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Altered functional connectivity in the fear network of firefighters with repeated traumatic stress.

Wed, 11/28/2018 - 13:20
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Altered functional connectivity in the fear network of firefighters with repeated traumatic stress.

Br J Psychiatry. 2018 Nov 27;:1-7

Authors: Jeong H, Park S, Dager SR, Lim SM, Lee SL, Hong H, Ma J, Ha E, Hong YS, Kang I, Lee EH, Yoon S, Kim JE, Kim J, Lyoo IK

Abstract
BACKGROUND: Firefighters are routinely exposed to various traumatic events and often experience a range of trauma-related symptoms. Although these repeated traumatic exposures rarely progress to the development of post-traumatic stress disorder, firefighters are still considered to be a vulnerable population with regard to trauma.AimsTo investigate how the human brain responds to or compensates for the repeated experience of traumatic stress.
METHOD: We included 98 healthy firefighters with repeated traumatic experiences but without any diagnosis of mental illness and 98 non-firefighter healthy individuals without any history of trauma. Functional connectivity within the fear circuitry, which consists of the dorsal anterior cingulate cortex, insula, amygdala, hippocampus and ventromedial prefrontal cortex (vmPFC), was examined using resting-state functional magnetic resonance imaging. Trauma-related symptoms were evaluated using the Impact of Event Scale - Revised.
RESULTS: The firefighter group had greater functional connectivity between the insula and several regions of the fear circuitry including the bilateral amygdalae, bilateral hippocampi and vmPFC as compared with healthy individuals. In the firefighter group, stronger insula-amygdala connectivity was associated with greater severity of trauma-related symptoms (β = 0.36, P = 0.005), whereas higher insula-vmPFC connectivity was related to milder symptoms in response to repeated trauma (β = -0.28, P = 0.01).
CONCLUSIONS: The current findings suggest an active involvement of insular functional connectivity in response to repeated traumatic stress. Functional connectivity of the insula in relation to the amygdala and vmPFC may be potential pathways that underlie the risk for and resilience to repeated traumatic stress, respectively.Declaration of interestNone.

PMID: 30477594 [PubMed - as supplied by publisher]

Abnormal resting state activity of left middle occipital gyrus and its functional connectivity in female patients with major depressive disorder.

Wed, 11/28/2018 - 13:20
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Abnormal resting state activity of left middle occipital gyrus and its functional connectivity in female patients with major depressive disorder.

BMC Psychiatry. 2018 Nov 26;18(1):370

Authors: Teng C, Zhou J, Ma H, Tan Y, Wu X, Guan C, Qiao H, Li J, Zhong Y, Wang C, Zhang N

Abstract
BACKGROUND: Women are more susceptible to major depressive disorder (MDD). A possible explanation is that women have a trait tendency to engage in a ruminative response style. Depending on cognitive model of depression, attention bias, memory bias and self-referential bias were closely related among depressed patients. Previous studies have explored the neural mechanism of the cognitive biases by using amplitude of low frequency fluctuations (ALFF) or functional connectivity (FC), and few combined these two metrics, especially focusing on female patients.
METHODS: We assessed 25 female patients diagnosed with MDD and 13 well matched healthy controls (HCs) using Rs-fMRI. Two metrics ALFF and FC based on abnormal ALFF were explored and made comparisons.
RESULTS: Compared with HCs, female patients with MDD showed that one cluster with significantly decreased ALFF in the left middle occipital gyrus(L-MOG). Furtherly we founded depressed female subjects showed significantly lower FC between the L-MOG seed and left orbitofrontal cortex, and significantly higher FC between the L-MOG seed and left medial prefrontal gyrus and left hippocampus.
CONCLUSIONS: Our results showed L-MOG may act as a connection, which involved in the processing of cognitive biases of MDD by connected with limbic-cortical regions in resting state. These findings may enhance the understanding of the neurobiological mechanism in female patients with MDD.

PMID: 30477561 [PubMed - in process]

Training effects of Interactive Metronome® on golf performance and brain activity in professional woman golf players.

Wed, 11/28/2018 - 13:20
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Training effects of Interactive Metronome® on golf performance and brain activity in professional woman golf players.

Hum Mov Sci. 2018 Oct;61:63-71

Authors: Kim JH, Han JK, Han DH

Abstract
During putting in golf, the direction and velocity of the club head should be consistent across swings. In order to maintain consistency in swing timing, the cerebellum provides temporal information, motor timing, control of rhythm, and timing of movements. We utilized Interactive Metronome (IM), a brain training software program that combines the concepts of neurotechnology with the abilities of a computer, to improve an individual's rhythm and timing. We propose that IM would activate neural networks involved in decreasing variation in putt swing. Twenty professional female golfers (KLPGA) were randomly assigned to either an IM training group (n = 10, 35-40 min per session, twice a week for 6 weeks) or a control group (n = 10). The golf putting movements and brain activity were analyzed using Kinovea Software and resting state functional MRI, respectively. Consistency was measured as the standard deviation of mean swing speed (SSD) during three sections of the swing: backswing (AD-BS), backswing-impact (BS-IMP), and impact-finish (IMP-FIS). Our results show that the consistency of the IM group improved in the time between the back swing and impact in the 2 m putt and 5 m putt compared to the control group. Using functional MRI, after the training period, the IM group showed increased functional connectivity from the superior cerebellar vermis to the right medial frontal gyrus, left superior temporal gyrus, right middle occipital gyrus, right middle temporal gyrus, right cingulate gyrus, and right supramarginal gyrus (uncorrected p < 0.001, voxels > 40). These findings suggest that IM training in professional female golf players may improve consistency in putt timing. In addition, IM training may increase brain connectivity from the cerebellum to the frontal cortex, which plays an important role in motor control and timing.

PMID: 30029204 [PubMed - indexed for MEDLINE]

Sleep quality and adolescent default mode network connectivity.

Wed, 11/28/2018 - 13:20
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Sleep quality and adolescent default mode network connectivity.

Soc Cogn Affect Neurosci. 2018 03 01;13(3):290-299

Authors: Tashjian SM, Goldenberg D, Monti MM, Galván A

Abstract
Sleep suffers during adolescence and is related to academic, emotional and social behaviors. How this normative change relates to ongoing brain development remains unresolved. The default mode network (DMN), a large-scale brain network important for complex cognition and socioemotional processing, undergoes intra-network integration and inter-network segregation during adolescence. Using resting state functional connectivity and actigraphy over 14 days, we examined correlates of naturalistic individual differences in sleep duration and quality in the DMN at rest in 45 human adolescents (ages 14-18). Variation in sleep quality, but not duration, was related to weaker intrinsic DMN connectivity, such that those with worse quality sleep evinced weaker intra-network connectivity at rest. These novel findings suggest sleep quality, a relatively unexplored sleep index, is related to adolescent brain function in a network that contributes to behavioral maturation and undergoes development during adolescence.

PMID: 29432569 [PubMed - indexed for MEDLINE]

Amygdala-orbitofrontal structural and functional connectivity in females with anxiety disorders, with and without a history of conduct disorder.

Wed, 11/28/2018 - 13:20
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Amygdala-orbitofrontal structural and functional connectivity in females with anxiety disorders, with and without a history of conduct disorder.

Sci Rep. 2018 01 18;8(1):1101

Authors: Lindner P, Flodin P, Larm P, Budhiraja M, Savic-Berglund I, Jokinen J, Tiihonen J, Hodgins S

Abstract
Conduct disorder (CD) and anxiety disorders (ADs) are often comorbid and both are characterized by hyper-sensitivity to threat, and reduced structural and functional connectivity between the amygdala and orbitofrontal cortex (OFC). Previous studies of CD have not taken account of ADs nor directly compared connectivity in the two disorders. We examined three groups of young women: 23 presenting CD and lifetime AD; 30 presenting lifetime AD and not CD; and 17 with neither disorder (ND). Participants completed clinical assessments and diffusion-weighted and resting-state functional MRI scans. The uncinate fasciculus was reconstructed using tractography and manual dissection, and structural measures extracted. Correlations of resting-state activity between amygdala and OFC seeds were computed. The CD + AD and AD groups showed similarly reduced structural integrity of the left uncinate compared to ND, even after adjusting for IQ, psychiatric comorbidity, and childhood maltreatment. Uncinate integrity was associated with harm avoidance traits among AD-only women, and with the interaction of poor anger control and anxiety symptoms among CD + AD women. Groups did not differ in functional connectivity. Reduced uncinate integrity observed in CD + AD and AD-only women may reflect deficient emotion regulation in response to threat, common to both disorders, while other neural mechanisms determine the behavioral response.

PMID: 29348532 [PubMed - indexed for MEDLINE]

Towards a Complete Taxonomy of Resting State Networks Across Wakefulness and Sleep: An Assessment of Spatially Distinct Resting State Networks Using Independent Component Analysis.

Tue, 11/27/2018 - 12:00

Towards a Complete Taxonomy of Resting State Networks Across Wakefulness and Sleep: An Assessment of Spatially Distinct Resting State Networks Using Independent Component Analysis.

Sleep. 2018 Nov 26;:

Authors: Houldin E, Fang Z, Ray LB, Owen AM, Fogel SM

Abstract
Resting state network (RSN) functional connectivity (FC) has been investigated under a wealth of different healthy and compromised conditions. However such investigations are often dependent on the defined spatial boundaries and nodes of so-called canonical RSNs, themselves the product of extensive deliberations over distinctions between functional magnetic resonance imaging (fMRI) noise and neural signal, specifically in the context of the healthy waking state. However, a similar unbiased cataloguing of noise and networks remains to be done in other states, particularly sleep, a healthy alternate mode of the brain that supports distinct operations from wakefulness, such as dreaming and memory consolidation. The purpose of this study was to explicitly test the hypothesis that there are RSNs unique to sleep. Simultaneous electroencephalography (EEG) and fMRI was used to record brain activity of non-sleep-deprived subjects. Independent component analysis (ICA) was performed on both rapid eye movement (REM; N = 7) and non-REM sleep stage fMRI data (non-REM2; N = 28, non-REM3; N = 11), with the resulting components spatially correlated with the canonical RSNs, for the purpose of identifying spatially distinct RSNs. Surprisingly, all low-correlation components were positively identified as noise, and all high-correlation components comprised the canonical set of RSNs typically observed in wake, indicating that sleep is supported by much the same RSN architecture as wakefulness, despite the unique operations performed during sleep. This further indicates that the implicit assumptions of prior studies, i.e., that the canonical RSNs apply to sleep FC analysis, are valid and have not overlooked sleep-specific RSNs.

PMID: 30476346 [PubMed - as supplied by publisher]

MRI-related anxiety in healthy individuals, intrinsic BOLD oscillations at 0.1 Hz in precentral gyrus and insula, and heart rate variability in low frequency bands.

Tue, 11/27/2018 - 12:00

MRI-related anxiety in healthy individuals, intrinsic BOLD oscillations at 0.1 Hz in precentral gyrus and insula, and heart rate variability in low frequency bands.

PLoS One. 2018;13(11):e0206675

Authors: Pfurtscheller G, Schwerdtfeger A, Fink D, Brunner C, Aigner CS, Brito J, Andrade A

Abstract
Participation in magnetic resonance imaging (MRI) scanning is associated with increased anxiety, thus possibly impacting baseline recording for functional MRI studies. The goal of the paper is to elucidate the significant hemispheric asymmetry between blood-oxygenation-level-dependent (BOLD) signals from precentral gyrus (PCG) and insula in 23 healthy individuals without any former MRI experience recently published in a PLOSONE paper. In addition to BOLD signals state anxiety and heart rate variability (HRV) were analyzed in two resting state sessions (R1, R2). Phase-locking and time delays from BOLD signals were computed in the frequency band 0.07-0.13 Hz. Positive (pTD) and negative time delays (nTD) were found. The pTD characterize descending neural BOLD oscillations spreading from PCG to insula and nTD characterize ascending vascular BOLD oscillations related to blood flow in the middle cerebral artery. HRV power in two low frequency bands 0.06-0.1 Hz and 0.1-0.14 Hz was computed. Based on the anxiety change from R1 to R2, two groups were separated: one with a strong anxiety decline (large change group) and one with a moderate decline or even anxiety increase (small change group). A significant correlation was found only between the left-hemispheric time delay (pTD, nTD) and anxiety change, with a dominance of nTD in the large change group. The analysis of within-scanner HRV revealed a pronounced increase of low frequency power between both resting states, dominant in the band 0.06-0.1 Hz in the large change group and in the band 0.1-0.14 Hz in the small change group. These results suggest different mechanisms related to anxiety processing in healthy individuals. One mechanism (large anxiety change) could embrace an increase of blood circulation in the territory of the left middle cerebral artery (vascular BOLD) and another (small anxiety change) translates to rhythmic central commands (neural BOLD) in the frequency band 0.1-0.14 Hz.

PMID: 30475859 [PubMed - in process]

Aberrant functional connectivity of neural circuits associated with social and sensorimotor deficits in young children with autism spectrum disorder.

Tue, 11/27/2018 - 12:00

Aberrant functional connectivity of neural circuits associated with social and sensorimotor deficits in young children with autism spectrum disorder.

Autism Res. 2018 Nov 26;:

Authors: Chen H, Wang J, Uddin LQ, Wang X, Guo X, Lu F, Duan X, Wu L, Chen H

Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by atypical functional integration of brain regions. The vast majority of neuroimaging studies of ASD have focused on older children, adolescents, and adults with the disorder. Very little work has explored whole-brain functional connectivity of young children with ASD. Here, we collected resting-state functional magnetic resonance imaging data from 58 young children (mean age 4.98 years; 29 with ASD; 29 matched healthy controls [HC]). All children were under sedation during scanning. A functional "connectedness" method was first used to seek for brain regions showing atypical functional connectivity (FC) in children with ASD. Then, a recurrent-seek strategy was applied to reveal atypical FC circuits in ASD children. FC matrices between regions-of-interest (ROIs) were compared between ASD and HC. Finally, a support vector regression (SVR) method was used to assess the relationship between the FC circuits and ASD symptom severity. Two atypical FC circuits comprising 23 ROIs in ASD were revealed: one predominantly comprised brain regions involved with social cognition showing under-connectivity in ASD; the other predominantly comprised sensory-motor and visual brain regions showing over-connectivity in ASD. The SVR analysis showed that the two FC circuits were separately related to social deficits and restricted behavior scores. These findings indicate disrupted FC of neural circuits involved in the social and sensorimotor processes in young children with ASD. The finding of the atypical FC patterns in young children with ASD underscores the utility of studying younger children with the disorder, and highlights nuanced patterns of brain connectivity underlying behavior closer to disorder onset. Autism Res 2018. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder. Understanding brain functional alterations at early ages is important for understanding biological mechanisms of ASD. Here, we found two atypical brain functional circuits in young children with ASD that were related to social and sensorimotor function. These results show how atypical patterns of brain functional connectivity in young children with of ASD may underlie core symptoms of the disorder.

PMID: 30475453 [PubMed - as supplied by publisher]

Resting-state brain activity in Chinese boys with low functioning autism spectrum disorder.

Tue, 11/27/2018 - 12:00
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Resting-state brain activity in Chinese boys with low functioning autism spectrum disorder.

Ann Gen Psychiatry. 2018;17:47

Authors: Li G, Rossbach K, Jiang W, Du Y

Abstract
Background: This study aimed to explore the resting-state fMRI changes in Chinese boys with low functioning autism spectrum disorder (LFASD) and the correlation with clinical symptoms.
Methods: The current study acquired resting-state fMRI data from 15 Chinese boys with LFASD and 15 typically developing (TD) boys to examine the local brain activity using the regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) indexes; the researchers also examined these measures and their possible relationships with clinical symptoms using the autism behavior checklist.
Results: Results indicated that boys with LFASD exhibited increased ReHo in the right precuneus and inferior parietal gyrus (IPG), increased ALFF in right middle temporal gyrus, angular gyrus and IPG. However, no correlation was found between the ALFF/ReHo score and clinical symptoms in the LFASD group.
Conclusions: Some of the brain regions had ReHo/ALFF values that were higher in the boys with LFASD than the TD group and these differentiated brain areas in boys with LFASD were all on the right cerebrum, which supported 'atypical rightward asymmetry' in boys with LFASD.

PMID: 30473720 [PubMed]

Increased cognitive complexity reveals abnormal brain network activity in individuals with corpus callosum dysgenesis.

Tue, 11/27/2018 - 12:00
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Increased cognitive complexity reveals abnormal brain network activity in individuals with corpus callosum dysgenesis.

Neuroimage Clin. 2018 Nov 14;:

Authors: Hearne LJ, Dean RJ, Robinson GA, Richards LJ, Mattingley JB, Cocchi L

Abstract
Cognitive reasoning is thought to require functional interactions between whole-brain networks. Such networks rely on both cerebral hemispheres, with the corpus callosum providing cross-hemispheric communication. Here we used high-field functional magnetic resonance imaging (7 T fMRI), a well validated cognitive task, and brain network analyses to investigate the functional networks underlying cognitive reasoning in individuals with corpus callosum dysgenesis (CCD), an anatomical abnormality that affects the corpus callosum. Participants with CCD were asked to solve cognitive reasoning problems while their brain activity was measured using fMRI. The complexity of these problems was parametrically varied by changing the complexity of relations that needed to be established between shapes within each problem matrix. Behaviorally, participants showed a typical reduction in task performance as problem complexity increased. Task-evoked neural activity was observed in brain regions known to constitute two key cognitive control systems: the fronto-parietal and cingulo-opercular networks. Under low complexity demands, network topology and the patterns of local neural activity in the CCD group closely resembled those observed in neurotypical controls. By contrast, when asked to solve more complex problems, participants with CCD showed a reduction in neural activity and connectivity within the fronto-parietal network. These complexity-induced, as opposed to resting-state, differences in functional network activity help resolve the apparent paradox between preserved network architecture found at rest in CCD individuals, and the heterogeneous deficits they display in response to cognitive task demands [preprint: https://doi.org/10.1101/312629].

PMID: 30473430 [PubMed - as supplied by publisher]

Neuroimaging Applications in Tourette's Syndrome.

Tue, 11/27/2018 - 12:00
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Neuroimaging Applications in Tourette's Syndrome.

Int Rev Neurobiol. 2018;143:65-108

Authors: Martino D, Ganos C, Worbe Y

Abstract
Tics are neurodevelopmental hyperkinetic symptoms typically associated with unpleasant sensory experiences called premonitory urges. Tourette syndrome (TS) is the primary chronic tic disorder for which medical surveillance is most frequently required, and is associated with a complex phenotypical spectrum encompassing different types of abnormal behaviors. Animal models of tics support their link to phasic activity changes throughout the sensorimotor loop of the cortico-basal ganglia-thalamo-cortical network. Event-related functional magnetic resonance imaging (fMRI) studies on patients with TS showed that the supplementary motor area relays preparatory signals related to tics to the primary motor area and other cortical regions relevant to action monitoring, following which cortico-basal ganglia-thalamo-cortical activation leads to the manifestation of tics. Despite their methodological heterogeneity, structural MRI studies highlighted the existence of anatomical markers of distinct sub-phenotypes of the TS spectrum. Initial evidence suggests that combining MRI structural methods and functional intrinsic connectivity assessed during resting state could even discriminate between TS patients and control groups. MR-spectroscopy and positron emission tomography studies suggest that TS may be related to a complex interplay between different neurotransmitters (particularly dopamine, GABA and glutamate), but discrepancy across studies prevents firm conclusions. Recent volumetric, cortical thickness and fMRI studies results showed an association between premonitory urges and somatosensory and insular cortical regions, involved in the processing of interoceptive and enteroceptive stimuli and motor output modulation. Finally, both structural and functional MRI studies have provided important support to the subtyping of the TS spectrum with respect to behavioral co-morbidities, in line with a "dimensional approach" to the classification of neuropsychiatric disorders, which is based on the identification of neurocognitive endophenotypes and of their anatomical substrate.

PMID: 30473198 [PubMed - in process]

Spatial and Temporal Organization of the Individual Human Cerebellum.

Tue, 11/27/2018 - 12:00
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Spatial and Temporal Organization of the Individual Human Cerebellum.

Neuron. 2018 Nov 21;100(4):977-993.e7

Authors: Marek S, Siegel JS, Gordon EM, Raut RV, Gratton C, Newbold DJ, Ortega M, Laumann TO, Adeyemo B, Miller DB, Zheng A, Lopez KC, Berg JJ, Coalson RS, Nguyen AL, Dierker D, Van AN, Hoyt CR, McDermott KB, Norris SA, Shimony JS, Snyder AZ, Nelson SM, Barch DM, Schlaggar BL, Raichle ME, Petersen SE, Greene DJ, Dosenbach NUF

Abstract
The cerebellum contains the majority of neurons in the human brain and is unique for its uniform cytoarchitecture, absence of aerobic glycolysis, and role in adaptive plasticity. Despite anatomical and physiological differences between the cerebellum and cerebral cortex, group-average functional connectivity studies have identified networks related to specific functions in both structures. Recently, precision functional mapping of individuals revealed that functional networks in the cerebral cortex exhibit measurable individual specificity. Using the highly sampled Midnight Scan Club (MSC) dataset, we found the cerebellum contains reliable, individual-specific network organization that is significantly more variable than the cerebral cortex. The frontoparietal network, thought to support adaptive control, was the only network overrepresented in the cerebellum compared to the cerebral cortex (2.3-fold). Temporally, all cerebellar resting state signals lagged behind the cerebral cortex (125-380 ms), supporting the hypothesis that the cerebellum engages in a domain-general function in the adaptive control of all cortical processes.

PMID: 30473014 [PubMed - in process]

The instability of functional connectivity in patients with schizophrenia and their siblings: A dynamic connectivity study.

Tue, 11/27/2018 - 12:00
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The instability of functional connectivity in patients with schizophrenia and their siblings: A dynamic connectivity study.

Schizophr Res. 2018 05;195:183-189

Authors: Guo S, Zhao W, Tao H, Liu Z, Palaniyappan L

Abstract
BACKGROUND: The distributed connectivity among brain regions is in a constant state of flux, even when a subject is at rest. This instability (temporal variability), when optimal, may contribute to efficient cross-network communications. We investigate the role of this variability in the genetic diathesis and symptom expression of schizophrenia.
METHODS: Resting state functional MRI data acquired from 116 subjects (28 patients with schizophrenia, 28 siblings and 60 matched healthy controls). Using a sliding-window dynamic connectivity approach, we quantified the variability of whole-brain connectivity (dynamic functional connectivity or dFC) of each of the 90 brain regions obtained using a parcellation scheme that covered all contiguous brain regions of the cerebral cortex.
RESULTS: We noted a high degree of instability anchored on the precuneus in patients with schizophrenia compared to both healthy controls (t=3.60, p=0.0005) and unaffected siblings (t=3.61, p=0.001) indicating a role for dFC of precuneus in the clinical expression of schizophrenia. Compared to patients, siblings also showed an increase in medial orbitofrontal but reduced putaminal instability; these latter changes were not seen in patients when compared to controls, indicating a lack of specificity for diathesis or expression related effects.
CONCLUSIONS: Instability in the intrinsic connectivity of precuneus, a functional core hub with a major role in task-free self-processing, is likely to be a core substrate of the clinical expression of schizophrenia.

PMID: 29153446 [PubMed - indexed for MEDLINE]

Visual deprivation selectively reshapes the intrinsic functional architecture of the anterior insula subregions.

Tue, 11/27/2018 - 12:00
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Visual deprivation selectively reshapes the intrinsic functional architecture of the anterior insula subregions.

Sci Rep. 2017 03 30;7:45675

Authors: Liu L, Yuan C, Ding H, Xu Y, Long M, Li Y, Liu Y, Jiang T, Qin W, Shen W, Yu C

Abstract
The anterior insula (AI) is the core hub of salience network that serves to identify the most relevant stimuli among vast sensory inputs and forward them to higher cognitive regions to guide behaviour. As blind subjects were usually reported with changed perceptive abilities for salient non-visual stimuli, we hypothesized that the resting-state functional network of the AI is selectively reorganized after visual deprivation. The resting-state functional connectivity (FC) of the bilateral dorsal and ventral AI was calculated for twenty congenitally blind (CB), 27 early blind (EB), 44 late blind (LB) individuals and 50 sighted controls (SCs). The FCs of the dorsal AI were strengthened with the dorsal visual stream, while weakened with the ventral visual stream in the blind than the SCs; in contrast, the FCs of the ventral AI of the blind was strengthened with the ventral visual stream. Furthermore, these strengthened FCs of both the dorsal and ventral AI were partially negatively associated with the onset age of blindness. Our result indicates two parallel pathways that selectively transfer non-visual salient information between the deprived "visual" cortex and salience network in blind subjects.

PMID: 28358391 [PubMed - indexed for MEDLINE]

Resting state functional connectivity patterns associated with pharmacological treatment resistance in temporal lobe epilepsy.

Mon, 11/26/2018 - 11:20

Resting state functional connectivity patterns associated with pharmacological treatment resistance in temporal lobe epilepsy.

Epilepsy Res. 2018 Nov 17;149:37-43

Authors: Pressl C, Brandner P, Schaffelhofer S, Blackmon K, Dugan P, Holmes M, Thesen T, Kuzniecky R, Devinsky O, Freiwald WA

Abstract
There are no functional imaging based biomarkers for pharmacological treatment response in temporal lobe epilepsy (TLE). In this study, we investigated whether there is an association between resting state functional brain connectivity (RsFC) and seizure control in TLE. We screened a large database containing resting state functional magnetic resonance imaging (Rs-fMRI) data from 286 epilepsy patients. Patient medical records were screened for seizure characterization, EEG reports for lateralization and location of seizure foci to establish uniformity of seizure localization within patient groups. Rs-fMRI data from patients with well-controlled left TLE, patients with treatment-resistant left TLE, and healthy controls were analyzed. Healthy controls and cTLE showed similar functional connectivity patterns, whereas trTLE exhibited a significant bilateral decrease in thalamo-hippocampal functional connectivity. This work is the first to demonstrate differences in neural network connectivity between well-controlled and treatment-resistant TLE. These differences are spatially highly focused and suggest sites for the etiology and possibly treatment of TLE. Altered thalamo-hippocampal RsFC thus is a potential new biomarker for TLE treatment resistance.

PMID: 30472489 [PubMed - as supplied by publisher]

Age-related differences in default-mode network connectivity in response to intermittent theta-burst stimulation and its relationships with maintained cognition and brain integrity in healthy aging.

Mon, 11/26/2018 - 11:20

Age-related differences in default-mode network connectivity in response to intermittent theta-burst stimulation and its relationships with maintained cognition and brain integrity in healthy aging.

Neuroimage. 2018 Nov 22;:

Authors: Abellaneda-Pérez K, Vaqué-Alcázar L, Vidal-Piñeiro D, Jannati A, Solana E, Bargalló N, Santarnecchi E, Pascual-Leone A, Bartrés-Faz D

Abstract
The default-mode network (DMN) is affected by advancing age, where particularly long-range connectivity has been consistently reported to be reduced as compared to young individuals. We examined whether there were any differences in the effects of intermittent theta-burst stimulation (iTBS) in DMN connectivity between younger and older adults, its associations with cognition and brain integrity, as well as with long-term cognitive status. Twenty-four younger and 27 cognitively normal older adults were randomly assigned to receive real or sham iTBS over the left inferior parietal lobule between two resting-state functional magnetic resonance imaging (rs-fMRI) acquisitions. Three years later, those older adults who had received real iTBS underwent a cognitive follow-up assessment. Among the younger adults, functional connectivity increased following iTBS in distal DMN areas from the stimulation site. In contrast, older adults exhibited increases in connectivity following iTBS in proximal DMN regions. Moreover, older adults with functional responses to iTBS resembling those of the younger participants exhibited greater brain integrity and higher cognitive performance at baseline and at the 3-year follow-up, along with less cognitive decline. Finally, we observed that 'young-like' functional responses to iTBS were also related to the educational background attained amongst older adults. The present study reveals that functional responses of the DMN to iTBS are modulated by age. Furthermore, combining iTBS and rs-fMRI in older adults may allow characterizing distinctive cognitive profiles in aging and its progression, probably reflecting network plasticity systems that may entail a neurobiological substrate of cognitive reserve.

PMID: 30472372 [PubMed - as supplied by publisher]

Interactions between gut permeability and brain structure and function in health and irritable bowel syndrome.

Mon, 11/26/2018 - 11:20

Interactions between gut permeability and brain structure and function in health and irritable bowel syndrome.

Neuroimage Clin. 2018 Nov 17;:

Authors: Witt ST, Bednarska O, Keita ÅV, Icenhour A, Jones MP, Elsenbruch S, Söderholm JD, Engström M, Mayer EA, Walter S

Abstract
Changes in brain-gut interactions have been implicated in the pathophysiology of chronic visceral pain in irritable bowel syndrome (IBS). Different mechanisms of sensitization of visceral afferent pathways may contribute to the chronic visceral pain reports and associated brain changes that characterize IBS. They include increased gut permeability and gut associated immune system activation, and an imbalance in descending pain inhibitory and facilitatory mechanisms. In order to study the involvement of these mechanisms, correlations between gut epithelial permeability and live bacterial passage, and structural and functional brain connectivity were measured in women with moderate-to-severe IBS and healthy women. The relationships between gut permeability and functional and anatomical connectivity were significantly altered in IBS compared with the healthy women. IBS participants with lower epithelial permeability reported increased IBS symptoms, which was associated with increased functional and structural connectivity in endogenous pain facilitation regions. The findings suggest that relationships between gut permeability and the brain are significantly altered in IBS and suggest the existence of IBS subtypes based on these interactions.

PMID: 30472166 [PubMed - as supplied by publisher]

Prism adaptation changes resting-state functional connectivity in the dorsal stream of visual attention networks in healthy adults: A fMRI study.

Mon, 11/26/2018 - 11:20

Prism adaptation changes resting-state functional connectivity in the dorsal stream of visual attention networks in healthy adults: A fMRI study.

Cortex. 2018 Oct 31;:

Authors: Tsujimoto K, Mizuno K, Nishida D, Tahara M, Yamada E, Shindo S, Kasuga S, Liu M

Abstract
Unilateral spatial neglect (USN) can be defined as a failure to orient to contra-lesional stimuli in the absence of either sensory or motor defects. Although the behavioral and clinical effects of prism adaptation (PA) are widely accepted, its underlying mechanisms are still controversial. However, recent neuroimaging and neurophysiological studies support the idea that PA affects the visual attention and sensorimotor networks including in the parietal cortex and cerebellum. We investigate the effect of PA on functional connectivity (FC) in attention and sensorimotor networks, evaluating changes of resting-state FC before and after PA in healthy individuals using functional magnetic resonance imaging (fMRI). MR sessions were conducted before PA, after PA (Post1), and 1 h after PA (Post2). The FC between the right frontal eye (FEF) field and the right intraparietal sulcus was significantly decreased at Post1 and that between the right FEF and the right anterior cingulate cortex was significantly increased after PA and recovered within 1 h. This is the first study to demonstrate transient changes of resting-state FC in the right dorsal attention network (DAN) by PA in healthy adults using fMRI. These results will contribute to the elucidation of the underling mechanism of PA therapy and to devising new therapies for USN and/or other higher cortical dysfunctions.

PMID: 30471844 [PubMed - as supplied by publisher]

Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

Mon, 11/26/2018 - 11:20

Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

Prog Brain Res. 2018;242:159-177

Authors: Müller F, Liechti ME, Lang UE, Borgwardt S

Abstract
The effects of hallucinogenic drugs on the human brain have been studied since the earliest days of neuroimaging in the 1990s. However, approaches are often hard to compare and results are heterogeneous. In this chapter, we summarize studies investigating the effects of hallucinogens on the resting brain, with a special emphasis on replicability and limitations. In previous studies, similarities were observed between psilocybin, LSD, and ayahuasca, with respect to decreases in cerebral blood flow and increases in global functional connectivity in the precuneus and thalamus. Additionally, LSD consistently decreased functional connectivity within distinct resting state networks. Little convergence was observed for connectivity between networks and for blood flow in other brain regions. Although these studies are limited by small sample sizes and might be biased by unspecific drug effects on physiological parameters and the vascular system, current results indicate that neuroimaging could be a useful tool to elucidate the neuronal correlates of hallucinogenic effects.

PMID: 30471679 [PubMed - in process]

Amyloid beta-positive subjects exhibit longitudinal network-specific reductions in spontaneous brain activity.

Sun, 11/25/2018 - 16:20
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Amyloid beta-positive subjects exhibit longitudinal network-specific reductions in spontaneous brain activity.

Neurobiol Aging. 2018 Oct 11;74:191-201

Authors: Avants BB, Hutchison RM, Mikulskis A, Salinas-Valenzuela C, Hargreaves R, Beaver J, Chiao P, Alzheimer's Disease Neuroimaging Initiative

Abstract
Amyloid beta (Aβ) deposition and cognitive decline are key features of Alzheimer's disease. The relationship between Aβ status and changes in neuronal function over time, however, remains unclear. We evaluated the effect of baseline Aβ status on reference region spontaneous brain activity (SBA-rr) using resting-state functional magnetic resonance imaging and fluorodeoxyglucose positron emission tomography in patients with mild cognitive impairment. Patients (N = 62, [43 Aβ-positive]) from the Alzheimer's Disease Neuroimaging Initiative were divided into Aβ-positive and Aβ-negative groups via prespecified cerebrospinal fluid Aβ42 or 18F-florbetapir positron emission tomography standardized uptake value ratio cutoffs measured at baseline. We analyzed interaction of biomarker-confirmed Aβ status with SBA-rr change over a 2-year period using mixed-effects modeling. SBA-rr differences between Aβ-positive and Aβ-negative subjects increased significantly over time within subsystems of the default and visual networks. Changes exhibit an interaction with memory performance over time but were independent of glucose metabolism. Results reinforce the value of resting-state functional magnetic resonance imaging in evaluating Alzheimer''s disease progression and suggest spontaneous neuronal activity changes are concomitant with cognitive decline.

PMID: 30471630 [PubMed - as supplied by publisher]

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