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Abnormal Interactions of the Salience Network, Central Executive Network, and Default-Mode Network in Patients With Different Cognitive Impairment Loads Caused by Leukoaraiosis.

Sat, 07/06/2019 - 18:18

Abnormal Interactions of the Salience Network, Central Executive Network, and Default-Mode Network in Patients With Different Cognitive Impairment Loads Caused by Leukoaraiosis.

Front Neural Circuits. 2019;13:42

Authors: Chen H, Li Y, Liu Q, Shi Q, Wang J, Shen H, Chen X, Ma J, Ai L, Zhang YM

Abstract
Leukoaraiosis (LA) is associated with cognitive impairment in the older people which can be demonstrated in functional connectivity (FC) based on resting-state functional magnetic resonance imaging (rs-fMRI). This study is to explore the FC changes in LA patients with different cognitive status by three network models. Fifty-three patients with LA were divided into three groups: the normal cognition (LA-NC; n = 14, six males), mild cognitive impairment (LA-MCI; n = 27, 13 males), and vascular dementia (LA-VD; n = 12, six males), according to the Mini Mental State Exam (MMSE) and Clinical Dementia Rating (CDR). The three groups and 30 matched healthy controls (HCs; 11 males) underwent rs-fMRI. The data of rs-fMRI were analyzed by independent components analysis (ICA) and region of interest (ROI) analysis by the REST toolbox. Then the FC was respectively analyzed by the default-mode network (DMN), salience networks (SNs) and the central executive network (CEN) with their results compared among the different groups. For inter-brain network analysis, there were negative FC between the SN and DMN in LA groups, and the FC decreased when compared with HC group. While there were enhanced inter-brain network FC between the SN and CEN as well as within the SN. The FC in patients with LA can be detected by different network models of rs-fMRI. The multi-model analysis is helpful for the further understanding of the cognitive changes in those patients.

PMID: 31275116 [PubMed - in process]

Impairment in the goal-directed corticostriatal learning system as a biomarker for obsessive-compulsive disorder.

Sat, 07/06/2019 - 18:18
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Impairment in the goal-directed corticostriatal learning system as a biomarker for obsessive-compulsive disorder.

Psychol Med. 2019 Jul 05;:1-11

Authors: Dong C, Yang Q, Liang J, Seger CA, Han H, Ning Y, Chen Q, Peng Z

Abstract
BACKGROUND: Compulsive behaviors in obsessive-compulsive disorder (OCD) have been related to impairment within the associative cortical-striatal system connecting the caudate and prefrontal cortex that underlies consciously-controlled goal-directed learning and behavior. However, little is known whether this impairment may serve as a biomarker for vulnerability to OCD.
METHODS: Using resting-state functional magnetic resonance imaging (fMRI), we employed Granger causality analysis (GCA) to measure effective connectivity (EC) in previously validated striatal sub-regions, including the caudate, putamen, and the nucleus accumbens, in 35 OCD patients, 35 unaffected first-degree relatives and 35 matched healthy controls.
RESULTS: Both OCD patients and their first-degree relatives showed greater EC than controls between the left caudate and the orbital frontal cortex (OFC). Both OCD patients and their first-degree relatives showed lower EC than controls between the left caudate and lateral prefrontal cortex. These results are consistent with findings from task-related fMRI studies which found impairment in the goal-directed system in OCD patients.
CONCLUSIONS: The same changes in EC were present in both OCD patients and their unaffected first-degree relatives suggest that impairment in the goal-directed learning system may be a biomarker for OCD.

PMID: 31272523 [PubMed - as supplied by publisher]

Directed functional connectivity of the hippocampus in patients with presbycusis.

Fri, 07/05/2019 - 21:18
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Directed functional connectivity of the hippocampus in patients with presbycusis.

Brain Imaging Behav. 2019 Jul 03;:

Authors: Chen YC, Yong W, Xing C, Feng Y, Haidari NA, Xu JJ, Gu JP, Yin X, Wu Y

Abstract
Presbycusis, associated with a diminished quality of life characterized by bilateral sensorineural hearing loss at high frequencies, has become an increasingly critical public health problem. This study aimed to identify directed functional connectivity (FC) of the hippocampus in patients with presbycusis and to explore the causes if the directed functional connections of the hippocampus were disrupted. Presbycusis patients (n = 32) and age-, sex-, and education-matched healthy controls (n = 40) were included in this study. The seed regions of bilateral hippocampus were selected to identify directed FC in patients with presbycusis using Granger causality analysis (GCA) approach. Correlation analyses were conducted to detect the associations of disrupted directed FC of hippocampus with clinical measures of presbycusis. Compared to healthy controls, decreased directed FC between inferior parietal lobule, insula, right supplementary motor area, middle temporal gyrus and hippocampus were detected in presbycusis patients. Furthermore, a negative correlation between TMB score and the decline of directed FC from left inferior parietal lobule to left hippocampus (r = -0.423, p = 0.025) and from right inferior parietal lobule to right hippocampus (r = -0.516, p = 0.005) were also observed. The decreased directed functional connections of the hippocampus were detected in patients with presbycusis, which was associated with specific cognitive performance. This study mainly emphasizes the crucial role of hippocampus in presbycusis and will enhance our understanding of the neuropathological mechanisms of presbycusis.

PMID: 31270776 [PubMed - as supplied by publisher]

Individual differences in resting state connectivity and giving social support: implications for health.

Thu, 07/04/2019 - 21:17

Individual differences in resting state connectivity and giving social support: implications for health.

Soc Cogn Affect Neurosci. 2019 Jul 03;:

Authors: Inagaki TK, Meyer ML

Abstract
There is a growing appreciation for the health benefits of giving support, though variability in such behavior exists. Based on the possibility that the dorsomedial (DMPFC) default network subsystem is associated with social thinking and behavior, integrity of this subsystem may facilitate giving support to others. The current study tested associations between DMPFC subsystem connectivity at rest and tendencies related to giving support. During an fMRI session, 45 participants completed an emotional social cues task, a resting state scan, and self-report measures of social support. Supportive behavior during the month following the scan was also assessed. Greater DMPFC subsystem connectivity at rest was associated with greater support-giving (though not receiving or perceiving support), at the time of the scan and one month later. Results held after adjusting for extraversion. In addition, greater resting state DMPFC subsystem connectivity was associated with attenuated dorsal anterior cingulate (DACC), anterior insula (AI), and amygdala activity to others' negative emotional social cues, suggesting DMPFC subsystem integrity at rest is also associated with the dampened withdrawal response proposed to facilitate care for others in need. Together, results begin to hint at an additional role for the 'default' social brain: giving support to others.

PMID: 31269205 [PubMed - as supplied by publisher]

Mindfulness-Based Stress Reduction-related changes in posterior cingulate resting brain connectivity.

Thu, 07/04/2019 - 21:17

Mindfulness-Based Stress Reduction-related changes in posterior cingulate resting brain connectivity.

Soc Cogn Affect Neurosci. 2019 Jul 03;:

Authors: Kral TRA, Imhoff-Smith T, Dean DC, Grupe D, Adluru N, Patsenko E, Mumford JA, Goldman R, Rosenkranz MA, Davidson RJ

Abstract
Mindfulness meditation training has been shown to increase resting state functional connectivity between nodes of the frontoparietal executive control network (dorsolateral prefrontal cortex [DLPFC]) and the default mode network (posterior cingulate cortex [PCC]). We investigated whether these effects generalized to a Mindfulness-Based Stress Reduction (MBSR) course, and tested for structural and behaviorally relevant consequences of change in connectivity. Healthy, meditation-naïve adults were randomized to either MBSR (N=48), an active (N=47) or waitlist (N=45) control group. Participants completed behavioral testing, resting state fMRI scans, and diffusion tensor scans at pre-randomization (T1), post-intervention (T2) and approximately 5.5 months later (T3). We found increased T2-T1 PCC-DLPFC resting connectivity for MBSR relative to control groups. Although these effects did not persist through long-term follow-up (T3-T1), MBSR participants showed a significantly stronger relationship between days of practice (T1 to T3) and increased PCC-DLPFC resting connectivity than participants in the active control group. Increased PCC-DLPFC resting connectivity in MBSR participants was associated with increased microstructural connectivity of a white matter tract connecting these regions, and increased self-reported attention. These data show that MBSR increases PCC-DLPFC resting connectivity, which is related to increased practice time, attention, and structural connectivity.

PMID: 31269203 [PubMed - as supplied by publisher]

Modulating functional connectivity between medial frontopolar cortex and amygdala by inhibitory and excitatory transcranial magnetic stimulation.

Thu, 07/04/2019 - 21:17

Modulating functional connectivity between medial frontopolar cortex and amygdala by inhibitory and excitatory transcranial magnetic stimulation.

Hum Brain Mapp. 2019 Jul 03;:

Authors: Riedel P, Heil M, Bender S, Dippel G, Korb FM, Smolka MN, Marxen M

Abstract
The prefrontal-limbic network in the human brain plays a major role in social cognition, especially cognitive control of emotion. The medial frontopolar cortex (mFP; Brodmann Area 10) and the amygdala are part of this network and display correlated neuronal activity in time, as measured by functional magnetic resonance imaging (fMRI). This functional connectivity is dynamic, sensitive to training, and affected in mental disorders. However, the effects of neurostimulation on functional connectivity within this network have not yet been systematically investigated. Here, we investigate the effects of both low- and high-frequency repetitive transcranial magnetic stimulation (rTMS) to the right mFP on functional connectivity between mFP and amygdala, as measured with resting state fMRI (rsfMRI). Three groups of healthy participants received either low-frequency rTMS (1 Hz; N = 18), sham TMS (1 Hz, subthreshold; N = 18) or high-frequency rTMS (20 Hz; N = 19). rsfMRI was acquired before and after (separate days). We hypothesized a modulation of functional connectivity in opposite directions compared to sham TMS through adjustment of the stimulation frequency. Groups differed in functional connectivity between mFP and amygdala after stimulation compared to before stimulation (low-frequency: decrease, high-frequency: increase). Motion or induced changes in neuronal activity were excluded as confounders. Results show that rTMS is effective for increasing and decreasing functional coherence between prefrontal and limbic regions. This finding is relevant for social and affective neuroscience as well as novel treatment approaches in psychiatry.

PMID: 31268615 [PubMed - as supplied by publisher]

Temporal Variability-Based Functional Brain Lateralization Study in ADHD.

Thu, 07/04/2019 - 21:17

Temporal Variability-Based Functional Brain Lateralization Study in ADHD.

J Atten Disord. 2019 Jul 03;:1087054719859074

Authors: Zou H, Yang J

Abstract
Objective: The aim of this work is to explore the relationship between temporal variability and brain lateralization in ADHD. Method: The temporal variabilities of 116 brain regions based on resting-state functional magnetic resonance imaging (rs-fMRI) data were calculated for analysis. Results: Between-group comparison revealed that in comparison with the controls, ADHD participants showed significantly higher temporal variability in the left superior frontal gyrus (medial), left rectus gyrus, left inferior parietal lobule and angular gyrus, and lower temporal variability in the amygdala, left caudate and putamen. Besides, ADHD patients exhibited significantly increased leftward lateralization in the orbitofrontal cortex (inferior), and decreased rightward lateralization in the orbitofrontal cortex (medial) and rectus gyrus, compared with controls. Lateralization indices were also found to be related with clinical characteristics of ADHD patients. Conclusion: Our results may help us deeper in understanding the pathology of ADHD.

PMID: 31268386 [PubMed - as supplied by publisher]

Shedding light on migraine with aura: the clarifying role of advanced neuroimaging investigations.

Thu, 07/04/2019 - 21:17

Shedding light on migraine with aura: the clarifying role of advanced neuroimaging investigations.

Expert Rev Neurother. 2019 Jul 03;:1-12

Authors: Russo A, Silvestro M, Tessitore A, Tedeschi G

Abstract
Introduction: While migraine with aura is a complex neurological syndrome with a well-characterized clinical phenotype, its pathophysiology still has grey areas which could be partially clarified by microstructural and functional neuroimaging investigations. Areas covered: This article, summarizing the most significant findings from advanced neuroimaging studies, aims to achieve a unifying pathophysiological model of the migraine aura. A comprehensive review has been conducted of PubMed citations by entering the key word 'neuroimaging' combined with 'migraine with aura' AND/OR 'MRI.' Other keywords included 'grey matter' OR 'white matter', 'structural' OR 'functional'. Expert opinion: Converging evidence from advanced neuroimaging investigations underlined the critical role of the extrastriate visual cortex, and in particular the lingual gyrus, in the genesis of the aura phenomenon. However, the relationship between the aura and the headache phase of migraine attacks has not been completely clarified, to date, and underlying pathophysiological mechanisms need to be further elucidated.

PMID: 31267785 [PubMed - as supplied by publisher]

NMDA receptor antagonists traxoprodil and lanicemine improve hippocampal-prefrontal coupling and reward-related networks in rats.

Thu, 07/04/2019 - 21:17
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NMDA receptor antagonists traxoprodil and lanicemine improve hippocampal-prefrontal coupling and reward-related networks in rats.

Psychopharmacology (Berl). 2019 Jul 02;:

Authors: Becker R, Gass N, Kußmaul L, Schmid B, Scheuerer S, Schnell D, Dorner-Ciossek C, Weber-Fahr W, Sartorius A

Abstract
RATIONALE: The N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine is known to have not only a rapid antidepressant effect but also dissociative side effects. Traxoprodil and lanicemine, also NMDA antagonists, are candidate antidepressant drugs with fewer side effects.
OBJECTIVES: In order to understand their mechanism of action, we investigated the acute effects of traxoprodil and lanicemine on brain connectivity using resting-state functional magnetic resonance imaging (rs-fMRI).
METHODS: Functional connectivity (FC) alterations were examined using interregional correlation networks. Graph theoretical methods were used for whole brain network analysis. As interest in NMDAR antagonists as potential antidepressants was triggered by the antidepressant effect of ketamine, results were compared to previous findings from our ketamine studies.
RESULTS: Similar to ketamine but to a smaller extent, traxoprodil increased hippocampal-prefrontal (Hc-PFC) coupling. Unlike ketamine, traxoprodil decreased connectivity within the PFC. Lanicemine had no effect on these properties. The improvement of Hc-PFC coupling corresponds well to clinical result, showing ketamine to have a greater antidepressant effect than traxoprodil, while lanicemine has a weak and transient effect. Connectivity changes overlapping between the drugs as well as alterations of local network properties occurred mostly in reward-related regions.
CONCLUSION: The antidepressant effect of NMDA antagonists appears to be associated with enhanced Hc-PFC coupling. The effects on local network properties and regional connectivity suggest that improvement of reward processing might also be important for understanding the mechanisms underlying the antidepressant effects of these drugs.

PMID: 31267156 [PubMed - as supplied by publisher]

Multimodal Sparse Classifier for Adolescent Brain Age Prediction.

Wed, 07/03/2019 - 18:17

Multimodal Sparse Classifier for Adolescent Brain Age Prediction.

IEEE J Biomed Health Inform. 2019 Jun 28;:

Authors: Hosseinzadeh Kassani P, Gossmann A, Wang YP

Abstract
The study of healthy brain development helps to better understand both brain transformation and connectivity patterns, which happen during childhood to adulthood. This study presents a sparse machine learning solution across whole-brain functional connectivity (FC) measures of three data sets, derived from resting state functional magnetic resonance imaging (rs-fMRI) and two task fMRI data including a working memory n-back task (nb-fMRI) and an emotion identification task (em-fMRI). The fMRI data are collected from the Philadelphia Neurodevelopmental Cohort (PNC) for the prediction of brain age in adolescents. Due to extremely large variable-to-instance ratio of PNC data, a high dimensional matrix with several irrelevant and highly correlated features is generated, and hence a sparse learning approach is necessary to extract effective features from fMRI data. We propose a sparse learner based on the residual errors along the estimation of an inverse problem for extreme learning machine (ELM). Our proposed method is able to overcome the overlearning problem by pruning several redundant features and their corresponding output weights. The proposed multimodal sparse ELM classifier based on residual errors (RES-ELM) is highly competitive in terms of classification accuracy compared to its counterparts such as conventional ELM, and sparse Bayesian learning ELM.

PMID: 31265424 [PubMed - as supplied by publisher]

Striatal functional connectivity in chronic ketamine users: a pilot study.

Wed, 07/03/2019 - 18:17

Striatal functional connectivity in chronic ketamine users: a pilot study.

Am J Drug Alcohol Abuse. 2019 Jul 02;:1-13

Authors: Hung CC, Zhang S, Chen CM, Duann JR, Lin CP, Lee TS, Li CR

Abstract
Background: The striatum supports motivated behavior and impulse control. Altered striatal activation and connectivity has been observed in link with impulse control dysfunction in individuals with drug addiction. Objectives: We examined how resting state functional connectivity (rsFC) of the striatum is altered as a result of chronic ketamine misuse. Methods: Thirty-six ketamine users (10 women) and 20 healthy controls (9 women) completed an assessment with the Barratt Impulsiveness Scale (BIS-11) and magnetic resonance imaging. In SPM we examined voxel-wise connectivities of the caudate, pallidum, putamen, and ventral striatum in ketamine users (versus healthy controls) and in association with BIS-11 score and duration of use, all at a corrected threshold. Results: Compared to controls, ketamine users showed higher connectivity between caudate and dorsal anterior cingulate cortex and between pallidum and bilateral cerebellum. In ketamine users, putamen showed higher connectivity with the left orbitofrontal cortex (OFC) in association with both BIS-11 score and months of ketamine use. Mediation analyses suggest that the connectivity z score mediated the relationship between impulsivity and duration of use. Conclusions: These preliminary findings highlighted altered striatal connectivity in chronic ketamine users, and the potential role of putamen OFC connectivity in supporting the correlation between impulsivity and duration of ketamine use. If replicated in a larger sample, these findings may represent neural markers of ketamine misuse.

PMID: 31264888 [PubMed - as supplied by publisher]

Microstates as Disease and Progression Markers in Patients With Mild Cognitive Impairment.

Wed, 07/03/2019 - 18:17
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Microstates as Disease and Progression Markers in Patients With Mild Cognitive Impairment.

Front Neurosci. 2019;13:563

Authors: Musaeus CS, Nielsen MS, Høgh P

Abstract
Network dysfunction is well established in patients with Alzheimer's disease (AD) and has been shown to be present early in the disease. This is especially interesting in patients with mild cognitive impairment (MCI) since they are more likely to develop AD. In EEG, one type of network analysis is microstates where the EEG is divided into quasi-stable states and these microstates have been linked to networks found with resting state functional MRI. In the current exploratory study, we therefore wanted to explore the changes in microstates in MCI, and AD compared to healthy controls (HC) and whether microstates were able to separate patients with MCI who progressed (pMCI) and those who remained stable (sMCI). EEGs were recorded at baseline for 17 patients with AD, 27 patients with MCI, and 38 older HC and the patients were followed for 3 years. To investigate whole-brain dynamics we extracted different microstate parameters. We found that patients with MCI, and AD had significantly higher occurrence (p-value = 0.028), and coverage (p-value = 0.010) for microstate A compared to HC. However, we did not find any significant systematic deviation of the transition probabilities from randomness for any of the groups. No significant differences were found between pMCI and sMCI but the largest difference in duration was found for microstate D. Microstate A has been linked to the temporal lobes in studies combining EEG and fMRI and the temporal lobes are the most affected by AD pathology in the early stages of the disease. This supports our idea that microstate A may be the first affected microstate in early AD. Even though not significant between pMCI and sMCI, Microstate D has previously been shown to be associated with both frontal and parietal areas as measured with fMRI and may correspond to underlying pathological changes in the progression of MCI to AD. However, larger studies are needed to confirm these findings.

PMID: 31263397 [PubMed]

Sex differences in cognitive flexibility and resting brain networks in middle-aged marmosets.

Wed, 07/03/2019 - 18:17
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Sex differences in cognitive flexibility and resting brain networks in middle-aged marmosets.

eNeuro. 2019 Jul 01;:

Authors: LaClair M, Febo M, Nephew B, Gervais NJ, Poirier G, Workman K, Chumachenko S, Payne L, Moore MC, King JA, Lacreuse A

Abstract
Sex differences in human cognitive performance are well characterized. However, the neural correlates of these differences remain elusive. This issue may be clarified using nonhuman primates, for which sociocultural influences are minimized. We used the marmoset (Callithrix jacchus) to investigate sex differences in two aspects of executive function: Reversal Learning and Intradimensional/Extradimensional (ID/ED) set shifting. Stress reactivity and motor function were also assessed. In agreement with human literature, females needed more trials than males to acquire the reversals. No sex differences in ED set shifting or motivational measures were observed. The findings suggest enhanced habit formation in females, perhaps due to striatal estrogenic effects. Both sexes showed increased urinary cortisol during social separation stressor, but females showed an earlier increase in cortisol and a greater increase in agitated locomotion, possibly indicating enhanced stress reactivity. Independent of sex, basal cortisol predicted cognitive performance. No sex differences were found in motor performance. Associations between brain networks and reversal learning performance were investigated using resting state fMRI. Resting state functional connectivity analyses revealed sex differences in cognitive networks, with differences in overall neural network metrics and specific regions, including the prefrontal cortex, caudate, putamen, and nucleus accumbens. Correlations between cognitive flexibility and neural connectivity indicate that sex differences in cognitive flexibility are related to sex-dependent patterns of resting brain networks. Overall, our findings reveal sex differences in reversal learning, brain networks, and their relationship in the marmoset, positioning this species as an excellent model to investigate the biological basis of cognitive sex differences.SIGNIFICANCE STATEMENT We examined sex differences in multiple outcomes (cognition, motor function, stress reactivity and resting state functional connectivity) in middle-aged marmosets. We found that female marmosets had poorer reversal learning relative to males. Resting state functional connectivity analyses revealed substantial sex differences in cognitive networks, with differences in both overall neural network metrics and specific regions, including the prefrontal cortex, caudate, putamen, and nucleus accumbens. Sex-dependent correlations between reversal learning and neural connectivity measures indicate that the sex difference in cognitive performance is related to sex-dependent patterns of resting brain networks. Although these data are correlational and cannot determine causal effects, they are consistent with human resting state data, supporting the idea that cognitive sex differences have identifiable intrinsic neural correlates.

PMID: 31262949 [PubMed - as supplied by publisher]

Identifying individuals using fNIRS-based cortical connectomes.

Tue, 07/02/2019 - 21:16
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Identifying individuals using fNIRS-based cortical connectomes.

Biomed Opt Express. 2019 Jun 01;10(6):2889-2897

Authors: de Souza Rodrigues J, Ribeiro FL, Sato JR, Mesquita RC, Júnior CEB

Abstract
The fMRI-based functional connectome was shown to be sufficiently unique to allow individual identification (fingerprinting). We aimed to test whether a fNIRS-based connectome could also be used to identify individuals. Forty-four participants performed experimental protocols that consisted of two periods of resting-state interleaved by a cognitive task period. Connectome identification was performed for all possible pairwise combinations of the three periods. The influence of hemodynamic global variation was tested using global signal regression and principal component analysis. High identification accuracies well-above chance level (2.3%) were observed overall, being particularly high (93%) to the oxyhemoglobin signal between resting conditions. Our results suggest that fNIRS is a suitable technique to assess connectome fingerprints.

PMID: 31259059 [PubMed]

Altered spontaneous brain activity patterns in patients with corneal ulcer using amplitude of low-frequency fluctuation: An fMRI study.

Tue, 07/02/2019 - 21:16
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Altered spontaneous brain activity patterns in patients with corneal ulcer using amplitude of low-frequency fluctuation: An fMRI study.

Exp Ther Med. 2019 Jul;18(1):125-132

Authors: Shi WQ, Wu W, Ye L, Jiang N, Liu WF, Shu YQ, Su T, Lin Q, Min YL, Li B, Zhu PW, Shao Y

Abstract
The aim of the present study was to investigate the altered spontaneous brain activity in patients with corneal ulcer (CU) through the amplitude of low-frequency fluctuation (ALFF) technique and the association with their visual performance. A total of 40 patients with CU and 40 healthy controls (HCs) matched for sex, age and educational level were enrolled. Resting-state functional magnetic resonance imaging (rs-fMRI) was performed to examine the probands. Spontaneous cerebral activity variations were investigated using the ALFF technique. The average ALFF values of the CU patients and the HCs were classified by utilizing receiver operating characteristic (ROC) curves. Contrary to HCs, the CU patients had significantly lower ALFF values in the left cerebellar anterior lobe, right middle frontal gyrus and left middle frontal gyrus, but higher ALFF values in the right cerebellar inferior lobe, left cerebellar inferior lobe, left inferior temporal gyrus, right fusiform gyrus, left superior frontal gyrus, right angular gyrus and bilateral superior frontal gyrus. ROC curve analysis of each brain region indicated that the accuracy of ALFF value specificity between the CU and HCs of the area under the curve was perfect. In conclusion, abnormal spontaneous activities were detected in numerous brain regions of CU patients, which may provide useful information for understanding the dysfunction of CU. These activity changes in brain regions may be used as effective clinical indicators for CU.

PMID: 31258645 [PubMed]

L-Dopa Modulation of Brain Connectivity in Parkinson's Disease Patients: A Pilot EEG-fMRI Study.

Tue, 07/02/2019 - 21:16
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L-Dopa Modulation of Brain Connectivity in Parkinson's Disease Patients: A Pilot EEG-fMRI Study.

Front Neurosci. 2019;13:611

Authors: Evangelisti S, Pittau F, Testa C, Rizzo G, Gramegna LL, Ferri L, Coito A, Cortelli P, Calandra-Buonaura G, Bisquoli F, Bianchini C, Manners DN, Talozzi L, Tonon C, Lodi R, Tinuper P

Abstract
Studies of functional neurosurgery and electroencephalography in Parkinson's disease have demonstrated abnormally synchronous activity between basal ganglia and motor cortex. Functional neuroimaging studies investigated brain dysfunction during motor task or resting state and primarily have shown altered patterns of activation and connectivity for motor areas. L-dopa administration relatively normalized these functional alterations. The aim of this pilot study was to examine the effects of L-dopa administration on functional connectivity in early-stage PD, as revealed by simultaneous recording of functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) data. Six patients with diagnosis of probable PD underwent EEG-fMRI acquisitions (1.5 T MR scanner and 64-channel cap) before and immediately after the intake of L-dopa. Regions of interest in the primary motor and sensorimotor regions were used for resting state fMRI analysis. From the EEG data, weighted partial directed coherence was computed in the inverse space after the removal of gradient and cardioballistic artifacts. fMRI results showed that the intake of L-dopa increased functional connectivity within the sensorimotor network, and between motor areas and both attention and default mode networks. EEG connectivity among regions of the motor network did not change significantly, while regions of the default mode network showed a strong tendency to increase their outflow toward the rest of the brain. This pilot study provided a first insight into the potentiality of simultaneous EEG-fMRI acquisitions in PD patients, showing for both techniques the analogous direction of increased connectivity after L-dopa intake, mainly involving motor, dorsal attention and default mode networks.

PMID: 31258465 [PubMed]

Naturalistic Stimuli in Neuroscience: Critically Acclaimed.

Tue, 07/02/2019 - 21:16
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Naturalistic Stimuli in Neuroscience: Critically Acclaimed.

Trends Cogn Sci. 2019 Jun 27;:

Authors: Sonkusare S, Breakspear M, Guo C

Abstract
Cognitive neuroscience has traditionally focused on simple tasks, presented sparsely and using abstract stimuli. While this approach has yielded fundamental insights into functional specialisation in the brain, its ecological validity remains uncertain. Do these tasks capture how brains function 'in the wild', where stimuli are dynamic, multimodal, and crowded? Ecologically valid paradigms that approximate real life scenarios, using stimuli such as films, spoken narratives, music, and multiperson games emerged in response to these concerns over a decade ago. We critically appraise whether this approach has delivered on its promise to deliver new insights into brain function. We highlight the challenges, technological innovations, and clinical opportunities that are required should this field meet its full potential.

PMID: 31257145 [PubMed - as supplied by publisher]

Influence of muscarinic M1 receptor antagonism on brain choline levels and functional connectivity in medication-free subjects with psychosis: A placebo controlled, cross-over study.

Sun, 06/30/2019 - 21:13
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Influence of muscarinic M1 receptor antagonism on brain choline levels and functional connectivity in medication-free subjects with psychosis: A placebo controlled, cross-over study.

Psychiatry Res Neuroimaging. 2019 Jun 23;290:5-13

Authors: Vingerhoets C, Bakker G, Schrantee A, van der Pluijm M, Bloemen OJN, Reneman L, Caan M, Booij J, van Amelsvoort TAMJ

Abstract
An increasing number of studies implicate the muscarinic cholinergic system in cognitive dysfunction associated with psychosis. This study examined the effect of muscarinic M1 receptor modulation on anterior cingulate cortex (ACC) and striatal choline concentrations and the relation with cognitive performance, as well as functional connectivity of cognitive networks. Thirty medication-free subjects with a psychosis spectrum disorder and 30 gender, age and IQ-matched healthy control subjects underwent 1H-proton magnetic resonance spectroscopy (1H-MRS) twice, once after placebo and once after a single dose of biperiden (M1 receptor antagonist, 4 mg). A subset of 19 psychotic subjects and 28 controls underwent resting-state functional magnetic resonance imaging (rs-fMRI) as well. No significant differences were found in ACC and striatal choline levels, nor in functional connectivity, between the two groups after placebo. Moreover, M1 antagonism did not significantly affect choline levels or functional connectivity. No correlations were found between choline levels and cognition as well as psychotic symptoms. Our findings do not support an association between the cholinergic system and cognition and psychotic symptoms. However, the lack of group differences in choline concentrations and functional connectivity, both after biperiden and placebo, may indicate that there were no severe cholinergic abnormalities present in our sample.

PMID: 31252222 [PubMed - as supplied by publisher]

Detailed mapping of human habenula resting-state functional connectivity.

Sun, 06/30/2019 - 21:13
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Detailed mapping of human habenula resting-state functional connectivity.

Neuroimage. 2019 Jun 25;:

Authors: Ely BA, Stern ER, Kim JW, Gabbay V, Xu J

Abstract
The habenula (Hb) inhibits dopaminergic reward signaling in response to negative outcomes and has been linked to numerous functional domains relevant to mental health, including reward prediction, motivation, and aversion processing. Despite its important neuroscientific and clinical implications, however, the human Hb remains poorly understood due to its small size and the associated technical hurdles to in vivo functional magnetic resonance imaging (fMRI) investigation. Using high-resolution 3T fMRI data from 68 healthy young adults acquired through the Human Connectome Project, we developed a rigorous approach for mapping the whole-brain resting-state functional connectivity of the human Hb. Our study combined an optimized strategy for defining subject-level connectivity seeds to maximize Hb BOLD sensitivity with high-quality surface-based alignment for robust functional localization and cortical sensitivity. We identified significant positive Hb connectivity with: (i) conserved brainstem targets, including the dopaminergic ventral tegmental area, serotonergic raphe nuclei, and periaqueductal gray; (ii) subcortical structures related to reward and motor function, including the nucleus accumbens, dorsal striatum, pallidum, thalamus, and cerebellum; and (iii) cortical areas associated with the Salience Network and early sensory processing, including the dorsal anterior cingulate, anterior insula, and primary visual and auditory cortices. Hb connectivity was strongly biased towards task-positive brain regions, with weak or negative connectivity observed throughout the task-negative Default Mode Network. Our study provides a detailed characterization of Hb resting-state functional connectivity in healthy young adults, demonstrating both the feasibility and clinical potential of studying the human Hb using high-resolution 3T fMRI.

PMID: 31252057 [PubMed - as supplied by publisher]

Latent resting-state network dynamics in boys and girls with attention-deficit/hyperactivity disorder.

Sun, 06/30/2019 - 21:13
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Latent resting-state network dynamics in boys and girls with attention-deficit/hyperactivity disorder.

PLoS One. 2019;14(6):e0218891

Authors: Scofield JE, Johnson JD, Wood PK, Geary DC

Abstract
Neuroimaging studies of subjects with ADHD typically show altered functional connectivity in prefrontal, striatal, and several temporal brain regions. While the majority of studies have focused on connectivity that is averaged over time, we investigated the temporal dynamics of brain network changes in resting-state fMRI. Using the ADHD-200 consortium, we characterized the time course of latent state changes using Hidden Markov Modeling, and compared state changes between boys and girls with ADHD along with typically developing controls. Sex differences were found in latent state switching, with boys dwelling longer in a given state than girls, and concurrently having fewer overall state transitions. These sex differences were found in children with ADHD and in typically developing controls. Children with ADHD were also found to be more variable in terms of state transitions than controls. These findings add to the growing literature on neural sex differences and may be related to the sex difference in focal versus diffuse attention.

PMID: 31251765 [PubMed - in process]