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Patterns of intrinsic brain activity in essential tremor with resting tremor and tremor-dominant Parkinson's disease.

Wed, 01/29/2020 - 20:09
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Patterns of intrinsic brain activity in essential tremor with resting tremor and tremor-dominant Parkinson's disease.

Brain Imaging Behav. 2020 Jan 27;:

Authors: Li JY, Lu ZJ, Suo XL, Li NN, Lei D, Wang L, Peng JX, Duan LR, Xi J, Jiang Y, Gong QY, Peng R

Abstract
The clinical pictures of essential tremor (ET) with resting tremor (rET) and tremor-dominant Parkinson's disease (tPD) are often quite mimic at the early stage, current approaches to the diagnosis and treatment therefore remain challenging. The regional homogeneity (ReHo) method under resting-state functional magnetic resonance imaging (rs-fMRI) would help exhibit the patterns in neural activity, which further contribute to differentiate these disorders and explore the relationship between symptoms and regional functional abnormalities. Sixty-eight Chinese participants were recruited, including 19 rET patients, 24 tPD patients and 25 age- and gender-matched healthy controls (HCs). All participants underwent clinical assessment and rs-fMRI with a ReHo method to investigate the alterations of neural activity, and the correlation between them. Differences were compared by two-sample t-test (corrected with AlphaSim, p < 0.05). Compared with HCs, patients' groups both displayed decreased ReHo in the default mode network (DMN), bilateral putamen and bilateral cerebellum. While tPD patients specifically exihibited decreased ReHo in the bilateral supplementary motor area (SMA) and precentral gyrus (M1). The correlation analysis revealed that ReHo in the bilateral putamen, right SMA and left cerebellum_crus I were negatively correlated with the UPDRS-III score, respectively, in tPD group. Our results indicated the rET patients may share part of the pathophysiological mechanism of tPD patients. In addition, we found disorder-specific involvement of the SMA and M1 in tPD. Such a distinction may lend itself to use as a potential biomarker for differentiating between these two diseases.

PMID: 31989422 [PubMed - as supplied by publisher]

Resting-state connectivity stratifies premanifest Huntington's disease by longitudinal cognitive decline rate.

Wed, 01/29/2020 - 20:09
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Resting-state connectivity stratifies premanifest Huntington's disease by longitudinal cognitive decline rate.

Sci Rep. 2020 Jan 27;10(1):1252

Authors: Polosecki P, Castro E, Rish I, Pustina D, Warner JH, Wood A, Sampaio C, Cecchi GA

Abstract
Patient stratification is critical for the sensitivity of clinical trials at early stages of neurodegenerative disorders. In Huntington's disease (HD), genetic tests make cognitive, motor and brain imaging measurements possible before symptom manifestation (pre-HD). We evaluated pre-HD stratification models based on single visit resting-state functional MRI (rs-fMRI) data that assess observed longitudinal motor and cognitive change rates from the multisite Track-On HD cohort (74 pre-HD, 79 control participants). We computed longitudinal performance change on 10 tasks (including visits from the preceding TRACK-HD study when available), as well as functional connectivity density (FCD) maps in single rs-fMRI visits, which showed high test-retest reliability. We assigned pre-HD subjects to subgroups of fast, intermediate, and slow change along single tasks or combinations of them, correcting for expectations based on aging; and trained FCD-based classifiers to distinguish fast- from slow-progressing individuals. For robustness, models were validated across imaging sites. Stratification models distinguished fast- from slow-changing participants and provided continuous assessments of decline applicable to the whole pre-HD population, relying on previously-neglected white matter functional signals. These results suggest novel correlates of early deterioration and a robust stratification strategy where a single MRI measurement provides an estimate of multiple ongoing longitudinal changes.

PMID: 31988371 [PubMed - in process]

Topographic mapping as a basic principle of functional organization for visual and prefrontal functional connectivity.

Wed, 01/29/2020 - 20:09
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Topographic mapping as a basic principle of functional organization for visual and prefrontal functional connectivity.

eNeuro. 2020 Jan 27;:

Authors: O'Rawe JF, Leung HC

Abstract
The organization of region-to-region functional connectivity has major implications for understanding information transfer and transformation between brain regions. We extended connective field mapping methodology to 3-dimensional anatomical space to derive estimates of cortico-cortical functional organization. Using multiple publicly available human (both male and female) resting-state fMRI data samples for model testing and replication analysis, we have three main findings. First, we found that the functional connectivity between early visual regions maintained a topographic relationship along the anterior-posterior dimension, which corroborates previous research. Higher order visual regions showed a pattern of connectivity that supports convergence and biased sampling, which has implications for their receptive field properties. Second, we demonstrated that topographic organization is a fundamental aspect of functional connectivity across the entire cortex, with higher topographic connectivity between regions within a functional network than across networks. The principle gradient of topographic connectivity across the cortex resembled whole brain gradients found in previous work. Last but not least, we showed that the organization of higher order regions such as the lateral prefrontal cortex demonstrate functional gradients of topographic connectivity and convergence. These organizational features of the lateral prefrontal cortex predict task based activation patterns, particularly visual specialization and higher order rules. In sum, these findings suggest that topographic input is a fundamental motif of functional connectivity between cortical regions for information processing and transfer, with maintenance of topography potentially important for preserving the integrity of information from one region to another.Significance Statement Quantifying spatial patterns of region-to-region functional connectivity provides an avenue for testing theories of corticocortical information transformation and organization. This work demonstrates that this quantification is feasible not only in early visual cortex, but even in highly multimodal regions where spatial topography is less clear. Overall, we show that topographic relationships as a common motif functional connectivity across the cortex between regions within the same functional network and that analyzing the lateral prefrontal cortex in terms of topographic connectivity reveals organizational features that voxelwise connectivity analysis misses.

PMID: 31988218 [PubMed - as supplied by publisher]

Portable, field-based neuroimaging using high-density diffuse optical tomography.

Wed, 01/29/2020 - 20:09
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Portable, field-based neuroimaging using high-density diffuse optical tomography.

Neuroimage. 2020 Jan 24;:116541

Authors: Fishell AK, Arbeláez AM, Valdés CP, Burns-Yocum TM, Sherafati A, Richter EJ, Torres M, Eggebrecht AT, Smyser CD, Culver JP

Abstract
Behavioral and cognitive tests in individuals who were malnourished as children have revealed malnutrition-related deficits that persist throughout the lifespan. These findings have motivated recent neuroimaging investigations that use highly portable functional near-infrared spectroscopy (fNIRS) instruments to meet the demands of brain imaging experiments in low-resource environments and enable longitudinal investigations of brain function in the context of long-term malnutrition. However, recent studies in healthy subjects have demonstrated that high-density diffuse optical tomography (HD-DOT) can significantly improve image quality over that obtained with sparse fNIRS imaging arrays. In studies of both task activations and resting state functional connectivity, HD-DOT is beginning to approach the data quality of fMRI for superficial cortical regions. In this work, we developed a customized HD-DOT system for use in malnutrition studies in Cali, Colombia. Our results evaluate the performance of the HD-DOT instrument for assessing brain function in a cohort of malnourished children. In addition to demonstrating portability and wearability, we show the HD-DOT instrument's sensitivity to distributed brain responses using a sensory processing task and measurements of homotopic functional connectivity. Task-evoked responses to the passive word listening task produce activations localized to bilateral superior temporal gyrus, replicating previously published work using this paradigm. Evaluating this localization performance across sparse and dense reconstruction schemes indicates that greater localization consistency is associated with a dense array of overlapping optical measurements. These results provide a foundation for additional avenues of investigation, including identifying and characterizing a child's individual malnutrition burden and eventually contributing to intervention development.

PMID: 31987995 [PubMed - as supplied by publisher]

Graph theory analysis of functional connectivity combined with machine learning approaches demonstrate widespread network differences and predict clinical variables in temporal lobe epilepsy.

Tue, 01/28/2020 - 20:06

Graph theory analysis of functional connectivity combined with machine learning approaches demonstrate widespread network differences and predict clinical variables in temporal lobe epilepsy.

Brain Connect. 2020 Jan 26;:

Authors: Mazrooyisedani M, Nair VA, Camille Garcia-Ramos C, Mohanty R, Meyerand ME, Hermann B, Prabhakaran V, Ahmed R

Abstract
Understanding how global brain networks are affected in epilepsy may elucidate the pathogenesis of seizures and its accompanying neurobehavioral comorbidities. We investigated functional changes within neural networks in temporal lobe epilepsy (TLE) using graph theory analysis of resting-state connectivity. 27 TLE presurgical patients (age 41.0 ± 12.3 years), and 85 age, gender and handedness equivalent healthy controls (HC) (age 39.7±16.9 years) were enrolled. Eyes-closed resting-state fMRI scans were analyzed to compare network properties and functional connectivity changes. TLE subjects showed significantly higher global efficiency, lower clustering coefficient ratio and lower shortest path lengths ratio compared to HC, as an indication of a more synchronized, yet less segregated network. A trend of functional reorganization with a shift of network hubs to the contralateral hemisphere was noted in TLE subjects. Support vector machine (SVM) with linear kernel was trained to separate between neural networks in TLE and HC subjects based on graph measurements. SVM analysis allowed separation between TLE and HC networks with 80.66% accuracy using 8 features of graph measurements. Support vector regression (SVR) was used to predict neurocognitive performance from graph metrics. A SVR linear predictor showed discriminative prediction accuracy for 4 key neurocognitive variables in TLE (absolute R-value range: 0.61 - 0.75) Despite temporal onset of epilepsy, our results showed both local and global network topology differences that reflect widespread alterations in functional connectivity in TLE. Network differences are discriminative between TLE and HCs using data driven analysis and predicted severity of neurocognitive sequelae in our cohort.

PMID: 31984759 [PubMed - as supplied by publisher]

Decreased functional connectivity of hippocampal subregions and methylation of the NR3C1 gene in Han Chinese adults who lost their only child.

Tue, 01/28/2020 - 20:06
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Decreased functional connectivity of hippocampal subregions and methylation of the NR3C1 gene in Han Chinese adults who lost their only child.

Psychol Med. 2020 Jan 27;:1-10

Authors: Qi R, Luo Y, Zhang L, Weng Y, Surento W, Xu Q, Jahanshad N, Li L, Cao Z, Lu GM, Thompson PM

Abstract
BACKGROUND: Losing one's only child is a major traumatic life event that may lead to post-traumatic stress disorder (PTSD); however, the underlying mechanisms of its psychological consequences remain poorly understood. Here, we investigated subregional hippocampal functional connectivity (FC) networks based on resting-state functional magnetic resonance imaging and the deoxyribonucleic acid methylation of the human glucocorticoid receptor gene (NR3C1) in adults who had lost their only child.
METHODS: A total of 144 Han Chinese adults who had lost their only child (51 adults with PTSD and 93 non-PTSD adults [trauma-exposed controls]) and 50 controls without trauma exposure were included in this fMRI study (age: 40-67 years). FCs between hippocampal subdivisions (four regions in each hemisphere: cornu ammonis1 [CA1], CA2, CA3, and dentate gyrus [DG]) and methylation levels of the NR3C1 gene were compared among the three groups.
RESULTS: Trauma-exposed adults, regardless of PTSD diagnosis, had weaker positive FC between the left hippocampal CA1, left DG, and the posterior cingulate cortex, and weaker negative FC between the right CA1, right DG, and several frontal gyri, relative to healthy controls. Compared to non-PTSD adults, PTSD adults showed decreased negative FC between the right CA1 region and the right middle/inferior frontal gyri (MFG/IFG), and decreased negative FC between the right DG and the right superior frontal gyrus and left MFG. Both trauma-exposed groups showed lower methylation levels of the NR3C1 gene.
CONCLUSIONS: Adults who had lost their only child may experience disrupted hippocampal network connectivity and NR3C1 methylation status, regardless of whether they have developed PTSD.

PMID: 31983347 [PubMed - as supplied by publisher]

Targeting the centromedian thalamic nucleus for deep brain stimulation.

Sun, 01/26/2020 - 23:04
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Targeting the centromedian thalamic nucleus for deep brain stimulation.

J Neurol Neurosurg Psychiatry. 2020 Jan 24;:

Authors: Warren AEL, Dalic LJ, Thevathasan W, Roten A, Bulluss KJ, Archer J

Abstract
OBJECTIVES: Deep brain stimulation (DBS) of the centromedian thalamic nucleus (CM) is an emerging treatment for multiple brain diseases, including the drug-resistant epilepsy Lennox-Gastaut syndrome (LGS). We aimed to improve neurosurgical targeting of the CM by: (1) developing a structural MRI approach for CM visualisation, (2) identifying the CM's neurophysiological characteristics using microelectrode recordings (MERs) and (3) mapping connectivity from CM-DBS sites using functional MRI (fMRI).
METHODS: 19 patients with LGS (mean age=28 years) underwent presurgical 3T MRI using magnetisation-prepared 2 rapid acquisition gradient-echoes (MP2RAGE) and fMRI sequences; 16 patients proceeded to bilateral CM-DBS implantation and intraoperative thalamic MERs. CM visualisation was achieved by highlighting intrathalamic borders on MP2RAGE using Sobel edge detection. Mixed-effects analysis compared two MER features (spike firing rate and background noise) between ventrolateral, CM and parafasicular nuclei. Resting-state fMRI connectivity was assessed using implanted CM-DBS electrode positions as regions of interest.
RESULTS: The CM appeared as a hyperintense region bordering the comparatively hypointense pulvinar, mediodorsal and parafasicular nuclei. At the group level, reduced spike firing and background noise distinguished CM from the ventrolateral nucleus; however, these trends were not found in 20%-25% of individual MER trajectories. Areas of fMRI connectivity included basal ganglia, brainstem, cerebellum, sensorimotor/premotor and limbic cortex.
CONCLUSIONS: In the largest clinical trial of DBS undertaken in patients with LGS to date, we show that accurate targeting of the CM is achievable using 3T MP2RAGE MRI. Intraoperative MERs may provide additional localising features in some cases; however, their utility is limited by interpatient variability. Therapeutic effects of CM-DBS may be mediated via connectivity with brain networks that support diverse arousal, cognitive and sensorimotor processes.

PMID: 31980515 [PubMed - as supplied by publisher]

Hippocampal plasticity underpins long-term cognitive gains from resistance exercise in MCI.

Sat, 01/25/2020 - 20:02
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Hippocampal plasticity underpins long-term cognitive gains from resistance exercise in MCI.

Neuroimage Clin. 2020 Jan 14;25:102182

Authors: Broadhouse KM, Singh MF, Suo C, Gates N, Wen W, Brodaty H, Jain N, Wilson GC, Meiklejohn J, Singh N, Baune BT, Baker M, Foroughi N, Wang Y, Kochan N, Ashton K, Brown M, Li Z, Mavros Y, Sachdev PS, J Valenzuela M

Abstract
Dementia affects 47 million individuals worldwide, and assuming the status quo is projected to rise to 150 million by 2050. Prevention of age-related cognitive impairment in older persons with lifestyle interventions continues to garner evidence but whether this can combat underlying neurodegeneration is unknown. The Study of Mental Activity and Resistance Training (SMART) trial has previously reported within-training findings; the aim of this study was to investigate the long-term neurostructural and cognitive impact of resistance exercise in Mild Cognitive Impairment (MCI). For the first time we show that hippocampal subareas particularly susceptible to volume loss in Alzheimer's disease (AD) are protected by resistance exercise for up to one year after training. One hundred MCI participants were randomised to one of four training groups: (1) Combined high intensity progressive resistance and computerised cognitive training (PRT+CCT), (2) PRT+Sham CCT, (3) CCT+Sham PRT, (4) Sham physical+sham cognitive training (SHAM+SHAM). Physical, neuropsychological and MRI assessments were carried out at baseline, 6 months (directly after training) and 18 months from baseline (12 months after intervention cessation). Here we report neuro-structural and functional changes over the 18-month trial period and the association with global cognitive and executive function measures. PRT but not CCT or PRT+CCT led to global long-term cognitive improvements above SHAM intervention at 18-month follow-up. Furthermore, hippocampal subfields susceptible to atrophy in AD were protected by PRT revealing an elimination of long-term atrophy in the left subiculum, and attenuation of atrophy in left CA1 and dentate gyrus when compared to SHAM+SHAM (p = 0.023, p = 0.020 and p = 0.027). These neuroprotective effects mediated a significant portion of long-term cognitive benefits. By contrast, within-training posterior cingulate plasticity decayed after training cessation and was unrelated to long term cognitive benefits. Neither general physical activity levels nor fitness change over the 18-month period mediated hippocampal trajectory, demonstrating that enduring hippocampal subfield plasticity is not a simple reflection of post-training changes in fitness or physical activity participation. Notably, resting-state fMRI analysis revealed that both the hippocampus and posterior cingulate participate in a functional network that continued to be upregulated following intervention cessation. Multiple structural mechanisms may contribute to the long-term global cognitive benefit of resistance exercise, developing along different time courses but functionally linked. For the first time we show that 6 months of high intensity resistance exercise is capable of not only promoting better cognition in those with MCI, but also protecting AD-vulnerable hippocampal subfields from degeneration for at least 12 months post-intervention. These findings emphasise the therapeutic potential of resistance exercise; however, future work will need to establish just how long-lived these outcomes are and whether they are sufficient to delay dementia.

PMID: 31978826 [PubMed - as supplied by publisher]

Resting-state effective connectivity in the motive circuit of methamphetamine users: a case controlled fMRI study.

Sat, 01/25/2020 - 20:02
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Resting-state effective connectivity in the motive circuit of methamphetamine users: a case controlled fMRI study.

Behav Brain Res. 2020 Jan 21;:112498

Authors: Siyah Mansoory M, Farnia V

Abstract
Methamphetamine (MA) and other psychostimulants target the motive circuit of the brain, which is involved in reward, behavioral sensitization, and relapse to drug-seeking/taking behavior. In spite of this fact, the data regarding the effective connectivity (EC) in this circuit among MA users is scarce. The present study aimed to assess resting-state EC in the motive circuit of MA users during abstinence using the fMRI technique. Seventeen MA users after abstinence and 18 normal controls were examined using a 3 T Siemens fMRI scanner. After extracting time series of the motive circuit, EC differences in the motive circuit were analyzed using dynamic causal modeling (DCM). The findings revealed that abstinent MA users had an enhanced EC from the prefrontal cortex (PFC) to the ventral palladium (VP) (PFC→VP) and on the mediodorsal thalamus (MD) self-loop (MD→MD), but they showed a decreased connectivity on the VP self-loop (VP→VP) compared to healthy controls. The findings suggest that abstinent MA users may suffer from a limited pathology in connectivity within the motive circuit involved in reward, behavioral sensitization, and relapse. The enhanced PFC→VP seems to be a compensatory mechanism to control or regulate the subcortical regions involved in reward and behavioral sensitization. Furthermore, the enhanced connectivity on the MD self-loop and the decreased connectivity on the VP self-loop in abstinent MA users may, at least partially, affect the output of the limbic system, which can be seen in the behavioral sensitization and relapse processes. Nonetheless, further investigation in this area is strongly recommended to elucidate the exact mechanisms involved.

PMID: 31978492 [PubMed - as supplied by publisher]

Weighted average of shared trajectory: a new estimator for dynamic functional connectivity efficiently estimates both rapid and slow changes over time.

Sat, 01/25/2020 - 20:02
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Weighted average of shared trajectory: a new estimator for dynamic functional connectivity efficiently estimates both rapid and slow changes over time.

J Neurosci Methods. 2020 Jan 21;:108600

Authors: Faghiri A, Iraji A, Damaraju E, Belger A, Ford J, Mathalon D, Mcewen S, Mueller B, Pearlson G, Preda A, Turner J, Vaidya JG, Van Erp T, Calhoun VD

Abstract
BACKGROUND: Dynamic functional network connectivity (dFNC) of the brain has attracted considerable attention recently. Many approaches have been suggested to study dFNC with sliding window Pearson correlation (SWPC) being the most well-known. SWPC needs a relatively large sample size to reach a robust estimation but using large window sizes prevents us to detect rapid changes in dFNC.
NEW METHOD: Here we first calculate the gradients of each time series pair and use the magnitude of these gradients to calculate weighted average of shared trajectory (WAST) as a new estimator for dFNC.
RESULTS: Using WAST to compare healthy control and schizophrenia patients using a large dataset, we show disconnectivity between different regions associated with schizophrenia. In addition, WAST results reveals patients with schizophrenia stay longer in a connectivity state with negative connectivity between motor and sensory regions than do healthy controls.
COMPARISON WITH EXISTING METHODS: We compare WAST with SWPC and multiplication of temporal derivatives (MTD) using different simulation scenarios. We show that WAST enables us to detect very rapid changes in dFNC (undetected by SWPC) while MTD performance is generally lower.
CONCLUSIONS: As large window sizes are unable to detect short states, using shorter window size is desirable if the estimator is robust enough. We provide evidence that WAST requires fewer samples (compared to SWPC) to reach a robust estimation. As a result, we were able to identify rapidly varying dFNC patterns undetected by SWPC while still being able to robustly estimate slower dFNC patterns.

PMID: 31978489 [PubMed - as supplied by publisher]

Human hippocampal CA3 damage disrupts both recent and remote episodic memories.

Sat, 01/25/2020 - 20:02
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Human hippocampal CA3 damage disrupts both recent and remote episodic memories.

Elife. 2020 Jan 24;9:

Authors: Miller TD, Chong TT, Aimola Davies AM, Johnson MR, Irani SR, Husain M, Ng TW, Jacob S, Maddison P, Kennard C, Gowland PA, Rosenthal CR

Abstract
Neocortical-hippocampal interactions support new episodic (event) memories, but there is conflicting evidence about the dependence of remote episodic memories on the hippocampus. In line with systems consolidation and computational theories of episodic memory, evidence from model organisms suggests that the cornu ammonis 3 (CA3) hippocampal subfield supports recent, but not remote, episodic retrieval. In this study, we demonstrated that recent and remote memories were susceptible to a loss of episodic detail in human participants with focal bilateral damage to CA3. Graph theoretic analyses of 7.0-Tesla resting-state fMRI data revealed that CA3 damage disrupted functional integration across the medial temporal lobe (MTL) subsystem of the default network. The loss of functional integration in MTL subsystem regions was predictive of autobiographical episodic retrieval performance. We conclude that human CA3 is necessary for the retrieval of episodic memories long after their initial acquisition and functional integration of the default network is important for autobiographical episodic memory performance.

PMID: 31976861 [PubMed - in process]

Regional Increases in Brain Signal Variability Are Associated with Pain Intensity Reductions Following Repeated Eccentric Exercise Bouts.

Sat, 01/25/2020 - 20:02
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Regional Increases in Brain Signal Variability Are Associated with Pain Intensity Reductions Following Repeated Eccentric Exercise Bouts.

Eur J Pain. 2020 Jan 24;:

Authors: Boissoneault J, Sevel L, Stennett B, Alappattu M, Bishop M, Robinson M

Abstract
BACKGROUND: Traditional pain interventions limit fluctuations in pain sensation, which may paradoxically impair endogenous pain modulatory systems (EPMS). However, controlled exposures to clinically relevant pain (e.g. delayed onset muscle soreness, DOMS) may build capacity in the EPMS. Emerging evidence suggests regional signal variability (RSV) may be an important indicator of efficiency and modulatory capacity within brain regions. The present study sought to determine the role of RSV in both susceptibility to and trainability of pain response following repeated DOMS inductions.
METHODS: Baseline and follow-up resting-state fMRI was performed on 12 healthy volunteers ~40 days apart. Between scanning visits, participants received four weekly DOMS inductions in alternating elbow flexors and supplied seven days of post-induction pain ratings. Voxel-wise standard deviation of signal intensity was calculated to measure RSV. Associations among DOMS-related pain and RSV were assessed with regression. Relationships among baseline and change measurements were probed (i.e. susceptibility to DOMS; trainability following multiple inductions).
RESULTS: Significant association between baseline RSV in left MFG and right cerebellum and reductions in DOMS-related pain unpleasantness were detected. Furthermore, increases in RSV were associated with reduced DOMS pain intensity (left lingual gyrus, right MTG, left MTG, left precuneus) and unpleasantness (left MTG, right SFG).
DISCUSSION: Findings suggest that RSV may be an indicator of EPMS resilience and responsivity to training, as well as an indicator that is responsive to training. Involved regions underlie cognitive, affective, and representation processes. Results further clarify the potential role of RSV as an indicator of pain modulation and resilience.
SIGNIFICANCE: Regional signal variability may be an important indicator of endogenous pain modulatory system responsivity to training following repeated bouts of clinically relevant pain and may in fact be responsive to training itself.

PMID: 31976587 [PubMed - as supplied by publisher]

Creative music therapy to promote brain function and brain structure in preterm infants: A randomized controlled pilot study.

Fri, 01/24/2020 - 23:01
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Creative music therapy to promote brain function and brain structure in preterm infants: A randomized controlled pilot study.

Neuroimage Clin. 2020 Jan 13;25:102171

Authors: Haslbeck FB, Jakab A, Held U, Bassler D, Bucher HU, Hagmann C

Abstract
Cognitive and neurobehavioral problems are among the most severe adverse outcomes in very preterm infants. Such neurodevelopmental impairments may be mitigated through nonpharmacological interventions such as creative music therapy (CMT), an interactive, resource- and needs-oriented approach that provides individual social contact and musical stimulation. The aim was to test the feasibility of a study investigating the role of CMT and to measure the short- and medium-term effects of CMT on structural and functional brain connectivity with MRI. In this randomized, controlled clinical pilot feasibility trial, 82 infants were randomized to either CMT or standard care. A specially trained music therapist provided CMT via infant-directed humming and singing in lullaby style. To test the short-term effects of CMT on brain structure and function, diffusion tensor imaging data and resting-state functional imaging data were acquired. Clinical feasibility was achieved despite moderate parental refusal mainly in the control group after randomization. 40 infants remained as final cohort for the MRI analysis. Structural brain connectivity appears to be moderately affected by CMT, structural connectomic analysis revealed increased integration in the posterior cingulate cortex only. Lagged resting-state MRI analysis showed lower thalamocortical processing delay, stronger functional networks, and higher functional integration in predominantly left prefrontal, supplementary motor, and inferior temporal brain regions in infants treated with CMT. This trial provides unique evidence that CMT has beneficial effects on functional brain activity and connectivity in networks underlying higher-order cognitive, socio-emotional, and motor functions in preterm infants. Our results indicate the potential of CMT to improve long-term neurodevelopmental outcomes in children born very preterm.

PMID: 31972397 [PubMed - as supplied by publisher]

The functional implications and modifiability of resting-state brain network complexity in older adults.

Fri, 01/24/2020 - 23:01
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The functional implications and modifiability of resting-state brain network complexity in older adults.

Neurosci Lett. 2020 Jan 20;:134775

Authors: Zhou J, Lo OY, Halko MA, Harrison R, Lipsitz LA, Manor B

Abstract
The dynamics of the resting-state activity in brain functional networks are complex, containing meaningful patterns over multiple temporal scales. Such physiologic complexity is often diminished in older adults. Here we aim to examine if the resting-state complexity within functional brain networks is sensitive to functional status in older adults and if repeated exposure to transcranial direct current stimulation (tDCS) would modulate such complexity. Twelve older adults with slow gait and mild-to-moderate executive dysfunction and 12 age- and sex-matched controls completed a baseline resting-state fMRI (rs-fMRI). Ten participants in the functionally-limited group then completed ten 20-minute sessions of real (n = 6) or sham (n = 4) tDCS targeting the left prefrontal cortex over a two-week period as well as a follow-up rs-fMRI. The resting-state complexity associated with seven functional networks was quantified by averaging the multiscale entropy (MSE) of the blood oxygen level-dependent (BOLD) time-series for all voxels within each network. Compared to controls, functionally-limited group exhibited lower complexity in the motor, ventral attention, limbic, executive and default mode networks (F > 6.3, p < 0.02). Within this group, those who received tDCS exhibited greater complexity within the ventral, executive and limbic networks (p < 0.04) post intervention as compared to baseline, while no significant changes in sham group was observed. This study provides preliminary evidence that older adults with functional limitations had diminished complexity of resting-state brain network activity and repeated exposure to tDCS may increase that resting-state complexity, warranting future studies to establish such complexity as a marker of brain health in older adults.

PMID: 31972253 [PubMed - as supplied by publisher]

Behavioral deficits in left hemispatial neglect are related to a reduction of spontaneous neuronal activity in the right superior parietal lobule.

Fri, 01/24/2020 - 23:01
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Behavioral deficits in left hemispatial neglect are related to a reduction of spontaneous neuronal activity in the right superior parietal lobule.

Neuropsychologia. 2020 Jan 20;:107356

Authors: Machner B, von der Gablentz J, Göttlich M, Heide W, Helmchen C, Sprenger A, Münte TF

Abstract
Focal brain lesions may induce dysfunctions in distant brain regions leading to behavioral impairments. Based on this concept of 'diaschisis', spatial neglect following stroke has been related to structural damage of the right-lateralized ventral attention network (VAN) and disrupted inter-hemispheric functional connectivity (FC) in the bilateral dorsal attention network (DAN). We questioned whether neglect-related behavioral deficits may be determined by local dysfunction of a specific region within these brain networks. We investigated acute right-hemisphere stroke patients with left hemispatial neglect using resting-state functional MRI, neuropsychological tests of spatial attention and clinical assessment of neglect-related functional disability. In addition to conventional FC analyses between different cortical regions of interest (ROIs) in the DAN/VAN, we extracted the fractional amplitude of low frequency fluctuations (fALFF) from each ROI as a marker of regional spontaneous neuronal activity. Although DAN regions (as opposed to the VAN regions) were largely spared from structural brain damage, they exhibited a significant reduction of inter-hemispheric FC. However, significant fMRI-behavior correlations were revealed specifically for the fALFF of one DAN-ROI in the right superior parietal lobule (SPL): the smaller the fALFF in the right posterior intraparietal sulcus, the more severe the patient's pathological attention bias and neglect-related functional impairment. In line with 'diaschisis', our findings confirm a crucial role of the non-lesioned but dysfunctional right SPL for the emergence of spatial neglect and its behavioral consequences. They further support targeting the SPL dysfunction by non-invasive brain stimulation in neglect rehabilitation.

PMID: 31972231 [PubMed - as supplied by publisher]

Modulation of Distinct Intrinsic Resting State Brain Networks by Acute Exercise Bouts of Differing Intensity.

Fri, 01/24/2020 - 23:01
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Modulation of Distinct Intrinsic Resting State Brain Networks by Acute Exercise Bouts of Differing Intensity.

Brain Plast. 2019 Dec 26;5(1):39-55

Authors: Schmitt A, Upadhyay N, Martin JA, Rojas S, Strüder HK, Boecker H

Abstract
Acute exercise bouts alter resting state functional connectivity (rs-FC) within cognitive, sensorimotor, and affective networks, but it remains unknown how these effects are influenced by exercise intensity. Twenty-five male athletes underwent individual fitness assessments using an incremental treadmill test. On separate days, they performed 'low' (35% below lactate threshold) and 'high' (20% above lactate threshold) intensity exercise bouts of 30 min. Rs-fMRI and Positive and Negative Affect Scale (PANAS) were acquired before and after each exercise bout. Networks of interest were extracted from twenty-two participants (3 dropouts). Pre-to-post changes and between conditions effects were evaluated using FSL's randomise by applying repeated measures ANOVA. Results were reported at p < 0.05, corrected for multiple comparisons using threshold free cluster enhancement. PANAS revealed a significant increase in positive mood after both exercise conditions. Significant effects were observed between conditions in the right affective and reward network (ARN), the right fronto parietal network (FPN) and the sensorimotor network (SMN). Pre-to-post comparisons after 'low' exercise intensity revealed a significant increase in rs-FC in the left and right FPN, while after 'high'-intensity exercise rs-FC decreased in the SMN and the dorsal attention network (DAN) and increased in the left ARN. Supporting recent findings, this study is the first to report distinct rs-FC alterations driven by exercise intensity: (i) Increased rs-FC in FPN may indicate beneficial functional plasticity for cognitive/attentional processing, (ii) increased rs-FC in ARN may be linked to endogenous opioid-mediated internal affective states. Finally, (iii) decreased rs-FC in the SMN may signify persistent motor fatigue. The distinct effects on rs-FC fit with theories of transient persistent network alterations after acute exercise bouts that are mediated by different exercise intensities and impact differentially on cognitive/attentional or affective responses.

PMID: 31970059 [PubMed]

Current Challenges in Translational and Clinical fMRI and Future Directions.

Fri, 01/24/2020 - 23:01
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Current Challenges in Translational and Clinical fMRI and Future Directions.

Front Psychiatry. 2019;10:924

Authors: Specht K

Abstract
Translational neuroscience is an important field that brings together clinical praxis with neuroscience methods. In this review article, the focus will be on functional neuroimaging (fMRI) and its applicability in clinical fMRI studies. In the light of the "replication crisis," three aspects will be critically discussed: First, the fMRI signal itself, second, current fMRI praxis, and, third, the next generation of analysis strategies. Current attempts such as resting-state fMRI, meta-analyses, and machine learning will be discussed with their advantages and potential pitfalls and disadvantages. One major concern is that the fMRI signal shows substantial within- and between-subject variability, which affects the reliability of both task-related, but in particularly resting-state fMRI studies. Furthermore, the lack of standardized acquisition and analysis methods hinders the further development of clinical relevant approaches. However, meta-analyses and machine-learning approaches may help to overcome current shortcomings in the methods by identifying new, and yet hidden relationships, and may help to build new models on disorder mechanisms. Furthermore, better control of parameters that may have an influence on the fMRI signal and that can easily be controlled for, like blood pressure, heart rate, diet, time of day, might improve reliability substantially.

PMID: 31969840 [PubMed]

Continuous reorganization of cortical information flow in multiple sclerosis: A longitudinal fMRI effective connectivity study.

Thu, 01/23/2020 - 20:00
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Continuous reorganization of cortical information flow in multiple sclerosis: A longitudinal fMRI effective connectivity study.

Sci Rep. 2020 Jan 21;10(1):806

Authors: Fleischer V, Muthuraman M, Anwar AR, Gonzalez-Escamilla G, Radetz A, Gracien RM, Bittner S, Luessi F, Meuth SG, Zipp F, Groppa S

Abstract
Effective connectivity (EC) is able to explore causal effects between brain areas and can depict mechanisms that underlie repair and adaptation in chronic brain diseases. Thus, the application of EC techniques in multiple sclerosis (MS) has the potential to determine directionality of neuronal interactions and may provide an imaging biomarker for disease progression. Here, serial longitudinal structural and resting-state fMRI was performed at 12-week intervals over one year in twelve MS patients. Twelve healthy subjects served as controls (HC). Two approaches for EC quantification were used: Causal Bayesian Network (CBN) and Time-resolved Partial Directed Coherence (TPDC). The EC strength was correlated with the Expanded Disability Status Scale (EDSS) and Fatigue Scale for Motor and Cognitive functions (FSMC). Our findings demonstrated a longitudinal increase in EC between specific brain regions, detected in both the CBN and TPDC analysis in MS patients. In particular, EC from the deep grey matter, frontal, prefrontal and temporal regions showed a continuous increase over the study period. No longitudinal changes in EC were attested in HC during the study. Furthermore, we observed an association between clinical performance and EC strength. In particular, the EC increase in fronto-cerebellar connections showed an inverse correlation with the EDSS and FSMC. Our data depict continuous functional reorganization between specific brain regions indicated by increasing EC over time in MS, which is not detectable in HC. In particular, fronto-cerebellar connections, which were closely related to clinical performance, may provide a marker of brain plasticity and functional reserve in MS.

PMID: 31964982 [PubMed - in process]

An fMRI-based neural marker for migraine without aura.

Thu, 01/23/2020 - 20:00
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An fMRI-based neural marker for migraine without aura.

Neurology. 2020 Jan 21;:

Authors: Tu Y, Zeng F, Lan L, Li Z, Maleki N, Liu B, Chen J, Wang C, Park J, Lang C, Yujie G, Liu M, Fu Z, Zhang Z, Liang F, Kong J

Abstract
OBJECTIVE: To identify and validate an fMRI-based neural marker for migraine without aura (MwoA) and to examine its association with treatment response.
METHODS: We conducted cross-sectional studies with resting-state fMRI data from 230 participants and machine learning analyses. In studies 1 through 3, we identified, cross-validated, independently validated, and cross-sectionally validated an fMRI-based neural marker for MwoA. In study 4, we assessed the relationship between the neural marker and treatment responses in migraineurs who received a 4-week real or sham acupuncture treatment, or were waitlisted, in a registered clinical trial.
RESULTS: In study 1 (n = 116), we identified a neural marker with abnormal functional connectivity within the visual, default mode, sensorimotor, and frontal-parietal networks that could discriminate migraineurs from healthy controls (HCs) with 93% sensitivity and 89% specificity. In study 2 (n = 38), we investigated the generalizability of the marker by applying it to an independent cohort of migraineurs and HCs and achieved 84% sensitivity and specificity. In study 3 (n = 76), we verified the specificity of the marker with new datasets of migraineurs and patients with other chronic pain disorders (chronic low back pain and fibromyalgia) and demonstrated 78% sensitivity and 76% specificity for discriminating migraineurs from nonmigraineurs. In study 4 (n = 116), we found that the changes in the marker responses showed significant correlation with the changes in headache frequency in response to real acupuncture.
CONCLUSION: We identified an fMRI-based neural marker that captures distinct characteristics of MwoA and can link disease pattern changes to brain changes.

PMID: 31964691 [PubMed - as supplied by publisher]

Human brain functional network organization is disrupted following whole-brain radiation therapy.

Thu, 01/23/2020 - 20:00
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Human brain functional network organization is disrupted following whole-brain radiation therapy.

Brain Connect. 2020 Jan 22;:

Authors: Mitchell T, Seitzman B, Ballard N, Petersen SE, Shimony J, Leuthardt E

Abstract
Radiation therapy plays a vital role in the treatment of brain cancers, but frequently results in cognitive decline in the patients who receive it. Because the underlying mechanisms for this decline remains poorly understood, the brain is typically treated as a single, uniform volume when evaluating the toxic effects of radiation therapy plans. This ignorance represents a significant deficit in the field of radiation oncology, as the technology exists to manipulate dose distributions to spare regions of the brain, but there exists no body of knowledge regarding what is critical to spare. This deficit exists due to the numerous confounding factors that are frequently associated with radiotherapy, including the tumors themselves, other treatments such as surgery and chemotherapy, and dose gradients across the brain. Here, we present a case in which a 57 year-old male patient received a uniform dose of radiation across the whole brain, did not receive concurrent chemotherapy, had minimal surgical intervention and a small tumor burden, and received resting-state functional MRI scans before and after radiation therapy. To our knowledge, this is the first study on the effects of whole brain radiotherapy on functional network organization, and this patient's treatment regimen represents a rare and non-replicable opportunity to isolate the effects of radiation on functional connectivity. We observed substantial changes in the subject's behavior and functional network organization over a 12-month timeframe. Interestingly, the homogenous radiation dose to the brain had a heterogeneous effect on cortical networks, and the functional networks most affected correspond with observed cognitive behavioral deficits. This novel study suggests that the cognitive decline that occurs after whole-brain radiation therapy may be network specific and related to the disruption of large-scale distributed functional systems, and indicates that functional MRI is a promising avenue of study for optimizing cognitive outcomes following radiation therapy.

PMID: 31964163 [PubMed - as supplied by publisher]