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Common increased hippocampal volume but specific changes in functional connectivity in schizophrenia patients in remission and non-remission following electroconvulsive therapy: A preliminary study.

Mon, 11/18/2019 - 14:40
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Common increased hippocampal volume but specific changes in functional connectivity in schizophrenia patients in remission and non-remission following electroconvulsive therapy: A preliminary study.

Neuroimage Clin. 2019 Nov 08;24:102081

Authors: Jiang Y, Xu L, Li X, Tang Y, Wang P, Li C, Yao D, Wang J, Luo C

Abstract
Electroconvulsive therapy (ECT) is considered a treatment option in patients with drug-resistant schizophrenia (SZ). However, approximately one-third of patients do not benefit from ECT in the clinic. Thus, it is critical to investigate differences between ECT responders and non-responders. Accumulated evidence has indicated that one region of ECT action is the hippocampus, which also plays an important role in SZ pathophysiology. To date, no studies have investigated differences in ECT effects in the hippocampus between treatment responders and non-responders. This study recruited twenty-one SZ patients treated for four weeks with ECT (MSZ, n = 21) and twenty-one SZ patients who received pharmaceutical therapy (DSZ, n = 21). The MSZ group was further categorized into responders (MSR, n = 10) or non-responders (MNR, n = 11) based on treatment outcomes by the criterion of a 50% reduction in the Positive and Negative Syndrome Scale total scores. Using structural and resting-state functional MRI, we measured the hippocampal volume and functional connectivity (FC) in all SZ patients (before and after treatment) and 23 healthy controls. In contrast to pharmaceutical therapy, ECT induced bilateral hippocampal volume increases in the MSZ. Both the MSR and MNR exhibited hippocampal expansion after ECT, whereas a lower baseline volume in one of hippocampal subfield (hippocampus-amygdala transition area) was found in the MNR. After ECT, increased FC between the hippocampus and brain networks associated with cognitive function was only observed in the MSR. The mechanism of action of ECT in schizophrenia is complex. A combination of baseline impairment level, ECT-introduced morphological changes and post-ECT FC increases in the hippocampus may jointly contribute to the post-ECT symptom improvements in patients with SZ.

PMID: 31734526 [PubMed - as supplied by publisher]

Rumination network dysfunction in major depression: A brain connectome study.

Mon, 11/18/2019 - 14:40
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Rumination network dysfunction in major depression: A brain connectome study.

Prog Neuropsychopharmacol Biol Psychiatry. 2019 Nov 14;:109819

Authors: Zhang R, Kranz GS, Zou W, Deng Y, Huang X, Lin K, Lee TMC

Abstract
BACKGROUND: Rumination is a central feature of major depressive disorder (MDD). Knowledge of the neural structures that underpin rumination offers significant insight into depressive pathophysiology and may help to develop potential intervention strategies for MDD, a mental illness that has become the leading cause of disability worldwide.
METHODS: Using resting-state fMRI and graph theory, this study adopted a connectome approach to examine the functional topological organization of the neural network associated with rumination in MDD. Data from 96 participants were analyzed, including 51 patients with MDD and 45 healthy controls.
RESULTS: We found altered functional integration and segregation of neural networks associated with depressive rumination as indicated by reduced global and local efficiency in MDD patients compared with controls. Interestingly, these metrics correlated positively with depression severity, as measured by the Hamilton Depression Rating Scale. Moreover, mediation analysis indicated that the association between network metrics and depression severity was mediated by the ruminative tendency of patients. Disrupted nodal centralities were located in regions associated with emotional processing, visual mental imagery, and attentional control.
CONCLUSION: Our results highlight rumination as a two-edged sword that reflects a disease-specific neuropathology but also points to a functionality of depressive symptoms with evolutionary meaning.

PMID: 31734293 [PubMed - as supplied by publisher]

Single-subject manual independent component analysis and resting state fMRI connectivity outcomes in patients with juvenile absence epilepsy.

Mon, 11/18/2019 - 14:40
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Single-subject manual independent component analysis and resting state fMRI connectivity outcomes in patients with juvenile absence epilepsy.

Magn Reson Imaging. 2019 Nov 14;:

Authors: Parsons N, Bowden S, Vogrin S, D'Souza W

Abstract
The quality of fMRI data impacts functional connectivity measures and consequently, the decisions that clinicians and researchers make regarding functional connectivity interpretation. The present study used resting state fMRI to investigate resting state network connectivity in a sample of patients with Juvenile Absence Epilepsy. Single-subject manual independent component analysis was used in two levels, whereby all noise components were removed, and cerebrospinal fluid pulsation components only were isolated and removed. Improved temporal signal to noise ratios and functional connectivity metrics were observed in each of the cleaning levels for both epilepsy and control cohorts. Results showed full, single-subject manual independent component analysis reduced the number of functional connectivity correlations and increased the strength of these correlations. Similar effects were also observed for the cerebrospinal fluid pulsation only cleaned data relative to the uncleaned, and fully cleaned data. Single-subject manual independent component analysis coupled with short TR multiband acquisition can significantly improve the validity of findings derived from fMRI data sets.

PMID: 31734272 [PubMed - as supplied by publisher]

Impaired motor skills and atypical functional connectivity of the sensorimotor system in 40- to 65-year-old adults with autism spectrum disorders.

Sun, 11/17/2019 - 13:40
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Impaired motor skills and atypical functional connectivity of the sensorimotor system in 40- to 65-year-old adults with autism spectrum disorders.

Neurobiol Aging. 2019 Sep 27;:

Authors: Linke AC, Kinnear MK, Kohli JS, Fong CH, Lincoln AJ, Carper RA, Müller RA

Abstract
Impairments in fine and gross motor function, coordination, and balance in early development are common in autism spectrum disorders (ASDs). It is unclear whether these deficits persist into adulthood and whether they may be exacerbated by additional motor problems that often emerge in typical aging. We assessed motor skills and used resting-state functional magnetic resonance imaging to study intrinsic functional connectivity of the sensorimotor network in 40- to 65-year-old adults with ASDs (n = 17) and typically developing matched adults (n = 19). Adults with ASDs scored significantly lower on assessments of motor skills compared with an age-matched group of typical control adults. In addition, functional connectivity of the sensorimotor system was reduced and the pattern of connectivity was more heterogeneous in adults with ASDs. A negative correlation between functional connectivity of the motor system and motor skills, however, was only found in the typical control group. Findings suggest behavioral impairment and atypical brain organization of the motor system in middle-age adults with ASDs, accompanied by pronounced heterogeneity.

PMID: 31732217 [PubMed - as supplied by publisher]

Cingulate cortex in Parkinson's disease.

Sun, 11/17/2019 - 13:40
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Cingulate cortex in Parkinson's disease.

Handb Clin Neurol. 2019;166:253-266

Authors: Vogt BA

Abstract
Once a diagnosis of Parkinson's disease (PD) has been made, even in its earliest prodromal form of subjective memory impairment, cognitive impairment has begun and involves anterior cingulate cortex (ACC). While the Braak staging scheme showed mid- to later-stage PD progression from cingulate allocortex adjacent to the corpus callosum and progressing into its neocortical moieties, the last decade has produced substantial information on the role of cingulate cortex in multiple symptoms, not just global measures of cognition. Voxel-based morphometry has been used in many studies of mild cognitive impairment (MCI) in PD to show reduced thickness in ACC and posterior cingulate cortex (PCC). Regional cerebral blood flow is altered in association with verbal IQ in all the PCC and anterior midcingulate cortex and executive impairments in ACC. Diffusion tensor imaging shows reduced fractional anisotropy throughout the entire cingulum bundle. Amnestic MCI is associated with reduced dopamine-2 receptor binding in ACC and, even in cognitively normal PD cases, dopaminergic pathways in ACC are impaired early in association with executive and language functions. The cholinergic system also has substantial changes in nicotinic and muscarinic receptor binding, and therapy with donepezil improves Mini-Mental State Exam scores and metabolism in pACC and dPCC. Cingulate cortex is also engaged in two critical symptoms: apathy and visual hallucinations. Finally, one can be optimistic that cingulate cortex will play an important role in developing new biomarkers of early PD. These methods have already been shown to be useful in cingulate cortex and include magnetic resonance spectroscopy, next-generation gene expression, and the new α-synuclein proximity ligation assay that specifically recognizes α-synuclein oligomers. Thus the future is bright for developing multivariate, multimodal biomarkers that include cingulate cortex.

PMID: 31731914 [PubMed - in process]

Cingulate role in Tourette syndrome.

Sun, 11/17/2019 - 13:40
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Cingulate role in Tourette syndrome.

Handb Clin Neurol. 2019;166:165-221

Authors: O'Neill J, Piacentini JC, Peterson BS

Abstract
This chapter comprehensively reviews the published record for neurosurgical, neurostimulatory, and neuroimaging evidence of the involvement of the cingulate gyrus in Gilles de la Tourette syndrome (TS). The most noteworthy evidence comes from neuroimaging. Neuroimaging findings were rarely exclusive to the cingulate cortex and tended to implicate multiple other cortices as well. Some results are reflective of obsessive-compulsive (OC) symptoms of TS. Copious findings, however, drawn from structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), resting-state functional magnetic resonance imaging (rsfMRI), task fMRI, and positron emission tomography (PET) implicate six of the eight cingulate subregions in TS. Gauged by MRI, cortical thinning and/or below-normal volume are seen in subgenual anterior cingulate cortex (sACC), pregenual anterior cingulate cortex (pACC), anterior middle cingulate cortex (aMCC), and posterior middle cingulate cortex (pMCC), correlating with tic severity in sACC, pACC, and aMCC. Moreover, in pMCC, dorsal posterior cingulate cortex (dPCC), and ventral posterior cingulate cortex (vPCC), cortical thickness is a candidate biomarker shared across siblings with TS. Loss of cortex may reflect excitotoxicity secondary to insufficient local GABAergic inhibition, a notion supported by the few relevant MRS and PET studies conducted to date, recommending continued development of GABAergic and glutamatergic pharmacologic agents to treat TS. Measurements of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) obtained with DTI indicate that the white matter proximal to sACC, pACC, pMCC, and dPCC may also represent a seat of pathology in TS. rsfMRI reveals abnormal functional connectivity of pACC and dPCC with the globus pallidus internus, a favored target of therapeutic deep brain stimulation (DBS) for TS. In whole-brain network (graph theory) analysis, dPCC functional connectivity is related to the severity and complexity of tics. In task fMRI, in contrast, the pMCC seems to play a preeminent role in premonitory urges and preparation for tics as well as normal urges to urinate, swallow, and yawn. Strong monkey PET and EEG evidence ties vocal tics to spike discharges, α-activity, and regional blood flow in the pACC unleashed by failure of GABAergic inhibition in the ventral striatum. Tic suppression in fMRI scans is associated with increased blood oxygenation level-dependent activity in sACC, pACC, and aMCC, but decreased activity in pMCC and dPCC. Activity in the former three subregions may represent volitional effort, physical discomfort, and emotional distress that accompanies mounting tic urges; pMCC and dPCC may be more instrumental in amplifying than suppressing urges. Needs for future neuroimaging work in TS include longitudinal studies-particularly those striving to predict which individual pediatric patients will continue to suffer from TS as adults and studies of treatment response-particularly of behavioral therapies, which are as efficacious as pharmacology. Transcranial magnetic stimulation and related therapies such as cranial electrotherapy stimulation, which showed good efficacy in a recent trial, merit continued exploration. TS research using DTI, MRS, and PET will no doubt continue to benefit in coming years from technological advances such as ultrahigh-field scanners, multichannel head coils, and novel (including GABAergic and glutamatergic) ligands.

PMID: 31731911 [PubMed - in process]

Network convergence zones in the anterior midcingulate cortex.

Sun, 11/17/2019 - 13:40
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Network convergence zones in the anterior midcingulate cortex.

Handb Clin Neurol. 2019;166:103-111

Authors: Margulies DS, Uddin LQ

Abstract
Situated medially and centrally in the brain, the anterior midcingulate cortex (aMCC) is a nexus of control. This specialized neocortical brain region participates in large-scale brain networks underlying attention, motor, and limbic processes. The functional diversity and proximity of cognitive and affective subdivisions within this region are its distinguishing features, rendering it an effective site for integration across domains. Here we review comparative neuroanatomic, meta-analytic, and connectomic analyses contributing to the emerging picture of the aMCC as comprising functionally diverse, flexible network nodes involved in multiple regulatory behaviors. We further present data providing evidence for an organizing gradient along the anterior and midcingulate cortex and explore the implications of these findings for understanding the functional role of the anterior midcingulate within this spectrum. We conclude by highlighting open questions and proposing future directions for investigations into the functional role of this important network convergence zone.

PMID: 31731907 [PubMed - in process]

Multi-band SWIFT enables quiet and artefact-free EEG-fMRI and awake fMRI studies in rat.

Sat, 11/16/2019 - 19:00
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Multi-band SWIFT enables quiet and artefact-free EEG-fMRI and awake fMRI studies in rat.

Neuroimage. 2019 Nov 12;:116338

Authors: Paasonen J, Laakso H, Pirttimäki T, Stenroos P, Salo RA, Zhurakovskaya E, Lehto LJ, Tanila H, Garwood M, Michaeli S, Idiyatullin D, Mangia S, Gröhn O

Abstract
Functional magnetic resonance imaging (fMRI) studies in animal models provide invaluable information regarding normal and abnormal brain function, especially when combined with complementary stimulation and recording techniques. The echo planar imaging (EPI) pulse sequence is the most common choice for fMRI investigations, but it has several shortcomings. EPI is one of the loudest sequences and very prone to movement and susceptibility-induced artefacts, making it suboptimal for awake imaging. Additionally, the fast gradient-switching of EPI induces disrupting currents in simultaneous electrophysiological recordings. Therefore, we investigated whether the unique features of Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) overcome these issues at a high 9.4 T magnetic field, making it a potential alternative to EPI. MB-SWIFT had 32-dB and 20-dB lower peak and average sound pressure levels, respectively, than EPI with typical fMRI parameters. Body movements had little to no effect on MB-SWIFT images or functional connectivity analyses, whereas they severely affected EPI data. The minimal gradient steps of MB-SWIFT induced significantly lower currents in simultaneous electrophysiological recordings than EPI, and there were no electrode-induced distortions in MB-SWIFT images. An independent component analysis of the awake rat functional connectivity data obtained with MB-SWIFT resulted in near whole-brain level functional parcellation, and simultaneous electrophysiological and fMRI measurements in isoflurane-anesthetized rats indicated that MB-SWIFT signal is tightly linked to neuronal resting-state activity. Therefore, we conclude that the MB-SWIFT sequence is a robust preclinical brain mapping tool that can overcome many of the drawbacks of conventional EPI fMRI at high magnetic fields.

PMID: 31730923 [PubMed - as supplied by publisher]

Effects of Motion Related Outliers in Dynamic Functional Connectivity Using the Sliding Window Method.

Sat, 11/16/2019 - 19:00
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Effects of Motion Related Outliers in Dynamic Functional Connectivity Using the Sliding Window Method.

J Neurosci Methods. 2019 Nov 12;:108519

Authors: Savva AD, Kassinopoulos M, Smyrnis N, Matsopoulos GK, Mitsis GD

Abstract
BACKGROUND: It has been suggested that the use of window functions, other than the rectangular, in the sliding window method, may be beneficial for reducing the effects of motion-related outliers in the time-series, when assessing dynamic functional connectivity (dFC) in resting-state fMRI (rs-fMRI).
METHODOLOGY: Ten window functions for a wide range of window lengths (20-150 s) combined with Pearson and Kendall correlation metrics, were investigated. One hundred high quality rs-fMRI datasets from healthy controls, were used to systematically assess the effect of varying the window function and length on dFC assessment. To this end, two approaches were implemented: a) simulated outliers were added to the experimental data and b) the experimental data were divided into low and high motion subgroups.
RESULTS: The presence of experimental motion-noise tended to inflate the number of dynamic connections for longer (≥100 s) wide-shaped windows, while shorter (20-30 s) narrow-shaped windows exhibited increased sensitivity in the presence of simulated outliers. Moreover, window sizes from 60 s to 90 s were mildly affected by motion-related effects. In most cases, the number of dynamic connections increased, and gradually lower frequencies were captured, with an increasing window size.
CONCLUSIONS: Subject motion considerably affects the obtained dFC patterns; thus, it is preferable to perform motion artefact removal in the pre-processing stage rather than using alternative window functions to mitigate their effects. Provided that motion-noise is not excessive, the choice of a rectangular window is adequate. Finally, low frequency oscillations in functional connectivity seem to play an important role in the context of dFC assessment.

PMID: 31730872 [PubMed - as supplied by publisher]

Increased soluble amyloid-beta causes early aberrant brain network hypersynchronisation in a mature-onset mouse model of amyloidosis.

Sat, 11/16/2019 - 19:00
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Increased soluble amyloid-beta causes early aberrant brain network hypersynchronisation in a mature-onset mouse model of amyloidosis.

Acta Neuropathol Commun. 2019 Nov 14;7(1):180

Authors: Ben-Nejma IRH, Keliris AJ, Daans J, Ponsaerts P, Verhoye M, Van der Linden A, Keliris GA

Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly. According to the amyloid hypothesis, the accumulation and deposition of amyloid-beta (Aβ) peptides play a key role in AD. Soluble Aβ (sAβ) oligomers were shown to be involved in pathological hypersynchronisation of brain resting-state networks in different transgenic developmental-onset mouse models of amyloidosis. However, the impact of protein overexpression during brain postnatal development may cause additional phenotypes unrelated to AD. To address this concern, we investigated sAβ effects on functional resting-state networks in transgenic mature-onset amyloidosis Tet-Off APP (TG) mice. TG mice and control littermates were raised on doxycycline (DOX) diet from 3d up to 3 m of age to suppress transgenic Aβ production. Thereafter, longitudinal resting-state functional MRI was performed on a 9.4 T MR-system starting from week 0 (3 m old mice) up to 28w post DOX treatment. Ex-vivo immunohistochemistry and ELISA analysis was performed to assess the development of amyloid pathology. Functional Connectivity (FC) analysis demonstrated early abnormal hypersynchronisation in the TG mice compared to the controls at 8w post DOX treatment, particularly across regions of the default mode-like network, known to be affected in AD. Ex-vivo analyses performed at this time point confirmed a 20-fold increase in total sAβ levels preceding the apparition of Aβ plaques and inflammatory responses in the TG mice compared to the controls. On the contrary at week 28, TG mice showed an overall hypoconnectivity, coinciding with a widespread deposition of Aβ plaques in the brain. By preventing developmental influence of APP and/or sAβ during brain postnatal development, we demonstrated FC abnormalities potentially driven by sAβ neurotoxicity on resting-state neuronal networks in mature-induced TG mice. Thus, the Tet-Off APP mouse model could be a powerful tool while used as a mature-onset model to shed light into amyloidosis mechanisms in AD.

PMID: 31727182 [PubMed - in process]

Stimulating the hippocampal posterior-medial network enhances task-dependent connectivity and memory.

Fri, 11/15/2019 - 18:20
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Stimulating the hippocampal posterior-medial network enhances task-dependent connectivity and memory.

Elife. 2019 Nov 14;8:

Authors: Warren KN, Hermiller MS, Nilakantan AS, Voss JL

Abstract
Successful episodic memory involves dynamic increases in activity across distributed hippocampal networks, including the posterior-medial (PMN) and the anterior-temporal (ATN) networks. We tested whether this up-regulation of functional connectivity during memory processing can be enhanced within hippocampal networks by noninvasive stimulation, and whether such task-dependent connectivity enhancement predicts memory improvement. Participants received stimulation targeting the PMN or an out-of-network control location. We compared the effects of stimulation on fMRI connectivity during an autobiographical retrieval task versus during rest within the PMN and the ATN. PMN-targeted stimulation significantly increased connectivity during autobiographical retrieval versus rest within the PMN. This effect was not observed in the ATN, or in either network following control stimulation. Task-dependent increases in connectivity within the medial temporal lobe predicted improved performance of a separate episodic memory test. It is therefore possible to enhance the task-dependent regulation of hippocampal network connectivity that supports memory processing using noninvasive stimulation.

PMID: 31724946 [PubMed - in process]

Temporal stability of fMRI in medetomidine-anesthetized rats.

Fri, 11/15/2019 - 18:20
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Temporal stability of fMRI in medetomidine-anesthetized rats.

Sci Rep. 2019 Nov 13;9(1):16673

Authors: Sirmpilatze N, Baudewig J, Boretius S

Abstract
Medetomidine has become a popular choice for anesthetizing rats during long-lasting sessions of blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI). Despite this, it has not yet been thoroughly established how commonly reported fMRI readouts evolve over several hours of medetomidine anesthesia and how they are affected by the precise timing, dose, and route of administration. We used four different protocols of medetomidine administration to anesthetize rats for up to six hours and repeatedly evaluated somatosensory stimulus-evoked BOLD responses and resting state functional connectivity. We found that the temporal evolution of fMRI readouts strongly depended on the method of administration. Intravenous administration of a medetomidine bolus (0.05 mg/kg), combined with a subsequent continuous infusion (0.1 mg/kg/h), led to temporally stable measures of stimulus-evoked activity and functional connectivity throughout the anesthesia. Deviating from the above protocol-by omitting the bolus, lowering the medetomidine dose, or using the subcutaneous route-compromised the stability of these measures in the initial two-hour period. We conclude that both an appropriate protocol of medetomidine administration and a suitable timing of fMRI experiments are crucial for obtaining consistent results. These factors should be considered for the design and interpretation of future rat fMRI studies.

PMID: 31723186 [PubMed - in process]

Quantitative imaging of brain energy metabolisms and neuroenergetics using in vivo X-nuclear 2H, 17O and 31P MRS at ultra-high field.

Fri, 11/15/2019 - 18:20
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Quantitative imaging of brain energy metabolisms and neuroenergetics using in vivo X-nuclear 2H, 17O and 31P MRS at ultra-high field.

J Magn Reson. 2018 07;292:155-170

Authors: Zhu XH, Lu M, Chen W

Abstract
Brain energy metabolism relies predominantly on glucose and oxygen utilization to generate biochemical energy in the form of adenosine triphosphate (ATP). ATP is essential for maintaining basal electrophysiological activities in a resting brain and supporting evoked neuronal activity under an activated state. Studying complex neuroenergetic processes in the brain requires sophisticated neuroimaging techniques enabling noninvasive and quantitative assessment of cerebral energy metabolisms and quantification of metabolic rates. Recent state-of-the-art in vivo X-nuclear MRS techniques, including 2H, 17O and 31P MRS have shown promise, especially at ultra-high fields, in the quest for understanding neuroenergetics and brain function using preclinical models and in human subjects under healthy and diseased conditions.

PMID: 29866434 [PubMed - indexed for MEDLINE]

Altered brain connectivity in sudden unexpected death in epilepsy (SUDEP) revealed using resting-state fMRI.

Thu, 11/14/2019 - 16:20

Altered brain connectivity in sudden unexpected death in epilepsy (SUDEP) revealed using resting-state fMRI.

Neuroimage Clin. 2019 Oct 28;24:102060

Authors: LA A, Rm H, M G, R K, Ja O, Sb V, S O, Ca S, Sd L, L L, B D

Abstract
The circumstances surrounding SUDEP suggest autonomic or respiratory collapse, implying central failure of regulation or recovery. Characterisation of the communication among brain areas mediating such processes may shed light on mechanisms and noninvasively indicate risk. We used rs-fMRI to examine network properties among brain structures in people with epilepsy who suffered SUDEP (n = 8) over an 8-year follow-up period, compared with matched high- and low-risk subjects (n = 16/group) who did not suffer SUDEP during that period, and a group of healthy controls (n = 16). Network analysis was employed to explore connectivity within a 'regulatory-subnetwork' of brain regions involved in autonomic and respiratory regulation, and over the whole-brain. Modularity, the extent of network organization into separate modules, was significantly reduced in the regulatory-subnetwork, and the whole-brain, in SUDEP and high-risk. Increased participation, a local measure of inter-modular belonging, was evident in SUDEP and high-risk groups, particularly among thalamic structures. The medial prefrontal thalamus was increased in SUDEP compared with all other control groups, including high-risk. Patterns of hub topology were similar in SUDEP and high-risk, but were more extensive in low-risk patients, who displayed greater hub prevalence and a radical reorganization of hubs in the subnetwork. SUDEP is associated with reduced functional organization among cortical and sub-cortical brain regions mediating autonomic and respiratory regulation. Living high-risk subjects demonstrated similar patterns, suggesting such network measures may provide prospective risk-indicating value, though a crucial difference between SUDEP and high-risk was altered connectivity of the medial thalamus in SUDEP, which was also elevated compared with all sub-groups. Disturbed thalamic connectivity may reflect a potential non-invasive marker of elevated SUDEP risk.

PMID: 31722289 [PubMed - as supplied by publisher]

Hubs disruption in mesial temporal lobe epilepsy. A resting-state fMRI study on a language-and-memory network.

Thu, 11/14/2019 - 16:20

Hubs disruption in mesial temporal lobe epilepsy. A resting-state fMRI study on a language-and-memory network.

Hum Brain Mapp. 2019 Nov 13;:

Authors: Roger E, Pichat C, Torlay L, David O, Renard F, Banjac S, Attyé A, Minotti L, Lamalle L, Kahane P, Baciu M

Abstract
Mesial temporal lobe epilepsy (mTLE) affects the brain networks at several levels and patients suffering from mTLE experience cognitive impairment for language and memory. Considering the importance of language and memory reorganization in this condition, the present study explores changes of the embedded language-and-memory network (LMN) in terms of functional connectivity (FC) at rest, as measured with functional MRI. We also evaluate the cognitive efficiency of the reorganization, that is, whether or not the reorganizations support or allow the maintenance of optimal cognitive functioning despite the seizure-related damage. Data from 37 patients presenting unifocal mTLE were analyzed and compared to 48 healthy volunteers in terms of LMN-FC using two methods: pairwise correlations (region of interest [ROI]-to-ROI) and graph theory. The cognitive efficiency of the LMN-FC reorganization was measured using correlations between FC parameters and language and memory scores. Our findings revealed a large perturbation of the LMN hubs in patients. We observed a hyperconnectivity of limbic areas near the dysfunctional hippocampus and mainly a hypoconnectivity for several cortical regions remote from the dysfunctional hippocampus. The loss of FC was more important in left mTLE (L-mTLE) than in right (R-mTLE) patients. The LMN-FC reorganization may not be always compensatory and not always useful for patients as it may be associated with lower cognitive performance. We discuss the different connectivity patterns obtained and conclude that interpretation of FC changes in relation to neuropsychological scores is important to determine cognitive efficiency, suggesting the concept of "connectome" would gain to be associated with a "cognitome" concept.

PMID: 31721361 [PubMed - as supplied by publisher]

Allelic variant in SLC6A3 rs393795 affects cerebral regional homogeneity and gait dysfunction in patients with Parkinson's disease.

Thu, 11/14/2019 - 16:20

Allelic variant in SLC6A3 rs393795 affects cerebral regional homogeneity and gait dysfunction in patients with Parkinson's disease.

PeerJ. 2019;7:e7957

Authors: Wang L, Yuan Y, Wang J, Shen Y, Zhi Y, Li J, Wang M, Zhang K

Abstract
Aims: We sought to explore the role of the SLC6A3 rs393795 allelic variant in cerebral spontaneous activity and clinical features in Parkinson's disease (PD) via imaging genetic approach.
Methods: Our study recruited 50 PD and 45 healthy control (HC) participants to provide clinical, genetic, and resting state functional magnetic resonance imaging (rs-fMRI) data. All subjects were separated into 16 PD-AA, 34 PD-CA/CC, 14 HC-AA, and 31 HC-CA/CC four subgroups according to SLC6A3 rs393795 genotyping. Afterwards, main effects and interactions of groups (PD versus HC) and genotypes (AA versus CA/CC) on cerebral function reflected by regional homogeneity (ReHo) were explored using two-way analysis of covariance (ANCOVA) after controlling age and gender. Finally, Spearman' s correlations were employed to investigate the relationships between significantly interactive brain regions and clinical manifestations in PD subgroups.
Results: Compared with HC subjects, PD patients exhibited increased ReHo signals in left middle temporal gyrus and decreased ReHo signals in left pallidum. Compared with CA/CC carriers, AA genotype individuals showed abnormal increased ReHo signals in right inferior frontal gyrus (IFG) and supplementary motor area (SMA). Moreover, significant interactions (affected by both disease factor and allelic variation) were detected in right inferior temporal gyrus (ITG). Furthermore, aberrant increased ReHo signals in right ITG were observed in PD-AA in comparison with PD-CA/CC. Notably, ReHo values in right ITG were negatively associated with Tinetti Mobility Test (TMT) gait subscale scores and positively related to Freezing of Gait Questionnaire (FOG-Q) scores in PD-AA subgroup.
Conclusions: Our findings suggested that SLC6A3 rs393795 allelic variation might have a trend to aggravate the severity of gait disorders in PD patients by altering right SMA and IFG function, and ultimately result in compensatory activation of right ITG. It could provide us with a new perspective for exploring deeply genetic mechanisms of gait disturbances in PD.

PMID: 31720106 [PubMed]

Dissociable neural substrates of opioid and cocaine use identified via connectome-based modelling.

Thu, 11/14/2019 - 16:20

Dissociable neural substrates of opioid and cocaine use identified via connectome-based modelling.

Mol Psychiatry. 2019 Nov 12;:

Authors: Lichenstein SD, Scheinost D, Potenza MN, Carroll KM, Yip SW

Abstract
Opioid use disorder is a major public health crisis. While effective treatments are available, outcomes vary widely across individuals and relapse rates remain high. Understanding neural mechanisms of treatment response may facilitate the development of personalized and/or novel treatment approaches. Methadone-maintained, polysubstance-using individuals (n = 53) participated in fMRI scanning before and after substance-use treatment. Connectome-based predictive modeling (CPM)-a recently developed, whole-brain approach-was used to identify pretreatment connections associated with abstinence during the 3-month treatment. Follow-up analyses were conducted to determine the specificity of the identified opioid abstinence network across different brain states (cognitive vs. reward task vs. resting-state) and different substance use outcomes (opioid vs. cocaine abstinence). Posttreatment fMRI data were used to assess network changes over time and within-subject replication. To determine further clinical relevance, opioid abstinence network strength was compared with healthy subjects (n = 38). CPM identified an opioid abstinence network (p = 0.018), characterized by stronger within-network motor/sensory connectivity, and reduced connectivity between the motor/sensory network and medial frontal, default mode, and frontoparietal networks. This opioid abstinence network was anatomically distinct from a previously identified cocaine abstinence network. Relationships between abstinence and opioid and cocaine abstinence networks replicated across multiple brain states but did not generalize across substances. Network connectivity measured at posttreatment related to abstinence at 6-month follow-up (p < 0.009). Healthy comparison subjects displayed intermediate network strengths relative to treatment responders and nonresponders. These data indicate dissociable anatomical substrates of opioid vs. cocaine abstinence. Results may inform the development of novel opioid-specific treatment approaches to combat the opioid epidemic.

PMID: 31719641 [PubMed - as supplied by publisher]

Functional maintenance in the multiple demand network characterizes superior fluid intelligence in aging.

Thu, 11/14/2019 - 16:20

Functional maintenance in the multiple demand network characterizes superior fluid intelligence in aging.

Neurobiol Aging. 2019 Sep 20;:

Authors: Zuo N, Salami A, Liu H, Yang Z, Jiang T

Abstract
The multiple demand network (MDN) is conceptualized as the core processing system for multitasking. Increasing evidence also provides strong support for the involvement of the MDN in fluid intelligence (gF), that is, the ability to solve new problems. However, the underlying neural mechanisms of declining intelligence in old age are poorly explored, particularly whether maintenance of the functional architecture of the MDN can characterize superior intelligence in successful aging. Here, we used eigenvector centrality (EC) to explore the resting-state functional architecture of the MDN in terms of its communication across the entire brain. We found gF to be negatively associated with age and that the MDN EC competitively mediated age-related decline in gF over the aging lifespan, suggesting that excessive cross-talk from the MDN is deleterious for intelligence. Critically, older individuals with comparable MDN EC as younger individuals exhibited superior gF compared with their age-matched counterparts. Taken together, these data provide support for the maintenance of youth-like functional architecture of the MDN and its implication for superior intelligence in successful aging.

PMID: 31718925 [PubMed - as supplied by publisher]

Evidence for Depressogenic Spontaneous Thoughts and Altered Resting-State Connectivity in Adolescents With a Maltreatment History.

Thu, 11/14/2019 - 16:20
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Evidence for Depressogenic Spontaneous Thoughts and Altered Resting-State Connectivity in Adolescents With a Maltreatment History.

J Am Acad Child Adolesc Psychiatry. 2018 09;57(9):687-695.e4

Authors: Hoffmann F, Viding E, Puetz VB, Gerin MI, Sethi A, Rankin G, McCrory EJ

Abstract
OBJECTIVE: Childhood maltreatment has been associated with major depressive disorder (MDD). Atypical self-generated thoughts (SGT), lacking in positive and privileging negative content-a feature of ruminative thinking-might represent one vulnerability factor for developing depression. Rumination in MDD has been linked to alterations in resting-state functional connectivity (RSFC) of the subgenual anterior cingulate cortex (sgACC) to the default mode network and the fronto-parietal network (FPN). This study aimed to investigate online SGT content and its variability, as well as sgACC RSFC, as potential risk markers for depression in adolescents who experienced maltreatment.
METHOD: Adolescents 12 to 16 years old (29 with maltreatment history [MT] and 39 with no maltreatment history [NMT]) performed an established mind-wandering task. Participants made nondemanding number discriminations during which intermittent questions probed their SGTs that were classified as off-task, positive, negative, self-related, other-related, past-oriented, or future-oriented. Resting-state data were acquired separately for 22 of 29 MT and 27 39 NMT adolescents, and seed-based functional connectivity analyses of the sgACC were performed.
RESULTS: MT, relative to the NMT adolescents, generated significantly fewer positively valenced thoughts, and exhibited more extreme ratings for positively valenced thoughts. MT adolescents also showed significantly reduced RSFC between the sgACC and the FPN. Group differences in depressive symptoms between the MT and NMT adolescents were partly accounted by differences in sgACC-FPN RSFC.
CONCLUSION: Adolescents who experienced maltreatment show a reduction in positively valenced spontaneous thoughts and reduced sgACC-FPN RSFC at the neural level. These may contribute to a ruminative thinking style, representing risk factors for developing depression later in life.

PMID: 30196872 [PubMed - indexed for MEDLINE]

X-Chromosome Effects on Attention Networks: Insights from Imaging Resting-State Networks in Turner Syndrome.

Thu, 11/14/2019 - 16:20
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X-Chromosome Effects on Attention Networks: Insights from Imaging Resting-State Networks in Turner Syndrome.

Cereb Cortex. 2018 09 01;28(9):3176-3183

Authors: Green T, Saggar M, Ishak A, Hong DS, Reiss AL

Abstract
Attention deficit hyperactivity disorder (ADHD) is strongly affected by sex, but sex chromosomes' effect on brain attention networks and cognition are difficult to examine in humans. This is due to significant etiologic heterogeneity among diagnosed individuals. In contrast, individuals with Turner syndrome (TS), who have substantially increased risk for ADHD symptoms, share a common genetic risk factor related to the absence of the X-chromosome, thus serving as a more homogeneous genetic model. Resting-state functional MRI was employed to examine differences in attention networks between girls with TS (n = 40) and age- sex- and Tanner-matched controls (n = 33). We compared groups on resting-state functional connectivity measures from data-driven independent components analysis (ICA) and hypothesis-based seed analysis. Using ICA, reduced connectivity was observed in both frontoparietal and dorsal attention networks. Similarly, using seeds in the bilateral intraparietal sulcus (IPS), reduced connectivity was observed between IPS and frontal and cerebellar regions. Finally, we observed a brain-behavior correlation between IPS-cerebellar connectivity and cognitive attention measures. These findings indicate that X-monosomy contributes affects to attention networks and cognitive dysfunction that might increase risk for ADHD. Our findings not only have clinical relevance for girls with TS, but might also serve as a biological marker in future research examining the effects of the intervention that targets attention skills.

PMID: 28981595 [PubMed - indexed for MEDLINE]

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