New resting-state fMRI related studies at PubMed

Hyper- and hypo-connectivity in sensorimotor network of drug-naïve patients with cervical dystonia

Mon, 08/02/2021 - 10:00

Parkinsonism Relat Disord. 2021 Jul 22;90:15-20. doi: 10.1016/j.parkreldis.2021.07.020. Online ahead of print.


BACKGROUND: Cervical dystonia (CD) is the most common form of focal dystonia with involuntary movements and postures of the head. The pathogenesis and neural mechanisms underlying CD have not been fully elucidated.

METHODS: Twenty-seven newly drug-naïve patients with CD and 21 healthy controls (HCs) were recruited with clinical assessment and resting-state functional magnetic resonance imaging (rs-fMRI) scanning. Severity of CD was measured by Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui scores. Whole-brain voxel-wise intrinsic connectivity (IC) and seed-based functional connectivity (FC) analyses were performed for detection of changes in the CD group relative to HCs, controlling for age, gender, and global time series correlation, followed by correlation analyses of IC, seed-based FC and clinically relevant features, respectively.

RESULTS: In comparison with HCs, CD patients showed significantly increased IC measurement in the anterior part of the left supramarginal gyrus and extended to the inferior left postcentral gyrus (AL-SMG/IL-PCG). With this cluster as a seed, decreased FC was found in the right precentral and postcentral gyrus. Moreover, the regional IC value in the AL-SMG/IL-PCG was significantly positively correlated with TWSTRS-1 (severity) score, and significantly negatively correlated with the associated seed-based FC strength.

CONCLUSIONS: Our results showed signs of both hyper- and hypo-connectivity in bilateral regions of the sensorimotor network related to CD. The imbalance of functional connectivity (both hyper- and hypo-) may hint both overloading and disrupted somatosensory or sensorimotor integration dysfunction within the sensorimotor network underlying the pathophysiology of CD, thus providing a network target for future therapies.

PMID:34340003 | DOI:10.1016/j.parkreldis.2021.07.020

Imbalance Between Prefronto-Thalamic and Sensorimotor-Thalamic Circuitries Associated with Working Memory Deficit in Schizophrenia

Mon, 08/02/2021 - 10:00

Schizophr Bull. 2021 Aug 2:sbab086. doi: 10.1093/schbul/sbab086. Online ahead of print.


BACKGROUND: Thalamocortical circuit imbalance characterized by prefronto-thalamic hypoconnectivity and sensorimotor-thalamic hyperconnectivity has been consistently documented at rest in schizophrenia (SCZ). However, this thalamocortical imbalance has not been studied during task engagement to date, limiting our understanding of its role in cognitive dysfunction in schizophrenia.

METHODS: Both n-back working memory (WM) task-fMRI and resting-state fMRI data were collected from 172 patients with SCZ and 103 healthy control subjects (HC). A replication sample with 49 SCZ and 48 HC was independently obtained. Sixteen thalamic subdivisions were employed as seeds for the analysis.

RESULTS: During both task-performance and rest, SCZ showed thalamic hyperconnectivity with sensorimotor cortices, but hypoconnectivity with prefrontal-cerebellar regions relative to controls. Higher sensorimotor-thalamic connectivity and lower prefronto-thalamic connectivity both relate to poorer WM performance (lower task accuracy and longer response time) and difficulties in discriminating target from nontarget (lower d' score) in n-back task. The prefronto-thalamic hypoconnectivity and sensorimotor-thalamic hyperconnectivity were anti-correlated both in SCZ and HCs; this anti-correlation was more pronounced with less cognitive demand (rest>0-back>2-back). These findings replicated well in the second sample. Finally, the hypo- and hyper-connectivity patterns during resting-state positively correlated with the hypo- and hyper-connectivity during 2-back task-state in SCZ respectively.

CONCLUSIONS: The thalamocortical imbalance reflected by prefronto-thalamic hypoconnectivity and sensorimotor-thalamic hyperconnectivity is present both at rest and during task engagement in SCZ and relates to working memory performance. The frontal reduction, sensorimotor enhancement pattern of thalamocortical imbalance is a state-invariant feature of SCZ that affects a core cognitive function.

PMID:34337670 | DOI:10.1093/schbul/sbab086

Fast Independent Component Analysis Algorithm-Based Diagnosis of L5 Nerve Root Compression and Changes of Brain Functional Areas Using 3D Functional Magnetic Resonance Imaging

Mon, 08/02/2021 - 10:00

J Healthc Eng. 2021 Jul 22;2021:5063021. doi: 10.1155/2021/5063021. eCollection 2021.


In this paper, the application of 3-dimensional (3D) functional magnetic resonance imaging (FMRI) in the diagnosis of the 5th lumbar (L5) nerve root compression and brain functional areas in patients with lumbar disc herniation (LDH) was analyzed. The traditional fast independent component analysis (Fast ICA) algorithm was optimized based on the modified whitening matrix to establish a new type of Modified-Fast ICA (M-Fast ICA) algorithm that was compared with the introduced traditional Fast ICA and ICA. M-Fast ICA was applied to the 3D FMRI diffusion tensor imaging (DTI) evaluation of 65 patients with L5 nerve root pain due to LDH (group A) and 50 healthy volunteers (group B). The values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the lumbar nerve roots (L3, L4, L5, and the 1st sacral vertebra (S1)) were recorded among subjects from the two groups. Besides, the score of edema degree in the lumbar nerve roots (L5 and S1) and activity of brain functional areas were also recorded among all subjects of the two groups. The results showed that the mean square error of M-Fast ICA was smaller than that of traditional Fast ICA and ICA, while its signal-to-noise ratio (SNR) was greater than that of Fast ICA and ICA (P < 0.05). The FA of L5 and S1 nerve roots in patients of group A was sharply lower than the values of group B, while the ADC of patients in group A was greater than that of the control group (P < 0.05). Besides, the score of edema in L5 and S1 nerve roots of patients in group A increased in contrast to group B (P < 0.05). The brain areas were activated after surgery including bilateral temporal lobe, left thalamus, splenium of corpus callosum, and right internal capsule. In conclusion, the 3D image denoising performance of M-Fast ICA optimized and constructed in this study was superior to that of the traditional Fast ICA and ICA. The FA of patients with L5 nerve root pain due to LDH decreased steeply, while the ADC increased dramatically. L5 nerve root pain caused by LDH resulted in changes in brain functional areas of the patients to inhibit the resting state default network activity, and the corresponding brain functional areas could be activated through treatment.

PMID:34336154 | PMC:PMC8321732 | DOI:10.1155/2021/5063021

Abnormal Functional Connectivity of the Amygdala in Mild Cognitive Impairment Patients With Depression Symptoms Revealed by Resting-State fMRI

Mon, 08/02/2021 - 10:00

Front Psychiatry. 2021 Jul 15;12:533428. doi: 10.3389/fpsyt.2021.533428. eCollection 2021.


Convergent evidence indicates that individuals with symptoms of depression exhibit altered functional connectivity (FC) of the amygdala, which is a key brain region in processing emotions. At present, the characteristics of amygdala functional circuits in patients with mild cognitive impairment (MCI) with and without depression are not clear. The current study examined the features of amygdala FC in patients with MCI with depression symptoms (D-MCI) using resting-state functional magnetic resonance imaging. We acquired resting-state functional magnetic resonance imaging data from 16 patients with D-MCI, 18 patients with MCI with no depression (nD-MCI), and 20 healthy controls (HCs) using a 3T scanner and compared the strength of amygdala FC between the three groups. Patients with D-MCI exhibited significant FC differences in the amygdala-medial prefrontal cortex and amygdala-sensorimotor networks. These results suggest that the dysfunction of the amygdala-medial prefrontal cortex network and the amygdala-sensorimotor network might be involved in the neural mechanism underlying depression in MCI.

PMID:34335316 | PMC:PMC8319717 | DOI:10.3389/fpsyt.2021.533428

Brain Frequency-Specific Changes in the Spontaneous Neural Activity Are Associated With Cognitive Impairment in Patients With Presbycusis

Mon, 08/02/2021 - 10:00

Front Aging Neurosci. 2021 Jul 14;13:649874. doi: 10.3389/fnagi.2021.649874. eCollection 2021.


Presbycusis (PC) is characterized by preferential hearing loss at high frequencies and difficulty in speech recognition in noisy environments. Previous studies have linked PC to cognitive impairment, accelerated cognitive decline and incident Alzheimer's disease. However, the neural mechanisms of cognitive impairment in patients with PC remain unclear. Although resting-state functional magnetic resonance imaging (rs-fMRI) studies have explored low-frequency oscillation (LFO) connectivity or amplitude of PC-related neural activity, it remains unclear whether the abnormalities occur within all frequency bands or within specific frequency bands. Fifty-one PC patients and fifty-one well-matched normal hearing controls participated in this study. The LFO amplitudes were investigated using the amplitude of low-frequency fluctuation (ALFF) at different frequency bands (slow-4 and slow-5). PC patients showed abnormal LFO amplitudes in the Heschl's gyrus, dorsolateral prefrontal cortex (dlPFC), frontal eye field and key nodes of the speech network exclusively in slow-4, which suggested that abnormal spontaneous neural activity in PC was frequency dependent. Our findings also revealed that stronger functional connectivity between the dlPFC and the posterodorsal stream of auditory processing, as well as lower functional coupling between the PCC and key nodes of the DMN, which were associated with cognitive impairments in PC patients. Our study might underlie the cross-modal plasticity and higher-order cognitive participation of the auditory cortex after partial hearing deprivation. Our findings indicate that frequency-specific analysis of ALFF could provide valuable insights into functional alterations in the auditory cortex and non-auditory regions involved in cognitive impairment associated with PC.

PMID:34335224 | PMC:PMC8316979 | DOI:10.3389/fnagi.2021.649874

Decreased Functional Connectivity of Vermis-Ventral Prefrontal Cortex in Bipolar Disorder

Mon, 08/02/2021 - 10:00

Front Hum Neurosci. 2021 Jul 16;15:711688. doi: 10.3389/fnhum.2021.711688. eCollection 2021.


Objectives: To investigate changes in functional connectivity between the vermis and cerebral regions in the resting state among subjects with bipolar disorder (BD). Methods: Thirty participants with BD and 28 healthy controls (HC) underwent the resting state functional magnetic resonance imaging (fMRI). Resting-state functional connectivity (rsFC) of the anterior and posterior vermis was examined. For each participant, rsFC maps of the anterior and posterior vermis were computed and compared across the two groups. Results: rsFC between the whole vermis and ventral prefrontal cortex (VPFC) was significantly lower in the BD groups compared to the HC group, and rsFC between the anterior vermis and the middle cingulate cortex was likewise significantly decreased in the BD group. Limitations: 83.3% of the BD participants were taking medication at the time of the study. Our findings may in part be attributed to treatment differences because we did not examine the effects of medication on rsFC. Further, the mixed BD subtypes in our current study may have confounding effects influencing the results. Conclusions: These rsFC differences of vermis-VPFC between groups may contribute to the BD mood regulation.

PMID:34335214 | PMC:PMC8322441 | DOI:10.3389/fnhum.2021.711688

Brain Functional Changes in Stroke Following Rehabilitation Using Brain-Computer Interface-Assisted Motor Imagery With and Without tDCS: A Pilot Study

Mon, 08/02/2021 - 10:00

Front Hum Neurosci. 2021 Jul 16;15:692304. doi: 10.3389/fnhum.2021.692304. eCollection 2021.


Brain-computer interface-assisted motor imagery (MI-BCI) or transcranial direct current stimulation (tDCS) has been proven effective in post-stroke motor function enhancement, yet whether the combination of MI-BCI and tDCS may further benefit the rehabilitation of motor functions remains unknown. This study investigated brain functional activity and connectivity changes after a 2 week MI-BCI and tDCS combined intervention in 19 chronic subcortical stroke patients. Patients were randomized into MI-BCI with tDCS group and MI-BCI only group who underwent 10 sessions of 20 min real or sham tDCS followed by 1 h MI-BCI training with robotic feedback. We derived amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and functional connectivity (FC) from resting-state functional magnetic resonance imaging (fMRI) data pre- and post-intervention. At baseline, stroke patients had lower ALFF in the ipsilesional somatomotor network (SMN), lower ReHo in the contralesional insula, and higher ALFF/Reho in the bilateral posterior default mode network (DMN) compared to age-matched healthy controls. After the intervention, the MI-BCI only group showed increased ALFF in contralesional SMN and decreased ALFF/Reho in the posterior DMN. In contrast, no post-intervention changes were detected in the MI-BCI + tDCS group. Furthermore, higher increases in ALFF/ReHo/FC measures were related to better motor function recovery (measured by the Fugl-Meyer Assessment scores) in the MI-BCI group while the opposite association was detected in the MI-BCI + tDCS group. Taken together, our findings suggest that brain functional re-normalization and network-specific compensation were found in the MI-BCI only group but not in the MI-BCI + tDCS group although both groups gained significant motor function improvement post-intervention with no group difference. MI-BCI and tDCS may exert differential or even opposing impact on brain functional reorganization during post-stroke motor rehabilitation; therefore, the integration of the two strategies requires further refinement to improve efficacy and effectiveness.

PMID:34335210 | PMC:PMC8322606 | DOI:10.3389/fnhum.2021.692304

Intrinsic Network Brain Dysfunction Correlates With Temporal Complexity in Generalized Anxiety Disorder and Panic Disorder

Mon, 08/02/2021 - 10:00

Front Hum Neurosci. 2021 Jul 15;15:647518. doi: 10.3389/fnhum.2021.647518. eCollection 2021.


Background: Generalized anxiety disorder (GAD) and panic disorder (PD) are the two severe subtypes of anxiety disorders (ADs), which are similar in clinical manifestation, pathogenesis, and treatment. Earlier studies have taken a whole-brain perspective on GAD and PD in the assumption that intrinsic fluctuations are static throughout the entire scan. However, it has recently been suggested that the dynamic alternations in functional connectivity (FC) may reflect the changes in macroscopic neural activity patterns underlying the critical aspects of cognition and behavior, and thus may act as biomarkers of disease. Methods: In this study, the resting-state functional MRI (fMRI) data were collected from 26 patients with GAD, 22 patients with PD, and 26 healthy controls (HCs). We investigated dynamic functional connectivity (DFC) by using the group spatial independent component analysis, a sliding window approach, and the k-means clustering methods. For group comparisons, the temporal properties of DFC states were analyzed statistically. Results: The dynamic analysis demonstrated two discrete connectivity "States" across the entire group, namely, a more segregated State I and a strongly integrated State II. Compared with HCs, patients with both GAD and PD spent more time in the weakly within-network State I, while performing fewer transitions and dwelling shorter in the integrated State II. Additionally, the analysis of DFC strength showed that connections associated with ADs were identified including the regions that belonged to default mode (DM), executive control (EC), and salience (SA) networks, especially the connections between SA and DM networks. However, no significant difference was found between the GAD and PD groups in temporal features and connection strength. Conclusions: More common but less specific alterations were detected in the GAD and PD groups, which implied that they might have similar state-dependent neurophysiological mechanisms and, in addition, could hopefully help us better understand their abnormal affective and cognitive performances in the clinic.

PMID:34335204 | PMC:PMC8319536 | DOI:10.3389/fnhum.2021.647518

Editorial: Neuroimaging Approaches to the Study of Tinnitus and Hyperacusis

Mon, 08/02/2021 - 10:00

Front Neurosci. 2021 Jul 14;15:700670. doi: 10.3389/fnins.2021.700670. eCollection 2021.


PMID:34335173 | PMC:PMC8316917 | DOI:10.3389/fnins.2021.700670

Changes in Resting-State Spontaneous Brain Activity in Patients With Allergic Rhinitis: A Pilot Neuroimaging Study

Mon, 08/02/2021 - 10:00

Front Neurosci. 2021 Jul 14;15:697299. doi: 10.3389/fnins.2021.697299. eCollection 2021.


BACKGROUND: Allergic rhinitis (AR) is an inflammatory disorder of the nose caused by immunoglobulin E (IgE)-mediated immune response to allergens. Apart from the typical symptoms of sneezing, itching, rhinorrhea, and nasal congestion, behavioral complications were also reported to be associated with the progression of AR, such as cognitive deficits, mood changes, memory decline, attention deficiency, poor school performance, anxiety, and depression. Recent human studies have suggested that alterations in brain function caused by allergen exposure may precipitate high levels of anxiety and emotional reactivity in asthma patients. But until now, there is no direct evidence of the relationship between brain activity and allergic rhinitis.

METHODS: Resting-state functional magnetic resonance imaging (rs-fMRI) was used to excavate whether there remain functional changes of brain activity in AR patients. We measured the amplitude of low-frequency fluctuation (ALFF) and the z conversion of ALFF (zALFF) in 20 patients with AR and 20 age- and sex-matched healthy controls (HCs) using the rs-fMRI data.

RESULTS: Compared with healthy controls, AR patients exhibited lower ALFF values in the precuneus (PCUN) and higher ALFF values in the anterior cingulate cortex (ACC). The ALFF values of these features were significantly correlated with the visual analog scale (VAS) scores, the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores, the subscales of RQLQ, and specific IgE, partly.

CONCLUSION: We found changes in resting-state spontaneous brain activity in AR patients with hypoactivity in the PCUN and hyperactivity of the ACC. The brain-related symptoms of AR might be another potential clinical intervention target for improving the life quality of AR patients. Further attention to brain activity is essential for a deeper understanding of AR.

PMID:34335172 | PMC:PMC8317644 | DOI:10.3389/fnins.2021.697299

Altered Topological Properties of Static/Dynamic Functional Networks and Cognitive Function After Radiotherapy for Nasopharyngeal Carcinoma Using Resting-State fMRI

Mon, 08/02/2021 - 10:00

Front Neurosci. 2021 Jul 14;15:690743. doi: 10.3389/fnins.2021.690743. eCollection 2021.


OBJECTIVES: The purpose of this study was to (1) explore the changes in topological properties of static and dynamic brain functional networks after nasopharyngeal carcinoma (NPC) radiotherapy (RT) using rs-fMRI and graph theoretical analysis, (2) explore the correlation between cognitive function and changes in brain function, and (3) add to the understanding of the pathogenesis of radiation brain injury (RBI).

METHODS: Fifty-four patients were divided into 3 groups according to time after RT: PT1 (0-6 months); PT2 (>6 to ≤12 months); and PT3 (>12 months). 29 normal controls (NCs) were included. The subjects' topological properties were evaluated by graph-theoretic network analysis, the functional connectivity of static functional networks was calculated using network-based statistics, and the dynamic functional network matrix was subjected to cluster analysis. Finally, correlation analyses were conducted to explore the relationship between the altered network parameters and cognitive function.

RESULTS: Assortativity, hierarchy, and network efficiency were significantly abnormal in the PT1 group compared with the NC or PT3 group. The small-world variance in the PT3 group was smaller than that in NCs. The Nodal ClustCoeff of Postcentral_R in the PT2 group was significantly smaller than that in PT3 and NC groups. Functional connectivities were significantly reduced in the patient groups. Most of the functional connectivities of the middle temporal gyrus (MTG) were shown to be significantly reduced in all three patient groups. Most of the functional connectivities of the insula showed significantly reduced in the PT1 and PT3 groups, and most of the functional connectivities in brain regions such as frontal and parietal lobes showed significantly reduced in the PT2 and PT3 groups. These abnormal functional connectivities were correlated with scores on multiple scales that primarily assessed memory, executive ability, and overall cognitive function. The frequency F of occurrence of various states in each subject differed significantly, and the interaction effect of group and state was significant.

CONCLUSION: The disruption of static and dynamic functional network stability, reduced network efficiency and reduced functional connectivity may be potential biomarkers of RBI. Our findings may provide new insights into the pathogenesis of RBI from the perspective of functional networks.

PMID:34335167 | PMC:PMC8316765 | DOI:10.3389/fnins.2021.690743

Sporadic Creutzfeldt-Jakob disease: A case report

Mon, 08/02/2021 - 10:00

Am J Emerg Med. 2021 Jul 22:S0735-6757(21)00604-5. doi: 10.1016/j.ajem.2021.07.038. Online ahead of print.


Being considered among the most fatal neurological conditions, Creutzfeldt-Jakob disease is a transmissible spongiform encephalopathy characterized by its unknown etiology and rapidly progressive neurodegenerative symptoms that often lead to a mean survival of 6 to 12 months. The accumulation of the prionic protein causes brain matter degeneration, which leads to a set of clinical findings that include rapidly progressive dementia, myoclonus, tremors, cerebellar ataxia, and extrapyramidal signs. This clinical presentation is non-specific, which makes CJD a very difficult condition to diagnose, due to the low level of clinical suspicion. However, combining this clinical presentation with neuroimaging, a lumbar puncture and an encephalogram will help us make the correct diagnosis. We present the case of a 57-year-old male presenting to the Emergency department with complaint of personality change and intermittent memory loss. The patient's physical exam was significant for resting pill roll tremor, bilateral cogwheel rigidity, dysmetria, and shuffling gait. Magnetic resonance imaging of his brain showed symmetric bilateral diffusion signal abnormality involving the cortex, bilateral caudate heads and putamina. Continuous electroencephalogram revealed multiple bifrontal delta discharges with triphasic morphology. Lumbar puncture was significant for presence of 14-3-3 protein in cerebrospinal fluid. The multiple examinations performed in conjunction with the previous findings supported the diagnosis of acute encephalopathy secondary to sporadic CJD.

PMID:34334283 | DOI:10.1016/j.ajem.2021.07.038

Regional Homogeneity Brain Alterations in Schizophrenia: An Activation Likelihood Estimation Meta-Analysis

Mon, 08/02/2021 - 10:00

Psychiatry Investig. 2021 Aug 2. doi: 10.30773/pi.2021.0062. Online ahead of print.


OBJECTIVE: Resting state functional magnetic resonance imaging (rsfMRI) provides a lot of evidence for local abnormal brain activity in schizophrenia, but the results are not consistent. Our aim is to find out the consistent abnormal brain regions of the patients with schizophrenia by using regional homogeneity (ReHo), and indirectly understand the degree of brain damage of the patients with drug-naive first episode schizophrenia (Dn-FES) and chronic schizophrenia.

METHODS: We performed the experiment by activation likelihood estimation (ALE) software to analysis the differences between people with schizophrenia group (all schizophrenia group and chronic schizophrenia group) and healthy controls.

RESULTS: Thirteen functional imaging studies were included in quantitative meta-analysis. All schizophrenia group showed decreased ReHo in bilateral precentral gyrus (PreCG) and left middle occipital gyrus (MOG), and increased ReHo in bilateral superior frontal gyrus (SFG) and right insula. Chronic schizophrenia group showed decreased ReHo in bilateral MOG, right fusiform gyrus, left PreCG, left cerebellum, right precuneus, left medial frontal gyrus and left anterior cingulate cortex (ACC). No significant increased brain areas were found in patients with chronic schizophrenia.

CONCLUSION: Our findings suggest that patients with chronic schizophrenia have more extensive brain damage than FES, which may contribute to our understanding of the progressive pathophysiology of schizophrenia.

PMID:34333896 | DOI:10.30773/pi.2021.0062

Modelling a multiplex brain network by local transfer entropy

Sat, 07/31/2021 - 10:00

Sci Rep. 2021 Jul 30;11(1):15525. doi: 10.1038/s41598-021-93190-z.


This paper deals with the information transfer mechanisms underlying causal relations between brain regions under resting condition. fMRI images of a large set of healthy individuals from the 1000 Functional Connectomes Beijing Zang dataset have been considered and the causal information transfer among brain regions studied using Transfer Entropy concepts. Thus, we explored the influence of a set of states in two given regions at time t (At Bt.) over the state of one of them at a following time step (Bt+1) and could observe a series of time-dependent events corresponding to four kinds of interactions, or causal rules, pointing to (de)activation and turn off mechanisms and sharing some features with positive and negative functional connectivity. The functional architecture emerging from such rules was modelled by a directional multilayer network based upon four interaction matrices and a set of indexes describing the effects of the network structure in several dynamical processes. The statistical significance of the models produced by our approach was checked within the used database of homogeneous subjects and predicts a successful extension, in due course, to detect differences among clinical conditions and cognitive states.

PMID:34330935 | DOI:10.1038/s41598-021-93190-z

Interindividual variability of functional connectome in schizophrenia

Fri, 07/30/2021 - 10:00

Schizophr Res. 2021 Jul 27;235:65-73. doi: 10.1016/j.schres.2021.07.010. Online ahead of print.


Schizophrenia is a complex psychiatric disorder that displays an outstanding interindividual variability in clinical manifestation and neurobiological substrates. A better characterization and quantification of this heterogeneity could guide the search for both common abnormalities (linked to lower intersubject variability) and the presence of biological subtypes (leading to a greater heterogeneity across subjects). In the current study, we address interindividual variability in functional connectome by means of resting-state fMRI in a large sample of patients with schizophrenia and healthy controls. Among the different metrics of distance/dissimilarity used to assess variability, geodesic distance showed robust results to head motion. The main findings of the current study point to (i) a higher between subject heterogeneity in the functional connectome of patients, (ii) variable levels of heterogeneity throughout the cortex, with greater variability in frontoparietal and default mode networks, and lower variability in the salience network, and (iii) an association of whole-brain variability with levels of clinical symptom severity and with topological properties of brain networks, suggesting that the average functional connectome overrepresents those patients with lower functional integration and with more severe clinical symptoms. Moreover, after performing a graph theoretical analysis of brain networks, we found that patients with more severe clinical symptoms had decreased connectivity at both whole-brain level and within the salience network, and that patients with higher negative symptoms had large-scale functional integration deficits.

PMID:34329851 | DOI:10.1016/j.schres.2021.07.010

Increased attentional network activity in premature ejaculation patients with anxiety revealed by resting-state fMRI

Fri, 07/30/2021 - 10:00

Eur J Neurosci. 2021 Jul 29. doi: 10.1111/ejn.15402. Online ahead of print.


Psychological account hypothesizes that premature ejaculation (PE) is a learned pattern of rapid ejaculation maintained by anxiety about sexual failure, while neuropsychological accounts hypothesizes that PE is the result of dysfunction of central nervous system regulating ejaculatory. However, the central neural mechanism underlying PE patients with anxiety remains unclear. Resting-state functional magnetic resonance imaging (fMRI) data were collected in 20 PE (diagnoses based on PE Guidelines drafted by the International Society for Sexual Medicine (ISSM)) patients with anxiety and 25 matched healthy controls (HC) from January 2019 to December 2020. The values of fractional amplitude of low-frequency fluctuation (fALFF) were compared between groups. Moreover, the correlations between fALFF and the severity of PE and anxiety of patients were examined. PE patients with anxiety had increased fALFF values in the right inferior frontal gyrus (opercular part) and middle frontal gyrus. In addition, significant positive correlations were found between the scores of PE diagnostic tool (PEDT) and fALFF values of the right inferior frontal gyrus (opercular part), as well as the right middle frontal gyrus. Moreover, fALFF values of the right inferior frontal gyrus (opercular part) and middle frontal gyrus were positively correlated with the scores of self-rating anxiety scale (SAS). Our results suggested that increased attentional network activity might play a critical role in the neural basis of PE patients with anxiety.

PMID:34327757 | DOI:10.1111/ejn.15402

The association between white matter hyperintensities, cognition and regional neural activity in healthy subjects

Fri, 07/30/2021 - 10:00

Eur J Neurosci. 2021 Jul 29. doi: 10.1111/ejn.15403. Online ahead of print.


White matter hyperintensities (WMH) are common findings that can be found in physiological aging. Several studies suggest that the disruption of white matter tracts included in WMH could induce abnormal functioning of the respective linked cortical structures, with consequent repercussion on the cerebral functions, included the cognitive sphere. In this cross-sectional research, we analyzed the effects of the total WMH burden (tWMHb) on resting-state functional magnetic resonance imaging (rs-fMRI) and cognition. Functional and structural MR data, as well as the scores of the trail-making test subtests A (TMT-A) and B (TMT-B) of 75 healthy patients, were extracted from the public available Leipzig Study for Mind-Body-Emotion Interactions dataset. tWMHb was extracted from structural data. Spearman's correlation analyses were made for investigating correlations between WMHb and the scores of the cognitive tests. The fractional amplitude of low-frequency fluctuations (fALFF) method was applied for analyzing the rs-fMRI data, adopting a multiple regression model for studying the effects of tWMHb on brain activity. Three different sub-analyses were conducted using different statistical methods. We observed statistically significant correlations between WMHb and the scores of the cognitive tests. The fALFF analysis revealed that tWMHb is associated with the reduction of regional neural activity of several brain areas (in particular the prefrontal cortex, precuneus, and cerebellar crus I/II). We conclude that our findings clarify better the relationships between WMH and cognitive impairment, evidencing that tWMHb is associated with impairments of the neurocognitive function in healthy subjects by inducing a diffuse reduction of the neural activity.

PMID:34327745 | DOI:10.1111/ejn.15403

Research progress on mechanism and imaging of temporal lobe injury induced by radiotherapy for head and neck cancer

Fri, 07/30/2021 - 10:00

Eur Radiol. 2021 Jul 29. doi: 10.1007/s00330-021-08164-6. Online ahead of print.


Radiotherapy (RT) is an effective treatment for head and neck cancer (HNC). Radiation-induced temporal lobe injury (TLI) is a serious complication of RT. Late symptoms of radiation-induced TLI are irreversible and manifest as memory loss, cognitive impairment, and even temporal lobe necrosis (TLN). It is currently believed that the mechanism of radiation-induced TLI involves microvascular injury, neuron and neural stem cell injury, glial cell damage, inflammation, and the production of free radicals. Significant RT-related structural changes and dose-dependent changes in gray matter (GM) and white matter (WM) volume and morphology were observed through computed tomography (CT) and magnetic resonance imaging (MRI) which were common imaging assessment tools. Diffusion tensor imaging (DTI), dispersion kurtosis imaging (DKI), susceptibility-weighted imaging (SWI), resting-state functional magnetic resonance (rs-fMRI), magnetic resonance spectroscopy (MRS), and positron emission tomography (PET) can be used for early diagnosis and prognosis evaluation according to functional, molecular, and cellular processes of TLI. Early diagnosis of TLI is helpful to reduce the incidence of TLN and its related complications. This review summarizes the clinical features, mechanisms, and imaging of radiation-induced TLI in HNC patients. KEY POINTS: • Radiation-induced temporal lobe injury (TLI) is a clinical complication and its symptoms mainly include memory impairment, headache, and cognitive impairment. • The mechanisms of TLI include microvascular injury, cell injury, and inflammatory and free radical injury. Significant RT-related structural changes and dose-dependent changes in TL volume and morphology were observed through CT and MRI. • SWI, MRS, DTI, and DKI and other imaging examinations can detect anatomical and functional, molecular, and cellular changes of TLI.

PMID:34327577 | DOI:10.1007/s00330-021-08164-6

Abnormal Degree Centrality in White Matter Hyperintensities: A Resting-State Functional Magnetic Resonance Imaging Study

Fri, 07/30/2021 - 10:00

Front Psychiatry. 2021 Jul 13;12:684553. doi: 10.3389/fpsyt.2021.684553. eCollection 2021.


Background: White matter hyperintensities (WMHs) are a common occurrence with aging and are associated with cognitive impairment. However, the neurobiological mechanisms of WMHs remain poorly understood. Functional magnetic resonance imaging (fMRI) is a prominent tool that helps in non-invasive examinations and is increasingly used to diagnose neuropsychiatric diseases. Degree centrality (DC) is a common and reliable index in fMRI, which counts the number of direct connections for a given voxel in a network and reflects the functional connectivity within brain networks. We explored the underlying mechanism of cognitive impairment in WMHs from the perspective of DC. Methods: A total of 104 patients with WMHs and 37 matched healthy controls (HCs) were enrolled in the current study. All participants underwent individual and overall cognitive function tests and resting-state fMRI (rs-fMRI). WMHs were divided into three groups (39 mild WMHs, 37 moderate WMHs, and 28 severe WMHs) according to their Fazekas scores, and the abnormal DC values in the WMHs and HCs groups were analyzed. Results: There was a significant difference in the right inferior frontal orbital gyrus and left superior parietal gyrus between the WMHs and HCs groups. The functional connectivity between the right inferior frontal orbital gyrus and left inferior temporal gyrus, left superior parietal gyrus, and left parietal inferior gyrus was also different in the WMHs group. Conclusion: The change in DC value may be one of the underlying mechanisms of cognitive impairment in individuals with WMHs, which provides us with a new approach to delaying cognitive impairment in WMHs.

PMID:34326785 | PMC:PMC8315277 | DOI:10.3389/fpsyt.2021.684553

Altered Neurovascular Coupling in Patients with Chronic Myofascial Pain

Thu, 07/29/2021 - 10:00

Pain Physician. 2021 Aug;24(5):E601-E610.


BACKGROUND: Despite previous reports on cerebral structures and functional connectivity in patients with myofascial pain (MFP), it is not clear whether alterations in neurovascular coupling occur in these patients.

OBJECTIVES: We analyzed the coupling between resting-state cerebral blood flow (CBF) and functional connectivity strength (FCS) for observation of neurovascular coupling in patients with chronic MFP.

STUDY DESIGN: Observational study.

SETTING: University hospital.

METHODS: Resting-state functional magnetic resonance imaging and arterial spin labeling were performed in 23 patients with chronic MFP and 23 healthy controls (HC) for the calculation of FCS and CBF. The whole-brain gray matter CBF-FCS correlations and CBF/FCS ratios of the various voxels of the 2 groups were subsequently compared.

RESULTS: Compared with the HC, the patients with MFP experienced a decrease in whole-brain gray matter CBF-FCS coupling. In patients with MFP, a decrease in CBF/FCS was found in the bilateral superior temporal gyri, right parahippocampal gyrus, right hippocampus, caudate nucleus, right medial prefrontal cortex, and the periaqueductal gray matter (PAG), whereas an increase in CBF/FCS was found in the bilateral lingual gyri, posterior cingulate cortex, and bilateral inferior parietal lobules. In addition, the CBF/FCS of the PAG in patients with MFP was significantly negatively correlated with the pain visual analog scale score and pain duration.

LIMITATIONS: Alterations in neurovascular coupling in patients with MFP were observed only before treatment. Therefore, there is a lack of data on the alterations that occurred after treatment.

CONCLUSION: This study demonstrated for the first time that impairment of neurovascular coupling in the brain may be a potential neuropathological mechanism of chronic MFP.