New resting-state fMRI related studies at PubMed

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Resting state functional network switching rate is differently altered in bipolar disorder and major depressive disorder.

Thu, 05/14/2020 - 12:00

Resting state functional network switching rate is differently altered in bipolar disorder and major depressive disorder.

Hum Brain Mapp. 2020 May 13;:

Authors: Han S, Cui Q, Wang X, Li L, Li D, He Z, Guo X, Fan YS, Guo J, Sheng W, Lu F, Chen H

Abstract
The clinical misdiagnosis ratio of bipolar disorder (BD) patients to major depressive disorder (MDD) patients is high. Recent findings hypothesize that the ability to flexibly recruit functional neural networks is differently altered in BD and MDD patients. This study aimed to explore distinct aberrance of network flexibility during dynamic networks configuration in BD and MDD patients. Resting state functional magnetic resonance imaging of 40 BD patients, 61 MDD patients, and 61 matched healthy controls were recruited. Dynamic functional connectivity matrices for each subject were constructed with a sliding window method. Then, network switching rate of each node was calculated and compared among the three groups. BD and MDD patients shared decreased network switching rate of regions including left precuneus, bilateral parahippocampal gyrus, and bilateral dorsal medial prefrontal cortex. Apart from these regions, MDD patients presented specially decreased network switching rate in the bilateral anterior insula, left amygdala, and left striatum. Taken together, BD and MDD patients shared decreased network switching rate of key hubs in default mode network and MDD patients presented specially decreased switching rate in salience network and striatum. We found shared and distinct aberrance of network flexibility which revealed altered adaptive functions during dynamic networks configuration of BD and MDD.

PMID: 32400932 [PubMed - as supplied by publisher]

Large-Scale Neuronal Network Dysfunction in Diabetic Retinopathy.

Thu, 05/14/2020 - 12:00
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Large-Scale Neuronal Network Dysfunction in Diabetic Retinopathy.

Neural Plast. 2020;2020:6872508

Authors: Huang X, Tong Y, Qi CX, Dan HD, Deng QQ, Shen Y

Abstract
Diabetic retinopathy (DR) patients are at an increased risk of cognitive decline and dementia. There is accumulating evidence that specific functional and structural architecture changes in the brain are related to cognitive impairment in DR patients. However, little is known regarding whether the functional architecture of resting-state networks (RSNs) changes in DR patients. The purpose of this study was to investigate the intranetwork functional connectivity (FC) and functional network connectivity (FNC) of RSN changes in DR patients using independent component analysis (ICA). Thirty-four DR patients (18 men and 16 women; mean age, 53.53 ± 8.67 years) and 38 nondiabetic healthy controls (HCs) (15 men and 23 women; mean age, 48.63 ± 11.83 years), closely matched for age, sex, and education, underwent resting-state magnetic resonance imaging scans. ICA was applied to extract the nine RSNs. Then, two-sample t-tests were conducted to investigate different intranetwork FCs within nine RSNs between the two groups. The FNC toolbox was used to assess interactions among RSNs. Pearson correlation analysis was conducted to explore the relationship between intranetwork FCs and clinical variables in the DR group. A receiver operating characteristic (ROC) curve was conducted to assess the ability of the intranetwork FCs of RSNs in discriminating between the two groups. Compared to the HC group, DR patients showed significant decreased intranetwork FCs within the basal ganglia network (BGN), visual network (VN), ventral default mode network (vDMN), right executive control network (rECN), salience network (SN), left executive control network (lECN), auditory network (AN), and dorsal default mode network (dDMN). In addition, FNC analysis showed increased VN-BGN, VN-vDMN, VN-dDMN, vDMN-lECN, SN-BGN, lECN-dDMN, and AN-BGN FNCs in the DR group, relative to the HC group. Furthermore, altered intranetwork FCs of RSNs were significantly correlated with the glycosylated hemoglobin (HbA1c) level in DR patients. A ROC curve showed that these specific intranetwork FCs of RSNs discriminated between the two groups with a high degree of sensitivity and specificity. Our study highlighted that DR patients had widespread deficits in both low-level perceptual and higher-order cognitive networks. Our results offer important insights into the neural mechanisms of visual loss and cognitive decline in DR patients.

PMID: 32399026 [PubMed - in process]

Ventral and dorsal visual pathways exhibit abnormalities of static and dynamic connectivities, respectively, in patients with schizophrenia.

Thu, 05/14/2020 - 12:00
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Ventral and dorsal visual pathways exhibit abnormalities of static and dynamic connectivities, respectively, in patients with schizophrenia.

Schizophr Res. 2019 04;206:103-110

Authors: Deng Y, Liu K, Cheng D, Zhang J, Chen H, Chen B, Li Y, Wang W, Kong Y, Wen G

Abstract
Previous studies suggest that schizophrenia-related visual perceptual abnormalities are primarily attributed to deficits of the dorsal rather than ventral visual pathway. In this study, we comparatively explored changes in dorsal and ventral networks in schizophrenia patients in both static and dynamic functional connectivity (FC). Resting-state MR scans were acquired for forty schizophrenia patients and twenty-four healthy controls matched for age and gender. The dorsal and ventral visual networks were defined based on the resultant coordinates from activation likelihood estimation analyses. Static and dynamic network properties were calculated based on the full-range and segmented blood oxygen level dependent time series, respectively. The results indicated that the ventral and dorsal visual networks exhibited abnormalities in static FC and dynamic FC, respectively, in the schizophrenia group. Static FC assessments in the ventral visual network showed a significantly decreased clustering coefficient and shortened characteristic path length in patients with schizophrenia. Dynamic FC assessments in the dorsal visual network showed significantly higher mean temporal variability (p = 0.026) and higher regional FC variability of the right fusiform gyrus (p < 0.001) in patients with schizophrenia, and the latter was correlated with the total and negative scores of the Positive and Negative Syndrome Scale. In summary, this study reveals differential patterns of connectivity abnormalities of the ventral and dorsal visual networks in patients with schizophrenia. These preliminary evidences may help us better interpret the mechanisms underlying visual perceptual impairments in patients with schizophrenia and their relationship with psychosis.

PMID: 30545760 [PubMed - indexed for MEDLINE]

Predictive value of electroencephalography connectivity measures for motor training outcome in multiple sclerosis: an observational longitudinal study.

Thu, 05/14/2020 - 12:00
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Predictive value of electroencephalography connectivity measures for motor training outcome in multiple sclerosis: an observational longitudinal study.

Eur J Phys Rehabil Med. 2019 Dec;55(6):743-753

Authors: Tramonti C, Imperatori LS, Fanciullacci C, Lamola G, Lettieri G, Bernardi G, Cecchetti L, Ricciardi E, Chisari C

Abstract
BACKGROUND: Neurophysiological investigations represent powerful tools to shed light on brain plasticity in multiple sclerosis (MS) patients.
AIM: We investigated the relationship between electroencephalography (EEG)-based connectivity, the extent of brain lesions and changes in motor performance after an intensive task-oriented circuit training (TOCT).
DESIGN: Observational longitudinal study.
SETTING: Outpatients training program.
POPULATION: Sixteen MS patients (10F; mean age =51.4 years; range: 27-67; mean disease duration =15.1 years; range: 2-26; mean Expanded Disability Status Scale 4.4; range: 3.5-5.5), were included in our study.
METHODS: MS patients with mild gait impairment were evaluated through functional scales and submitted to TOCT. Resting-state EEG was performed before (T0) and after (T1) rehabilitation. Alpha-band weighted Phase Lag Index (wPLI) and broadband weighted Symbolic Mutual Information (wSMI) connectivity analyses were performed. White matter lesion load was measured using MRI prior to the TOCT. Neurophysiological and structural parameters were then related to behavioral changes.
RESULTS: Dynamic Gait Index significantly improved after TOCT (F(1,14) =13.10, P=0.003). Moreover, the interaction between TOCT and age was observed for changes in Timed Up and Go (TUG) performance (F(1,14) = 7.75, P=0.015), indicating that older patients only benefited in this measure. Regarding the relationship between EEG connectivity and TOCT outcome, we observed positive correlations between changes in TUG and strength (P=0.017) and efficiency (Pone-tail =0.029) of alpha-band wPLI connectivity at T0. Such correlation was mainly driven by antero-posterior regional interactions (P=0.038), rather than by inter-hemispheric connectivity (P=0.089). Moreover, we observed a positive correlation between performance improvements and wSMI connectivity at T1 (P=0.001) as well as the difference between T0 and T1 (P=0.005). Lesion load percentage was not related to functional improvement after TOCT (Pone-tail=0.137).
CONCLUSIONS: Results of the current study demonstrated that baseline alpha-band wPLI connectivity predicts TOCT outcome in MS patients. Moreover, broadband wSMI tracks neural changes that accompany treatment-related variations in motor performance.
CLINICAL REHABILITATION IMPACT: Our findings suggest that EEG-based connectivity measures may represent a potential tool for customizing rehabilitative management of the disease.

PMID: 30370753 [PubMed - indexed for MEDLINE]

Altered Time-Frequency Feature in Default Mode Network of Autism Based on Improved Hilbert-Huang Transform.

Wed, 05/13/2020 - 10:40

Altered Time-Frequency Feature in Default Mode Network of Autism Based on Improved Hilbert-Huang Transform.

IEEE J Biomed Health Inform. 2020 May 07;:

Authors: Zhang H, Li R, Wen X, Li Q, Wu X

Abstract
Autism Spectrum Disorder (ASD) is a pervasive neurodevelopmental disorder characterized by restricted interests and repetitive behaviors. Non-invasive measurements of brain activity with functional magnetic resonance imaging (fMRI) have demonstrated that the abnormality in the default mode network (DMN) is a crucial neural basis of ASD, but the time-frequency characteristic of the network has not yet been revealed. Hilbert-Huang transform (HHT) is conducive to feature extraction of biomedical signals and has recently been suggested as an effective method to explore the time-frequency feature of the brain activity and mechanism. In this study, the resting-state fMRI dataset of 105 subjects including 59 ASD participants and 46 healthy control (HC) participants were involved in the original time-frequency clustering analysis based on improved HHT and modified k-means clustering with label-replacement. Compared with HC, ASD selectively showed enhanced Hilbert Weight Frequency (HWF) in high frequency bands in crucial regions of the DMN, including the medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC) and anterior cingulate cortex (ACC). Time-frequency clustering analysis revealed altered DMN organization in ASD. In the posterior DMN, the PCC and bilateral precuneus were separated for HC but clustered for ASD; in the anterior DMN, the clusters of ACC, dorsal MPFC, and ventral MPFC were relatively scattered for ASD. This study paves a promising way to uncover the alteration in the DMN of ASD and identify a potential neuroimaging biomarker for diagnostic reference.

PMID: 32396111 [PubMed - as supplied by publisher]

Resting-state and task-based centrality of dorsolateral prefrontal cortex predict resilience to 1 Hz repetitive transcranial magnetic stimulation.

Wed, 05/13/2020 - 10:40

Resting-state and task-based centrality of dorsolateral prefrontal cortex predict resilience to 1 Hz repetitive transcranial magnetic stimulation.

Hum Brain Mapp. 2020 May 12;:

Authors: Fitzsimmons SMDD, Douw L, van den Heuvel OA, van der Werf YD, Vriend C

Abstract
Repetitive transcranial magnetic stimulation (rTMS) is used to investigate normal brain function in healthy participants and as a treatment for brain disorders. Various subject factors can influence individual response to rTMS, including brain network properties. A previous study by our group showed that "virtually lesioning" the left dorsolateral prefrontal cortex (dlPFC; important for cognitive flexibility) using 1 Hz rTMS reduced performance on a set-shifting task. We aimed to determine whether this behavioural response was related to topological features of pre-TMS resting-state and task-based functional networks. 1 Hz (inhibitory) rTMS was applied to the left dlPFC in 16 healthy participants, and to the vertex in 17 participants as a control condition. Participants performed a set-shifting task during fMRI at baseline and directly after a single rTMS session 1-2 weeks later. Functional network topology measures were calculated from resting-state and task-based fMRI scans using graph theoretical analysis. The dlPFC-stimulated group, but not the vertex group, showed reduced setshifting performance after rTMS, associated with lower task-based betweenness centrality (BC) of the dlPFC at baseline (p = .030) and a smaller reduction in task-based BC after rTMS (p = .024). Reduced repeat trial accuracy after rTMS was associated with higher baseline resting state node strength of the dlPFC (p = .017). Our results suggest that behavioural response to 1 Hz rTMS to the dlPFC is dependent on baseline functional network features. Individuals with more globally integrated stimulated regions show greater resilience to rTMS effects, while individuals with more locally well-connected regions show greater vulnerability.

PMID: 32395892 [PubMed - as supplied by publisher]

Using fMRI to Assess Brain Activity in People With Down Syndrome: A Systematic Review.

Wed, 05/13/2020 - 10:40

Using fMRI to Assess Brain Activity in People With Down Syndrome: A Systematic Review.

Front Hum Neurosci. 2020;14:147

Authors: Carbó-Carreté M, Cañete-Massé C, Peró-Cebollero M, Guàrdia-Olmos J

Abstract
Background: In the last few years, many investigations have focused on brain activity in general and in populations with different pathologies using non-invasive techniques such as electroencefalography (EEG), positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and magnetic resonance imaging (MRI). However, the use of non-invasive techniques to detect brain signals to evaluate the cognitive activity of people with Down syndrome (DS) has not been sufficiently addressed. The objective of this study is to describe the state-of-the-art in fMRI techniques for recording brain signals in people with DS. Method: A systematic review was performed based on PRISMA recommendations; only nine papers on this topic have been published. Three independent researchers selected all relevant information from each paper. Analyses of information concordance showed a high value of agreement between researchers. Results: Although few relevant works have been published, the use of fMRI in people with DS is becoming an appropriate option to study brain function in this population. Of the nine identified papers, five used task designs, and four used resting-state paradigms. Conclusion: Thus, we emphasize the need to incorporate rigorous cognitive activity procedures in evaluations of the DS population. We suggest several factors (such as head correction movements and paired sample techniques) that must be considered when designing an fMRI study with a task or a resting-state paradigm in a DS population.

PMID: 32395104 [PubMed]

Paired associated magnetic stimulation promotes neural repair in the rat middle cerebral artery occlusion model of stroke.

Wed, 05/13/2020 - 10:40

Paired associated magnetic stimulation promotes neural repair in the rat middle cerebral artery occlusion model of stroke.

Neural Regen Res. 2020 Nov;15(11):2047-2056

Authors: Gao BY, Sun CC, Xia GH, Zhou ST, Zhang Y, Mao YR, Liu PL, Zheng Y, Zhao D, Li XT, Xu J, Xu DS, Bai YL

Abstract
Paired associative stimulation has been used in stroke patients as an innovative recovery treatment. However, the mechanisms underlying the therapeutic effectiveness of paired associative stimulation on neurological function remain unclear. In this study, rats were randomly divided into middle cerebral occlusion model (MCAO) and paired associated magnetic stimulation (PAMS) groups. The MCAO rat model was produced by middle cerebral artery embolization. The PAMS group received PAMS on days 3 to 20 post MCAO. The MCAO group received sham stimulation, three times every week. Within 18 days after ischemia, rats were subjected to behavioral experiments-the foot-fault test, the balance beam walking test, and the ladder walking test. Balance ability was improved on days 15 and 17, and the foot-fault rate was less in their affected limb on day 15 in the PAMS group compared with the MCAO group. Western blot assay showed that the expression levels of brain derived neurotrophic factor, glutamate receptor 2/3, postsynaptic density protein 95 and synapsin-1 were significantly increased in the PAMS group compared with the MCAO group in the ipsilateral sensorimotor cortex on day 21. Resting-state functional magnetic resonance imaging revealed that regional brain activities in the sensorimotor cortex were increased in the ipsilateral hemisphere, but decreased in the contralateral hemisphere on day 20. By finite element simulation, the electric field distribution showed a higher intensity, of approximately 0.4 A/m2, in the ischemic cortex compared with the contralateral cortex in the template. Together, our findings show that PAMS upregulates neuroplasticity-related proteins, increases regional brain activity, and promotes functional recovery in the affected sensorimotor cortex in the rat MCAO model. The experiments were approved by the Institutional Animal Care and Use Committee of Fudan University, China (approval No. 201802173S) on March 3, 2018.

PMID: 32394960 [PubMed]

Neuroprotective effects of exercise in people with progressive multiple sclerosis (Exercise PRO-MS): study protocol of a phase II trial.

Wed, 05/13/2020 - 10:40
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Neuroprotective effects of exercise in people with progressive multiple sclerosis (Exercise PRO-MS): study protocol of a phase II trial.

BMC Neurol. 2020 May 11;20(1):177

Authors: Gravesteijn AS, Beckerman H, de Jong BA, Hulst HE, de Groot V

Abstract
BACKGROUND: Neurodegeneration, rather than inflammation, plays a key role in the progressive phase of multiple sclerosis (MS). Current disease modifying treatment options for people with progressive MS (PMS) do not specifically target neurodegeneration. Preliminary evidence suggests that exercise therapy might have neuroprotective effects. However, neuroprotective effect studies of exercise interventions in PMS are scarce and the possible mode of action underlying neuroprotective effects of exercise are unknown and need to be elucidated. The main aim of this phase II trial is to assess whether progressive resistance training (PRT) and high intensity interval training (HIIT), can slow down neurodegeneration in people with PMS.
METHODS: In a single-blinded phase II clinical trial with an extended baseline period, 60 people with PMS will be randomly assigned to PRT or HIIT. The participants should have had a relapse onset of MS with confirmed disease progression, however still ambulatory. The duration of the study is 48 weeks, consisting of 16 weeks baseline period (no intervention), 16 weeks intervention and 16 weeks follow-up. Patient-tailored training will be performed 3 times per week for one hour in groups, led by an experienced physiotherapist. The primary outcome measure is neurodegeneration, measured as whole brain atrophy on magnetic resonance imaging (MRI). Secondary outcome parameters will include other biomarkers associated with neurodegeneration (i.e. regional brain atrophy, lesion load, white matter integrity, resting state functional connectivity, blood biomarkers (brain derived neurotrophic factor (BDNF) and serum neurofilament light (sNFL)), patient functioning (physical and cognitive) and cardiovascular risk factors.
DISCUSSION: Besides the primary outcome measures, this study will examine a large variety of biomarkers associated with neurodegeneration after an exercise intervention. Combining outcome parameters may help to elucidate the mode of action underlying neuroprotective effects of exercise.
TRIAL REGISTRATION: This trial is prospectively registered at the Dutch Trial Registry (number NL8265, date 06-01-2020).

PMID: 32393193 [PubMed - in process]

Topological View of Flows Inside the BOLD Spontaneous Activity of the Human Brain.

Tue, 05/12/2020 - 22:00
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Topological View of Flows Inside the BOLD Spontaneous Activity of the Human Brain.

Front Comput Neurosci. 2020;14:34

Authors: Don APH, Peters JF, Ramanna S, Tozzi A

Abstract
Spatio-temporal brain activities with variable delay detectable in resting-state functional magnetic resonance imaging (rs-fMRI) give rise to highly reproducible structures, termed cortical lag threads, that propagate from one brain region to another. Using a computational topology of data approach, we found that persistent, recurring blood oxygen level dependent (BOLD) signals in triangulated rs-fMRI videoframes display previously undetected topological findings, i.e., vortex structures that cover brain activated regions. Measure of persistence of vortex shapes in BOLD signal propagation is carried out in terms of Betti numbers that rise and fall over time during spontaneous activity of the brain. Importantly, a topology of data given in terms of geometric shapes of BOLD signal propagation offers a practical approach in coping with and sidestepping massive noise in neurodata, such as unwanted dark (low intensity) regions in the neighborhood of non-zero BOLD signals. Our findings have been codified and visualized in plots able to track the non-trivial BOLD signals that appear intermittently in a sequence of rs-fMRI videoframes. The end result of this tracking of changing lag structures is a so-called persistent barcode, which is a pictograph that offers a convenient visual means of exhibiting, comparing, and classifying brain activation patterns.

PMID: 32390820 [PubMed]

Vigilance Effects in Resting-State fMRI.

Tue, 05/12/2020 - 22:00
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Vigilance Effects in Resting-State fMRI.

Front Neurosci. 2020;14:321

Authors: Liu TT, Falahpour M

Abstract
Measures of resting-state functional magnetic resonance imaging (rsfMRI) activity have been shown to be sensitive to cognitive function and disease state. However, there is growing evidence that variations in vigilance can lead to pronounced and spatially widespread differences in resting-state brain activity. Unless properly accounted for, differences in vigilance can give rise to changes in resting-state activity that can be misinterpreted as primary cognitive or disease-related effects. In this paper, we examine in detail the link between vigilance and rsfMRI measures, such as signal variance and functional connectivity. We consider how state changes due to factors such as caffeine and sleep deprivation affect both vigilance and rsfMRI measures and review emerging approaches and methodological challenges for the estimation and interpretation of vigilance effects.

PMID: 32390792 [PubMed]

Altered Patterns of Functional Connectivity and Causal Connectivity in Salience Subnetwork of Subjective Cognitive Decline and Amnestic Mild Cognitive Impairment.

Tue, 05/12/2020 - 22:00
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Altered Patterns of Functional Connectivity and Causal Connectivity in Salience Subnetwork of Subjective Cognitive Decline and Amnestic Mild Cognitive Impairment.

Front Neurosci. 2020;14:288

Authors: Cai C, Huang C, Yang C, Lu H, Hong X, Ren F, Hong D, Ng E

Abstract
The subjective cognitive decline (SCD) may last for decades prior to the onset of dementia and has been proposed as a risk population for development to amnestic mild cognitive impairment (aMCI) and Alzheimer disease (AD). Disruptions of functional connectivity and causal connectivity (CC) in the salience network (SN) are generally perceived as prominent hallmarks of the preclinical AD. Nevertheless, the alterations in anterior SN (aSN), and posterior SN (pSN) remain unclear. Here, we hypothesized that both the functional connectivity (FC) and CC of the SN subnetworks, comprising aSN and pSN, were distinct disruptive in the SCD and aMCI. We utilized resting-state functional magnetic resonance imaging to investigate the altered FC and CC of the SN subnetworks in 28 healthy controls, 23 SCD subjects, and 29 aMCI subjects. In terms of altered patterns of FC in SN subnetworks, aSN connected to the whole brain was significantly increased in the left orbital superior frontal gyrus, left insula lobule, right caudate lobule, and left rolandic operculum gyrus (ROG), whereas decreased FC was found in the left cerebellum superior lobule and left middle temporal gyrus when compared with the HC group. Notably, no prominent statistical differences were obtained in pSN. For altered patterns of CC in SN subnetworks, compared to the HC group, the aberrant connections in aMCI group were separately involved in the right cerebellum inferior lobule (CIL), right supplementary motor area (SMA), and left ROG, whereas the SCD group exhibited more regions of aberrant connection, comprising the right superior parietal lobule, right CIL, left inferior parietal lobule, left post-central gyrus (PG), and right angular gyrus. Especially, SCD group showed increased CC in the right CIL and left PG, whereas the aMCI group showed decreased CC in the left pre-cuneus, corpus callosum, and right SMA when compared to the SCD group. Collectively, our results suggest that analyzing the altered FC and CC observed in SN subnetworks, served as impressible neuroimaging biomarkers, may supply novel insights for designing preclinical interventions in the preclinical stages of AD.

PMID: 32390791 [PubMed]

Neural correlates of fluctuations in the intermediate band for heart rate and respiration are related to interoceptive perception.

Tue, 05/12/2020 - 22:00
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Neural correlates of fluctuations in the intermediate band for heart rate and respiration are related to interoceptive perception.

Psychophysiology. 2020 May 10;:e13594

Authors: Keller M, Pelz H, Perlitz V, Zweerings J, Röcher E, Baqapuri HI, Mathiak K

Abstract
Supratentorial brain structures such as the insula and the cingulate cortex modulate the autonomic nervous system (ANS). The neural underpinnings of separate frequency bands for variability in cardiac and respiratory data have been suggested in explaining parasympathetic and sympathetic ANS modulation. As an extension, an intermediate (IM) band in peripheral physiology has been considered to reflect psychophysiological states during rest. Using functional magnetic resonance imaging (fMRI), we investigated the neural correlates associated with IM band variability in cardiac and respiratory rate and identified dissociable networks for LF, IM, and HF bands in both modalities. Cardiac and respiratory IM band fluctuations correlated with blood oxygen level-dependent (BOLD) signal in the mid and posterior insula and the secondary somatosensory area, that is, regions related to interoceptive perception. These data suggest that in addition to the commonly considered LF and HF bands, other frequency components represent relevant physiological constituents. The IM band may be instrumental for assessment of the CNS-ANS interaction. In particular, the relation between the IM band and interoception may be of physiological and clinical interest.

PMID: 32390178 [PubMed - as supplied by publisher]

Acute Posttrauma Resting-State Functional Connectivity of Periaqueductal Gray Prospectively Predicts Posttraumatic Stress Disorder Symptoms.

Tue, 05/12/2020 - 22:00
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Acute Posttrauma Resting-State Functional Connectivity of Periaqueductal Gray Prospectively Predicts Posttraumatic Stress Disorder Symptoms.

Biol Psychiatry Cogn Neurosci Neuroimaging. 2020 Mar 28;:

Authors: Webb EK, Huggins AA, Belleau EL, Taubitz LE, Hanson JL, deRoon-Cassini TA, Larson CL

Abstract
BACKGROUND: Posttraumatic stress disorder (PTSD) is characterized by hyperarousal, avoidance, and intrusive/re-experiencing symptoms. The periaqueductal gray (PAG), which generates behavioral responses to physical and psychological stressors, is also implicated in threat processing. Distinct regions of the PAG elicit opposing responses to threatening or stressful stimuli; the ventrolateral PAG evokes passive coping strategies (e.g., analgesia), whereas the dorsolateral PAG (dlPAG) promotes active responses (e.g., fight or flight). We investigated whether altered PAG resting-state functional connectivity (RSFC) prospectively predicted PTSD symptoms.
METHODS: A total of 48 trauma-exposed individuals underwent an RSFC scan 2 weeks posttraumatic injury. Self-report measures, including the visual analog scale for pain and the Impact of Event Scale, were collected at 2 weeks and 6 months posttrauma. We analyzed whether acute bilateral PAG RSFC was a marker of risk for total 6-month symptom severity and specific symptom clusters. In an exploratory analysis, we investigated whether dlPAG RSFC predicted PTSD symptoms.
RESULTS: After adjusting for physical pain ratings, greater acute posttrauma PAG-frontal pole and PAG-posterior cingulate cortex connectivity was positively associated with 6-month total PTSD symptoms. Weaker dlPAG-superior/inferior parietal lobule connectivity predicted both higher hyperarousal and higher intrusive symptoms, while weaker dlPAG-supramarginal gyrus RSFC was associated with only hyperarousal symptoms.
CONCLUSIONS: Altered connectivity of the PAG 2 weeks posttrauma prospectively predicted PTSD symptoms. These findings suggest that aberrant PAG function may serve as a marker of risk for chronic PTSD symptoms, possibly by driving specific symptom clusters, and more broadly that connectivity of specific brain regions may underlie specific symptom profiles.

PMID: 32389746 [PubMed - as supplied by publisher]

Altered information flow and microstructure abnormalities of visual cortex in normal-tension glaucoma : evidences from rest-state fMRI and DKI.

Tue, 05/12/2020 - 22:00
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Altered information flow and microstructure abnormalities of visual cortex in normal-tension glaucoma : evidences from rest-state fMRI and DKI.

Brain Res. 2020 May 07;:146874

Authors: Li T, Qu X, Chen W, Wang Q, Wang H, Wang Y, Huang C, Zhang X, Wang N, Xian J

Abstract
Normal tension glaucoma (NTG) is a neurodegenerative disease involves multiple brain areas, but the mechanism remains unclear. The aim of this study is to investigate the correlation between structural injury and functional reorganization in the brain of NTG, using resting-state functional MRI and diffusion kurtosis imaging (DKI) data acquired for 26 NTG patients and 24 control subjects. Granger causality analysis (GCA) was used to calculate the effective connectivity (EC) between visual cortices and the whole brain to reflect the information flow. The fractional anisotropy (FA), mean kurtosis (MK), axial kurtosis (AK), and radial kurtosis (RK) derived from DKI of visual cortices were extracted to evaluate structural injury. Microstructural abnormalities were detected in bilateral BA17, BA18, and BA19. NTG patients showed significantly decreased EC from BA17 to higher visual cortices and increase EC from higher visual cortices to BA17. The EC from BA17 to posterior cingulate cortex (PCC) and from PCC to BA17 both significantly increased, while the EC from right BA18 and BA19 to PCC significantly decreased. Decreased EC between somatosensory cortex and BA17, as well as the decreased ECs between supramarginal gyrus (SMA) and BA17/BA19 were detected. Several abnormal ECs were significantly correlated with microstructural injuries of BA17 and BA18. In conclusion, NTG causes reorganization of information flows among visual cortices and other brain areas, which is consistent with brain microstructural injury.

PMID: 32389589 [PubMed - as supplied by publisher]

A 24-Month Follow-Up Study of the Effect of Intra-Articular Injection of Autologous Microfragmented Fat Tissue on Proteoglycan Synthesis in Patients with Knee Osteoarthritis.

Tue, 05/12/2020 - 22:00
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A 24-Month Follow-Up Study of the Effect of Intra-Articular Injection of Autologous Microfragmented Fat Tissue on Proteoglycan Synthesis in Patients with Knee Osteoarthritis.

Genes (Basel). 2019 12 17;10(12):

Authors: Borić I, Hudetz D, Rod E, Jeleč Ž, Vrdoljak T, Skelin A, Polašek O, Plečko M, Trbojević-Akmačić I, Lauc G, Primorac D

Abstract
Osteoarthritis (OA) is a widely prevalent disease worldwide, and with an increasingly ageing society, it has become a challenge for the field of regenerative medicine. OA is a disease process involving multiple joint tissues, including those not visible on radiography, and is a complex disease process with multiple phenotypes that require evaluation by a multimodality imaging assessment. The purpose of this study was to evaluate the effect of micro-fragmented fat tissue intra-articular injection 24 months after application in two ways: Indirectly using functional magnetic resonance imaging (MRI) assessment analyzing the glycosaminoglycans (GAG) content in cartilage by means of delayed gadolinium (Gd)-enhanced magnetic resonance imaging of cartilage (dGEMRIC), as well as clinical outcome on observed level of GAG using standard orthopedic physical examination including VAS assessment. In our previous study assessing comprehensive results after 12 months, the dGEMRIC results have drawn attention. The present study explores the long-term effect of intra-articular injection of autologous microfragmented adipose tissue to host chondrocytes and cartilage proteoglycans in patients with knee OA. A prospective, non-randomized, interventional, single-center, open-label clinical trial was conducted from January 2016 to April 2018. A total of 17 patients were enrolled in the study, and 32 knees were assessed in a 12-month follow-up, but only 10 patients of them with 18 knees are included in a 24-month follow-up. The rest of the seven patients dropped out of the study 12 months after follow-up: three patients underwent knee arthroplasty, and the remaining four did not fulfil the basic criteria of 24 months involvement in the study. Surgical intervention (lipoaspiration), followed by tissue processing and intra-articular injection of the final microfragmented adipose tissue product into the affected knee(s), was performed in all patients. Patients were assessed for a visual analog scale (VAS), dGEMRIC at the baseline, three, six, 12 and 24 months after the treatment. A magnetic resonance sequence in dGEMRIC due to infiltration of the anionic, negatively-charged contrast gadopentetate dimeglumine (Gd-DTPA2) into the cartilage indicated that the contents of cartilage glycosaminoglycans significantly increased in specific areas of the treated knee joint. Our results suggest that this method of single intra-articular injection of autologous microfragmented adipose tissue improves GAG content on a significant scale, with over half of the measurements suggesting relevant improvement 24 months after intra-articular injection opposed to the expected GAG decrease over the natural course of the disease.

PMID: 31861180 [PubMed - indexed for MEDLINE]

Impaired hippocampal functional connectivity in patients with drug resistant, generalized tonic-clonic seizures.

Tue, 05/12/2020 - 22:00
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Impaired hippocampal functional connectivity in patients with drug resistant, generalized tonic-clonic seizures.

Neuroreport. 2019 07 03;30(10):700-706

Authors: Wang Z, Wang X, Rong R, Xu Y, Zhang B, Wang Z

Abstract
The aim of this study was to better understand the imaging features of drug-resistant epilepsy (DRE), especially in idiopathic generalized tonic-clonic seizure (GTCS), as well as to discover the associated mechanisms and functional connectivity (FC). A total of 31 idiopathic generalized epilepsy-GTCS patients and 17 healthy controls were enrolled. For each patient, resting-state functional MRI was performed. After a 12-month follow-up observation, patients were further divided into either drug-resistant (DR) or drug-sensitive (DS) groups. Compared to the DS group, DR patients had previously received more types of antiepileptic drugs and had taken more types of failed antiepileptic drugs. There were distinct FC changes toward the left thalamus, left putamen, left precuneus, and right precentral gyrus in the left hippocampus between DR and DS patients. FCs in the DR group largely decreased or remained unchanged, while DS patients exhibited compensatory enhancement. Disease duration was negatively correlated with FC between the left hippocampus and the left thalamus-putamen in patients with DRE. Further, DRE patients had an extremely high area under the curve (0.978) and a cut-off FC between the left hippocampus and thalamus-putamen of 0.282. Together, hippocampal FCs in patients with DR GTCS were impaired and time-dependently correlated with disease duration. Hippocampal FCs in DS patients showed overall compensatory enhancement, which could be used as a sensitive and specific marker to identify and predict DR GTCS.

PMID: 31116131 [PubMed - indexed for MEDLINE]

The medial temporal lobe in nociception: a meta-analytic and functional connectivity study.

Tue, 05/12/2020 - 22:00
Related Articles

The medial temporal lobe in nociception: a meta-analytic and functional connectivity study.

Pain. 2019 06;160(6):1245-1260

Authors: Ayoub LJ, Barnett A, Leboucher A, Golosky M, McAndrews MP, Seminowicz DA, Moayedi M

Abstract
Recent neuroimaging studies implicate the medial temporal lobe (MTL) in nociception and pain modulation. Here, we aim to identify which subregions of the MTL are involved in human pain and to test its connectivity in a cohort of chronic low-back pain patients (CBP). We conducted 2 coordinate-based meta-analyses to determine which regions within the MTL showed consistent spatial patterns of functional activation (1) in response to experimental pain in healthy participants and (2) in chronic pain compared with healthy participants. We followed PRISMA guidelines and performed activation likelihood estimate (ALE) meta-analyses. The first meta-analysis revealed consistent activation in the right anterior hippocampus (right antHC), parahippocampal gyrus, and amygdala. The second meta-analysis revealed consistently less activation in patients' right antHC, compared with healthy participants. We then conducted a seed-to-voxel resting state functional connectivity of the right antHC seed with the rest of the brain in 77 CBP and 79 age-matched healthy participants. We found that CBP had significantly weaker antHC functional connectivity to the medial prefrontal cortex compared with healthy participants. Taken together, these data indicate that the antHC has abnormally lower activity in chronic pain and reduced connectivity to the medial prefrontal cortex in CBP. Future studies should investigate the specific role of the antHC in the development and management of chronic pain.

PMID: 30747905 [PubMed - indexed for MEDLINE]

Neurometabolites and sport-related concussion: From acute injury to one year after medical clearance.

Mon, 05/11/2020 - 14:20

Neurometabolites and sport-related concussion: From acute injury to one year after medical clearance.

Neuroimage Clin. 2020 Apr 22;27:102258

Authors: Churchill NW, Hutchison MG, Graham SJ, Schweizer TA

Abstract
Sport-related concussion is associated with acute disturbances in neurometabolic function, with effects that may last weeks to months after injury. However, is presently unknown whether these disturbances resolve at medical clearance to return to play (RTP) or continue to evolve over longer time intervals. Moreover, little is known about how these neurometabolic changes correlate with other measures of brain structure and function. In this study, these gaps were addressed by evaluating ninety-nine (99) university-level athletes, including 33 with sport-related concussion and 66 without recent injury, using multi-parameter magnetic resonance imaging (MRI), which included single-voxel spectroscopy (SVS), diffusion tensor imaging (DTI) and resting-state functional MRI (fMRI). The concussed athletes were scanned at the acute phase of injury (27/33 imaged), medical clearance to RTP (25/33 imaged), one month post-RTP (25/33 imaged) and one year post-RTP (13/33 imaged). We measured longitudinal changes in N-acetyl aspartate (NAA) and myo-inositol (Ins), over the course of concussion recovery. Concussed athletes showed no significant abnormalities or longitudinal change in NAA values, whereas Ins was significantly elevated at RTP and one month later. Interestingly, Ins response was attenuated by a prior history of concussion. Subsequent analyses identified significant associations between Ins values, DTI measures of white matter microstructure and fMRI measures of functional connectivity. These associations varied over the course of concussion recovery, suggesting that elevated Ins values at RTP and beyond reflect distinct changes in brain physiology, compared to acute injury. These findings provide novel information about neurometabolic recovery after a sport-related concussion, with disturbances that persist beyond medical clearance to RTP.

PMID: 32388345 [PubMed - as supplied by publisher]

Impaired topographic organization in Parkinson's disease with mild cognitive impairment.

Mon, 05/11/2020 - 14:20

Impaired topographic organization in Parkinson's disease with mild cognitive impairment.

J Neurol Sci. 2020 Apr 29;414:116861

Authors: Hou Y, Wei Q, Ou R, Yang J, Gong Q, Shang H

Abstract
BACKGROUND: Mild cognitive impairment (MCI) is common in Parkinson's disease (PD), and graph theory approaches can be performed to investigate the topographic organization in newly diagnosed drug-naïve PD patients with MCI.
METHOD: We recruited PD patients with MCI (PD-MCI), PD patients with cognitive unimpaired (PD-CU), and age- and sex-matched healthy controls (HCs). Resting-state functional MRI (fMRI) whole-brain connectivity was examined, and topographic properties were measured with age, sex and education as covariates. Correlation analyses were performed between topographic features and cognitive scores.
RESULTS: Newly diagnosed drug-naïve PD patients and HCs presented small-world properties, and PD patients had increasing random organizations of brain networks, especially in PD patients with MCI. We also found a descending trend (HC > PD-CU > PD-MCI) in the clustering coefficient (Cp), characteristic path length (Lp) and local efficiency (Eloc), and a rising trend (HC < PD-CU < PD-MCI) in the global efficiency (Eglob). Only PD patients with MCI showed decreased nodal centralities in nodes of the sensorimotor network (SMN), default mode network (DMN), and the ventral anterior prefrontal cortex (vent aPFC), and increased nodal centralities in nodes of the cingulo-opercular network (CON), occipital network, and the ventral lateral prefrontal cortex (vlPFC). The increased nodal centralities in the parietal node of CON negatively correlated with cognitive scores in all PD patients.
CONCLUSION: Our results suggested that newly diagnosed drug-naïve PD patients had increasing random organizations of brain networks, especially in PD-MCI patients. Nodal changes were mainly observed in PD-MCI patients.

PMID: 32387848 [PubMed - as supplied by publisher]

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