New resting-state fMRI related studies at PubMed

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Sexual Dimorphism of Resting-State Network Connectivity in Healthy Ageing.

Fri, 02/23/2018 - 13:20

Sexual Dimorphism of Resting-State Network Connectivity in Healthy Ageing.

J Gerontol B Psychol Sci Soc Sci. 2018 Feb 17;:

Authors: Jamadar SD, Sforazzini F, Raniga P, Ferris NJ, Paton B, Bailey MJ, Brodtmann A, Yates PA, Donnan GA, Ward SA, Woods RL, Storey E, McNeil JJ, Egan GF, ASPREE Investigator Group

Abstract
Objectives: The onset of many illnesses is confounded with age and sex. Increasing age is a risk factor for the development of many illnesses, and sexual dimorphism influences brain anatomy, function, and cognition. Here, we examine frequency-specific connectivity in resting-state networks in a large sample (n = 406) of healthy aged adults.
Method: We quantify frequency-specific connectivity in three resting-state networks known to be implicated in age-related decline: the default mode, dorsal attention, and salience networks, using multiband functional magnetic resonance imaging. Frequency-specific connectivity was quantified in four bands: low (0.015-0.027 Hz), moderately low (0.027-0.073 Hz), moderately high (0.073-0.198 Hz), and high (0.198-0.5 Hz) frequency bands, using mean intensity and spatial extent. Differences in connectivity between the sexes in each of the three networks were examined.
Results: Each network showed the largest intensity and spatial extent at low frequencies and smallest extent at high frequencies. Males showed greater connectivity than females in the salience network. Females showed greater connectivity than males in the default mode network.
Discussion: Results in this healthy aged cohort are compatible with those obtained in young samples, suggesting that frequency-specific connectivity, and differences between the sexes, are maintained into older age. Our results indicate that sex should be considered as an influencing factor in studies of resting-state connectivity.

PMID: 29471348 [PubMed - as supplied by publisher]

Causal Evidence for a Neural Component of Spatially Global Hemodynamic Signals.

Fri, 02/23/2018 - 13:20

Causal Evidence for a Neural Component of Spatially Global Hemodynamic Signals.

Neuron. 2018 Feb 21;97(4):734-736

Authors: Müsch K, Honey CJ

Abstract
In this issue of Neuron, Turchi et al. (2018) reversibly inactivate the basal forebrain to show that this region magnifies global neocortical signal fluctuations without altering the topography of canonical resting-state networks. Thus, spatially diffuse signals measurable via functional neuroimaging may track large-scale neuromodulatory state changes in the primate brain.

PMID: 29470965 [PubMed - in process]

Differential effects of oxycodone and venlafaxine on resting state functional connectivity-A randomized placebo-controlled magnetic resonance imaging study.

Fri, 02/23/2018 - 13:20
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Differential effects of oxycodone and venlafaxine on resting state functional connectivity-A randomized placebo-controlled magnetic resonance imaging study.

CNS Neurosci Ther. 2018 Feb 21;:

Authors: Hansen TM, Lelic D, Olesen AE, Drewes AM, Frøkjaer JB

Abstract
AIM: Different mechanisms may be involved in the antinociceptive effects of oxycodone (opioid) and venlafaxine (serotonin-norepinephrine reuptake inhibitor), and the aim of this study was to investigate the effect of these drugs on brain functional connectivity.
METHODS: Resting state functional magnetic resonance imaging was acquired in 20 healthy volunteers before and after a 5-day treatment with oxycodone, venlafaxine, or placebo in a randomized, double-blind, crossover study. Functional connectivity analyses were performed between four predefined seeds (dorsal anterior cingulate cortex, rostral anterior cingulate cortex, posterior insula, and prefrontal cortex), and the whole brain.
RESULTS: The overall interpretation was that there were differences between the effects of oxycodone and venlafaxine on functional connectivity. Oxycodone mainly showed decreased functional connectivity between limbic structures and to supralimbic areas (all P < 0.05). Venlafaxine also showed decreased functional connectivity between limbic structures and to supralimbic areas, but increased functional connectivity to structures in the midbrain and brain stem was also found (all P < 0.05).
CONCLUSIONS: Oxycodone and venlafaxine showed differential effects on resting-state functional connectivity as compared to placebo. This supports that the two drugs exert different mechanisms, and that the drugs in combination may exert additive effects and could potentially improve pain therapy.

PMID: 29468854 [PubMed - as supplied by publisher]

Research note: a resting-state, cerebello-amygdaloid intrinsically connected network.

Fri, 02/23/2018 - 13:20
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Research note: a resting-state, cerebello-amygdaloid intrinsically connected network.

Cerebellum Ataxias. 2018;5:4

Authors: Habas C

Abstract
Background: Previous ROI-based functional connectivity studies found functional coherence between cerebellum and cerebral amygdale, at rest. Moreover, some neurospychiatric symptoms were accompanied by abnormal activations of these two brain areas. Therefore, the aim of the study was to identify a putative, resting-state intrinsically connected cerebello-amygdaloid network.
Methods: ICA-based analysis was performed on brain resting-state functional images of 15 volunteers.
Results: The first ICA spatial component corresponded to a circuit including: dentate nuclei, lobules VI and VIII, the basolateral amygdala, the substantia nigra, the posterior insula, claustrum and the parietal opercule.
Conclusion: A new intrinsically connected network linking cerebellum and amygdala is described, which could be in charge of sensorimotor, emotional and motivational integration of somesthesic stimuli before recruiting more specialized circuits such as ventral striatum or attentional and salience networks.

PMID: 29468083 [PubMed]

Classification of Autism Spectrum Disorder Using Random Support Vector Machine Cluster.

Fri, 02/23/2018 - 13:20
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Classification of Autism Spectrum Disorder Using Random Support Vector Machine Cluster.

Front Genet. 2018;9:18

Authors: Bi XA, Wang Y, Shu Q, Sun Q, Xu Q

Abstract
Autism spectrum disorder (ASD) is mainly reflected in the communication and language barriers, difficulties in social communication, and it is a kind of neurological developmental disorder. Most researches have used the machine learning method to classify patients and normal controls, among which support vector machines (SVM) are widely employed. But the classification accuracy of SVM is usually low, due to the usage of a single SVM as classifier. Thus, we used multiple SVMs to classify ASD patients and typical controls (TC). Resting-state functional magnetic resonance imaging (fMRI) data of 46 TC and 61 ASD patients were obtained from the Autism Brain Imaging Data Exchange (ABIDE) database. Only 84 of 107 subjects are utilized in experiments because the translation or rotation of 7 TC and 16 ASD patients has surpassed ±2 mm or ±2°. Then the random SVM cluster was proposed to distinguish TC and ASD. The results show that this method has an excellent classification performance based on all the features. Furthermore, the accuracy based on the optimal feature set could reach to 96.15%. Abnormal brain regions could also be found, such as inferior frontal gyrus (IFG) (orbital and opercula part), hippocampus, and precuneus. It is indicated that the method of random SVM cluster may apply to the auxiliary diagnosis of ASD.

PMID: 29467790 [PubMed]

Age-Dependent Modulations of Resting State Connectivity Following Motor Practice.

Fri, 02/23/2018 - 13:20
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Age-Dependent Modulations of Resting State Connectivity Following Motor Practice.

Front Aging Neurosci. 2018;10:25

Authors: Solesio-Jofre E, Beets IAM, Woolley DG, Pauwels L, Chalavi S, Mantini D, Swinnen SP

Abstract
Recent work in young adults has demonstrated that motor learning can modulate resting state functional connectivity. However, evidence for older adults is scarce. Here, we investigated whether learning a bimanual tracking task modulates resting state functional connectivity of both inter- and intra-hemispheric regions differentially in young and older individuals, and whether this has behavioral relevance. Both age groups learned a set of complex bimanual tracking task variants over a 2-week training period. Resting-state and task-related functional magnetic resonance imaging scans were collected before and after training. Our analyses revealed that both young and older adults reached considerable performance gains. Older adults even obtained larger training-induced improvements relative to baseline, but their overall performance levels were lower than in young adults. Short-term practice resulted in a modulation of resting state functional connectivity, leading to connectivity increases in young adults, but connectivity decreases in older adults. This pattern of age differences occurred for both inter- and intra-hemispheric connections related to the motor network. Additionally, long-term training-induced increases were observed in intra-hemispheric connectivity in the right hemisphere across both age groups. Overall, at the individual level, the long-term changes in inter-hemispheric connectivity correlated with training-induced motor improvement. Our findings confirm that short-term task practice shapes spontaneous brain activity differentially in young and older individuals. Importantly, the association between changes in resting state functional connectivity and improvements in motor performance at the individual level may be indicative of how training shapes the short-term functional reorganization of the resting state motor network for improvement of behavioral performance.

PMID: 29467646 [PubMed]

Alterations of Resting-State Static and Dynamic Functional Connectivity of the Dorsolateral Prefrontal Cortex in Subjects with Internet Gaming Disorder.

Fri, 02/23/2018 - 13:20
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Alterations of Resting-State Static and Dynamic Functional Connectivity of the Dorsolateral Prefrontal Cortex in Subjects with Internet Gaming Disorder.

Front Hum Neurosci. 2018;12:41

Authors: Han X, Wu X, Wang Y, Sun Y, Ding W, Cao M, Du Y, Lin F, Zhou Y

Abstract
Internet gaming disorder (IGD), a major behavior disorder, has gained increasing attention. Recent studies indicate altered resting-state static functional connectivity (FC) of the dorsolateral prefrontal cortex (DLPFC) in subjects with IGD. Whereas static FC often provides information on functional changes in subjects with IGD, investigations of temporal changes in FC between the DLPFC and the other brain regions may shed light on the dynamic characteristics of brain function associated with IGD. Thirty subjects with IGD and 30 healthy controls (HCs) matched for age, gender and education status were recruited. Using the bilateral DLPFC as seeds, static FC and dynamic FC maps were calculated and compared between groups. Correlations between alterations in static FC and dynamic FC and clinical variables were also investigated within the IGD group. The IGD group showed significantly lower static FC between the right DLPFC and the left rolandic operculum while higher static FC between the right DLPFC and the left pars triangularis when compared to HCs. The IGD group also had significantly decreased dynamic FC between the right DLPFC and the left insula, right putamen and left precentral gyrus, and increased dynamic FC in the left precuneus. Moreover, the dynamic FC between the right DLPFC and the left insula was negatively correlated with the severity of IGD. Dynamic FC can be used as a powerful supplement to static FC, helping us obtain a more comprehensive understanding of large-scale brain network activity in IGD and put forward new ideas for behavioral intervention therapy for it.

PMID: 29467640 [PubMed]

Increased Posterior Insula-Sensorimotor Connectivity Is Associated with Cognitive Function in Healthy Participants with Sleep Complaints.

Fri, 02/23/2018 - 13:20
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Increased Posterior Insula-Sensorimotor Connectivity Is Associated with Cognitive Function in Healthy Participants with Sleep Complaints.

Front Hum Neurosci. 2018;12:35

Authors: Liu CH, Liu CZ, Zhu XQ, Fang JL, Lu SL, Tang LR, Wang CY, Liu QQ

Abstract
Insomnia is characterized by sensory hypersensitivity and cognitive impairments. Recent work has identified the insula as a central brain region involved in both bottom-up gating of sensory information and top-down cognitive control. However, the specific relationships between insular subregion connectivity and emotional and cognitive functions remain unclear. In this study, resting-state functional magnetic resonance imaging data were obtained from 25 healthy participants with sleep complaints (HPS) and 25 age-, gender- and educational level-matched healthy participants without insomnia complaints (HP). We performed insular subregion (ventral anterior, dorsal anterior and posterior) functional connectivity (FC) analyses, and cognitive function was measured with several validated test procedures (e.g., the Wisconsin Card Sorting Test [WCST], Continuous Performance Test [CPT] and Trail making Test [TMT]). There were no significant differences between the two groups for WCST, CPT and TMT scores. The HPS group showed enhanced connectivity from the right posterior insula (R-PI) to the left postcentral gyrus (L-postCG) compared to HP group. WCST random errors (RE), sleep disturbance scores and HAMA scores correlated with this connectivity measurement in both HP and HPS groups. Our results provide direct evidence that the posterior insula (PI) synchronizes with sensorimotor areas to detect homeostatic changes and suggest that alteration of the latter is related to executive dysfunction in subjects with insomnia.

PMID: 29467636 [PubMed]

Reorganization of the thalamocortical network in musicians.

Fri, 02/23/2018 - 13:20
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Reorganization of the thalamocortical network in musicians.

Brain Res. 2017 Jun 01;1664:48-54

Authors: Tanaka S, Kirino E

Abstract
The cortico-thalamocortical network is relevant to music performance in that the network can regulate sensitivity to afferent input or sound, mediate the integration of multimodal information required for the performance, and play a role in skilled performance control. We, therefore, predicted that this network would be reorganized via musical training-induced neuroplasticity. To test this hypothesis, we analyzed resting-state functional connectivity of the thalamocortical network in musicians (n=35) and nonmusicians (n=35). The seed-to-voxel functional connectivity analysis of the left thalamus seed showed enhanced connectivity voxels in the precuneus/posterior cingulate cortex (PCC) in musicians compared with nonmusicians. Region of interest (ROI)-to-ROI functional connectivity analysis showed that the auditory areas were also more strongly connected with the left thalamus in musicians. Discriminant analysis using the ROI-to-ROI functional connectivity data of the precuneus/PCC and auditory areas as predictors yielded an 87% correct discrimination of musicians from nonmusicians. Therefore, we can conclude that, as a consequence of long-term musical training, musicians have a characteristically organized thalamocortical network. The precuneus and PCC are principal nodes of the default mode network and play a pivotal role in the manipulation of mental imagery. We propose that the reorganized thalamocortical network in musicians contributes not only to higher sensitivity to sound but also to the integration of mental imagery with sound, which are both presumed to be important for better music performance.

PMID: 28377159 [PubMed - indexed for MEDLINE]

Insula and Inferior Frontal Gyrus' Activities Protect Memory Performance Against Alzheimer's Disease Pathology in Old Age.

Fri, 02/23/2018 - 13:20
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Insula and Inferior Frontal Gyrus' Activities Protect Memory Performance Against Alzheimer's Disease Pathology in Old Age.

J Alzheimers Dis. 2017;55(2):669-678

Authors: Lin F, Ren P, Lo RY, Chapman BP, Jacobs A, Baran TM, Porsteinsson AP, Foxe JJ, Alzheimer’s Disease Neuroimaging Initiative

Abstract
Apolipoprotein E (APOE) ɛ4 carriers and patients with amnestic mild cognitive impairment (MCI) have high risk of developing Alzheimer's disease (AD). The Scaffolding Theory of Aging and Cognition proposes that recruitment of additional frontal brain regions can protect cognition against aging. This thesis has yet to be fully tested in older adults at high risk for AD. In the present study, 75 older participants (mean age: 74 years) were included. Applying a voxel-wise approach, fractional amplitude of low-frequency fluctuations (fALFF) in resting-state functional neuroimaging data were analyzed as a function of APOEɛ4 status (carrier versus noncarrier) and clinical status (healthy control [HC] versus MCI) using a 2×2 analysis of covariance (ANCOVA). Measures of cognition and cerebrospinal fluid levels of amyloid- β were also obtained. Three frontal regions were identified with significant interaction effects using ANCOVA (corrected p < 0.01): left-insula, left-inferior frontal gyrus (IFG), and right-precentral gyrus. The HC/APOEɛ4 carrier group had significantly higher fALFF in all three regions than other groups. In the entire sample, for two regions (left insula and left IFG), a significant positive relationship between amyloid-β and memory was only observed among individuals with low fALFF. Our results suggest higher activity in frontal regions may explain being cognitively normal among a subgroup of APOEɛ4 carriers and protect against the negative impact of AD-associated pathology on memory. This is an observation with potential implications for AD therapeutics.

PMID: 27716674 [PubMed - indexed for MEDLINE]

Healthy and Pathological Brain Aging: From the Perspective of Oscillations, Functional Connectivity, and Signal Complexity.

Thu, 02/22/2018 - 18:40

Healthy and Pathological Brain Aging: From the Perspective of Oscillations, Functional Connectivity, and Signal Complexity.

Neuropsychobiology. 2018 Feb 21;:

Authors: Ishii R, Canuet L, Aoki Y, Hata M, Iwase M, Ikeda S, Nishida K, Ikeda M

Abstract
Healthy aging is associated with impairment in cognitive information processing. Several neuroimaging methods such as functional magnetic resonance imaging, positron emission tomography and near-infrared spectroscopy have been used to explore healthy and pathological aging by relying on hemodynamic or metabolic changes that occur in response to brain activity. Since electroencephalography (EEG) and magnetoencephalography (MEG) are able to measure neural activity directly with a high temporal resolution of milliseconds, these neurophysiological techniques are particularly important to investigate the dynamics of brain activity underlying neurocognitive aging. It is well known that age is a major risk factor for Alzheimer's disease (AD), and that synaptic dysfunction represents an early sign of this disease associated with hallmark neuropathological findings. However, the neurophysiological mechanisms underlying AD are not fully elucidated. This review addresses healthy and pathological brain aging from a neurophysiological perspective, focusing on oscillatory activity changes during the resting state, event-related potentials and stimulus-induced oscillatory responses during cognitive or motor tasks, functional connectivity between brain regions, and changes in signal complexity. We also highlight the accumulating evidence on age-related EEG/MEG changes and biological markers of brain neurodegeneration, including genetic factors, structural abnormalities on magnetic resonance images, and the biochemical changes associated with Aβ deposition and tau pathology.

PMID: 29466802 [PubMed - as supplied by publisher]

Shared and Distinct Regional Homogeneity Changes in Bipolar and Unipolar Depression.

Thu, 02/22/2018 - 18:40

Shared and Distinct Regional Homogeneity Changes in Bipolar and Unipolar Depression.

Neurosci Lett. 2018 Feb 18;:

Authors: Yao X, Yin Z, Liu F, Wei S, Zhou Y, Jiang X, Wei Y, Xu K, Wang F, Tang Y

Abstract
BACKGROUND: Bipolar depression (BD) is easily misdiagnosed as unipolar depression (UD) or major depressive disorder (MDD) because the depressive symptoms can overlap. Regional homogeneity (ReHo), a measure commonly used for analyzing resting-state fMRI data, has been applied to the study of various neuropsychiatric disorders. However, to date, studies directly comparing BD and UD using ReHo have been relatively scarce. Further investigation is needed to study the latent pathophysiological mechanisms of BD and UD.
METHODS: Fifty-five patients with BD and 76 patients with UD, as well as 113 healthy controls (HC), underwent resting-state functional magnetic resonance imaging (fMRI). We compared the voxel-wise ReHo across the whole brain for subjects in each of the three groups.
RESULTS: Significant differences were found in the left frontal cluster (LFC) across the three groups. There were differences between BD and UD in the LFC and left temporal cluster (LTC). In addition, differences between UD and HC existed in the LFC and the occipital cluster (OC). When comparing BD subjects with HC subjects, significant differences were found in all three clusters. No correlations were observed between the 17-item Hamilton Depression Rating Scale (HDRS-17) scores or sub-scores and the ReHo values of BD or UD patients.
CONCLUSION: ReHo values in the LFC differed significantly among BD, UD, and HC subjects. ReHo in the LTC showed significant differences between BD and UD that might serve as neuroimaging markers of BD. Further, BD and UD shared ReHo changes in the cuneus, suggesting that the cuneus might provide a depressive state neuroimaging marker of BD and UD patients.

PMID: 29466722 [PubMed - as supplied by publisher]

Multiple sclerosis-related fatigue: Altered resting-state functional connectivity of the ventral striatum and dorsolateral prefrontal cortex.

Thu, 02/22/2018 - 18:40

Multiple sclerosis-related fatigue: Altered resting-state functional connectivity of the ventral striatum and dorsolateral prefrontal cortex.

Mult Scler. 2018 Feb 01;:1352458518758911

Authors: Jaeger S, Paul F, Scheel M, Brandt A, Heine J, Pach D, Witt CM, Bellmann-Strobl J, Finke C

Abstract
OBJECTIVE: Since recent studies suggested a role of the striatum and prefrontal cortex for multiple sclerosis (MS)-related fatigue, we investigated resting-state functional connectivity alterations of striatal subdivisions and the dorsolateral prefrontal cortex (dlPFC).
METHODS: Resting-state functional magnetic resonance imaging was acquired in 77 relapsing-remitting MS patients (38 fatigued (F-MS), 39 non-fatigued (NF-MS)) and 41 matched healthy controls (HC). Fatigue severity was assessed using the fatigue severity scale. Seed-based connectivity analyses were performed using subregions of the striatum and the dlPFC as regions of interest applying non-parametric permutation testing.
RESULTS: Compared to HC and NF-MS patients, F-MS patients showed reduced caudate nucleus and ventral striatum functional connectivity with the sensorimotor cortex (SMC) and frontal, parietal, and temporal cortex regions. Fatigue severity correlated negatively with functional connectivity of the caudate nucleus and ventral striatum with the SMC and positively with functional connectivity of the dlPFC with the rostral inferior parietal gyrus and SMC.
CONCLUSION: MS-related fatigue is associated with reduced functional connectivity between the striatum and sensorimotor as well as attention and reward networks, in which the ventral striatum might be a key integration hub. Together with increased connectivity between the dlPFC and sensory cortical areas, these connectivity alterations shed light on the mechanisms of MS-related fatigue.

PMID: 29464981 [PubMed - as supplied by publisher]

Difference in regional neural fluctuations and functional connectivity in Crohn's disease: a resting-state functional MRI study.

Thu, 02/22/2018 - 18:40
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Difference in regional neural fluctuations and functional connectivity in Crohn's disease: a resting-state functional MRI study.

Brain Imaging Behav. 2018 Feb 20;:

Authors: Bao C, Liu P, Liu H, Jin X, Shi Y, Wu L, Zeng X, Zhang J, Wang D, Calhoun VD, Tian J, Wu H

Abstract
Patients with Crohn's disease (CD) are shown to have abnormal changes in brain structures. This study aimed to further investigate whether these patients have abnormal brain activities and network connectivity. Sixty patients with CD and 40 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (fMRI) scans. Amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) were used to assess differences in spontaneous regional brain activity and functional connectivity. Compared to the HCs, patients with CD showed significantly higher ALFF values in hippocampus and parahippocampus (HIPP/paraHIPP), anterior cingulate cortex, insula, superior frontal cortex and precuneus. The ALFF values were significantly lower in secondary somatosensory cortex (S2), precentral gyrus, and medial prefrontal cortex. Functional connectivities between left HIPP and left inferior temporal cortex, and right middle cingulate cortex, HIPP, and fusiform area were significantly lower. The functional connectivities between right HIPP and right inferior orbitofrontal cortex and left HIPP were also significantly lower. Patients with CD showed higher or lower spontaneous activity in multiple brain regions. Altered activities in these brain regions may collectively reflect abnormal function and regulation of visceral pain and sensation, external environmental monitoring, and cognitive processing in these patients. Lower functional connectivity of the hippocampus-limbic system was observed in these patients. These findings may provide more information to elucidate the neurobiological mechanisms of the disease.

PMID: 29464530 [PubMed - as supplied by publisher]

Amygdala hyper-connectivity in a mouse model of unpredictable early life stress.

Thu, 02/22/2018 - 18:40
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Amygdala hyper-connectivity in a mouse model of unpredictable early life stress.

Transl Psychiatry. 2018 Feb 21;8(1):49

Authors: Johnson FK, Delpech JC, Thompson GJ, Wei L, Hao J, Herman P, Hyder F, Kaffman A

Abstract
Childhood maltreatment is associated with a wide range of psychopathologies including anxiety that emerge in childhood and in many cases persist in adulthood. Increased amygdala activation in response to threat and abnormal amygdala connectivity with frontolimbic brain regions, such as the hippocampus and the prefrontal cortex, are some of the most consistent findings seen in individuals exposed to childhood maltreatment. The underlying mechanisms responsible for these changes are difficult to study in humans but can be elucidated using animal models of early-life stress. Such studies are especially powerful in the mouse where precise control of the genetic background and the stress paradigm can be coupled with resting-state fMRI (rsfMRI) to map abnormal connectivity in circuits that regulate anxiety. To address this issue we first compared the effects of two models of early-life stress, limited bedding (LB) and unpredictable postnatal stress (UPS), on anxiety-like behavior in juvenile and adult mice. We found that UPS, but not LB, causes a robust increase in anxiety in juvenile and adult male mice. Next, we used rsfMRI to compare frontolimbic connectivity in control and UPS adult male mice. We found increased amygdala-prefrontal cortex and amygdala-hippocampus connectivity in UPS. The strength of the amygdala-hippocampal and amygdala-prefrontal cortex connectivity was highly correlated with anxiety-like behavior in the open-field test and elevated plus maze. These findings are the first to link hyperconnectivity in frontolimbic circuits and increased anxiety in a mouse model of early-life stress, allowing for more mechanistic understanding of parallel findings in humans.

PMID: 29463821 [PubMed - in process]

Scholastic performance and functional connectivity of brain networks in children.

Thu, 02/22/2018 - 18:40
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Scholastic performance and functional connectivity of brain networks in children.

PLoS One. 2018;13(1):e0190073

Authors: Chaddock-Heyman L, Weng TB, Kienzler C, Erickson KI, Voss MW, Drollette ES, Raine LB, Kao SC, Hillman CH, Kramer AF

Abstract
One of the keys to understanding scholastic success is to determine the neural processes involved in school performance. The present study is the first to use a whole-brain connectivity approach to explore whether functional connectivity of resting state brain networks is associated with scholastic performance in seventy-four 7- to 9-year-old children. We demonstrate that children with higher scholastic performance across reading, math and language have more integrated and interconnected resting state networks, specifically the default mode network, salience network, and frontoparietal network. To add specificity, core regions of the dorsal attention and visual networks did not relate to scholastic performance. The results extend the cognitive role of brain networks in children as well as suggest the importance of network connectivity in scholastic success.

PMID: 29364911 [PubMed - indexed for MEDLINE]

The Effects of Gene Mutations on Default Mode Network in Familial Alzheimer's Disease.

Thu, 02/22/2018 - 18:40
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The Effects of Gene Mutations on Default Mode Network in Familial Alzheimer's Disease.

J Alzheimers Dis. 2017;56(1):327-334

Authors: Li X, Westman E, Thordardottir S, Ståhlbom AK, Almkvist O, Blennow K, Wahlund LO, Graff C

Abstract
Familial Alzheimer's disease (FAD) mutations have very high penetrance but age at onset and rate of disease progression differ. Neuroimaging and cerebrospinal fluid (CSF) examinations in mutation carriers (MCs) may provide an opportunity to identify early biomarkers that can be used to track disease progression from presymptomatic to the dementia stages of disease. The default mode network (DMN) is a resting state neuronal network composed of regions known to associate with amyloid deposition in AD. We hypothesized that functional connectivity in the DMN might change at pre-clinical stages in FAD MCs and correlate with changes in CSF biomarkers as a consequence of AD brain pathology. To test the hypothesis, we compared the functional connectivity in DMN between pre-MCs/MCs and non-carriers (NCs). No significant differences between pre-MCs and NCs were observed. When comparing all MCs with NCs, significant decreased functional connectivity in the right inferior parietal lobule, right precuneus, and left posterior cingulate cortex were found. We also found statistically significant correlations between CSF amyloid-β 42 and tau protein levels and average Z-score, a resting-state functional MRI measurement reflecting the degree of the correlation between a given voxel's time courses and the time courses corresponding to DMN, from the region with statistical difference. The observed disruption of DMN and pathological levels of AD CSF-biomarkers in FAD MCs are similar to the changes described in sporadic AD, which give further support that amyloid and tau pathology impairs neuronal and synaptic function.

PMID: 27911308 [PubMed - indexed for MEDLINE]

Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer's disease.

Wed, 02/21/2018 - 17:40

Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer's disease.

Brain. 2018 Feb 15;:

Authors: Franzmeier N, Düzel E, Jessen F, Buerger K, Levin J, Duering M, Dichgans M, Haass C, Suárez-Calvet M, Fagan AM, Paumier K, Benzinger T, Masters CL, Morris JC, Perneczky R, Janowitz D, Catak C, Wolfsgruber S, Wagner M, Teipel S, Kilimann I, Ramirez A, Rossor M, Jucker M, Chhatwal J, Spottke A, Boecker H, Brosseron F, Falkai P, Fliessbach K, Heneka MT, Laske C, Nestor P, Peters O, Fuentes M, Menne F, Priller J, Spruth EJ, Franke C, Schneider A, Kofler B, Westerteicher C, Speck O, Wiltfang J, Bartels C, Araque Caballero MÁ, Metzger C, Bittner D, Weiner M, Lee JH, Salloway S, Danek A, Goate A, Schofield PR, Bateman RJ, Ewers M

Abstract
Patients with Alzheimer's disease vary in their ability to sustain cognitive abilities in the presence of brain pathology. A major open question is which brain mechanisms may support higher reserve capacity, i.e. relatively high cognitive performance at a given level of Alzheimer's pathology. Higher functional MRI-assessed functional connectivity of a hub in the left frontal cortex is a core candidate brain mechanism underlying reserve as it is associated with education (i.e. a protective factor often associated with higher reserve) and attenuated cognitive impairment in prodromal Alzheimer's disease. However, no study has yet assessed whether such hub connectivity of the left frontal cortex supports reserve throughout the evolution of pathological brain changes in Alzheimer's disease, including the presymptomatic stage when cognitive decline is subtle. To address this research gap, we obtained cross-sectional resting state functional MRI in 74 participants with autosomal dominant Alzheimer's disease, 55 controls from the Dominantly Inherited Alzheimer's Network and 75 amyloid-positive elderly participants, as well as 41 amyloid-negative cognitively normal elderly subjects from the German Center of Neurodegenerative Diseases multicentre study on biomarkers in sporadic Alzheimer's disease. For each participant, global left frontal cortex connectivity was computed as the average resting state functional connectivity between the left frontal cortex (seed) and each voxel in the grey matter. As a marker of disease stage, we applied estimated years from symptom onset in autosomal dominantly inherited Alzheimer's disease and cerebrospinal fluid tau levels in sporadic Alzheimer's disease cases. In both autosomal dominant and sporadic Alzheimer's disease patients, higher levels of left frontal cortex connectivity were correlated with greater education. For autosomal dominant Alzheimer's disease, a significant left frontal cortex connectivity × estimated years of onset interaction was found, indicating slower decline of memory and global cognition at higher levels of connectivity. Similarly, in sporadic amyloid-positive elderly subjects, the effect of tau on cognition was attenuated at higher levels of left frontal cortex connectivity. Polynomial regression analysis showed that the trajectory of cognitive decline was shifted towards a later stage of Alzheimer's disease in patients with higher levels of left frontal cortex connectivity. Together, our findings suggest that higher resilience against the development of cognitive impairment throughout the early stages of Alzheimer's disease is at least partially attributable to higher left frontal cortex-hub connectivity.

PMID: 29462334 [PubMed - as supplied by publisher]

Longitudinal Associations Between Family Aggression, Externalizing Behavior, and the Structure and Function of the Amygdala.

Wed, 02/21/2018 - 17:40
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Longitudinal Associations Between Family Aggression, Externalizing Behavior, and the Structure and Function of the Amygdala.

J Res Adolesc. 2018 Mar;28(1):134-149

Authors: Saxbe D, Lyden H, Gimbel SI, Sachs M, Del Piero LB, Margolin G, Kaplan JT

Abstract
Using longitudinal data from 21 adolescents, we assessed family aggression (via mother, father, and youth report) in early adolescence, externalizing behavior in mid-adolescence, and magnetic resonance imaging (MRI) data in late adolescence. Amygdalae were manually traced, and used as seed regions for resting state analyses. Both family aggression and subsequent externalizing behavior predicted larger right amygdala volumes and stronger amygdala-frontolimbic/salience network connectivity and weaker amygdala-posterior cingulate connectivity. Externalizing behavior in mid-adolescence mediated associations between family aggression in early adolescence and resting state connectivity between the amygdala and the subgenual anterior cingulate cortex, medial prefrontal cortex, orbitofrontal cortex, and posterior cingulate cortex in late adolescence. Family adversity and adolescent behavior problems may share common neural correlates.

PMID: 29460354 [PubMed - in process]

Multimodal, noninvasive seizure network mapping software: A novel tool for preoperative epilepsy evaluation.

Wed, 02/21/2018 - 17:40
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Multimodal, noninvasive seizure network mapping software: A novel tool for preoperative epilepsy evaluation.

Epilepsy Behav. 2018 Feb 17;81:25-32

Authors: Neal EG, Maciver S, Vale FL

Abstract
BACKGROUND: Despite rigorous preoperative evaluation, epilepsy surgery achieves seizure freedom in only two-thirds of cases. Current preoperative evaluation does not include a detailed network analysis despite the association of network-level changes with epilepsy.
OBJECTIVE: We sought to create a software algorithm to map individualized epilepsy networks by combining noninvasive electroencephalography (EEG) source localization and nonconcurrent resting state functional magnetic resonance imaging (rsfMRI).
METHODS: Scalp EEG and rsfMRI data were acquired for three sample cases: one healthy control case, one case of right temporal lobe epilepsy, and one case of bitemporal seizure onset. Data from rsfMRI were preprocessed, and a time-series function was extracted. Connection coefficients were used to threshold out spurious connections and model global functional networks in a 3D map. Epileptic discharges were localized using a forward model of cortical mesh dipoles followed by an empirical Bayesian approach of inverse source reconstruction and co-registered with rsfMRI. Co-activating brain regions were mapped.
RESULTS: Three illustrative sample cases are presented. In the healthy control case, the software showed symmetrical global connectivity. In the right temporal lobe epilepsy case, asymmetry was found in the global connectivity metrics with a paucity of connectivity ipsilateral to the epileptogenic cortex. The superior longitudinal fasciculus, uncinate fasciculus, and commissural fibers connecting disparate and discontinuous cortical regions involved in the epilepsy network were visualized. In the case with bitemporal lobe epilepsy, global connectivity was symmetric. It showed a network of correlating cortical activity local to epileptogenic tissue in both temporal lobes. The network involved white matter tracks in a similar pattern to those seen in the right temporal case.
CONCLUSIONS: This modeling algorithm allows better definition of the global brain network and potentially demonstrates differences in connectivity between an epileptic and a non-epileptic brain. This finding may be useful for mapping cortico-cortical connections representing the putative epilepsy networks. With this methodology, we localized the epileptogenic brain and showed network asymmetry and long-distance cortical co-activation. This software tool is the first to use a multimodal, nonconcurrent, and noninvasive approach to model and visualize the epilepsy network.

PMID: 29459252 [PubMed - as supplied by publisher]

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