further studies are required to determine disease progression or therapeutic interventions' effect on migraine.

Brain network characteristics and cognitive performance in motor subtypes of Parkinson's disease: A resting state fMRI study

IntroductionParkinson's disease (PD) is a heterogeneous disorder with great variability in motor and non-motor manifestations. It is hypothesized that different motor subtypes are characterized by different neuropsychiatric and cognitive symptoms, but the underlying correlates in cerebral connectivity remain unknown. Our aim is to compare brain network connectivity between the postural instability and gait disorder (PIGD) and tremor-dominant (TD) subtypes, using both a within- and between-network analysis. MethodsThis cross-sectional resting-state fMRI study includes 81 PD patients, 54 belonging to the PIGD and 27 to the TD subgroup. Group-level spatial maps were created using independent component analysis. Differences in functional connectivity were investigated using dual regression analysis and inter-network connectivity analysis. An additional voxel-based morphometry analysis was performed to examine if results were influenced by grey matter atrophy. ResultsThe PIGD subgroup scored worse than the TD subgroup on all cognitive domains. Resting-state fMRI network analyses suggested that the connection between the visual and sensorimotor network is a potential differentiator between PIGD and TD subgroups. However, after correcting for dopaminergic medication use these results were not significant anymore. There was no between-group difference in grey matter volume. ConclusionDespite clear motor and cognitive differences between the PIGD and TD subtypes, no significant differences were found in network connectivity. Methodological challenges, substantial symptom heterogeneity and many involved variables make analyses and hypothesis building around PD subtypes highly complex. More sensitive visualisation methods combined with machine learning approaches may be required in the search for characteristic underpinnings of PD subtypes.

Reduced Gray Matter Volumes among Long Term Survivors of Head and Neck Cancer Treated with Radiation Therapy

<h3>Purpose/Objective(s)</h3> To investigate brain morphometry among long term survivors of head and neck cancer (HNC) treated with radiotherapy (RT). Specifically, we sought to calculate the brain age gap estimation among HNC survivors and to perform voxel-based morphometry (VBM) to calculate local gray matter volumes between HNC survivors and controls without history of cancer. <h3>Materials/Methods</h3> We recruited 39 HNC survivors (age range: 32.6y – 71.9y, 25.6% female) who were treated with RT >2y prior and who were currently without evidence of recurrent tumor. Participants underwent a multimodal magnetic resonance imaging (MRI) protocol. Scans were performed on a technology company's Prisma 3-Tesla using a 20-channel head coil. The scan protocol included T1-weighted imaging acquired at 1mm slice thickness. Brain age was estimated utilizing total brain gray matter, white matter, and cerebrospinal fluid with brainageR v2.1 and compared to chronologic age using the paired-samples T-test. VBM analysis was performed using Computational Anatomy Toolbox v12 with a regions of interest (ROI) approach utilizing the neuromorphometrics brain atlas. Gray matter volumes for ROIs were used to compare the study cohort to a normative sample of 35 adults age >45 years from the MGH-USC Human Connectome Project. Differences in gray matter volume were compared using the independent samples T-test controlled for total intracranial volume and sex and conservatively adjusted for multiple comparisons using the Holm-Bonferroni method. <h3>Results</h3> Estimated brain age was calculated for all participants; 1 participant was excluded from VBM analysis due to inadequate imaging quality. The mean estimated gray matter brain age of 60.2y was not significantly different to the mean chronologic age of the sample at 61.2y (p=0.353). Results from the VBM analysis demonstrated significantly reduced gray matter volume in the HNC survivors group compared to control group in the bilateral orbital gyrus, cingulate cortex, basal forebrain, thalamus, and cerebellum. In total, 35 left hemisphere regions of interest (ROIs) and 34 right hemisphere ROIs demonstrated reduced gray matter volume in the HNC survivor group at the p<0.001 significance level. No ROIs had increased gray matter among HNC survivors. <h3>Conclusion</h3> To our knowledge, this study is the first to assess brain morphometry among HNC survivors. We did not observe a brain age gap, but VBM gray matter volumes were significantly reduced in multiple brain regions, mostly subcortical and in the most inferior part of the cortex. Future research is needed to characterize how brain morphometry is related to patient outcomes as well as modifiable treatment factors such as brain radiation exposure.

Longitudinal neuroplasticity after ankle sprain in mice: A voxel-based morphometry study on 11.7T MRI.

Lateral ankle sprains (LAS) might lead to joint sensory deafferentation, which induces maladaptive neuroplasticity, especially the morphological atrophy of the cerebellar vermis. However, longitudinal evidence on the causality of injury and neural differences is still lacking. To this end, this study aimed to determine whether the morphology of the central nervous system would be altered before and after ligament transection in LAS mouse models. A total of 40 C57BL/6 mice were randomly divided among the LAS, Sham and Blank groups. We repeatedly performed the balance beam test and neural voxel-based morphometry (VBM) measurements using an 11.7 T magnetic resonance imagingbefore and 2 months after the surgery. The results showed that for balance outcomes, the LAS group had a significantly longer time and more slips of the balance beam tests compared with the Sham and Blank groups at 2 months after surgery, with no significant difference among the three groups before surgery. Regarding the VBM analysis, the LAS group showed significantly lower VBM values in the central lobule IIIof the cerebellar vermis and medial amygdalar nucleus (MEA) compared with the Sham and Blank groups after surgery, with no significant difference among the three groups before surgery. In conclusion, lateral ligament injuries might lead to morphological atrophy of the cerebellar vermis in animal models, which might pave the way for the pathological process of ankle instability after LAS.

Clinical correlates of R1 relaxometry and magnetic susceptibility changes in multiple sclerosis: a multi-parameter quantitative MRI study of brain iron and myelin

ObjectivesThe clinical impact of brain microstructural abnormalities in multiple sclerosis (MS) remains elusive. We aimed to characterize the topography of longitudinal relaxation rate (R1) and quantitative susceptibility (χ) changes, as indices of iron and myelin, together with brain atrophy, and to clarify their contribution to cognitive and motor disability in MS.MethodsIn this cross-sectional study, voxel-based morphometry, and voxel-based quantification analyses of R1 and χ maps were conducted in gray matter (GM) and white matter (WM) of 117 MS patients and 53 healthy controls. Voxel-wise between-group differences were assessed with nonparametric permutation tests, while correlations between MRI metrics and clinical variables (global disability, cognitive and motor performance) were assessed both globally and voxel-wise within clusters emerging from the between-group comparisons.ResultsMS patients showed widespread R1 decrease associated with more limited modifications of χ, with atrophy mainly involving deep GM, posterior and infratentorial regions (p < 0.02). While R1 and χ showed a parallel reduction in several WM tracts (p < 0.001), reduced GM R1 values (p < 0.001) were associated with decreased thalamic χ (p < 0.001) and small clusters of increased χ in the caudate nucleus and prefrontal cortex (p < 0.02). In addition to the atrophy, χ values in the cingulum and corona radiata correlated with global disability and motor performance, while focal demyelination correlated with cognitive performance (p < 0.04).ConclusionsWe confirmed the presence of widespread R1 changes, involving both GM and WM, and atrophy in MS, with less extensive modifications of tissue χ. While atrophy and χ changes are related to global and motor disability, R1 changes are meaningful correlates of cognition.Key Points• Compared to healthy controls, multiple sclerosis patients showed R1 and χ changes suggestive of iron increase within the basal ganglia and reduced iron and myelin content within (subnuclei of) the thalamus.• Thalamic volume and χ changes significantly predicted clinical disability, as well as pulvinar R1 and χ changes, independently from atrophy.• Atrophy-independent R1 and χ changes, suggestive of thalamic iron and myelin depletion, may represent a sensitive marker of subclinical inflammation.

Episodic future thinking predicts differences in delay discounting: The mediating role of hippocampal structure.

A growing body of evidence suggests that engagement in episodic future thinking (EFT) could reduce delay discounting rates. However, little is known about whether individual differences in the ability of EFT are associated with differences in delay discounting in young adults. In the present study, this association was tested in healthy college students (n = 106, 19.98 ± 1.56 years), and the neural basis underlying this association was also examined using voxel-based morphometry (VBM) method. Behavioral analysis indicated that individual differences in EFT ability can significantly negatively predict discounting rates. VBM analysis first revealed that the EFT score positively correlated with gray matter volume (GMV) of a cluster in hippocampus, while negatively correlated with GMV of a cluster in rostral anterior cingulate cortex. We also found the GMV of a cluster in the mPFC was positively correlated with delay discounting. ROI analysis further revealed that individual differences in delay discounting could be reliably predicted by the GMV in the hippocampus and mPFC. The final mediation analysis showed that the GMV of the hippocampus plays a significant mediating role in the association between EFT and delay discounting, and the indirect effect of the hippocampal GMV accounts for 33.2% of the total effect. Our results suggest that individuals’ EFT ability may be an important determinant of differences in delay discounting, and highlight the hippocampal structure as a neural biomarker for explaining the association between EFT ability and delay discounting.

Contralesional macrostructural plasticity in patients with frontal low-grade glioma: a voxel-based morphometry study.

Neuroplasticity can partially compensate for the neurological deficits caused by brain tumors. However, the structural plasticity of the brain caused by brain tumors is not fully understood. This study aimed to assess the structural plasticity of the contralesional hemisphere in patients with frontal low-grade gliomas (LGGs). A total of 25 patients with left frontal LGGs (LFLGGs), 19 patients with right frontal LGGs (RFLGGs), and 25 healthy controls (HCs) were enrolled in this study. High-resolution structural T1-weighted imaging and fluid attenuation inversion recovery were performed on all participants. Voxel-based morphometry (VBM) analysis was used to detect differences in the brain structural plasticity between patients with unilateral LGGs and HCs. VBM analysis revealed that compared with HCs, the gray matter volume (GMV) of the contralesional putamen and amygdala was significantly smaller and larger in the patients with RFLGGs and LFLGGs, respectively, while the GMVs of the contralesional cuneus and superior temporal gyrus (STG) were significantly larger in the patients with LFLGGs. The surviving clusters of the right hemisphere included 1357 voxels in the amygdala, 1680 voxels in the cuneus, 384 voxels in the STG, and 410 voxels in the putamen. The surviving clusters of the left hemisphere were 522 voxels in the amygdala and 320 voxels in the putamen. The unilateral frontal LGGs are accompanied by structural plasticity in the contralesional cortex and vary with tumor laterality. Contralesional structural reorganization may be one of the physiological basis for functional reorganization or compensation in the frontal LGGs.

Regional gray matter volume mediates the relationship between neuroticism and depressed emotion.

The underlying psychological mechanism of the effect of neuroticism on depressed emotion has been widely studied. However, the neural mechanism of this relationship remains unclear. Therefore, the present study aimed to apply voxel-based morphometry (VBM) to explore the neural mechanism of the relationship between depressed emotion and neuroticism in healthy and young participants through longitudinal tracking research. The behavioral results showed that neuroticism was positively related to depressed emotion at T1 and T2 (6 months later). The VBM analysis revealed that neuroticism positively associated with the gray matter volume (GMV) in the dorsal medial prefrontal cortex (dmPFC). Mediation analysis was conducted to investigate the neural basis of the association between depressed emotion and neuroticism. The mediation result revealed that GMV of the dmPFC partially mediates the relationship between neuroticism and depressed emotion at T1 but not T2. Together, these findings suggest that the gray matter volume of dmPFC could may affect the relationship between depressed emotion and neuroticism.

Structural plasticity of motor cortices assessed by voxel-based morphometry and immunohistochemical analysis following internal capsular infarcts in macaque monkeys.

Compensatory plastic changes in the remaining intact brain regions are supposedly involved in functional recovery following stroke. Previously, a compensatory increase in cortical activation occurred in the ventral premotor cortex (PMv), which contributed to the recovery of dexterous hand movement in a macaque model of unilateral internal capsular infarcts. Herein, we investigated the structural plastic changes underlying functional changes together with voxel-based morphometry (VBM) analysis of magnetic resonance imaging data and immunohistochemical analysis using SMI-32 antibody in a macaque model. Unilateral internal capsular infarcts were pharmacologically induced in 5 macaques, and another 5 macaques were used as intact controls for immunohistochemical analysis. Three months post infarcts, we observed significant increases in the gray matter volume (GMV) and the dendritic arborization of layer V pyramidal neurons in the contralesional rostral PMv (F5) as well as the primary motor cortex (M1). The histological analysis revealed shrinkage of neuronal soma and dendrites in the ipsilesional M1 and several premotor cortices, despite not always detecting GMV reduction by VBM analysis. In conclusion, compensatory structural changes occur in the contralesional F5 and M1 during motor recovery following internal capsular infarcts, and the dendritic growth of pyramidal neurons is partially correlated with GMV increase.

Higher brain structural heterogeneity in schizophrenia

As a highly heterogeneous disorder, schizophrenia shows notable interindividual variation in clinical manifestations. On that account, an increasing number of studies begin to examine the interindividual variability in neuroimaging characterization in schizophrenia. However, whether schizophrenia demonstrates higher interindividual morphological variability than health controls (HCs) remains unknown. T1-weighted anatomical images were obtained from patients with schizophrenia (n = 61) and matched HCs (n = 73). For each subject, voxel-wise gray matter volume was obtained using voxel-based morphometry analysis. We first inquired whether patients with schizophrenia showed higher interindividual structural variation than HCs using the person based similarity index (PBSI). Then, we examined differences of voxel-wise morphological coefficient of variation (CV) between schizophrenia and HCs. To further associate identified regions showing higher variability in schizophrenia with cognitive/functional processes, functional annotation was performed. Patients with schizophrenia exhibited lower PBSIs than matched HCs, suggesting higher interindividual morphological variability in schizophrenia. The following results showed that patients with schizophrenia exhibited higher CVs than HCs in distributed brain regions including the striatum, hippocampus, thalamus, parahippocampa gyrus, frontal gyrus, and amygdala. Brain regions showing higher CVs in schizophrenia were significantly implicated in affective, incentive and reward related terms. These results provide a new insight into the high clinical heterogeneity and facilitate personalized diagnose and treatment in schizophrenia.

Synergetic reorganization of the contralateral structure and function in patients with unilateral frontal glioma.

ObjectiveThis study aimed to investigate the contralateral structural and functional plasticity induced by frontal gliomas.MethodsPatients with left (n = 49) or right (n = 52) frontal diffuse glioma were enrolled along with 35 age- matched healthy controls (HCs). The gray-matter volumes (GMVs) of the contralesional region were measured using the voxel-based morphometry (VBM) analysis. Additionally, the amplitude of low-frequency fluctuation (ALFF) of the contralesional region was calculated via resting state functional magnetic resonance imaging (MRI) to assess functional alterations.ResultThe GMV of the contralateral orbitofrontal cortex of the right or left frontal gliomas was significantly larger than the corresponding GMV in the controls. In the patients with right frontal glioma, the GMV and ALFF in the left inferior frontal gyrus were significantly increased compared with those in the controls.ConclusionGlioma invasion of the frontal lobe can induce contralateral structural compensation and functional compensation, which show synergy in the left inferior frontal gyrus. Our findings explain why patients with unilateral frontal glioma can have functional balance, and offer the possibility of preserving the brain function while maximizing tumor removal.

Brain Anatomy Alterations and Mental Health Challenges Correlate to Email Addiction Tendency.

Despite the widespread use of email, our knowledge regarding the consequences of email addiction is lacking. The purpose of this study was to develop an email addiction tendency scale to evaluate its correlation to behavior and brain structure. Following this, the validity and reliability of the developed scale was investigated. We used voxel-based morphometry, correlation, and univariate regression analysis to assess the relationships between email addiction tendency scores and regional gray and white matter volumes, depression, and nonverbal reasoning abilities in a large sample of healthy young adults (n = 1152; mean age, 20.69 ± 1.84 years). The content validity ratio, content validity index, principal component analysis, and confirmatory factorial analysis all showed that the email addiction tendency scale (EATS) has high validity. Additionally, the Cronbach’s alpha internal consistency and split-half reliability coefficient showed that the EATS has high reliability. We found that email addiction tendency scores were significantly negatively correlated with nonverbal reasoning. We also observed that the email addiction tendency scores were significantly and positively correlated with depression symptom severity and gray matter volume of the left rostrolateral prefrontal cortex (RLPC) in subjects. These results indicate that email addiction tendency is associated with lower mental health outcomes and increased GMV in the left RLPC.

Analysis of the extent of limbic system changes in multiple sclerosis using FreeSurfer and voxel-based morphometry approaches.

Background and purposeThe limbic brain is involved in diverse cognitive, emotional, and autonomic functions. Injury of the various parts of the limbic system have been correlated with clinical deficits in MS. The purpose of this study was to comprehensively examine different regions of the subcortical limbic system to assess the extent of damage within this entire system as it may be pertinent in correlating with specific aspects of cognitive and behavioral dysfunction in MS by using a fully automated, unbiased segmentation approach.MethodsSixty-seven subjects were included in this study, including 52 with multiple sclerosis (MS) and 15 healthy controls. Only patients with stable MS disease, without any relapses, MRI activity, or disability progression were included. Subcortical limbic system segmentation was performed using the FreeSurfer pipeline ScLimbic, which provides volumes for fornix, mammillary bodies, hypothalamus, septal nuclei, nucleus accumbens, and basal forebrain. Hippocampus and anterior thalamic nuclei were added as additional components of the limbic circuitry, also segmented through FreeSurfer. Whole limbic region mask was generated by combining these structures and used for Voxel-based morphometry (VBM) analysis.ResultsThe mean [95% confidence interval] of the total limbic system volume was lower (0.22% [0.21–0.23]) in MS compared to healthy controls (0.27%, [0.25–0.29], p < .001). Pairwise comparisons of individual limbic regions between MS and controls was significant in the nucleus accumbens (0.046%, [0.043–0.050] vs. 0.059%, [0.051–0.066], p = .005), hypothalamus (0.062%, [0.059–0.065] vs. 0.074%, [0.068–0.081], p = .001), basal forebrain (0.038%, [0.036–0.040] vs. 0.047%, [0.042–0.051], p = .001), hippocampus (0.47%, [0.45–0.49] vs. 0.53%, [0.49–0.57], p = .004), and anterior thalamus (0.077%, [0.072–0.082] vs. 0.093%, [0.084–0.10], p = .001) after Bonferroni correction. Volume of several limbic regions was significantly correlated with T2 lesion burden and brain parenchymal fraction (BPF). Multiple regression model showed minimal influence of BPF on limbic brain volume and no influence of other demographic and disease state variables. VBM analysis showed cluster differences in the fornix and anterior thalamic nuclei at threshold p < 0.05 after adjusting for covariates but the results were insignificant after family-wise error corrections.ConclusionsThe results show evidence that brain volume loss is fairly extensive in the limbic brain. Given the significance of the limbic system in many disease states including MS, such volumetric analyses can be expanded to studying cognitive and emotional disturbances in larger clinical trials. FreeSurfer ScLimbic pipeline provided an efficient and reliable methodology for examining many of the subcortical structures related to the limbic brain.

The critical role of the orbitofrontal cortex for regret in an economic decision-making task.

Regret affects decision-making behavior, which is mediated by a cognitive process known as counterfactual thinking in economic science. Several studies indicate that orbitofrontal cortex (OFC) plays a crucial role in decision-making behavior. However, the neural correlates of regret trait and the function of the OFC in decision-making remain unclear. In this study, we employed a typical monetary decision-making task, a modified 'Wheel of Fortune gamble' paradigm, to investigate decision-making behavior and its neural mechanism. We combined voxel-based morphometry (VBM) and task-evoked functional magnetic resonance imaging (fMRI) analyses to explore the neural substrates of regret trait. VBM analyses revealed that individual Regret Scale Score was negatively associated with the gray-matter volume (GMV) in the frontal and temporal areas, including the bilateral OFC. These results indicate that individuals with high regret trait have smaller GMV in these areas. Moreover, we found stronger task-evoked activation of the left OFC in high regret trait individuals during the decision-maker's choice (choose conditions) phase, whereas we did not find this relationship in computer-selected's (follow conditions) choice phase. Using generalized psychophysiological interactions (PPI) analysis, we further found that the functional connectivity of the left OFC to right inferior frontal gyrus and left cerebellum was stronger in the complete feedback choose condition (under regret theoretical framework) than partial feedback choose condition (under disappointment theoretical framework). These findings verify the critical role of the OFC in the decision-making, more importantly, provide novel insights into the morphological and functional substrates of individual regret trait.

Neural basis of impaired narrative discourse comprehension in prodromal and mild dementia with lewy bodies.

Narrative discourse (ND) comprehension is a complex task that implies not only linguistic abilities but also other cognitive abilities, including efficient executive functioning. An executive dysfunction has been described in dementia with Lewy bodies (DLB) from the early stage. Here, we question the link between executive dysfunction in DLB and narrative comprehension. The aim of our study was to evaluate ND comprehension and to investigate the neuroanatomical basis for its impairment in the early stage of DLB. DLB patients (N = 26) and controls (N = 19) underwent the ND comprehension test of the Montreal Protocol for Evaluation of Communication (MEC). An additional, qualitative analysis was conducted on their verbal productions. Cognitive tests assessing verbal episodic memory, executive functions, naming and oral syntactic comprehension were also performed. Brain gray matter correlates of the ND comprehension test were examined using voxel-based morphometry (VBM). An ND comprehension impairment was found for prodromal and mild DLB patients as compared to controls. These difficulties were correlated with the Frontal Assessment Battery (FAB) score. ND comprehension impairment in DLB was further characterized by a deficit in the organization and the logic of the discourse. Moreover, VBM analysis revealed a correlation between striatal gray matter volumes and DLB patients’ ability to extract and organize relevant information (p < 0.05, FDR correction, cluster level). The ND comprehension impairment in DLB patients could be related to their executive dysfunction through a deficit of information selection and organization that correlates with the volumetric reduction of striatal gray matter.

Impaired interhemispheric synchrony in Parkinson's disease patients with apathy

BackgroundApathy is a common non-motor symptom in Parkinson's disease (PD), yet the neural mechanism remains unknown. It has been reported that the lateralization of dopamine levels is correlated with apathetic symptoms. We aimed to ascertain the role of lateralization in the neuropathogenesis of apathy in PD. MethodsTwenty-six apathetic PD patients (PD-A), twenty-seven nonapathetic PD patients (PD-NA), and twenty-three healthy controls (HCs) were recruited. All subjects underwent T1-weighted and resting state functional MRI scanning during OFF medication state. Voxel-mirrored Homotopic Connectivity (VMHC) and asymmetry voxel-based morphometry (asymmetry VBM) analysis were applied to detect the synchrony of homotopic connections between hemispheres and grey matter asymmetry index. ResultsCompared with both PD-NA and HCs groups, the PD-A group showed excessively decreased z-VMHC values in the nucleus accumbens (NAcc) and putamen. Additionally, both PD subgroups exhibited decreased z-VMHC values in the cerebellum lobule VIII compared with controls. However, no corresponding alteration in grey matter asymmetry index was found. Further, a negative correlation between the z-VMHC values of the NAcc and the Apathy Scale (AS) was confirmed in the PD-A group. Meanwhile, the same relationship was also confirmed between the putamen and AS. Notably, ROC curve analyses uncovered that the z-VMHC values of the NAcc and putamen could be a potential neuroimaging feature discerning apathetic PD patient, respectively. LimitationsThis is a cross-sectional study. ConclusionOur findings demonstrated that the asymmetric functional connectivity in the mesocorticolimbic and nigrostriatal systems might induce the pathophysiological mechanisms of apathy in PD.

Alterations of voxel-wise spontaneous activity and corresponding brain functional networks in multiple system atrophy patients with mild cognitive impairment.

Emerging evidence has indicated that cognitive impairment is an underrecognized feature of multiple system atrophy (MSA). Mild cognitive impairment (MCI) is related to a high risk of dementia. However, the mechanism underlying MCI in MSA remains controversial. In this study, we conducted the amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) analyses to detect the characteristics of local neural activity and corresponding network alterations in MSA patients with MCI (MSA-MCI). We enrolled 80 probable MSA patients classified as cognitively normal (MSA-NC, n=36) and MSA-MCI (n=44) and 40 healthy controls. Compared with MSA-NC, MSA-MCI exhibited decreased ALFF in the right dorsal lateral prefrontal cortex (RDLPFC) and increased ALFF in the right cerebellar lobule IX and lobule IV-V. In the secondary FC analyses, decreased FC in the left inferior parietal lobe (IPL) was observed when we set the RDLPFC as the seed region. Decreased FC in the bilateral cuneus, left precuneus, and left IPL and increased FC in the right middle temporal gyrus were shown when we set the right cerebellar lobule IX as the seed region. Furthermore, FC of DLPFC-IPL and cerebello-cerebral circuit, as well as ALFF alterations, were significantly correlated with Montreal Cognitive Assessment scores in MSA patients. We also employed whole-brain voxel-based morphometry analysis, but no gray matter atrophy was detected between the patient subgroups. Our findings indicate that altered spontaneous activity in the DLPFC and the cerebellum and disrupted DLPFC-IPL, cerebello-cerebral networks are possible biomarkers of early cognitive decline in MSA patients.

Frontostriatal Functional Connectivity Underlies the Association between Punishment Sensitivity and Procrastination.

Procrastination is defined as putting off an intended course of action voluntarily despite the harmful consequences. Previous studies have suggested that procrastination is associated with punishment sensitivity in that high punishment sensitivity results in increased negative utility for task performance. We hypothesized the effects of punishment sensitivity on procrastination would be mediated by a network connecting the caudate nucleus and prefrontal cortex, both of which have been previously associated with self-control and emotional control during procrastination. We employed voxel-based morphometry (VBM) and resting-state functional connectivity (rsFC) to examine the neural substrates of punishment sensitivity and its relationship with procrastination (N = 268). The behavioral results indicated a strong positive correlation between measures of punishment sensitivity and procrastination. The VBM analysis revealed that the gray matter (GM) volume of the right caudate was significantly positively correlated with punishment sensitivity. The primary rsFC analysis revealed connectivity between this caudate location and the bilateral middle frontal gyrus (MFG) was significantly negatively correlated with punishment sensitivity. A mediation model indicated punishment sensitivity completely mediated the relation between functional connectivity within a caudate–bilateral MFG network and procrastination. Our results support the theory that those with higher punishment sensitivity have weaker effective emotional self-control supported by the caudate–MFG network, resulting in greater procrastination.

A Multimodal Neuroimaging and Neuropsychological Study of Visual Hallucinations in Alzheimer's Disease.

Hallucinations in Alzheimer's disease (AD) have been linked to more severe cognitive and functional decline. However, research on visual hallucinations (VH), the most common type of hallucinations in AD, is limited. To investigate the cognitive and cerebral macrostructural and metabolic features associated with VH in AD. Twenty-four AD patients with VH, 24 with no VH (NVH), and 24 cognitively normal (CN) matched controls were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Differences in regional gray matter (GM) volumes and cognitive performance were investigated with whole brain voxel-based morphometry analyses of MRI structural brain scans, and analyses of neuropsychological tests. Glucose metabolic changes were explored in a sub-sample of patients who had FDG-PET scans available. More severe visuoconstructive and attentional deficits were found in AD VH compared with NVH. GM atrophy and hypometabolism were detected in occipital and temporal areas in VH patients in comparison with CN. On the other hand, NVH patients had atrophy and hypometabolism mainly in temporal areas. No differences in GM volume and glucose metabolism were found in the direct comparison between AD VH and NVH. In addition to the pattern of brain abnormalities typical of AD, occipital alterations were observed in patients with VH compared with CN. More severe visuoconstructive and attentional deficits were found in AD VH when directly compared with NVH, and might contribute to the emergence of VH in AD.