New resting-state fMRI related studies at PubMed

Subscribe to New resting-state fMRI related studies at PubMed feed New resting-state fMRI related studies at PubMed
NCBI: db=pubmed; Term=resting state fMRI
Updated: 51 min 27 sec ago

Lesion network mapping analysis identifies potential cause of post-operative depression in a case of cingulate low-grade glioma.

Mon, 10/14/2019 - 10:40
Related Articles

Lesion network mapping analysis identifies potential cause of post-operative depression in a case of cingulate low-grade glioma.

World Neurosurg. 2019 Oct 10;:

Authors: Mansouri A, Boutet A, Elias G, Germann J, Yan H, Babu H, Lozano AM, Valiante T

Abstract
BACKGROUND: Depression following resection of diffuse low-grade gliomas (DLGG) has rarely been described. The location of the tumor or surgical route are among a multitude of potential causes. Lesion-network mapping (LNM), leveraging high quality resting-state fMRI data from large samples of healthy adults, has been used to explore the broader network connectivity for given lesions. However, LNM has not been applied to large intra-axial masses or surgical lesions. Here we utilized LNM to examine a potential cause of postoperative depression in a patient with a cingulate DLGG (Zones I-III).
CASE DESCRIPTION: This 34-year female underwent surgery for medically refractory seizures attributable to the lesion. A near-total resection was attained through a single-stage, trans-cortical route through the medial prefrontal cortex. Despite seizure-freedom and lack of tumor growth (42 months follow-up), she developed symptoms of major depressive disorder (MDD) soon after surgery that have persisted. To identify functional networks potentially engaged by the surgical corridor and tumor resection cavity, both were segmented separately and used as seeds for normative resting-state fMRI connectivity mapping. Then, to study depression specifically, networks associated with the tumor and surgical approach were compared to those associated with subgenual cingulate deep brain stimulation (DBS). The LNM results suggested that the surgical corridor, rather than the tumor, had greater overlap with DBS-based depression networks (32% vs 8%).
CONCLUSION: The early postoperative development of MDD following resection of a cingulate region tumor, though likely multi-factorial, should be considered and patients appropriately counselled preoperatively. Further validation of LNM as a viable methodology for correlating symptoms to lesion(s) could make it a valuable tool in selection of surgical approach and patient counseling.

PMID: 31606510 [PubMed - as supplied by publisher]

Resting-state brain entropy in right temporal lobe epilepsy and its relationship with alertness.

Sun, 10/13/2019 - 16:00
Related Articles

Resting-state brain entropy in right temporal lobe epilepsy and its relationship with alertness.

Brain Behav. 2019 Oct 12;:e01446

Authors: Zhou M, Jiang W, Zhong D, Zheng J

Abstract
BACKGROUND: To date, no functional MRI (fMRI) studies have focused on brain entropy in right temporal lobe epilepsy (rTLE) patients. Here, we characterized brain entropy (BEN) alterations in patients with rTLE using resting-state functional MRI(rs-fMRI) and explored the relationship between BEN and alertness.
METHOD: Thirty-one rTLE patients and 33 controls underwent MRI scanning to investigate differences in BEN and resting-state functional connectivity (rs-FC) in regions of interest (ROIs) between patients and controls. Correlation analyses were performed to examine relationships between the BEN of each ROI and alertness reaction times (RTs) in rTLE patients.
RESULTS: Compared with controls, the BEN of rTLE patients was significantly increased in the right middle temporal gyrus, inferior temporal gyrus, and other regions of the left hemisphere and significantly decreased in the right middle frontal gyrus and left supplementary motor area (p < .05). The rs-FCs between the ROIs (at p < .01, with the left superior parietal lobule and right precentral gyrus defined as ROI1 and ROI2, respectively) and the whole brain showed an increasing trend in rTLE patients. In addition, the BEN of ROI2 was associated with the intrinsic alertness and phasic alertness RTs of patients with rTLE.
CONCLUSIONS: Our findings suggest that BEN is altered in patients with rTLE and that decreased BEN in the right precentral gyrus is positively related to intrinsic and phasic alertness; the abnormal FC in the brain regions with altered entropy suggests a reconstruction of brain functional connectivity. These findings suggest that BEN mapping may provide a useful tool for probing brain mechanisms related to TLE.

PMID: 31605452 [PubMed - as supplied by publisher]

Toward a Neural Model of the Openness-Psychoticism Dimension: Functional Connectivity in the Default and Frontoparietal Control Networks.

Sat, 10/12/2019 - 15:00
Related Articles

Toward a Neural Model of the Openness-Psychoticism Dimension: Functional Connectivity in the Default and Frontoparietal Control Networks.

Schizophr Bull. 2019 Oct 11;:

Authors: Blain SD, Grazioplene RG, Ma Y, DeYoung CG

Abstract
Psychosis proneness has been linked to heightened Openness to Experience and to cognitive deficits. Openness and psychotic disorders are associated with the default and frontoparietal networks, and the latter network is also robustly associated with intelligence. We tested the hypothesis that functional connectivity of the default and frontoparietal networks is a neural correlate of the openness-psychoticism dimension. Participants in the Human Connectome Project (N = 1003) completed measures of psychoticism, openness, and intelligence. Resting state functional magnetic resonance imaging was used to identify intrinsic connectivity networks. Structural equation modeling revealed relations among personality, intelligence, and network coherence. Psychoticism, openness, and especially their shared variance were related positively to default network coherence and negatively to frontoparietal coherence. These associations remained after controlling for intelligence. Intelligence was positively related to frontoparietal coherence. Research suggests that psychoticism and openness are linked in part through their association with connectivity in networks involving experiential simulation and cognitive control. We propose a model of psychosis risk that highlights roles of the default and frontoparietal networks. Findings echo research on functional connectivity in psychosis patients, suggesting shared mechanisms across the personality-psychopathology continuum.

PMID: 31603227 [PubMed - as supplied by publisher]

Relationship between Basal Forebrain Resting-State Functional Connectivity and Brain Amyloid-β Deposition in Cognitively Intact Older Adults with Subjective Memory Complaints.

Sat, 10/12/2019 - 15:00
Related Articles

Relationship between Basal Forebrain Resting-State Functional Connectivity and Brain Amyloid-β Deposition in Cognitively Intact Older Adults with Subjective Memory Complaints.

Radiology. 2019 01;290(1):167-176

Authors: Chiesa PA, Cavedo E, Grothe MJ, Houot M, Teipel SJ, Potier MC, Habert MO, Lista S, Dubois B, Hampel H, INSIGHT-preAD Study Group and the Alzheimer Precision Medicine Initiative (APMI)

Abstract
Purpose To evaluate the association between the global fibrillary amyloid-β pathology and the basal forebrain connectivity at rest in cognitively intact older adults at risk for Alzheimer disease. Materials and Methods This retrospective study was approved by the local ethics committee and written informed consent was obtained from all participants. Resting-state functional connectivity (RSFC) of anterior and posterior basal forebrain seeds was investigated, as well as PET-measured global amyloid-β load by using standardized uptake value ratio (SUVR) in 267 older cognitively intact individuals with subjective memory complaints (age range, 70-85 years; overall mean age, 75.8 years; 167 women [mean age, 75.9 years] and 100 men [mean age, 75.8 years]). The participants were from the Investigation of Alzheimer's Predictors in Subjective Memory Complainers (INSIGHT-preAD) cohort (date range, 2013-present). The relationship between SUVR and the basal forebrain RSFC was assessed, followed by the effects of apolipoprotein E (APOE) genotype and sex on the basal forebrain RSFC. Results Higher SUVR values correlated with lower posterior basal forebrain RSFC in the hippocampus and the thalamus (Pearson r =-0.23; P <.001 corrected for familywise error [FWE]). Both sex and APOE genotype impacted the associations between basal forebrain RSFC and the global amyloid deposition (t values >3.59; P <.05 corrected for FWE). Conclusion Data indicate a distinct in vivo association between posterior basal forebrain dynamics and global fibrillary amyloid-β pathology in cognitively intact older adults with subjective memory complaints; both apolipoprotein E and sex moderate such association. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Caspers in this issue.

PMID: 30351255 [PubMed - indexed for MEDLINE]

Abnormal dynamic functional connectivity density in patients with generalized anxiety disorder.

Fri, 10/11/2019 - 14:00
Related Articles

Abnormal dynamic functional connectivity density in patients with generalized anxiety disorder.

J Affect Disord. 2019 Oct 01;261:49-57

Authors: Chen Y, Cui Q, Xie A, Pang Y, Sheng W, Tang Q, Li D, Huang J, He Z, Wang Y, Chen H

Abstract
BACKGROUND: Numerous studies have revealed the abnormal static functional connectivity (FC) among different brain regions in patients with generalized anxiety disorder (GAD). However, little is known about the dynamic changes of FC in patients with GAD.
METHODS: This study investigated the whole-brain dynamic changes of FC in patients with GAD by combining global FC density (FCD) and sliding window correlation analyses. The standard deviation of dynamic FCD (dFCD) was calculated to evaluate its temporal variability along time. Support vector regression was then employed to predict the symptom severity of patients based on abnormal dynamic connectivity patterns.
RESULTS: The abnormal dFCD variability between 81 GAD patients and 80 healthy controls showed that the patients had higher dFCD variability in the bilateral dorsomedial prefrontal cortex (dmPFC) and left hippocampus while lower dFCD variability in the right postcentral gyrus. The abnormal dFCD variability of the left dmPFC is an important feature for anxiety prediction.
LIMITATIONS: The selection of sliding window length remains controversial, and most of our patients have been treated with medications. Future studies are expected to rule out the potential confounding effects from applying different parameters of the sliding window and recruiting large samples of medication-free patients.
CONCLUSION: The altered patterns of time-varying brain connectivity in the frontolimbic and sensorimotor areas may reflect abnormal dynamic neural communication between these regions and other regions of the brain, which may deepen our understanding of the disease.

PMID: 31600587 [PubMed - as supplied by publisher]

Short-term effects of video gaming on brain response during working memory performance.

Fri, 10/11/2019 - 14:00
Related Articles

Short-term effects of video gaming on brain response during working memory performance.

PLoS One. 2019;14(10):e0223666

Authors: Liu S, Kaufmann C, Labadie C, Ströhle A, Kuschpel MS, Garbusow M, Hummel R, Schad DJ, Rapp MA, Heinz A, Heinzel S

Abstract
Breaks filled with different break activities often interrupt cognitive performance in everyday life. Previous studies have reported that both enhancing and deteriorating effects on challenging ongoing tasks such as working memory updating, depend on the type of break activity. However, neural mechanisms of these break-related alterations in working memory performance have not been studied, to date. Therefore, we conducted a brain imaging study to identify the neurobiological correlates of effects on the n-back working memory task related to different break activities. Before performing the n-back task in the magnetic resonance imaging (MRI) scanner, young adults were exposed to break activities in the MRI scanner involving (i) eyes-open resting, (ii) listening to music, and (iii) playing the video game "Angry Birds". Heart rate was measured by a pulse oximeter during the experiment. We found that increased heart rate during gaming as well as decreased relaxation levels after a video gaming break was related to poorer n-back task performance, as compared to listening to music. On the neural level, video gaming reduced supplementary motor area activation during working memory performance. These results may indicate that video gaming during a break may affect working memory performance by interfering with arousal state and frontal cognitive control functions.

PMID: 31600305 [PubMed - in process]

Altered inter- and intrahemispheric functional connectivity dynamics in autistic children.

Fri, 10/11/2019 - 14:00
Related Articles

Altered inter- and intrahemispheric functional connectivity dynamics in autistic children.

Hum Brain Mapp. 2019 Oct 10;:

Authors: Guo X, Duan X, Chen H, He C, Xiao J, Han S, Fan YS, Guo J, Chen H

Abstract
Emerging evidence has associated autism spectrum disorder (ASD) with static functional connectivity abnormalities between multiple brain regions. However, the temporal dynamics of intra- and interhemispheric functional connectivity patterns remain unknown in ASD. Resting-state functional magnetic resonance imaging data were analyzed for 105 ASD and 102 demographically matched typically developing control (TC) children (age range: 7-12 years) available from the Autism Brain Imaging Data Exchange database. Whole-brain functional connectivity was decomposed into ipsilateral and contralateral functional connectivity, and sliding-window analysis was utilized to capture the intra- and interhemispheric dynamic functional connectivity density (dFCD) patterns. The temporal variability of the functional connectivity dynamics was further quantified using the standard deviation (SD) of intra- and interhemispheric dFCD across time. Finally, a support vector regression model was constructed to assess the relationship between abnormal dFCD variance and autism symptom severity. Both intra- and interhemispheric comparisons showed increased dFCD variability in the anterior cingulate cortex/medial prefrontal cortex and decreased variability in the fusiform gyrus/inferior temporal gyrus in autistic children compared with TC children. Autistic children additionally showed lower intrahemispheric dFCD variability in sensorimotor regions including the precentral/postcentral gyrus. Moreover, aberrant temporal variability of the contralateral dFCD predicted the severity of social communication impairments in autistic children. These findings demonstrate altered temporal dynamics of the intra- and interhemispheric functional connectivity in brain regions incorporating social brain network of ASD, and highlight the potential role of abnormal interhemispheric communication dynamics in neural substrates underlying impaired social processing in ASD.

PMID: 31600014 [PubMed - as supplied by publisher]

Task-evoked Negative BOLD Response and Functional Connectivity in the Default Mode Network are Representative of Two Overlapping but Separate Neurophysiological Processes.

Fri, 10/11/2019 - 14:00
Related Articles

Task-evoked Negative BOLD Response and Functional Connectivity in the Default Mode Network are Representative of Two Overlapping but Separate Neurophysiological Processes.

Sci Rep. 2019 Oct 09;9(1):14473

Authors: Parker DB, Razlighi QR

Abstract
The topography of the default mode network (DMN) can be obtained with one of two different functional magnetic resonance imaging (fMRI) methods: either from the spontaneous but organized synchrony of the low-frequency fluctuations in resting-state fMRI (rs-fMRI), known as "functional connectivity", or from the consistent and robust deactivations in task-based fMRI (tb-fMRI), here referred to as the "negative BOLD response" (NBR). These two methods are fundamentally different, but their results are often used interchangeably to describe the brain's resting-state, baseline, or intrinsic activity. While the DMN was initially defined by consistent task-based decreases in blood flow in a set of specific brain regions using PET imaging, recently nearly all studies on the DMN employ functional connectivity in rs-fMRI. In this study, we first show the high level of spatial overlap between NBR and functional connectivity of the DMN extracted from the same tb-fMRI scan; then, we demonstrate that the NBR in putative DMN regions can be significantly altered without causing any change in their overlapping functional connectivity. Furthermore, we present evidence that in the DMN, the NBR is more closely related to task performance than the functional connectivity. We conclude that the NBR and functional connectivity of the DMN reflect two separate but overlapping neurophysiological processes, and thus should be differentiated in studies investigating brain-behavior relationships in both healthy and diseased populations. Our findings further raise the possibility that the macro-scale networks of the human brain might internally exhibit a hierarchical functional architecture.

PMID: 31597927 [PubMed - in process]

Using resting-state intrinsic network connectivity to identify suicide risk in mood disorders.

Fri, 10/11/2019 - 14:00
Related Articles

Using resting-state intrinsic network connectivity to identify suicide risk in mood disorders.

Psychol Med. 2019 Oct 10;:1-11

Authors: Stange JP, Jenkins LM, Pocius S, Kreutzer K, Bessette KL, DelDonno SR, Kling LR, Bhaumik R, Welsh RC, Keilp JG, Phan KL, Langenecker SA

Abstract
BACKGROUND: Little is known about the neural substrates of suicide risk in mood disorders. Improving the identification of biomarkers of suicide risk, as indicated by a history of suicide-related behavior (SB), could lead to more targeted treatments to reduce risk.
METHODS: Participants were 18 young adults with a mood disorder with a history of SB (as indicated by endorsing a past suicide attempt), 60 with a mood disorder with a history of suicidal ideation (SI) but not SB, 52 with a mood disorder with no history of SI or SB (MD), and 82 healthy comparison participants (HC). Resting-state functional connectivity within and between intrinsic neural networks, including cognitive control network (CCN), salience and emotion network (SEN), and default mode network (DMN), was compared between groups.
RESULTS: Several fronto-parietal regions (k > 57, p < 0.005) were identified in which individuals with SB demonstrated distinct patterns of connectivity within (in the CCN) and across networks (CCN-SEN and CCN-DMN). Connectivity with some of these same regions also distinguished the SB group when participants were re-scanned after 1-4 months. Extracted data defined SB group membership with good accuracy, sensitivity, and specificity (79-88%).
CONCLUSIONS: These results suggest that individuals with a history of SB in the context of mood disorders may show reliably distinct patterns of intrinsic network connectivity, even when compared to those with mood disorders without SB. Resting-state fMRI is a promising tool for identifying subtypes of patients with mood disorders who may be at risk for suicidal behavior.

PMID: 31597581 [PubMed - as supplied by publisher]

Altered Spontaneous Brain Activity in Patients With Idiopathic Trigeminal Neuralgia: A Resting-state Functional MRI Study.

Fri, 10/11/2019 - 14:00
Related Articles

Altered Spontaneous Brain Activity in Patients With Idiopathic Trigeminal Neuralgia: A Resting-state Functional MRI Study.

Clin J Pain. 2018 07;34(7):600-609

Authors: Yuan J, Cao S, Huang Y, Zhang Y, Xie P, Zhang Y, Fu B, Zhang T, Song G, Yu T, Zhang M

Abstract
OBJECTIVES: To identify the changes of local coherence and intrinsic brain activity in resting-state idiopathic trigeminal neuralgia (ITN) patients by using regional homogeneity (ReHo) and fractional aptitude of low-frequency fluctuation (fALFF) analysis.
METHODS: ReHo and fALFF were analyzed in 23 ITN patients and 23 age-matched and sex-matched pain-free controls to detect the functional abnormality in the brains of ITN patients. Correlations between ReHo and fALFF were analyses. ITN pain intensity were also assessed in the ITN group.
RESULTS: Compared with pain-free controls, ITN patients exhibited significantly abnormal ReHo and fALFF in several brain regions, including the cerebellum, cingulate cortex, temporal lobe, putamen, occipital lobe, limbic lobe, precuneus, insula, medial, and superior frontal gyrus compared with healthy controls. Correlation analysis showed that ReHo values of several altered brain areas positively correlated with visual analog scale values. But no correlation was found between fALFF and visual analog scale.
DISCUSSION: Our results showed that ITN patients exhibited significantly abnormal spontaneous brain activity in several brain regions that are involved in pain modulation and perception. The present study reflects the maladaptive process of daily pain attacks and may enhance the understanding of how chronic pain affects local intrinsic brain activity.

PMID: 29252869 [PubMed - indexed for MEDLINE]

Functional connectivity underpinning changes in life-space mobility in older adults with mild cognitive impairment: A 12-month prospective study.

Thu, 10/10/2019 - 19:00
Related Articles

Functional connectivity underpinning changes in life-space mobility in older adults with mild cognitive impairment: A 12-month prospective study.

Behav Brain Res. 2019 Oct 06;:112216

Authors: Hsu CL, Crockett R, Chan P, Brinke LT, Doherty S, Liu-Ambrose T

Abstract
Subtle changes in mobility exist among older adults with mild cognitive impairment (MCI). Life-space mobility defines the frequency and extent of movements in the environment, and lower life-space mobility is associated with adverse health outcomes and MCI. Currently, the underlying mechanism of this association is not well understood. This study examined the functional neural correlates of life-space mobility in community-dwelling older adults with MCI. We first conducted a cross-sectional investigation of the association between resting-state default mode network (DMN) and sensori-motor network (SMN) connectivity and life-space mobility (assessed by the Life-Space Assessment (LSA)) among 60 community-dwelling older adults with MCI using aggregated data from two studies - baseline data from a randomized controlled trial (n = 20) and baseline data from a 12-month prospective study (n = 40). Using data from the 12-month prospective study (n = 35), we then examined whether baseline internetwork connectivity predicts reduced life-space mobility over 12 months. The cross-sectional analysis showed higher DMN-SMN connectivity was associated with lower LSA scores after adjusting for baseline global cognitive function and baseline age (p < 0.01). A significant reduction in LSA scores was observed in the 35 participants of the 12-month prospective study (paired sample t-test mean change=-6.53, p=0.01). Greater baseline DMN-SMN connectivity was associated with greater reduction in life-space mobility at 12 months (p = 0.04) after adjusting for baseline age, global cognitive function, and LSA score. Our findings suggest that lower and reduced life-space mobility in older adults with MCI may be due to altered functional architecture of the brain such that normal neuro-cognitive motor behaviours may be disrupted.

PMID: 31597084 [PubMed - as supplied by publisher]

Multivariate consistency of resting-state fMRI connectivity maps acquired on a single individual over 2.5 years, 13 sites and 3 vendors.

Thu, 10/10/2019 - 00:00
Related Articles

Multivariate consistency of resting-state fMRI connectivity maps acquired on a single individual over 2.5 years, 13 sites and 3 vendors.

Neuroimage. 2019 Oct 05;:116210

Authors: Badhwar A, Collin-Verreault Y, Orban P, Urchs S, Chouinard I, Vogel J, Potvin O, Duchesne S, Bellec P

Abstract
Studies using resting-state functional magnetic resonance imaging (rsfMRI) are increasingly collecting data at multiple sites in order to speed up recruitment or increase sample size. The main objective of this study was to assess the long-term consistency of rsfMRI connectivity maps derived at multiple sites and vendors using the Canadian Dementia Imaging Protocol (CDIP, www.cdip-pcid.ca). Nine to 10 min of functional BOLD images were acquired from an adult cognitively healthy volunteer scanned repeatedly at 13 Canadian sites on three scanner makes (General Electric, Philips and Siemens) over the course of 2.5 years. The consistency (spatial Pearson's correlation) of rsfMRI connectivity maps for seven canonical networks ranged from 0.3 to 0.8, with a negligible effect of time, but significant site and vendor effects. We noted systematic differences in data quality (i.e. head motion, number of useable time frames, temporal signal-to-noise ratio) across vendors, which may also confound some of these results, and could not be disentangled in this sample. We also pooled the long-term longitudinal data with a single-site, short-term (1 month) data sample acquired on 26 subjects (10 scans per subject), called HNU1. Using randomly selected pairs of scans from each subject, we quantified the ability of a data-driven unsupervised cluster analysis to match two scans of the same subjects. In this "fingerprinting" experiment, we found that scans from the Canadian subject (Csub) could be matched with high accuracy intra-site (>95% for some networks), but that the accuracy decreased substantially for scans drawn from different sites and vendors, even falling outside of the range of accuracies observed in HNU1. Overall, our results demonstrate good multivariate stability of rsfMRI measures over several years, but substantial impact of scanning site and vendors. How detrimental these effects are will depend on the application, yet our results demonstrate that new methods for harmonizing multisite analysis represent an important area for future work.

PMID: 31593793 [PubMed - as supplied by publisher]

Spatiotemporal brain activation pattern following acute citalopram challenge is dose dependent and associated with neuroticism: A human phMRI study.

Thu, 10/10/2019 - 00:00
Related Articles

Spatiotemporal brain activation pattern following acute citalopram challenge is dose dependent and associated with neuroticism: A human phMRI study.

Neuropharmacology. 2019 Oct 05;:107807

Authors: Edes AE, McKie S, Szabo E, Kokonyei G, Pap D, Zsombok T, Hullam G, Gonda X, Kozak LR, McFarquhar M, Anderson IM, Deakin JFW, Bagdy G, Juhasz G

Abstract
BACKGROUND: The initial effects of selective serotonin reuptake inhibitors (SSRIs) in the human living brain are poorly understood. We carried out a 3T resting state fMRI study with pharmacological challenge to determine the brain activation changes over time following different dosages of citalopram.
METHODS: During the study, 7.5 mg i.v. citalopram was administered to 32 healthy subjects. In addition, 11.25 mg citalopram was administered to a subset of 9 subjects to investigate the dose-response. Associations with neuroticism (assessed by the NEO PI-R) of the emerging brain activation to citalopram was also investigated.
RESULTS: Citalopram challenge evoked significant activation in brain regions that are part of the default mode network, the visual network and the sensorimotor network, extending to the thalamus, and midbrain. Most effects appeared to be dose-dependent and this was statistically significant in the middle cingulate gyrus. Individual citalopram-induced brain responses were positively correlated with neuroticism scores and its subscales in specific brain areas; anxiety subscale scores in thalamus and midbrain and self-consciousness scores in middle cingulate gyrus. There were no sex differences.
LIMITATIONS: We investigated only healthy subjects and we used a relatively low sample size in the 11.25 mg citalopram analysis.
DISCUSSION: Our results suggest that SSRIs acutely induce an increased arousal-like state of distributed cortical and subcortical systems that is mediated by enhanced serotonin neurotransmission according to levels of neuroticism and underpins trait sensitivity to environmental stimuli and stressors. Studies in depression are needed to determine how therapeutic effects eventually emerge.

PMID: 31593709 [PubMed - as supplied by publisher]

Persistent enhancement of hippocampal network connectivity by parietal rTMS is reproducible.

Thu, 10/10/2019 - 00:00
Related Articles

Persistent enhancement of hippocampal network connectivity by parietal rTMS is reproducible.

eNeuro. 2019 Oct 07;:

Authors: Freedberg M, Reeves JA, Toader AC, Hermiller MS, Voss JL, Wassermann EM

Abstract
Wang et al. (Science, 2014: 345, p. 1054) found that that five daily sessions of repetitive transcranial magnetic stimulation (rTMS) of the posterior parietal cortex (PPC) significantly increased functional connectivity (FC) in a network centered on the hippocampus, and caused a correlated increase in memory performance in humans. However, this finding has not been reproduced independently and the requirement for five sessions has not been validated. We aimed to reproduce the imaging results of this experiment, focusing on hippocampal FC changes and using fewer days of rTMS. We measured resting state FC before and after three (N = 9) or four (N = 6) consecutive daily PPC rTMS sessions, using similar delivery parameter settings as Wang et al. Eight subjects received three days of rTMS delivered to the vertex as a control. We employed whole-brain and hypothesis-based statistical approaches to test for hippocampal FC changes. Additionally, we calculated FC in 17 brain networks to determine whether the topographic pattern of FC change was similar between studies. We did not include behavioral testing in this study. PPC, but not vertex, rTMS caused significant changes in hippocampal FC to the same regions as in the previous study. Brain-wide changes in hippocampal FC significantly exceeded changes in global connectedness, indicating that the effect of PPC rTMS was specific to the hippocampal network. Baseline hippocampal FC measured before receiving stimulation predicted the degree of rTMS-induced hippocampal FC increase, as was the case in the previous study. These findings reproduce the imaging findings of Wang et al. and show that FC enhancement can occur after only 3-4 sessions of PPC rTMS.Significance Statement One of the most striking recent findings in the area of neuromodulation is that of Wang et al. (Science, 2014: 345, p. 1054), who reported that posterior parietal cortex (PPC) stimulation increased functional connectivity in a network related to declarative memory and centered on the hippocampus, a result with great potential experimental and clinical utility. We used a similar paradigm, with shorter treatment duration and reproduced the effects on connectivity, including specificity for the hippocampal network and dependence on the magnitude of baseline hippocampal connectivity. These results confirm and extend the initial finding and validate the technical approach.

PMID: 31591137 [PubMed - as supplied by publisher]

Control networks of the frontal lobes.

Thu, 10/10/2019 - 00:00
Related Articles

Control networks of the frontal lobes.

Handb Clin Neurol. 2019;163:333-347

Authors: Marek S, Dosenbach NUF

Abstract
The human brain is organized into specialized functional brain networks. Some networks are dedicated to early sensory processing, and others to generating motor outputs. Yet, the bulk of the human brain's functional networks is actually dedicated to control processes. The two control networks most important for the impressive repertoire of control-related behaviors that humans are able to instantiate and maintain are the frontoparietal and cinguloopercular networks. We provide evidence that these two control networks largely contribute to nonoverlapping domains of control. These networks largely have been studied using fMRI, which is sensitive only to infraslow activity. Complementary electrophysiological techniques have provided evidence that these networks manifest at substantially faster frequencies (delta-alpha band), supporting their role in coordination of whole-brain functional network activity. Both the frontoparietal and cinguloopercular networks demonstrate protracted development, supporting increases in control-related performance. Recent studies from our lab indicate these control networks exhibit measurable individual specificity, highlighting the importance of individualized paradigms in neuroimaging studies to advance our understanding of typical and atypical control network function throughout the life span.

PMID: 31590739 [PubMed - in process]

Characteristics of respiratory measures in young adults scanned at rest, including systematic changes and "missed" deep breaths.

Tue, 10/08/2019 - 10:20

Characteristics of respiratory measures in young adults scanned at rest, including systematic changes and "missed" deep breaths.

Neuroimage. 2019 Oct 04;:116234

Authors: Power JD, Lynch CJ, Dubin MJ, Silver BM, Martin A, Jones RM

Abstract
Breathing rate and depth influence the concentration of carbon dioxide in the blood, altering cerebral blood flow and thus functional magnetic resonance imaging (fMRI) signals. Such respiratory fluctuations can have substantial influence in studies of fMRI signal covariance in subjects at rest, the so-called "resting state functional connectivity" technique. If respiration is monitored during fMRI scanning, it is typically done using a belt about the subject's abdomen to record abdominal circumference. Several measures have been derived from these belt records, including the windowed envelope of the waveform (ENV), the windowed variance in the waveform (respiration variation, RV), and a measure of the amplitude of each breath divided by the cycle time of the breath (respiration volume per time, RVT). Any attempt to gauge respiratory contributions to fMRI signals requires a respiratory measure, but little is known about how these measures compare to each other, or how they perform beyond the small studies in which they were initially proposed. Here, we examine the properties of these measures in hundreds of healthy young adults scanned for an hour each at rest, a subset of the Human Connectome Project chosen for having high-quality physiological records. We find: 1) ENV, RV, and RVT are all correlated, and ENV and RV are more highly correlated to each other than to RVT; 2) respiratory events like deep breaths exhibit characteristic heart rate elevations, fMRI signal changes, head motions, and image quality abnormalities time-locked to large deflections in the belt traces; 3) all measures can "miss" deep breaths; 4) RVT "misses" deep breaths more than ENV or RV; 5) all respiratory measures change systematically over the course of a 14.4-min scan. We discuss the implication of these findings for the literature and ways to move forward in modeling respiratory influences on fMRI scans.

PMID: 31589990 [PubMed - as supplied by publisher]

Meta-analytic and functional connectivity evidence from functional magnetic resonance imaging for an anterior to posterior gradient of function along the hippocampal axis.

Tue, 10/08/2019 - 10:20

Meta-analytic and functional connectivity evidence from functional magnetic resonance imaging for an anterior to posterior gradient of function along the hippocampal axis.

Hippocampus. 2019 Oct 07;:

Authors: Grady CL

Abstract
There is considerable evidence from non-human animal studies that the anterior and posterior regions of the hippocampus have different anatomical connections and support different behavioural functions. Although there are some recent human studies using functional magnetic resonance imaging (fMRI) that have addressed this idea directly in the memory and spatial processing domains and provided support for it, there has been no broader meta-analysis of the fMRI literature to determine if there is consistent evidence for functional dissociations in anterior and posterior hippocampus across all of the different cognitive domains in which the hippocampus participates. The purpose of this review is to address this gap in our knowledge using three approaches. One approach involved PubMed searches to identify relevant fMRI papers reporting hippocampal activation during episodic encoding and retrieval, semantic retrieval, working memory, spatial navigation, simulation/scene construction, transitive inference, and social cognition tasks. The second was to use a large meta-analytic database (neurosynth) to find text terms and coactivation maps associated with the anterior and posterior hippocampal regions identified in the literature search. The third approach was to contrast the resting-state functional connectivity of the anterior and posterior hippocampal regions using a publicly available database that includes a large sample of adults. These three approaches provided converging evidence that not only are cognitive processes differently distributed along the hippocampal axis, but there also are distinct areas coactivated and functionally connected with the anterior and posterior segments. This anterior/posterior distinction involving multiple cognitive domains is consistent with the animal literature and provides strong support from fMRI for the idea of functional dissociations across the long axis of the hippocampus.

PMID: 31589003 [PubMed - as supplied by publisher]

Increased resting-state functional connectivity in suprasellar tumor patients with postoperative visual improvement.

Tue, 10/08/2019 - 10:20

Increased resting-state functional connectivity in suprasellar tumor patients with postoperative visual improvement.

Int J Med Sci. 2019;16(9):1245-1253

Authors: Ying J, Li C, Yuan T, Jin L, Wang R, Zuo Z, Zhang Y

Abstract
Background and Objective: Large suprasellar tumors often compress the optic chiasm and give rise to visual impairment. Most patients have significantly improved visual function at 1 to 4 months after chiasmal decompression surgery, and only a few individuals regain normal vision at 1 week after surgery. How the recovery of visual function in these patients affects the visual cortex is not fully understood. In this study, we aimed to investigate alterations in brain functional connectivity (FC) in suprasellar tumor patients with visual improvement using resting-state functional magnetic resonance imaging (rs-fMRI). Methods: This longitudinal study was conducted on 13 suprasellar tumor patients who had ophthalmological examinations and rs-fMRI at the following time points: within 1-week preoperation (Pre-op), 1-week postoperation (Post-1w) and 1-month postoperation (Post-1m). The visual impairment score (VIS), local functional correlation (LCOR) and FC values were subjected to one-way ANOVA. Pearson correlation coefficients between changes in the LCOR and clinical factors were calculated. Results: The VIS was significantly decreased at both Post-1w and Post-1m compared to that at Pre-op. Whole-brain analysis of LCOR values showed that the left V1 (primary occipital cortex) was increased significantly at Post-1m compared to that at Pre-op (p < 0.05, FDR corrected). ROI analysis exhibited a significant negative correlation between the LCOR and VIS changes at Post-1m compared to those at Pre-op (p < 0.05, r = - 0.60). FC analysis within the visual network showed that the FC strengths were significantly increased between the left V5 and the left V4, right V3a, left V3, left V2d, and right V5 at Post-1m compared to those at Pre-op (p < 0.05, FDR corrected). Additionally, the FC strengths were significantly increased between the left V5 and the left V1, right orbital-frontal gyrus and left posterior supramarginal gyrus at the whole-brain network level at Post-1m compared to those at Pre-op (p < 0.05, FDR corrected). Conclusions: Postoperative visual improvement can be reflected by the increased FC of the visual cortex at Post-1w and Post-1m, especially at Post-1m. The LCOR value of the left V1 was associated with improved visual outcomes and may be used to objectively assess early visual recovery after chiasmal decompression at Post-1m.

PMID: 31588190 [PubMed - in process]

Applying a network framework to the neurobiology of reading and dyslexia.

Tue, 10/08/2019 - 10:20
Related Articles

Applying a network framework to the neurobiology of reading and dyslexia.

J Neurodev Disord. 2018 12 13;10(1):37

Authors: Bailey SK, Aboud KS, Nguyen TQ, Cutting LE

Abstract
BACKGROUND: There is a substantial literature on the neurobiology of reading and dyslexia. Differences are often described in terms of individual regions or individual cognitive processes. However, there is a growing appreciation that the brain areas subserving reading are nested within larger functional systems, and new network analysis methods may provide greater insight into how reading difficulty arises. Yet, relatively few studies have adopted a principled network-based approach (e.g., connectomics) to studying reading. In this study, we combine data from previous reading literature, connectomics studies, and original data to investigate the relationship between network architecture and reading.
METHODS: First, we detailed the distribution of reading-related areas across many resting-state networks using meta-analytic data from NeuroSynth. Then, we tested whether individual differences in modularity, the brain's tendency to segregate into resting-state networks, are related to reading skill. Finally, we determined whether brain areas that function atypically in dyslexia, as identified by previous meta-analyses, tend to be concentrated in hub regions.
RESULTS: We found that most resting-state networks contributed to the reading network, including those subserving domain-general cognitive skills such as attention and executive function. There was also a positive relationship between the global modularity of an individual's brain network and reading skill, with the visual, default mode and cingulo-opercular networks showing the highest correlations. Brain areas implicated in dyslexia were also significantly more likely to have a higher participation coefficient (connect to multiple resting-state networks) than other areas.
CONCLUSIONS: These results contribute to the growing literature on the relationship between reading and brain network architecture. They suggest that an efficient network organization, i.e., one in which brain areas form cohesive resting-state networks, is important for skilled reading, and that dyslexia can be characterized by abnormal functioning of hub regions that map information between multiple systems. Overall, use of a connectomics framework opens up new possibilities for investigating reading difficulty, especially its commonalities across other neurodevelopmental disorders.

PMID: 30541433 [PubMed - indexed for MEDLINE]

Dissociable Frontostriatal Connectivity: Mechanism and Predictor of the Clinical Efficacy of Capsulotomy in Obsessive-Compulsive Disorder.

Tue, 10/08/2019 - 10:20
Related Articles

Dissociable Frontostriatal Connectivity: Mechanism and Predictor of the Clinical Efficacy of Capsulotomy in Obsessive-Compulsive Disorder.

Biol Psychiatry. 2018 12 15;84(12):926-936

Authors: Yin D, Zhang C, Lv Q, Chen X, Zeljic K, Gong H, Zhan S, Jin H, Wang Z, Sun B

Abstract
BACKGROUND: Little is known about the neural mechanism and response variability underlying neurosurgical interventions for intractable obsessive-compulsive disorder (OCD).
METHODS: Of 81 OCD patients screened for capsulotomy identified in our institutional database, 36 patients with clinical assessment before and after capsulotomy and imaging data (9 of 36 patients without postoperative imaging data used as an independent test group), and 29 healthy control subjects were retrospectively recruited. Twenty of 36 patients (56%) responded to the lesion procedure (determined as a ≥35% reduction in Yale-Brown Obsessive Compulsive Scale [Y-BOCS] score). Seed-based (i.e., ventral and dorsal caudate, medial dorsal thalamus, and ventral and dorsal putamen) resting-state functional connectivity was used to examine alterations in frontostriatal circuitry after capsulotomy.
RESULTS: The Y-BOCS score significantly decreased (p < .001) after capsulotomy in OCD patients. Functional connectivity between the ventral striatum/nucleus accumbens and the dorsal anterior cingulate cortex was reduced (p < .05, corrected) after the surgical procedure. Moreover, change in connectivity significantly correlated with alteration in Y-BOCS score (r = .41, p = .033). In addition, preoperative connectivity between the dorsal caudate and the dorsal anterior cingulate cortex could differentiate nonresponders from responders and predict changes in Y-BOCS score (R2 = .23, F1,25 = 7.56, p = .011), which was generalized in an independent test group.
CONCLUSIONS: We demonstrated that restoration of ventral frontostriatal connectivity was associated with clinical improvement in refractory OCD, suggesting a therapeutic mechanism of capsulotomy. Moreover, preoperative variations in dorsal frontostriatal connectivity predicted clinical response, which may offer a predictor of treatment outcome.

PMID: 29778276 [PubMed - indexed for MEDLINE]

Pages