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Patterns of Cerebellar Connectivity with Intrinsic Connectivity Networks in Autism Spectrum Disorders.

Sat, 01/11/2020 - 12:20
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Patterns of Cerebellar Connectivity with Intrinsic Connectivity Networks in Autism Spectrum Disorders.

J Autism Dev Disord. 2019 Nov;49(11):4498-4514

Authors: Bednarz HM, Kana RK

Abstract
There is growing evidence of altered connectivity in autism spectrum disorders (ASD) between the cerebellum and cortex. Three intrinsic connectivity networks (ICNs) are especially important to cognitive processing in ASD: the default mode network (DMN), executive control network (ECN), and salience networks (SNs). The goal of this study was to compare resting-state functional connectivity between the cerebellum and the DMN, ECN, and SN in ASD and typically developing children (n = 74, ages 7-12 years). Children with ASD showed stronger connectivity between the ventral DMN and left cerebellar lobules I-IV. No meaningful relationships were observed between ICN-cerebellar functional connectivity and ASD symptoms. These results suggest that the cerebellum contributes to altered network connectivity in ASD.

PMID: 31473949 [PubMed - indexed for MEDLINE]

Coupled Temporal Fluctuation and Global Signal Synchronization of Spontaneous Brain Activity in Hypnosis for Respiration Control: An fMRI Study.

Fri, 01/10/2020 - 11:20

Coupled Temporal Fluctuation and Global Signal Synchronization of Spontaneous Brain Activity in Hypnosis for Respiration Control: An fMRI Study.

Neuroscience. 2020 Jan 06;:

Authors: Liu Y, He Y, Li R, Yu S, Xu J, Xie Y

Abstract
Hypnosis is a psychological technology proved to be effective in respiratory motion control, which is essential to reduce radiation dose during radiotherapy. This study explored the neural mechanisms and cognitive neuroscience of hypnosis for respiration control by functional magnetic resonance imaging with a within-subject design of 15 healthy volunteers in rest state (RS) and hypnosis state (HS). Temporal fluctuation and signal synchronization of brain activity were employed to investigate the altered physiological performance in hypnosis. The altered correlations between temporal fluctuation and signal synchronization were examined within large scale of intrinsic networks which were identified by seed-wise functional connectivity. As a result, hypnosis was observed with increased activity in the right calcarine, bilateral fusiform gyrus and left middle temporal gyrus, and with decreased activity in the left cerebellum posterior lobe (inferior semilunar lobule part). Compared to RS, enhanced positive correlations were observed between temporal fluctuation and signal synchronization in HS. Most importantly, coupled correlation was observed between temporal fluctuation and global signal synchronization within the identified intrinsic networks (R = 0.3843, p > 0.05 in RS; R = 0.6212, p < 0.005 in HS). The findings provide implications for the neural basis of hypnosis for respiratory motion control and suggest the involvement of emotional processing and regulation of perceptual consciousness in hypnosis.

PMID: 31917344 [PubMed - as supplied by publisher]

Ultrasonographic Measures of Talar Cartilage Thickness Associate with Magnetic Resonance-Based Measures of Talar Cartilage Volume.

Fri, 01/10/2020 - 11:20

Ultrasonographic Measures of Talar Cartilage Thickness Associate with Magnetic Resonance-Based Measures of Talar Cartilage Volume.

Ultrasound Med Biol. 2020 Jan 06;:

Authors: Song K, Pietrosimone BG, Nissman DB, Wikstrom EA

Abstract
Our primary goal was to quantify associations between ultrasonographic (US) measurements of talar cartilage apparent thickness and magnetic resonance (MR)-based measures of talar cartilage volume in a heterogeneous sample of those with and without chronic ankle instability. Cartilage volume from MR and normalized cross-sectional area (CSA) and thickness from a transverse US image of the talar cartilage were calculated after 30 min of unloading. Overall talar and region of interest-specific morphology measures (i.e., volume, normalized CSA, thickness) were submitted for statistical analysis. Overall US-normalized CSA positively associated with the overall talar MR volume (r = 0.641, p < 0.001). Medial (r = 0.673, p < 0.001) and lateral US-normalized CSA (r = 0.584, p = 0.001) positively associated with MR volume in the anteromedial and anterolateral MR region of interest, respectively. No differences in US-based normalized CSA, thickness (p > 0.481) or MR-based volume (p > 0.287) were noted between the groups. US appears to be a clinically accessible and cost-effective method for evaluating average ankle cartilage apparent thickness.

PMID: 31917041 [PubMed - as supplied by publisher]

Nonreplication of functional connectivity differences in autism spectrum disorder across multiple sites and denoising strategies.

Fri, 01/10/2020 - 11:20

Nonreplication of functional connectivity differences in autism spectrum disorder across multiple sites and denoising strategies.

Hum Brain Mapp. 2020 Jan 09;:

Authors: He Y, Byrge L, Kennedy DP

Abstract
A rapidly growing number of studies on autism spectrum disorder (ASD) have used resting-state fMRI to identify alterations of functional connectivity, with the hope of identifying clinical biomarkers or underlying neural mechanisms. However, results have been largely inconsistent across studies, and there remains a pressing need to determine the primary factors influencing replicability. Here, we used resting-state fMRI data from the Autism Brain Imaging Data Exchange to investigate two potential factors: denoising strategy and data site (which differ in terms of sample, data acquisition, etc.). We examined the similarity of both group-averaged functional connectomes and group-level differences (ASD vs. control) across 33 denoising pipelines and four independently-acquired datasets. The group-averaged connectomes were highly consistent across pipelines (r = 0.92 ± 0.06) and sites (r = 0.88 ± 0.02). However, the group differences, while still consistent within site across pipelines (r = 0.76 ± 0.12), were highly inconsistent across sites regardless of choice of denoising strategies (r = 0.07 ± 0.04), suggesting lack of replication may be strongly influenced by site and/or cohort differences. Across-site similarity remained low even when considering the data at a large-scale network level or when considering only the most significant edges. We further show through an extensive literature survey that the parameters chosen in the current study (i.e., sample size, age range, preprocessing methods) are quite representative of the published literature. These results highlight the importance of examining replicability in future studies of ASD, and, more generally, call for extra caution when interpreting alterations in functional connectivity across groups of individuals.

PMID: 31916675 [PubMed - as supplied by publisher]

The influence of motion artefacts on magnetic resonance imaging of the clavicles for age estimation.

Fri, 01/10/2020 - 11:20

The influence of motion artefacts on magnetic resonance imaging of the clavicles for age estimation.

Int J Legal Med. 2020 Jan 08;:

Authors: De Tobel J, van Wijk M, Alberink I, Hillewig E, Phlypo I, van Rijn RR, Thevissen PW, Verstraete KL, de Haas MB

Abstract
PURPOSE: To determine how motion affects stage allocation to the clavicle's sternal end on MRI.
MATERIALS AND METHODS: Eighteen volunteers (9 females, 9 males) between 14 and 30 years old were prospectively scanned with 3-T MRI. One resting-state scan was followed by five intentional motion scans. Additionally, a control group of 72 resting-state scans were selected from previous research. Firstly, six observers allocated developmental stages to the clavicles independently. Secondly, they re-assessed the images, allocating developmental statuses (immature, mature). Finally, the resting-state scans of the 18 volunteers were assessed in consensus to decide on the "correct" stage/status. Results were compared between groups (control, prospective resting state, prospective motion), and between staging techniques (stages/statuses).
RESULTS: Inter-observer agreement was low (Krippendorff α 0.23-0.67). The proportion of correctly allocated stages (64%) was lower than correctly allocated statuses (83%). Overall, intentional motion resulted in fewer assessable images and less images of sufficient evidential value. The proportion of correctly allocated stages did not differ between resting-state (64%) and motion scans (65%), while correctly allocated statuses were more prevalent in resting-state scans (83% versus 77%). Remarkably, motion scans did not render a systematically higher or lower stage/status, compared to the consensus.
CONCLUSION: Intentional motion impedes clavicle MRI for age estimation. Still, in case of obvious disturbances, the forensic expert will consider the MRI unsuitable as evidence. Thus, the development of the clavicle as such and the staging technique seem to play a more important role in allocating a faulty stage for age estimation.

PMID: 31915965 [PubMed - as supplied by publisher]

High-Frequency Repetitive Transcranial Magnetic Stimulation Could Improve Impaired Working Memory Induced by Sleep Deprivation.

Fri, 01/10/2020 - 11:20

High-Frequency Repetitive Transcranial Magnetic Stimulation Could Improve Impaired Working Memory Induced by Sleep Deprivation.

Neural Plast. 2019;2019:7030286

Authors: Guo Z, Jiang Z, Jiang B, McClure MA, Mu Q

Abstract
Objective: To investigate whether and how the working memory impairment induced by sleep deprivation (SD) could be recovered by using repetitive transcranial magnetic stimulation (rTMS), as well as to clarify the corresponding brain activity changes.
Methods: Seventeen healthy adults received one session of 5.0 Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) following 24 hours of SD. Resting state functional magnetic resonance imaging (fMRI) and working memory test were performed during a rested waking period, after SD and rTMS. The amplitude of low-frequency fluctuations (ALFF) was used to detect the spontaneous neural activity changes after both SD and rTMS. The relationship between ALFF and the performance of working memory was also assessed by using correlation analysis.
Results: After SD, the participants exhibited lower response accuracies and longer reaction times on the working memory tests of letters and numbers. The decreased response accuracy of numbers was significantly improved after rTMS similarly to the state of the rested waking period after a normal night of sleep. ALFF values decreased from the rested waking period state to the state of SD in the brain regions involving the frontal gyrus, precuneus, angular gyrus, and parietal lobe which showed significantly increased ALFF after rTMS. Furthermore, significantly positive correlations were observed between changes of response accuracy and the changes of ALFF value of the inferior frontal gyrus and supramarginal gyrus.
Conclusion: These results indicate that high-frequency rTMS applied over left DLPFC may contribute to the recovery of the impaired working memory after SD by modulating the neural activity of related brain regions.

PMID: 31915432 [PubMed - in process]

Functional and structural neural bases of task specificity in isolated focal dystonia.

Fri, 01/10/2020 - 11:20
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Functional and structural neural bases of task specificity in isolated focal dystonia.

Mov Disord. 2019 04;34(4):555-563

Authors: Bianchi S, Fuertinger S, Huddleston H, Frucht SJ, Simonyan K

Abstract
BACKGROUND: Task-specific focal dystonias selectively affect movements during the production of highly learned and complex motor behaviors. Manifestation of some task-specific focal dystonias, such as musician's dystonia, has been associated with excessive practice and overuse, whereas the etiology of others remains largely unknown.
OBJECTIVES: In this study, we aimed to examine the neural correlates of task-specific dystonias in order to determine their disorder-specific pathophysiological traits.
METHODS: Using multimodal neuroimaging analyses of resting-state functional connectivity, voxel-based morphometry and tract-based spatial statistics, we examined functional and structural abnormalities that are both common to and distinct between four different forms of task-specific focal dystonias.
RESULTS: Compared to the normal state, all task-specific focal dystonias were characterized by abnormal recruitment of parietal and premotor cortices that are necessary for both modality-specific and heteromodal control of the sensorimotor network. Contrasting the laryngeal and hand forms of focal dystonia revealed distinct patterns of sensorimotor integration and planning, again involving parietal cortex in addition to inferior frontal gyrus and anterior insula. On the other hand, musician's dystonia compared to nonmusician's dystonia was shaped by alterations in primary and secondary sensorimotor cortices together with middle frontal gyrus, pointing to impairments of sensorimotor guidance and executive control.
CONCLUSION: Collectively, this study outlines a specialized footprint of functional and structural alterations in different forms of task-specific focal dystonia, all of which also share a common pathophysiological framework involving premotor-parietal aberrations. © 2019 International Parkinson and Movement Disorder Society.

PMID: 30840778 [PubMed - indexed for MEDLINE]

Pubertal maturation and sex effects on the default-mode network connectivity implicated in mood dysregulation.

Fri, 01/10/2020 - 11:20
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Pubertal maturation and sex effects on the default-mode network connectivity implicated in mood dysregulation.

Transl Psychiatry. 2019 02 25;9(1):103

Authors: Ernst M, Benson B, Artiges E, Gorka AX, Lemaitre H, Lago T, Miranda R, Banaschewski T, Bokde ALW, Bromberg U, Brühl R, Büchel C, Cattrell A, Conrod P, Desrivières S, Fadai T, Flor H, Grigis A, Gallinat J, Garavan H, Gowland P, Grimmer Y, Heinz A, Kappel V, Nees F, Papadopoulos-Orfanos D, Penttilä J, Poustka L, Smolka MN, Stringaris A, Struve M, van Noort BM, Walter H, Whelan R, Schumann G, Grillon C, Martinot MP, Martinot JL, IMAGEN Consortium

Abstract
This study examines the effects of puberty and sex on the intrinsic functional connectivity (iFC) of brain networks, with a focus on the default-mode network (DMN). Consistently implicated in depressive disorders, the DMN's function may interact with puberty and sex in the development of these disorders, whose onsets peak in adolescence, and which show strong sex disproportionality (females > males). The main question concerns how the DMN evolves with puberty as a function of sex. These effects are expected to involve within- and between-network iFC, particularly, the salience and the central-executive networks, consistent with the Triple-Network Model. Resting-state scans of an adolescent community sample (n = 304, male/female: 157/147; mean/std age: 14.6/0.41 years), from the IMAGEN database, were analyzed using the AFNI software suite and a data reduction strategy for the effects of puberty and sex. Three midline regions (medial prefrontal, pregenual anterior cingulate, and posterior cingulate), within the DMN and consistently implicated in mood disorders, were selected as seeds. Within- and between-network clusters of the DMN iFC changed with pubertal maturation differently in boys and girls (puberty-X-sex). Specifically, pubertal maturation predicted weaker iFC in girls and stronger iFC in boys. Finally, iFC was stronger in boys than girls independently of puberty. Brain-behavior associations indicated that lower connectivity of the anterior cingulate seed predicted higher internalizing symptoms at 2-year follow-up. In conclusion, weaker iFC of the anterior DMN may signal disconnections among circuits supporting mood regulation, conferring risk for internalizing disorders.

PMID: 30804326 [PubMed - indexed for MEDLINE]

In vivo measurement of brain network connectivity reflects progression and intrinsic disease severity in a model of temporal lobe epilepsy.

Fri, 01/10/2020 - 11:20
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In vivo measurement of brain network connectivity reflects progression and intrinsic disease severity in a model of temporal lobe epilepsy.

Neurobiol Dis. 2019 07;127:45-52

Authors: Bertoglio D, Jonckers E, Ali I, Verhoye M, Van der Linden A, Dedeurwaerdere S

Abstract
Different types of brain injury, such as status epilepticus (SE), trauma, or stroke may initiate the process of epileptogenesis and lead to the development of temporal lobe epilepsy. Epileptogenesis is characterized by an initial latent period during which impaired network communication and synaptic circuit alterations are occurring. Ultimately, these modifications result in the development of spontaneous recurrent seizures (SRS). Current knowledge on the functional connectivity network changes during epileptogenesis and how network alterations relate to seizure is very limited. To investigate these underlying network connectivity modifications, we imaged epileptic and control rats by means of resting-state functional MRI (rsfMRI) during epileptogenesis. A cohort of animals was video-electroencephalography (video-EEG) monitored continuously over 12 weeks to determine disease severity during the course of disease, with the first SRS appearing around 2 weeks post-SE for most of the animals. Epileptic animals displayed a significant wide-spread hyposynchrony at 2 weeks post-SE, followed by a significant increase in network synchronicity from 2 to 4 weeks post-SE. Interestingly, subjects with a delayed epilepsy onset demonstrated significantly lower synchronicity compared to controls and the epileptic group at 4 weeks post-SE. Finally, network connectivity at 4 weeks post-SE was found to correlate with seizure onset (r = 0.858, p < .0001) and disease severity measured over 12 weeks (e.g. cingulate cortex: r = 0.863, p = .002), suggesting a possible network strengthening upon seizure reoccurrence. Our findings indicate that epileptogenesis is characterized by an initial hyposynchrony of brain networks and the disease-associated progression reflects disease severity.

PMID: 30798008 [PubMed - indexed for MEDLINE]

Percent amplitude of fluctuation: A simple measure for resting-state fMRI signal at single voxel level.

Thu, 01/09/2020 - 16:20

Percent amplitude of fluctuation: A simple measure for resting-state fMRI signal at single voxel level.

PLoS One. 2020;15(1):e0227021

Authors: Jia XZ, Sun JW, Ji GJ, Liao W, Lv YT, Wang J, Wang Z, Zhang H, Liu DQ, Zang YF

Abstract
The amplitude of low-frequency fluctuation (ALFF) measures resting-state functional magnetic resonance imaging (RS-fMRI) signal of each voxel. However, the unit of blood oxygenation level-dependent (BOLD) signal is arbitrary and hence ALFF is sensitive to the scale of raw signal. A well-accepted standardization procedure is to divide each voxel's ALFF by the global mean ALFF, named mALFF. Although fractional ALFF (fALFF), a ratio of the ALFF to the total amplitude within the full frequency band, offers possible solution of the standardization, it actually mixes with the fluctuation power within the full frequency band and thus cannot reveal the true amplitude characteristics of a given frequency band. The current study borrowed the percent signal change in task fMRI studies and proposed percent amplitude of fluctuation (PerAF) for RS-fMRI. We firstly applied PerAF and mPerAF (i.e., divided by global mean PerAF) to eyes open (EO) vs. eyes closed (EC) RS-fMRI data. PerAF and mPerAF yielded prominently difference between EO and EC, being well consistent with previous studies. We secondly performed test-retest reliability analysis and found that (PerAF ≈ mPerAF ≈ mALFF) > (fALFF ≈ mfALFF). Head motion regression (Friston-24) increased the reliability of PerAF, but decreased all other metrics (e.g. mPerAF, mALFF, fALFF, and mfALFF). The above results suggest that mPerAF is a valid, more reliable, more straightforward, and hence a promising metric for voxel-level RS-fMRI studies. Future study could use both PerAF and mPerAF metrics. For prompting future application of PerAF, we implemented PerAF in a new version of REST package named RESTplus.

PMID: 31914167 [PubMed - in process]

Disruption of posterior brain functional connectivity and its relation to cognitive impairment in idiopathic REM sleep behavior disorder.

Thu, 01/09/2020 - 16:20

Disruption of posterior brain functional connectivity and its relation to cognitive impairment in idiopathic REM sleep behavior disorder.

Neuroimage Clin. 2019 Dec 23;25:102138

Authors: Campabadal A, Abos A, Segura B, Serradell M, Uribe C, Baggio HC, Gaig C, Santamaria J, Compta Y, Bargallo N, Junque C, Iranzo A

Abstract
BACKGROUND: Resting-state functional MRI has been proposed as a new biomarker of prodromal neurodegenerative disorders, but it has been poorly investigated in the idiopathic form of rapid-eye-movement sleep behavior disorder (IRBD), a clinical harbinger of subsequent synucleinopathy. Particularly, a complex-network approach has not been tested to study brain functional connectivity in IRBD patients.
OBJECTIVES: The aim of the current work is to characterize resting-state functional connectivity in IRBD patients using a complex-network approach and to determine its possible relation to cognitive impairment.
METHOD: Twenty patients with IRBD and 27 matched healthy controls (HC) underwent resting-state functional MRI with a 3T scanner and a comprehensive neuropsychological battery. The functional connectome was studied using threshold-free network-based statistics. Global and local network parameters were calculated based on graph theory and compared between groups. Head motion, age and sex were introduced as covariates in all analyses.
RESULTS: IRBD patients showed reduced cortico-cortical functional connectivity strength in comparison with HC in edges located in posterior regions (p <0.05, FWE corrected). This regional pattern was also shown in an independent analysis comprising posterior areas where a decreased connectivity in 51 edges was found, whereas no significant results were detected when an anterior network was considered (p <0.05, FWE corrected). In the posterior network, the left superior parietal lobule had reduced centrality in IRBD. Functional connectivity strength between left inferior temporal lobe and right superior parietal lobule positively correlated with mental processing speed in IRBD (r = .633; p = .003). No significant correlations were found in the HC group.
CONCLUSION: Our findings support the presence of disrupted posterior functional brain connectivity of IRBD patients similar to that found in synucleinopathies. Moreover, connectivity reductions in IRBD were associated with lower performance in mental processing speed domain.

PMID: 31911344 [PubMed - as supplied by publisher]

Twin MRI studies on genetic and environmental determinants of brain morphology and function in the early lifespan.

Thu, 01/09/2020 - 16:20

Twin MRI studies on genetic and environmental determinants of brain morphology and function in the early lifespan.

Neurosci Biobehav Rev. 2020 Jan 03;:

Authors: Maggioni E, Squarcina L, Dusi N, Diwadkar VA, Brambilla P

Abstract
Neurodevelopment represents a period of increased opportunity and vulnerability, during which a complex confluence of genetic and environmental factors influences brain growth trajectories, cognitive and mental health outcomes. Recently, magnetic resonance imaging (MRI) studies on twins have increased our knowledge of the extent to which genes, the environment and their interactions shape inter-individual brain variability. The present review draws from highly salient MRI studies in young twin samples to provide a robust assessment of the heritability of structural and functional brain changes during development. The available studies suggest that (as with many other traits), global brain morphology and network organization are highly heritable from early childhood to young adulthood. Conversely, genetic correlations among brain regions exhibit heterogeneous trajectories, and this heterogeneity reflects the progressive, experience-related increase in brain network complexity. Studies also support the key role of environment in mediating brain network differentiation via changes of genetic expression and hormonal levels. Thus, rest- and task-related functional brain circuits seem to result from a contextual and dynamic expression of heritability.

PMID: 31911159 [PubMed - as supplied by publisher]

Resting state fMRI reveals differential effects of glucose administration on central appetite signalling in young and old adults.

Wed, 01/08/2020 - 15:20

Resting state fMRI reveals differential effects of glucose administration on central appetite signalling in young and old adults.

J Psychopharmacol. 2020 Jan 07;:269881119894540

Authors: Peters R, White DJ, Scholey A

Abstract
BACKGROUND: Healthy aging has been associated with reduced appetite and lower energy intake, which can lead to loss of bodyweight, undernutrition and related health problems. The causes for the decline in caloric intake are multifactorial, involving physiological and non-physiological processes.
AIMS: Here we examined the effect of glucose on brain function in healthy adults as well as age-related, physiological changes in brain responses associated with macronutrient intake.
METHODS: Using a randomized, double-blind, balanced cross-over design, younger (n = 16, aged 21-30) and older (n = 16, aged 55-78) adults received a drink containing glucose and a taste-matched placebo after an overnight fast. Blood glucose and hunger were assessed at baseline and 20 min post-ingestion, after which participants underwent resting state functional magnetic resonance imaging.
RESULTS: Frequency-dependent changes associated with glucose administration in slow-5 (0.01-0.027 Hz) and slow-4 (0.027-0.073 Hz) amplitude of low-frequency fluctuations (ALFF) and fractional ALFF (fALFF) of the blood oxygen level-dependent (BOLD) signal were investigated within the young healthy adults, and then extended to the older age group. Consistent with previous reports, glucose decreased amplitude in slow-5 fALFF within the left orbitofrontal cortex and insular cortex in the young adults. We observed a significant interaction in slow-5 ALFF and fALFF in the left insula, such that younger participants showed a decrease in BOLD amplitude, whereas older participants showed an increase, after glucose administration. We further observed an interaction in slow-4 ALFF in the occipital region and precuneus, with older participants showing an increase in magnitude of slow-4 ALFF and younger participants showing a decrease in the same measure.
CONCLUSION: These age-related, frequency-dependent changes in the magnitude of the BOLD signal in the insula, a key region related to energy homeostasis following feeding, may point to a change in satiety or homeostatic signalling contributing to behavioural changes in energy intake during senescence.

PMID: 31909672 [PubMed - as supplied by publisher]

Effects of the dopamine transporter gene on striatal functional connectivity in youths with attention-deficit/hyperactivity disorder.

Wed, 01/08/2020 - 15:20

Effects of the dopamine transporter gene on striatal functional connectivity in youths with attention-deficit/hyperactivity disorder.

Psychol Med. 2020 Jan 07;:1-11

Authors: Shang CY, Lin HY, Gau SS

Abstract
BACKGROUND: The dopamine transporter gene (DAT1), striatal network dysfunction, and visual memory deficits have been consistently reported to be associated with attention-deficit/hyperactivity disorder (ADHD). This study aimed to examine the effects of the DAT1 rs27048 (C)/rs429699 (T) haplotype on striatal functional connectivity and visual memory performance in youths with ADHD.
METHOD: After excluding those who had excessive head motion, a total of 96 drug-naïve youths with ADHD and 114 typically developing (TD) youths were assessed with the resting-state functional magnetic resonance imaging and the delayed matching to sample (DMS) task for visual memory. We examined the effects of ADHD, DAT1 CT haplotype, and the ADHD × CT haplotype interaction on the functional connectivity of five striatal seeds. We also correlated visual memory performance with the functional connectivity of striatal subregions, which showed significant diagnosis × genotype interactions.
RESULTS: Compared with TD youths, ADHD youths showed significant hypoconnectivity of the left dorsal caudate (DC) with bilateral sensorimotor clusters. Significant diagnosis × genotype interactions were found in the connectivity between the left DC and the right sensorimotor cluster, and between the right DC and the left dorsolateral prefrontal/bilateral anterior cingulate clusters. Furthermore, the connectivity of the left DC showing significant diagnosis × genotype interactions was associated with DMS performance in youths with ADHD who carried the DAT1 CT haplotype.
CONCLUSIONS: A novel gene-brain-behavior association between the left DC functional connectivity and visual memory performance in ADHD youths with the DAT1 rs27048 (C)/rs429699 (T) haplotype suggests a differential effect of DAT1 genotype altering specific brain function causing neuropsychological dysfunction in ADHD.

PMID: 31907092 [PubMed - as supplied by publisher]

The effect of amyloid deposition on longitudinal resting-state functional connectivity in cognitively normal older adults.

Wed, 01/08/2020 - 15:20

The effect of amyloid deposition on longitudinal resting-state functional connectivity in cognitively normal older adults.

Alzheimers Res Ther. 2020 Jan 06;12(1):7

Authors: Lin C, Ly M, Karim HT, Wei W, Snitz BE, Klunk WE, Aizenstein HJ

Abstract
BACKGROUND: Pathological processes contributing to Alzheimer's disease begin decades prior to the onset of clinical symptoms. There is significant variation in cognitive changes in the presence of pathology, functional connectivity may be a marker of compensation to amyloid; however, this is not well understood.
METHODS: We recruited 64 cognitively normal older adults who underwent neuropsychological testing and biannual magnetic resonance imaging (MRI), amyloid imaging with Pittsburgh compound B (PiB)-PET, and glucose metabolism (FDG)-PET imaging for up to 6 years. Resting-state MRI was used to estimate connectivity of seven canonical neural networks using template-based rotation. Using voxel-wise paired t-tests, we identified neural networks that displayed significant changes in connectivity across time. We investigated associations among amyloid and longitudinal changes in connectivity and cognitive function by domains.
RESULTS: Left middle frontal gyrus connectivity within the memory encoding network increased over time, but the rate of change was lower with greater amyloid. This was no longer significant in an analysis where we limited the sample to only those with two time points. We found limited decline in cognitive domains overall. Greater functional connectivity was associated with better attention/processing speed and executive function (independent of time) in those with lower amyloid but was associated with worse function with greater amyloid.
CONCLUSIONS: Increased functional connectivity serves to preserve cognitive function in normal aging and may fail in the presence of pathology consistent with compensatory models.

PMID: 31907079 [PubMed - in process]

Patterns of brain regional functional coherence in cognitive impaired ALS.

Wed, 01/08/2020 - 15:20

Patterns of brain regional functional coherence in cognitive impaired ALS.

Int J Neurosci. 2020 Jan 06;:1-8

Authors: Hu T, Hou Y, Wei Q, Yang J, Luo C, Chen Y, Gong Q, Shang H

Abstract
Background: The aim of the study is to reveal the brain regional functional coherence alterations in the early-stage amyotrophic lateral sclerosis (ALS) patients with cognitive impairments.Methods: Resting state functional MRI (fMRI) was performed to characterize the amplitude of regional homogeneity (ReHo). Twenty-one ALS patients with cognitive impairments (ALSci), 21 ALS patients without cognitive impairments (ALSnci) and 21 healthy controls (HCs) were enrolled.Result: Compared with HCs, the ALSci subgroup showed increased ReHo in bilateral inferior parietal lobules (IPLs), precuneus and inferior cerebellar areas, and the ALSnci subgroup had increased ReHo in the left IPL and left inferior cerebellar area. The ALSci subgroup also had increased ReHo in the right IPL and right inferior cerebellar area relative to the ALSnci subgroup. Meantime, compared with HCs, both ALS subgroups showed decreased ReHo in bilateral sensorimotor cortices. The ReHo values in the right cerebellar area were negatively correlated with the Chinese version of Addenbrooke Cognitive Examination-revised (ACE-R) total scores in all ALS patients. In addition, the grey matter (GM) volume revealed no significant difference among three groups, which indicated that the altered ReHo was not caused by the anatomic change.Conclusion: The altered regional functional coherence might indicate the underlying deficits of ALS with and without cognitive impairments. Our findings support that ALS is a multisystem disease and provide the evidence that alterations of ReHo in the right inferior cerebellar area might be a special marker of ALS with cognitive impairment. Our results are preliminary and further investigations are needed.

PMID: 31906800 [PubMed - as supplied by publisher]

Internet gaming disorder: deficits in functional and structural connectivity in the ventral tegmental area-Accumbens pathway.

Wed, 01/08/2020 - 15:20
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Internet gaming disorder: deficits in functional and structural connectivity in the ventral tegmental area-Accumbens pathway.

Brain Imaging Behav. 2019 Aug;13(4):1172-1181

Authors: Wang R, Li M, Zhao M, Yu D, Hu Y, Wiers CE, Wang GJ, Volkow ND, Yuan K

Abstract
Dopamine projections from the ventral tegmental area (VTA) to the nucleus accumbens (NAc) and from the substantia nigra (SN) to the dorsal striatum are involved in addiction. However, relatively little is known about the implication of these circuits in Internet gaming disorder (IGD). This study examined the alteration of resting-state functional connectivity (RSFC) and diffusion tensor imaging (DTI) -based structural connectivity of VTA/SN circuits in 61 young male participants (33 IGD and 28 healthy controls). Correlation analysis was carried out to investigate the relationship between the neuroimaging findings and the behavioral Internet Addiction Test (IAT). Both the NAc and medial orbitofrontal cortex (mOFC) showed lower RSFC with VTA in IGD subjects compared with controls. Moreover, the RSFC strength of VTA-right NAc and VTA-left mOFC correlated negatively with IAT in IGD subjects. The IGD subjects also showed lower structural connectivity in bilateral VTA-NAc tracts compared with controls, but the connectivity did not correlate with IAT in IGD. We provide evidence that functional and structural connectivity of the VTA-NAc pathway, and functional connectivity of the VTA-mOFC pathway are implicated in IGD. Since these pathways are important for dopamine reward signals and salience attribution, the findings suggest involvement of the brain DA reward system in the neurobiology of IGD. The association of functional but not structural connectivity of VTA circuits with IAT suggests that while lower structural connectivity might underlie vulnerability for IGD, lower functional connectivity may modulate severity. These results strengthen the evidence that IGD shares similar neuropathology with other addictions.

PMID: 30054871 [PubMed - indexed for MEDLINE]

Prefrontal TDCS attenuates medial prefrontal connectivity upon being criticized in individuals scoring high on perceived criticism.

Wed, 01/08/2020 - 15:20
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Prefrontal TDCS attenuates medial prefrontal connectivity upon being criticized in individuals scoring high on perceived criticism.

Brain Imaging Behav. 2019 Aug;13(4):1060-1070

Authors: Dedoncker J, Vanderhasselt MA, Remue J, De Witte S, Wu GR, Hooley JM, De Raedt R, Baeken C

Abstract
The mechanisms by which transcranial direct current stimulation (tDCS) influences emotional processing - and whether this is related to individual vulnerability for psychopathology - are still poorly understood. The present study aimed to investigate if one prefrontal tDCS session modulates mood and neural functional connectivity after being exposed to negative information differently in individuals low or high in perceived criticism (PC), which has been related to vulnerability for psychiatric illness. In a randomized cross-over design, one session of MRI-compatible prefrontal tDCS (neuronavigated placement of the anodal electrode at the left dorsolateral prefrontal cortex and the cathodal electrode at the right supraorbital region; vs. sham) was administered to healthy females, prior to listening to self-referential criticism. PC-dependent (low vs. high PC) changes in mood and resting-state functional connectivity patterns following tDCS and after hearing criticism were explored. After being criticized all females (low and high PC) felt angrier and more depressed, both in the active tDCS or sham tDCS condition. However, in contrast to low PC females, in high PC females prefrontal tDCS reduced connectivity between the left dorsal anterior cingulate cortex and the right dorsomedial prefrontal cortex following criticism. Despite having no differential effects on self-reported mood, prefrontal tDCS reduces medial prefrontal neural connectivity after being criticized in high PC females compared to low PC females. Depending on individual vulnerability for psychopathology, a single tDCS session differentially affects neural processing of negative emotional information, especially in brain regions involved in monitoring, experiencing and appraising/evaluating emotional material.

PMID: 29974333 [PubMed - indexed for MEDLINE]

Hippocampal structural and functional integrity in multiple sclerosis patients with or without memory impairment: a multimodal neuroimaging study.

Wed, 01/08/2020 - 15:20
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Hippocampal structural and functional integrity in multiple sclerosis patients with or without memory impairment: a multimodal neuroimaging study.

Brain Imaging Behav. 2019 Aug;13(4):1049-1059

Authors: Karavasilis E, Christidi F, Velonakis G, Tzanetakos D, Zalonis I, Potagas C, Andreadou E, Efstathopoulos E, Kilidireas C, Kelekis N, Evdokimidis I

Abstract
The increasing evidence for a pure amnestic-like profile in multiple sclerosis (MS) introduces the role of hippocampal formation in MS episodic memory function. The aim of the present study was to investigate structural and functional hippocampal changes in mildly-disabled MS patients with and without memory impairment. Thirty-one MS patients with or without memory impairment and 16 healthy controls (HC) underwent MRI in a 3.0 T MRI scanner. Patients were categorized as memory preserved (MP) and memory impaired (MI) based on verbal and visual memory scores extracted from the Brief Repeatable Neuropsychological Battery. The acquisition protocol included high-resolution 3D-T1-weighted, diffusion weighted imaging and echo-planar imaging sequences for the analysis of hippocampal gray matter (GM) density, perforant pathway area (PPA) tractography, and hippocampal functional connectivity (FC), respectively. Compared to HC, we found decreased left and bilateral hippocampal GM density in MP and MI patients, respectively, decreased fractional anisotropy and increased radial diffusivity on left PPA in MI patients, and reduced FC in MI between left hippocampus and left superior frontal gyrus, precuneus/posterior cingulated cortex and lateral occipital gyrus/angular gyrus. The only differences between MP and MI were found in FC. Specifically, MP patients showed FC changes between left hippocampus and right temporo-occipital fusiform/lingual gyrus (increased FC) as well as supramarginal gyrus (decreased FC). In conclusion, we highlight the early detection of structural hippocampal changes in MS without neuropsychologically-detected memory deficits and decreased hippocampal FC in MS patients with impaired memory performance, when both GM density and PPA integrity are affected.

PMID: 29971687 [PubMed - indexed for MEDLINE]

12-h abstinence-induced functional connectivity density changes and craving in young smokers: a resting-state study.

Wed, 01/08/2020 - 15:20
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12-h abstinence-induced functional connectivity density changes and craving in young smokers: a resting-state study.

Brain Imaging Behav. 2019 Aug;13(4):953-962

Authors: Zhao S, Li Y, Li M, Wang R, Bi Y, Zhang Y, Lu X, Yu D, Yang L, Yuan K

Abstract
Studying the neural correlates of craving to smoke is of great importance to improve treatment outcomes in smoking addiction. According to previous studies, the critical roles of striatum and frontal brain regions had been revealed in addiction. However, few studies focused on the hub of brain regions in the 12 h abstinence induced craving in young smokers. Thirty-one young male smokers were enrolled in the present study. A within-subject experiment design was carried out to compare functional connectivity density between 12-h smoking abstinence and smoking satiety conditions during resting state in young adult smokers by using functional connectivity density mapping (FCDM). Then, the functional connectivity density changes during smoking abstinence versus satiety were further used to examine correlations with abstinence-induced changes in subjective craving. We found young adult smokers in abstinence state (vs satiety) had higher local functional connectivity density (lFCD) and global functional connectivity density (gFCD) in brain regions including striatal subregions (i.e., bilateral caudate and putamen), frontal regions (i.e., anterior cingulate cortex (ACC) and orbital frontal cortex (OFC)) and bilateral insula. We also found higher lFCD during smoking abstinence (vs satiety) in bilateral thalamus. Additionally, the lFCD changes of the left ACC, bilateral caudate and right OFC were positively correlated with the changes in craving induced by abstinence (i.e., abstinence minus satiety) in young adult smokers. The present findings improve the understanding of the effects of acute smoking abstinence on the hubs of brain gray matter in the abstinence-induces craving and may contribute new insights into the neural mechanism of abstinence-induced craving in young smokers in smoking addiction.

PMID: 29926324 [PubMed - indexed for MEDLINE]

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