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Structural and Functional Brain Parameters Related to Cognitive Performance Across Development: Replication and Extension of the Parieto-Frontal Integration Theory in a Single Sample.

Fri, 10/30/2020 - 12:00
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Structural and Functional Brain Parameters Related to Cognitive Performance Across Development: Replication and Extension of the Parieto-Frontal Integration Theory in a Single Sample.

Cereb Cortex. 2020 Oct 29;:

Authors: Gur RC, Butler ER, Moore TM, Rosen AFG, Ruparel K, Satterthwaite TD, Roalf DR, Gennatas ED, Bilker WB, Shinohara RT, Port A, Elliott MA, Verma R, Davatzikos C, Wolf DH, Detre JA, Gur RE

Abstract
The parieto-frontal integration theory (PFIT) identified a fronto-parietal network of regions where individual differences in brain parameters most strongly relate to cognitive performance. PFIT was supported and extended in adult samples, but not in youths or within single-scanner well-powered multimodal studies. We performed multimodal neuroimaging in 1601 youths age 8-22 on the same 3-Tesla scanner with contemporaneous neurocognitive assessment, measuring volume, gray matter density (GMD), mean diffusivity (MD), cerebral blood flow (CBF), resting-state functional magnetic resonance imaging measures of the amplitude of low frequency fluctuations (ALFFs) and regional homogeneity (ReHo), and activation to a working memory and a social cognition task. Across age and sex groups, better performance was associated with higher volumes, greater GMD, lower MD, lower CBF, higher ALFF and ReHo, and greater activation for the working memory task in PFIT regions. However, additional cortical, striatal, limbic, and cerebellar regions showed comparable effects, hence PFIT needs expansion into an extended PFIT (ExtPFIT) network incorporating nodes that support motivation and affect. Associations of brain parameters became stronger with advancing age group from childhood to adolescence to young adulthood, effects occurring earlier in females. This ExtPFIT network is developmentally fine-tuned, optimizing abundance and integrity of neural tissue while maintaining a low resting energy state.

PMID: 33119049 [PubMed - as supplied by publisher]

Effects of Head Motion on the Evaluation of Age-related Brain Network Changes Using Resting State Functional MRI.

Fri, 10/30/2020 - 12:00
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Effects of Head Motion on the Evaluation of Age-related Brain Network Changes Using Resting State Functional MRI.

Magn Reson Med Sci. 2020 Oct 27;:

Authors: Kato S, Bagarinao E, Isoda H, Koyama S, Watanabe H, Maesawa S, Mori D, Hara K, Katsuno M, Hoshiyama M, Naganawa S, Ozaki N, Sobue G

Abstract
PURPOSE: The estimation of functional connectivity (FC) measures using resting state functional MRI (fMRI) is often affected by head motion during functional imaging scans. Head motion is more common in the elderly than in young participants and could therefore affect the evaluation of age-related changes in brain networks. Thus, this study aimed to investigate the influence of head motion in FC estimation when evaluating age-related changes in brain networks.
METHODS: This study involved 132 healthy volunteers divided into 3 groups: elderly participants with high motion (OldHM, mean age (±SD) = 69.6 (±5.31), N = 44), elderly participants with low motion (OldLM, mean age (±SD) = 68.7 (±4.59), N = 43), and young adult participants with low motion (YugLM, mean age (±SD) = 27.6 (±5.26), N = 45). Head motion was quantified using the mean of the framewise displacement of resting state fMRI data. After preprocessing all resting state fMRI datasets, several resting state networks (RSNs) were extracted using independent component analysis (ICA). In addition, several network metrics were also calculated using network analysis. These FC measures were then compared among the 3 groups.
RESULTS: In ICA, the number of voxels with significant differences in RSNs was higher in YugLM vs. OldLM comparison than in YugLM vs. OldHM. In network analysis, all network metrics showed significant (P < 0.05) differences in comparisons involving low vs. high motion groups (OldHM vs. OldLM and OldHM vs. YugLM). However, there was no significant (P > 0.05) difference in the comparison involving the low motion groups (OldLM vs. YugLM).
CONCLUSION: Our findings showed that head motion during functional imaging could significantly affect the evaluation of age-related brain network changes using resting state fMRI data.

PMID: 33115986 [PubMed - as supplied by publisher]

Quantitative Identification of Functional Connectivity Disturbances in Neuropsychiatric Lupus Based on Resting-State fMRI: A Robust Machine Learning Approach.

Fri, 10/30/2020 - 12:00
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Quantitative Identification of Functional Connectivity Disturbances in Neuropsychiatric Lupus Based on Resting-State fMRI: A Robust Machine Learning Approach.

Brain Sci. 2020 Oct 25;10(11):

Authors: Simos NJ, Dimitriadis SI, Kavroulakis E, Manikis GC, Bertsias G, Simos P, Maris TG, Papadaki E

Abstract
Neuropsychiatric systemic lupus erythematosus (NPSLE) is an autoimmune entity comprised of heterogenous syndromes affecting both the peripheral and central nervous system. Research on the pathophysiological substrate of NPSLE manifestations, including functional neuroimaging studies, is extremely limited. The present study examined person-specific patterns of whole-brain functional connectivity in NPSLE patients (n = 44) and age-matched healthy control participants (n = 39). Static functional connectivity graphs were calculated comprised of connection strengths between 90 brain regions. These connections were subsequently filtered through rigorous surrogate analysis, a technique borrowed from physics, novel to neuroimaging. Next, global as well as nodal network metrics were estimated for each individual functional brain network and were input to a robust machine learning algorithm consisting of a random forest feature selection and nested cross-validation strategy. The proposed pipeline is data-driven in its entirety, and several tests were performed in order to ensure model robustness. The best-fitting model utilizing nodal graph metrics for 11 brain regions was associated with 73.5% accuracy (74.5% sensitivity and 73% specificity) in discriminating NPSLE from healthy individuals with adequate statistical power. Closer inspection of graph metric values suggested an increased role within the functional brain network in NSPLE (indicated by higher nodal degree, local efficiency, betweenness centrality, or eigenvalue efficiency) as compared to healthy controls for seven brain regions and a reduced role for four areas. These findings corroborate earlier work regarding hemodynamic disturbances in these brain regions in NPSLE. The validity of the results is further supported by significant associations of certain selected graph metrics with accumulated organ damage incurred by lupus, with visuomotor performance and mental flexibility scores obtained independently from NPSLE patients.

PMID: 33113768 [PubMed]

Resting-state posterior alpha rhythms are abnormal in subjective memory complaint seniors with preclinical Alzheimer's neuropathology and high education level: the INSIGHT-preAD study.

Fri, 10/30/2020 - 12:00
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Resting-state posterior alpha rhythms are abnormal in subjective memory complaint seniors with preclinical Alzheimer's neuropathology and high education level: the INSIGHT-preAD study.

Neurobiol Aging. 2020 06;90:43-59

Authors: Babiloni C, Lopez S, Del Percio C, Noce G, Pascarelli MT, Lizio R, Teipel SJ, González-Escamilla G, Bakardjian H, George N, Cavedo E, Lista S, Chiesa PA, Vergallo A, Lemercier P, Spinelli G, Grothe MJ, Potier MC, Stocchi F, Ferri R, Habert MO, Fraga FJ, Dubois B, Hampel H, INSIGHT-preAD Study Group

Abstract
Cognitive reserve is present in Alzheimer's disease (AD) seniors with high education attainment making them clinically resilient to extended brain neuropathology and neurodegeneration. Here, we tested whether subjective memory complaint (SMC) seniors with AD neuropathology and high education attainment of the prospective INSIGHT-preAD cohort (Paris) may present abnormal eyes-closed resting state posterior electroencephalographic rhythms around individual alpha frequency peak, typically altered in AD patients. The SMC participants negative to amyloid PET AD markers (SMCneg) with high (over low-moderate) education level showed higher posterior alpha 2 power density (possibly "neuroprotective"). Furthermore, amyloid PET-positive SMC (SMCpos) participants with high (over low-moderate) education level showed higher temporal alpha 3 power density (possibly "neuroprotective") and lower posterior alpha 2 power density (possibly "compensatory"). This effect may reflect cognitive reserve as no differences in brain gray-white matter, and cognitive functions were observed between these SMCpos/SMCneg subgroups. Preclinical Alzheimer's neuropathology may interact with education attainment and neurophysiological mechanisms generating cortical alpha rhythms around individual alpha frequency peak (i.e., alpha 2 and 3) in quiet wakefulness.

PMID: 32111391 [PubMed - indexed for MEDLINE]

Impairment of right ventricular strain evaluated by cardiovascular magnetic resonance feature tracking in patients with interstitial lung disease.

Thu, 10/29/2020 - 10:40

Impairment of right ventricular strain evaluated by cardiovascular magnetic resonance feature tracking in patients with interstitial lung disease.

Int J Cardiovasc Imaging. 2020 Oct 28;:

Authors: Kamide H, Kato S, Hayakawa K, Fukui K, Kitamura H, Ogura T, Iwasawa T, Kimura K, Tamura K, Utsunomiya D

Abstract
OBJECTIVES: The aims of this study were to investigate the relationship between pulmonary hypertension (PH) and right ventricular (RV) strain, and to evaluate the prognostic value of RV strain by cardiac magnetic resonance (CMR) feature tracking for patients with interstitial lung disease (ILD).
METHODS: A total of seventy ILD patients (mean age: 71 ± 8 years, 39 [56%] males) who underwent CMR and right heart catheterization (RHC) were studied. Using a 1.5T magnetic resonance (MR) scanner, steady-state free precession cine MR images encompassing the RV were acquired in all patients and 20 control subjects. RV longitudinal strain were calculated with a feature tracking algorithm. PH was defined as a mean pulmonary artery pressure of more than 20 mmHg at rest and a pulmonary vascular resistance ≥3 Woods unit.
RESULTS: The RV longitudinal strain was significantly impaired in the ILD patients with PH (n=18) than ILD patients without PH (n=52) (-13.3 ± 5.4% vs. -16.9±5.4%, p=0.048). The RV longitudinal strain differed significantly between the ILD patients without PH and the controls (n=20) (-16.9 ± 5.4% vs. -20.8 ± 6.2%, p=0.002). Five of 70 (7%) patients died within one-year after CMR scan. Area under receiver operating characteristics curve for predicting death was 0.900 (95%CI: 0.800 to 1.000) for RV strain, 0.643 (95%CI: 0.454 to 0.832) for RVEF.
CONCLUSIONS: Presence of PH was associated with impairment of RV strain, and RV strain could predict short-term mortality in patients with ILD. RV strain by feature tracking might be useful as a non-invasive prognostic marker for patients with ILD.

PMID: 33113068 [PubMed - as supplied by publisher]

Integration of Simultaneous Resting-State Electroencephalography, Functional Magnetic Resonance Imaging, and Eye-Tracker Methods to Determine and Verify Electroencephalography Vigilance Measure.

Thu, 10/29/2020 - 10:40

Integration of Simultaneous Resting-State Electroencephalography, Functional Magnetic Resonance Imaging, and Eye-Tracker Methods to Determine and Verify Electroencephalography Vigilance Measure.

Brain Connect. 2020 Oct 28;:

Authors: Mayeli A, Al Zoubi O, Misaki M, Stewart JL, Zotev V, Luo Q, Phillips R, Fischer S, Götz M, Paulus MP, Refai H, Bodurka J

Abstract
Background/Introduction: Concurrent electroencephalography and resting-state functional magnetic resonance imaging (rsfMRI) have been widely used for studying the (presumably) awake and alert human brain with high temporal/spatial resolution. Although rsfMRI scans are typically collected while individuals are instructed to focus their eyes on a fixated cross, objective and verified experimental measures to quantify degree of vigilance are not readily available. Electroencephalography (EEG) is the modality extensively used for estimating vigilance, especially during eyes-closed resting state. However, pupil size measured using an eye-tracker device could provide an indirect index of vigilance. Methods: Three 12-min resting scans (eyes open, fixating on the cross) were collected from 10 healthy control participants. We simultaneously collected EEG, fMRI, physiological, and eye-tracker data and investigated the correlation between EEG features, pupil size, and heart rate. Furthermore, we used pupil size and EEG features as regressors to find their correlations with blood-oxygen-level-dependent fMRI measures. Results: EEG frontal and occipital beta power (FOBP) correlates with pupil size changes, an indirect index for locus coeruleus activity implicated in vigilance regulation (r = 0.306, p < 0.001). Moreover, FOBP also correlated with heart rate (r = 0.255, p < 0.001), as well as several brain regions in the anticorrelated network, including the bilateral insula and inferior parietal lobule. Discussion: In this study, we investigated whether simultaneous EEG-fMRI combined with eye-tracker measurements can be used to determine EEG signal feature associated with vigilance measures during eyes-open rsfMRI. Our results support the conclusion that FOBP is an objective measure of vigilance in healthy human subjects.

PMID: 33112650 [PubMed - as supplied by publisher]

Socioeconomic Status Mediates Racial Differences Seen Using the AT(N) Framework.

Thu, 10/29/2020 - 10:40

Socioeconomic Status Mediates Racial Differences Seen Using the AT(N) Framework.

Ann Neurol. 2020 Oct 28;:

Authors: Meeker KL, Wisch JK, Hudson D, Coble D, Xiong C, Babulal GM, Gordon BA, Schindler SE, Cruchaga C, Flores S, Dincer A, Benzinger TL, Morris JC, Ances BM

Abstract
OBJECTIVES: African Americans are at greater risk for developing Alzheimer disease (AD) dementia than non-Hispanic Whites. In addition to biological considerations (e.g., genetic influences; comorbid disorders), social and environmental factors may increase the risk of AD dementia. This paper (1) Assesses neuroimaging biomarkers of amyloid (A), tau (T), and neurodegeneration (N) for potential racial differences. (2) Considers mediating effects of socioeconomic status (SES) and measures of small vessel and cardiovascular disease on observed race differences.
METHODS: Imaging measures of AT(N) (amyloid and tau positron emission tomography [PET] structural magnetic resonance imaging (MRI), and resting state functional connectivity (rs-fc) were collected from African American (n=131) and White (n=685) cognitively normal participants age 45 years and older. Measures of small vessel and cardiovascular disease (white matter hyperintensities [WMH] on MRI, blood pressure, body mass index [BMI]) and area-based socioeconomic status (SES) were included in mediation analyses.
RESULTS: Compared to White participants, African American participants had greater neurodegeneration, as measured by decreased cortical volumes (Cohen's f2 = 0.05, p < 0.001). SES mediated the relationship between race and cortical volumes. There were no significant race effects for amyloid, tau, or rs-fc signature.
INTERPRETATION: Modifiable factors such as differences in social contexts and resources, particularly area-level SES, may contribute to observed racial differences in AD. Future studies should emphasize collection of relevant psychosocial factors in addition to the development of intentional diversity and inclusion efforts to improve the racial/ethnic and socioeconomic representativeness of AD studies. This article is protected by copyright. All rights reserved.

PMID: 33111990 [PubMed - as supplied by publisher]

Distributed changes of the functional connectome in patients with glioblastoma.

Thu, 10/29/2020 - 10:40

Distributed changes of the functional connectome in patients with glioblastoma.

Sci Rep. 2020 Oct 27;10(1):18312

Authors: Nenning KH, Furtner J, Kiesel B, Schwartz E, Roetzer T, Fortelny N, Bock C, Grisold A, Marko M, Leutmezer F, Liu H, Golland P, Stoecklein S, Hainfellner JA, Kasprian G, Prayer D, Marosi C, Widhalm G, Woehrer A, Langs G

Abstract
Glioblastoma might have widespread effects on the neural organization and cognitive function, and even focal lesions may be associated with distributed functional alterations. However, functional changes do not necessarily follow obvious anatomical patterns and the current understanding of this interrelation is limited. In this study, we used resting-state functional magnetic resonance imaging to evaluate changes in global functional connectivity patterns in 15 patients with glioblastoma. For six patients we followed longitudinal trajectories of their functional connectome and structural tumour evolution using bi-monthly follow-up scans throughout treatment and disease progression. In all patients, unilateral tumour lesions were associated with inter-hemispherically symmetric network alterations, and functional proximity of tumour location was stronger linked to distributed network deterioration than anatomical distance. In the longitudinal subcohort of six patients, we observed patterns of network alterations with initial transient deterioration followed by recovery at first follow-up, and local network deterioration to precede structural tumour recurrence by two months. In summary, the impact of focal glioblastoma lesions on the functional connectome is global and linked to functional proximity rather than anatomical distance to tumour regions. Our findings further suggest a relevance for functional network trajectories as a possible means supporting early detection of tumour recurrence.

PMID: 33110138 [PubMed - in process]

Cerebellar alterations in cannabis users: A systematic review.

Thu, 10/29/2020 - 10:40
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Cerebellar alterations in cannabis users: A systematic review.

Addict Biol. 2019 11;24(6):1121-1137

Authors: Blithikioti C, Miquel L, Batalla A, Rubio B, Maffei G, Herreros I, Gual A, Verschure P, Balcells-Oliveró M

Abstract
Cannabis is the most used illicit substance in the world. As many countries are moving towards decriminalization, it is crucial to determine whether and how cannabis use affects human brain and behavior. The role of the cerebellum in cognition, emotion, learning, and addiction is increasingly recognized. Because of its high density in CB1 receptors, it is expected to be highly affected by cannabis use. The aim of this systematic review is to investigate how cannabis use affects cerebellar structure and function, as well as cerebellar-dependent behavioral tasks. Three databases were searched for peer-reviewed literature published until March 2018. We included studies that focused on cannabis effects on cerebellar structure, function, or cerebellar-dependent behavioral tasks. A total of 348 unique records were screened, and 40 studies were included in the qualitative synthesis. The most consistent findings include (1) increases in cerebellar gray matter volume after chronic cannabis use, (2) alteration of cerebellar resting state activity after acute or chronic use, and (3) deficits in memory, decision making, and associative learning. Age of onset and higher exposure to cannabis use were frequently associated with increased cannabis-induced alterations. Chronic cannabis use is associated with alterations in cerebellar structure and function, as well as with deficits in behavioral paradigms that involve the cerebellum (eg, eyeblink conditioning, memory, and decision making). Future studies should consider tobacco as confounding factor and use standardized methods for assessing cannabis use. Paradigms exploring the functional activity of the cerebellum may prove useful as monitoring tools of cannabis-induced impairment.

PMID: 30811097 [PubMed - indexed for MEDLINE]

Resting Brain Fluctuations Are Intrinsically Coupled to Visual Response Dynamics.

Wed, 10/28/2020 - 15:00

Resting Brain Fluctuations Are Intrinsically Coupled to Visual Response Dynamics.

Cereb Cortex. 2020 Oct 27;:

Authors: Belloy ME, Billings J, Abbas A, Kashyap A, Pan WJ, Hinz R, Vanreusel V, Van Audekerke J, Van der Linden A, Keilholz SD, Verhoye M, Keliris GA

Abstract
How do intrinsic brain dynamics interact with processing of external sensory stimuli? We sought new insights using functional magnetic resonance imaging to track spatiotemporal activity patterns at the whole brain level in lightly anesthetized mice, during both resting conditions and visual stimulation trials. Our results provide evidence that quasiperiodic patterns (QPPs) are the most prominent component of mouse resting brain dynamics. These QPPs captured the temporal alignment of anticorrelation between the default mode (DMN)- and task-positive (TPN)-like networks, with global brain fluctuations, and activity in neuromodulatory nuclei of the reticular formation. Specifically, the phase of QPPs prior to stimulation could significantly stratify subsequent visual response magnitude, suggesting QPPs relate to brain state fluctuations. This is the first observation in mice that dynamics of the DMN- and TPN-like networks, and particularly their anticorrelation, capture a brain state dynamic that affects sensory processing. Interestingly, QPPs also displayed transient onset response properties during visual stimulation, which covaried with deactivations in the reticular formation. We conclude that QPPs appear to capture a brain state fluctuation that may be orchestrated through neuromodulation. Our findings provide new frontiers to understand the neural processes that shape functional brain states and modulate sensory input processing.

PMID: 33108464 [PubMed - as supplied by publisher]

Distinct hierarchical alterations of intrinsic neural timescales account for different manifestations of psychosis.

Wed, 10/28/2020 - 15:00

Distinct hierarchical alterations of intrinsic neural timescales account for different manifestations of psychosis.

Elife. 2020 Oct 27;9:

Authors: Wengler K, Goldberg AT, Chahine G, Horga G

Abstract
Hierarchical perceptual-inference models of psychosis may provide a holistic framework for understanding psychosis in schizophrenia including heterogeneity in clinical presentations. Particularly, hypothesized alterations at distinct levels of the perceptual-inference hierarchy may explain why hallucinations and delusions tend to cluster together yet sometimes manifest in isolation. To test this, we used a recently developed resting-state fMRI measure of intrinsic neural timescale (INT), which reflects the time window of neural integration and captures hierarchical brain gradients. In analyses examining extended sensory hierarchies that we first validated, we found distinct hierarchical INT alterations for hallucinations versus delusions in the auditory and somatosensory systems, thus providing support for hierarchical perceptual-inference models of psychosis. Simulations using a large-scale biophysical model suggested local elevations of excitation-inhibition ratio at different hierarchical levels as a potential mechanism. More generally, our work highlights the robustness and utility of INT for studying hierarchical processes relevant to basic and clinical neuroscience.

PMID: 33107431 [PubMed - in process]

Strength of resting state functional connectivity and local GABA concentrations predict oral reading of real and pseudo-words.

Wed, 10/28/2020 - 15:00
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Strength of resting state functional connectivity and local GABA concentrations predict oral reading of real and pseudo-words.

Sci Rep. 2019 08 06;9(1):11385

Authors: Krishnamurthy LC, Krishnamurthy V, Crosson B, Rothman DL, Schwam DM, Greenberg D, Pugh KR, Morris RD

Abstract
Reading is a learned activity that engages multiple cognitive systems. In a cohort of typical and struggling adult readers we show evidence that successful oral reading of real words is related to gamma-amino-butyric acid (GABA) concentration in the higher-order language system, whereas reading of unfamiliar pseudo-words is not related to GABA in this system. We also demonstrate the capability of resting state functional connectivity (rsFC) combined with GABA measures to predict single real word compared to pseudo-word reading performance. Results show that the strength of rsFC between left fusiform gyrus (L-FG) and higher-order language systems predicts oral reading behavior of real words, irrespective of the local concentration of GABA. On the other hand, pseudo-words, which require grapheme-to-phoneme conversion, are not predicted by the connection between L-FG and higher-order language system. This suggests that L-FG may have a multi-functional role: lexical processing of real words and grapheme-to-phoneme processing of pseudo-words. Additionally, rsFC between L-FG, pre-motor, and putamen areas are positively related to the oral reading of both real and pseudo-words, suggesting that text may be converted into a phoneme sequence for speech initiation and production regardless of whether the stimulus is a real word or pseudo-word. In summary, from a systems neuroscience perspective, we show that: (i) strong rsFC between higher order visual, language, and pre-motor areas can predict and differentiate efficient oral reading of real and pseudo-words. (ii) GABA measures, along with rsFC, help to further differentiate the neural pathways for previously learned real words versus unfamiliar pseudo-words.

PMID: 31388067 [PubMed - indexed for MEDLINE]

Investigation of brain functional connectivity in patients with mild cognitive impairment: A functional near-infrared spectroscopy (fNIRS) study.

Wed, 10/28/2020 - 15:00
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Investigation of brain functional connectivity in patients with mild cognitive impairment: A functional near-infrared spectroscopy (fNIRS) study.

J Biophotonics. 2019 09;12(9):e201800298

Authors: Nguyen T, Kim M, Gwak J, Lee JJ, Choi KY, Lee KH, Kim JG

Abstract
This study examines brain functional connectivity in both cognitively normal seniors and patients with mild cognitive impairment (MCI) to elucidate prospective markers of MCI. A homemade four-channel functional near-infrared spectroscopy (fNIRS) system was employed to measure hemodynamic responses in the subjects' prefrontal cortex during a resting state, an oddball task, a 1-back task, and a verbal fluency task. Brain functional connectivity was calculated as the Pearson correlation coefficients between fNIRS channels. The results show that during the verbal fluency task, while the healthy control (HC) group presents a significantly stronger inter-hemispheric connectivity compared to intra-hemispheric connectivity, there is no difference between the inter- and intra-hemispheric connectivity in the MCI group. In addition, a comparison between the MCI and HC connectivity reveals that the MCI group has a statistically higher right and inter-hemispheric connectivity during the resting state, but a significantly lower left and inter-hemispheric connectivity during the verbal fluency test. These findings demonstrate the potential of fNIRS to study brain functional connectivity in neurodegenerative diseases.

PMID: 30963713 [PubMed - indexed for MEDLINE]

Quantitative and simultaneous measurement of oxygen consumption rates in rat brain and skeletal muscle using 17 O MRS imaging at 16.4T.

Tue, 10/27/2020 - 14:20

Quantitative and simultaneous measurement of oxygen consumption rates in rat brain and skeletal muscle using 17 O MRS imaging at 16.4T.

Magn Reson Med. 2020 Oct 26;:

Authors: Wiesner HM, Balla DZ, Scheffler K, Uğurbil K, Zhu XH, Chen W, Uludağ K, Pohmann R

Abstract
PURPOSE: Oxygen-17 (17 O) MRS imaging, successfully used in the brain, is extended by imaging the oxygen metabolic rate in the resting skeletal muscle and used to determine the total whole-body oxygen metabolic rate in the rat.
METHODS: During and after inhalations of 17 O2 gas, dynamic 17 O MRSI was performed in rats (n = 8) ventilated with N2 O or N2 at 16.4 T. Time courses of the H2 17 O concentration from regions of interest located in brain and muscle tissue were examined and used to fit an animal-adapted 3-phase metabolic model of oxygen consumption. CBF was determined with an independent washout method. Finally, body oxygen metabolic rate was calculated using a global steady-state approach.
RESULTS: Cerebral metabolic rate of oxygen consumption was 1.97 ± 0.19 μmol/g/min on average. The resting metabolic rate of oxygen consumption in skeletal muscle was 0.32 ± 0.12 μmol/g/min and >6 times lower than cerebral metabolic rate of oxygen consumption. Global oxygen consumed by the body was 24.2 ± 3.6 mL O2 /kg body weight/min. CBF was estimated to be 0.28 ± 0.02 mL/g/min and 0.34 ± 0.06 mL/g/min for the N2 and N2 O ventilation condition, respectively.
CONCLUSION: We have evaluated the feasibility of 17 O MRSI for imaging and quantifying the oxygen consumption rate in low metabolizing organs such as the skeletal muscle at rest. Additionally, we have shown that CBF is slightly increased in the case of ventilation with N2 O. We expect this study to be beneficial to the application of 17 O MRSI to a wider range of organs, although further validation is advised.

PMID: 33104248 [PubMed - as supplied by publisher]

Aberrant Advanced Cognitive and Attention-Related Brain Networks in Parkinson's Disease with Freezing of Gait.

Tue, 10/27/2020 - 14:20

Aberrant Advanced Cognitive and Attention-Related Brain Networks in Parkinson's Disease with Freezing of Gait.

Neural Plast. 2020;2020:8891458

Authors: Li Y, Ruan X, Li E, Zhang G, Liu Y, Du Y, Wang Z, Yu S, Yang R, Li M, Wei X

Abstract
Background: Freezing of gait (FOG) is a disabling gait disorder influencing patients with Parkinson's disease (PD). Accumulating evidence suggests that FOG is related to the functional alterations within brain networks. We investigated the changes in brain resting-state functional connectivity (FC) in patients with PD with FOG (FOG+) and without FOG (FOG-).
Methods: Resting-state functional magnetic resonance imaging (RS-fMRI) data were collected from 55 PD patients (25 FOG+ and 30 FOG-) and 26 matched healthy controls (HC). Differences in intranetwork connectivity between FOG+, FOG-, and HC individuals were explored using independent component analysis (ICA).
Results: Seven resting-state networks (RSNs) with abnormalities, including motor, executive, and cognitive-related networks, were found in PD patients compared to HC. Compared to FOG- patients, FOG+ patients had increased FC in advanced cognitive and attention-related networks. In addition, the FC values of the auditory network and default mode network were positively correlated with the Gait and Falls Questionnaire (GFQ) and Freezing of Gait Questionnaire (FOGQ) scores in FOG+ patients.
Conclusions: Our findings suggest that the neural basis of PD is associated with impairments of multiple functional networks. Notably, alterations of advanced cognitive and attention-related networks rather than motor networks may be related to the mechanism of FOG.

PMID: 33101404 [PubMed - in process]

Changes in Brain Function Networks in Patients With Amnestic Mild Cognitive Impairment: A Resting-State fMRI Study.

Tue, 10/27/2020 - 14:20

Changes in Brain Function Networks in Patients With Amnestic Mild Cognitive Impairment: A Resting-State fMRI Study.

Front Neurol. 2020;11:554032

Authors: Li X, Wang F, Liu X, Cao D, Cai L, Jiang X, Yang X, Yang T, Asakawa T

Abstract
Patients with amnestic mild cognitive impairment (aMCI) are at high risk of developing dementia. This study used resting-state functional magnetic resonance imaging (rs-fMRI) and an independent component analysis (ICA) approach to explore changes in functional connectivity (FC) in the default mode network (DMN), executive control network (ECN), and salience network (SN). Thirty patients with aMCI and 30 healthy controls (HCs) were enrolled. All the participants underwent an rs-fMRI scan. The brain FC in DMN, ECN, and SN was calculated using the ICA approach. We found that the FC of brain regions in DMN decreased significantly and that of brain regions in ECN increased, which was in accordance with the findings of previous studies on Alzheimer's disease (AD) and aMCI. We also found that the FC of brain regions in SN increased, which was different from the findings of previous studies on AD. The increase in FC in brain regions in SN might result from different pathophysiological states in AD and aMCI, indicating that a decrease in FC in SN does not occur in a person with aMCI. These results are consistent with those of previous studies using the voxel-mirrored homotopic connectivity approach and seed-based correlation analysis. We therefore considered that the decrease in FC in DMN and the increase in FC in ECN and SN might be peculiar patterns observed on the rs-fMRI of a person with aMCI. These findings may contribute to the development of imaging biomarkers for the diagnosis of aMCI.

PMID: 33101173 [PubMed]

Altered Brain Functional Connectivity Density in Fast-Ball Sports Athletes With Early Stage of Motor Training.

Tue, 10/27/2020 - 14:20

Altered Brain Functional Connectivity Density in Fast-Ball Sports Athletes With Early Stage of Motor Training.

Front Psychol. 2020;11:530122

Authors: Yang C, Luo N, Liang M, Zhou S, Yu Q, Zhang J, Zhang M, Guo J, Wang H, Yu J, Cui Q, Chen H, Gao Q

Abstract
The human brain shows neuroplastic adaptations caused by motor skill training. Of note, there is little known about the plastic architecture of the whole-brain network in resting state. The purpose of the present study was to detect how motor training affected the density distribution of whole-brain resting-state functional connectivity (FC). Resting-state functional magnetic resonance imaging data was assessed based on a comparison of fast-ball student athletes (SA) and non-athlete healthy controls (NC). The voxel-wise data-driven graph theory approach, global functional connectivity density (gFCD) mapping, was applied. Results showed that the SA group exhibited significantly decreased gFCD in brain regions centered at the left triangular part of the inferior frontal gyrus (IFG), extending to the opercular part of the left IFG and middle frontal gyrus compared to the NC group. In addition, findings suggested the idea of an increased neural efficiency of athletes' brain regions associated with attentional-motor modulation and executive control. Furthermore, behavioral results showed that in the SA group, faster executive control reaction time relates to smaller gFCD values in the left IFG. These findings suggested that the motor training would decrease the numbers of FC in IFG to accelerate the executive control with high attentional demands and enable SA to rapidly focus the attention to detect the intriguing target.

PMID: 33101115 [PubMed]

Decreased Resting-State Interhemispheric Functional Connectivity in Medication-Free Obsessive-Compulsive Disorder.

Tue, 10/27/2020 - 14:20

Decreased Resting-State Interhemispheric Functional Connectivity in Medication-Free Obsessive-Compulsive Disorder.

Front Psychiatry. 2020;11:559729

Authors: Jia C, Ou Y, Chen Y, Li P, Lv D, Yang R, Zhong Z, Sun L, Wang Y, Zhang G, Guo H, Sun Z, Wang W, Wang Y, Wang X, Guo W

Abstract
Objective: Decreased homotopic connectivity of brain networks such as the cortico-striato-thalamo-cortical (CSTC) circuits may contribute to the pathophysiology of obsessive-compulsive disorder (OCD). However, little is known about interhemispheric functional connectivity (FC) at rest in OCD. In this study, the voxel-mirrored homotopic connectivity (VMHC) method was applied to explore interhemispheric coordination at rest in OCD.
Methods: Forty medication-free patients with OCD and 38 sex-, age-, and education level-matched healthy controls (HCs) underwent a resting-state functional magnetic resonance imaging. The VMHC and support vector machine (SVM) methods were used to analyze the data.
Results: Patients with OCD had remarkably decreased VMHC values in the orbitofrontal cortex, thalamus, middle occipital gyrus, and precentral and postcentral gyri compared with HCs. A combination of the VMHC values in the thalamus and postcentral gyrus could optimally distinguish patients with OCD from HCs.
Conclusions: Our findings highlight the contribution of decreased interhemispheric FC within and outside the CSTC circuits in OCD and provide evidence to the pathophysiology of OCD.

PMID: 33101081 [PubMed]

Reduced Global-Brain Functional Connectivity of the Cerebello-Thalamo-Cortical Network in Patients With Dry Eye Disease.

Tue, 10/27/2020 - 14:20

Reduced Global-Brain Functional Connectivity of the Cerebello-Thalamo-Cortical Network in Patients With Dry Eye Disease.

Front Hum Neurosci. 2020;14:572693

Authors: Pan P, Wei S, Ou Y, Liu F, Li H, Jiang W, Li W, Lei Y, Guo W, Luo S

Abstract
Background: The pathophysiology of patients with dry eye disease (DED) is associated with abnormal functional connectivity (FC). The present study aims to probe alterations of voxel-wise brain-wide FC in patient with DED at rest in an unbiased way. Method: A total of 20 patients with DED and 23 controls matched by age, sex, and years of education underwent resting-state functional magnetic resonance imaging scans. Global-brain FC (GFC) was adopted to analyze the images. Support vector machine (SVM) was utilized to differentiate the patients from the controls. Results: Compared with the controls, patients with DED exhibited decreased GFC in the right cerebellum lobule VIII/inferior semi-lunar lobule and left thalamus that belonged to the cerebello-thalamo-cortical network. The GFC values in the left thalamus were positively correlated to the illness duration (r = 0.589, p = 0.006) in the patients. Decreased GFC values in the left thalamus could be used to discriminate the patients from the controls with optimal accuracy, sensitivity and specificity (88.37, 85.00, and 91.30%). Conclusions: Our findings indicate that decreased GFC in the brain regions associated with cerebello-thalamo-cortical network may provide a new insight for understanding the pathological changes of FC in DED. GFC values in the left thalamus may be utilized as a potential biomarker to identify the patients from the controls.

PMID: 33100998 [PubMed]

Investigation on the Alteration of Brain Functional Network and Its Role in the Identification of Mild Cognitive Impairment.

Tue, 10/27/2020 - 14:20

Investigation on the Alteration of Brain Functional Network and Its Role in the Identification of Mild Cognitive Impairment.

Front Neurosci. 2020;14:558434

Authors: Zhang L, Ni H, Yu Z, Wang J, Qin J, Hou F, Yang A, Alzheimer’s Disease Neuroimaging Initiative (ADNI)

Abstract
Mild cognitive impairment (MCI) is generally regarded as a prodromal stage of Alzheimer's disease (AD). In coping with the challenges caused by AD, we analyzed resting-state functional magnetic resonance imaging data of 82 MCI subjects and 93 normal controls (NCs). The alteration of brain functional network in MCI was investigated on three scales, including global metrics, nodal characteristics, and modular properties. The results supported the existence of small worldness, hubs, and community structure in the brain functional networks of both groups. Compared with NCs, the network altered in MCI over all the three scales. In scale I, we found significantly decreased characteristic path length and increased global efficiency in MCI. Moreover, altered global network metrics were associated with cognitive level evaluated by neuropsychological assessments. In scale II, the nodal betweenness centrality of some global hubs, such as the right Crus II of cerebellar hemisphere (CERCRU2.R) and fusiform gyrus (FFG.R), changed significantly and associated with the severity and cognitive impairment in MCI. In scale III, although anatomically adjacent regions tended to be clustered into the same module regardless of group, discrepancies existed in the composition of modules in both groups, with a prominent separation of the cerebellum and a less localized organization of community structure in MCI compared with NC. Taking advantages of random forest approach, we achieved an accuracy of 91.4% to discriminate MCI patients from NCs by integrating cognitive assessments and network analysis. The importance of the used features fed into the classifier further validated the nodal characteristics of CERCRU2.R and FFG.R could be potential biomarkers in the identification of MCI. In conclusion, the present study demonstrated that the brain functional connectome data altered at the stage of MCI and could assist the automatic diagnosis of MCI patients.

PMID: 33100958 [PubMed]

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