scholarly journals Modulation of Working Memory and Resting-State fMRI by tDCS of the Right Frontoparietal Network

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Monika Pupíková ◽  
Patrik Šimko ◽  
Martin Gajdoš ◽  
Irena Rektorová
Keyword(s):  
Working Memory ◽  
Resting State ◽  
Large Scale ◽  
Memory Task ◽  
Resting State Fmri ◽  
Resting State Functional Connectivity ◽  
Double Blind ◽  
Frontoparietal Network ◽  
Cognitive Speed ◽  
The Right

Many cognitive functions, including working memory, are processed within large-scale brain networks. We targeted the right frontoparietal network (FPN) with one session of transcranial direct current stimulation (tDCS) in an attempt to modulate the cognitive speed of a visual working memory task (WMT) in 27 young healthy subjects using a double-blind crossover design. We further explored the neural underpinnings of induced changes by performing resting-state fMRI prior to and immediately after each stimulation session with the main focus on the interaction between a task-positive FPN and a task-negative default mode network (DMN). Twenty minutes of 2 mA anodal tDCS was superior to sham stimulation in terms of cognitive speed manipulation of a subtask with processing of objects and tools in unconventional views (i.e., the higher cognitive load subtask of the offline WMT). This result was linked to the magnitude of resting-state functional connectivity decreases between the stimulated FPN seed and DMN seeds. We provide the first evidence for the action reappraisal mechanism of object and tool processing. Modulation of cognitive speed of the task by tDCS was reflected by FPN-DMN cross-talk changes.

scholarly journals White-Matter Hyperintensity Load and Differences in Resting-State Network Connectivity Based on Mild Cognitive Impairment Subtype

2021 ◽  
Vol 13 ◽  
Author(s):  
Martina Vettore ◽  
Matteo De Marco ◽  
Claudia Pallucca ◽  
Matteo Bendini ◽  
Maurizio Gallucci ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Resting State ◽  
Large Scale ◽  
Network Connectivity ◽  
Functional Networks ◽  
Frontoparietal Network ◽  
Definition Of ◽  
The Right

“Mild cognitive impairment” (MCI) is a diagnosis characterised by deficits in episodic memory (aMCI) or in other non-memory domains (naMCI). Although the definition of subtypes is helpful in clinical classification, it provides little insight on the variability of neurofunctional mechanisms (i.e., resting-state brain networks) at the basis of symptoms. In particular, it is unknown whether the presence of a high load of white-matter hyperintensities (WMHs) has a comparable effect on these functional networks in aMCI and naMCI patients. This question was addressed in a cohort of 123 MCI patients who had completed an MRI protocol inclusive of T1-weighted, fluid-attenuated inversion recovery (FLAIR) and resting-state fMRI sequences. T1-weighted and FLAIR images were processed with the Lesion Segmentation Toolbox to quantify whole-brain WMH volumes. The CONN toolbox was used to preprocess all fMRI images and to run an independent component analysis for the identification of four large-scale haemodynamic networks of cognitive relevance (i.e., default-mode, salience, left frontoparietal, and right frontoparietal networks) and one control network (i.e., visual network). Patients were classified based on MCI subtype (i.e., aMCI vs. naMCI) and WMH burden (i.e., low vs. high). Maps of large-scale networks were then modelled as a function of the MCI subtype-by-WMH burden interaction. Beyond the main effects of MCI subtype and WMH burden, a significant interaction was found in the salience and left frontoparietal networks. Having a low WMH burden was significantly more associated with stronger salience-network connectivity in aMCI (than in naMCI) in the right insula, and with stronger left frontoparietal-network connectivity in the right frontoinsular cortex. Vice versa, having a low WMH burden was significantly more associated with left-frontoparietal network connectivity in naMCI (than in aMCI) in the left mediotemporal lobe. The association between WMH burden and strength of connectivity of resting-state functional networks differs between aMCI and naMCI patients. Although exploratory in nature, these findings indicate that clinical profiles reflect mechanistic interactions that may play a central role in the definition of diagnostic and prognostic statuses.

scholarly journals Cognitive enhancement: Effects of methylphenidate, modafinil and caffeine on latent memory and resting state functional connectivity in healthy adults

2021 ◽  
Author(s):  
Maxi Becker ◽  
Dimitris Repantis ◽  
Martin Dresler ◽  
Simone Kuehn
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Medial Temporal Lobe ◽  
Large Scale ◽  
Cognitive Enhancement ◽  
Brain Regions ◽  
Controlled Study ◽  
Attention And Memory ◽  
Resting State Functional Connectivity ◽  
Double Blind

Stimulants like methylphenidate, modafinil and caffeine have repeatedly shown to enhance cognitive processes such as attention and memory. However, brain-functional mechanisms underlying such cognitive enhancing effects of stimulants are still poorly characterized. Here, we utilized behavioral and resting-state fMRI data from a double-blind randomized placebo-controlled study of methylphenidate, modafinil and caffeine in 48 healthy male adults. The results show that performance in different memory tasks is enhanced, and functional connectivity (FC) specifically between the fronto-parietal (FPN) and default mode (DMN) network is modulated by the stimulants in comparison to placebo. Decreased negative connectivity between right prefrontal and medial parietal but also between medial temporal lobe and visual brain regions predicted stimulant-induced latent memory enhancement. We discuss dopamine's role in attention and memory as well as its ability to modulate FC between large-scale neural networks (e.g. FPN and DMN) as a potential cognitive enhancement mechanism.

scholarly journals Heritability analysis with repeat measurements and its application to resting-state functional connectivity

2017 ◽  
Vol 114 (21) ◽  
pp. 5521-5526 ◽  
Author(s):  
Tian Ge ◽  
Avram J. Holmes ◽  
Randy L. Buckner ◽  
Jordan W. Smoller ◽  
Mert R. Sabuncu
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Large Scale ◽  
Resting State Fmri ◽  
Transient Effects ◽  
Resting State Functional Connectivity ◽  
Linear Mixed Effects ◽  
Heritability Analysis ◽  
Test Retest Reliability ◽  
Different Levels

Heritability, defined as the proportion of phenotypic variation attributable to genetic variation, provides important information about the genetic basis of a trait. Existing heritability analysis methods do not discriminate between stable effects (e.g., due to the subject’s unique environment) and transient effects, such as measurement error. This can lead to misleading assessments, particularly when comparing the heritability of traits that exhibit different levels of reliability. Here, we present a linear mixed effects model to conduct heritability analyses that explicitly accounts for intrasubject fluctuations (e.g., due to measurement noise or biological transients) using repeat measurements. We apply the proposed strategy to the analysis of resting-state fMRI measurements—a prototypic data modality that exhibits variable levels of test–retest reliability across space. Our results reveal that the stable components of functional connectivity within and across well-established large-scale brain networks can be considerably heritable. Furthermore, we demonstrate that dissociating intra- and intersubject variation can reveal genetic influence on a phenotype that is not fully captured by conventional heritability analyses.

scholarly journals Working Memory Training Is Associated with Changes in Resting State Functional Connectivity in Children Who Were Born Extremely Preterm: a Randomized Controlled Trial

2019 ◽  
Vol 3 (4) ◽  
pp. 376-387
Author(s):  
Chieh-En Jane Tseng ◽  
Leona Pascoe ◽  
Gehan Roberts ◽  
Lex W. Doyle ◽  
Katherine J. Lee ◽  
...  
Keyword(s):  
Working Memory ◽  
Resting State ◽  
Controlled Trial ◽  
Memory Performance ◽  
Central Executive ◽  
Working Memory Training ◽  
Memory Training ◽  
Resting State Functional Connectivity ◽  
Extremely Preterm ◽  
The Right

Abstract Children born extremely preterm (EP; < 28 weeks of gestation) or extremely low birth weight (ELBW; < 1000 g) are at increased risk of working memory deficits compared with their term-born peers and may benefit from working memory training. This study aimed to determine whether Cogmed Working Memory Training®, compared with a placebo training program, was associated with changes in resting-state functional connectivity (rsfc) and whether these changes correlated with working memory performance in EP/ELBW children. Twenty-one 7-year-old EP/ELBW children were enrolled in a double-blinded randomized controlled trial and had magnetic resonance imaging (MRI) assessments (Cogmed, n = 12; placebo (a non-adaptive version of Cogmed), n = 9). Prior to training (baseline) and 2 weeks post-training, all children received a cognitive assessment, inclusive of immediate memory and working memory measures and an MRI. The Cogmed Improvement Index was used as a measure of improvement in trained activities in the Cogmed group. Resting-state functional MRI was used to measure training-related changes in intra- and inter-network rsfc. The networks assessed include the default mode network, the left and right central executive networks, the bilateral executive network, the dorsal attention network, and the salience network. rsfc data were compared between treatment groups and investigated in relation to changes in working memory performance. There was little evidence of differences in intra- or inter-network rsfc strength changes from baseline to post-training between treatment groups. In the Cogmed group, working memory performance was associated with increased rsfc from baseline to post-training within the precuneus network, but not in the placebo group. In the Cogmed group, results that did not survive multiple comparison correction further showed that improvement in trained activities was associated with increased rsfc between the left central and bilateral executive networks, and with decreased rsfc within the right central executive network and between the right central executive and salience networks. Changes in rsfc may facilitate working memory performance following Cogmed training. Further studies are needed to investigate how changes in rsfc are associated with behavioral changes to better support working memory in vulnerable groups.

scholarly journals Networks of worry—towards a connectivity-based signature of late-life worry using higher criticism

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew R. Gerlach ◽  
Helmet T. Karim ◽  
Joseph Kazan ◽  
Howard J. Aizenstein ◽  
Robert T. Krafty ◽  
...  
Keyword(s):  
Older Adults ◽  
Functional Connectivity ◽  
Resting State ◽  
Large Scale ◽  
Resting State Fmri ◽  
Anterior Cingulate ◽  
Resting State Functional Connectivity ◽  
Targeted Interventions ◽  
Higher Criticism ◽  
Large Scale Network

AbstractSevere worry is a complex transdiagnostic phenotype independently associated with increased morbidity, including cognitive impairment and cardiovascular diseases. We investigated the neurobiological basis of worry in older adults by analyzing resting state fMRI using a large-scale network-based approach. We collected resting fMRI on 77 participants (>50 years old) with varying worry severity. We computed region-wise connectivity across the default mode network (DMN), anterior salience network, and left executive control network. All 22,366 correlations were regressed on worry severity and adjusted for age, sex, race, education, disease burden, depression, anxiety, rumination, and neuroticism. We employed higher criticism, a second-level method of significance testing for rare and weak features, to reveal the functional connectivity patterns associated with worry. The analysis suggests that worry has a complex, yet distinct signature associated with resting state functional connectivity. Intra-connectivities and inter-connectivities of the DMN comprise the dominant contribution. The anterior cingulate, temporal lobe, and thalamus are heavily represented with overwhelmingly negative association with worry. The prefrontal regions are also strongly represented with a mix of positive and negative associations with worry. Identifying the most salient connections may be useful for targeted interventions for reducing morbidity associated with severe worry in older adults.

scholarly journals Changes in global brain connectivity in LSD-induced altered states of consciousness are attributable to the 5-HT2A receptor

2017 ◽  
Author(s):  
Katrin H. Preller ◽  
Joshua B. Burt ◽  
Jie Lisa Ji ◽  
Charles Schleifer ◽  
Brendan Adkinson ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Resting State ◽  
Brain Connectivity ◽  
Subjective Effects ◽  
Critical Role ◽  
Resting State Fmri ◽  
Data Driven ◽  
Resting State Functional Connectivity ◽  
Double Blind ◽  
Global Brain

ABSTRACTLysergic acid diethylamide (LSD) is a psychedelic drug with predominantly agonist activity at various serotonin (5-HT) and dopamine receptors. Despite the therapeutic and scientific interest in LSD, the specific receptor contributions to its neurobiological effects remain largely unknown. To address this knowledge gap, we conducted a double-blind, randomized, counterbalanced, cross-over study during which 24 healthy participants received either i) placebo+placebo, ii) placebo+LSD (100 μg po), or iii) ketanserin – a selective 5-HT2A receptor antagonist. Here we focus on resting-state fMRI, a measure of spontaneous neural fluctuations that can map functional brain connectivity. We collected resting-state data 75 and 300 minutes after LSD/placebo administration. We quantified resting-state functional connectivity via a fully data-driven global brain connectivity (GBC) method to comprehensively map LSD neuropharmacological effects. LSD administration caused widespread GBC alterations that followed a specific topography: LSD reduced connectivity in associative areas, but concurrently increased connectivity across sensory and somatomotor areas. The 5-HT2A receptor antagonist, ketanserin, fully blocked the subjective and neural LSD effects. We show that whole-brain data-driven spatial patterns of LSD effects matched 5-HT2A receptor cortical gene expression in humans, which along with ketanserin effects, strongly implicates the 5-HT2A receptor in LSD’s neuropharmacology. Critically, the LSD-induced subjective effects were associated with somatomotor networks GBC changes. These data-driven neuropharmacological results pinpoint the critical role of 5-HT2A in LSD’s mechanism, which informs its neurobiology and guides rational development of psychedelic-based therapeutics

scholarly journals Altered Functional Connectivity and Sensory Processing in Blepharospasm and Hemifacial Spasm: Coexistence and Difference

2021 ◽  
Vol 12 ◽  
Author(s):  
Ting-Chun Fang ◽  
Chun-Ming Chen ◽  
Ming-Hong Chang ◽  
Chen-Hao Wu ◽  
Yi-Jen Guo
Keyword(s):  
Functional Connectivity ◽  
Sensory Processing ◽  
Hemifacial Spasm ◽  
Resting State ◽  
Large Scale ◽  
Detection Threshold ◽  
Image Data ◽  
Brain Regions ◽  
Resting State Functional Connectivity ◽  
The Right

Background: Blepharospasm (BSP) and hemifacial spasm (HFS) are both facial hyperkinesia however BSP is thought to be caused by maladaptation in multiple brain regions in contrast to the peripherally induced cause in HFS. Plausible coexisting pathophysiologies between these two distinct diseases have been proposed.Objectives: In this study, we compared brain resting state functional connectivity (rsFC) and quantitative thermal test (QTT) results between patients with BSP, HFS and heathy controls (HCs).Methods: This study enrolled 12 patients with BSP, 11 patients with HFS, and 15 HCs. All subjects received serial neuropsychiatric evaluations, questionnaires determining disease severity and functional impairment, QTT, and resting state functional MRI. Image data were acquired using seed-based analyses using the CONN toolbox.Results: A higher cold detection threshold was found in the BSP and HFS patients compared to the HCs. The BSP and HFS patients had higher rsFC between the anterior cerebellum network and left occipital regions compared to the HCs. In all subjects, impaired cold detection threshold in the QTT of lower extremities had a correlation with higher rsFC between the anterior cerebellar network and left lingual gyrus. Compared to the HCs, increased rsFC in right postcentral gyrus in the BSP patients and decreased rsFC in the right amygdala and frontal orbital cortex in the HFS subjects were revealed when the anterior cerebellar network was used as seed.Conclusions: Dysfunction of sensory processing detected by the QTT is found in the BSP and HSP patients. Altered functional connectivity between the anterior cerebellar network and left occipital region, especially the Brodmann area 19, may indicate the possibility of shared pathophysiology among BSP, HFS, and impaired cold detection threshold. Further large-scale longitudinal study is needed for testing this theory in the future.

scholarly journals Strengthened thalamoparietal functional connectivity in patients with hemifacial spasm: a cross-sectional resting-state fMRI study

2020 ◽  
Vol 93 (1108) ◽  
pp. 20190887 ◽  
Author(s):  
Xuan Niu ◽  
Hui Xu ◽  
Chenguang Guo ◽  
Tong Yang ◽  
Dustin Kress ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Hemifacial Spasm ◽  
Resting State ◽  
Resting State Fmri ◽  
Association Cortex ◽  
Resting State Networks ◽  
Supramarginal Gyrus ◽  
Resting State Functional Connectivity ◽  
Cross Sectional ◽  
The Right

Objective: In spite of the well-known importance of thalamus in hemifacial spasm (HFS), the thalamic resting-state networks in HFS is still rarely mentioned. This study aimed to investigate resting-state functional connectivity (FC) of the thalamus in HFS patients and examine its association with clinical measures. Methods: 25 HFS patients and 28 matched healthy controls underwent functional MRI at rest. Using the left and right thalamus as seed regions respectively, we compared the thalamic resting-state networks between patient and control groups using two independent sample t-test. Results: Compared with controls, HFS patients exhibited strengthened bilateral thalamus-seeded FC with the parietal cortex. Enhanced FC between right thalamus and left somatosensory association cortex was linked to worse motor disturbance, and the increased right thalamus-right supramarginal gyrus connection were correlated with improvement of affective symptoms. Conclusion: Our findings indicate that the right thalamus–left somatosensory association cortex hyperconnectivity may represent the underlying neuroplasticity related to sensorimotor dysfunction. In addition, the upregulated FC between the right thalamus and right supramarginal gyrus in HFS, is part of the thalamo-default mode network pathway involved in emotional adaptation. Advances in knowledge: This study provides new insights on the integrative role of thalamo-parietal connectivity, which participates in differential neural circuitry as a mechanism underlying motor and emotional functions in HFS patients.

scholarly journals Augmenting Frontal Dopamine Tone Enhances Maintenance over Gating Processes in Working Memory

2020 ◽  
pp. 1-13
Author(s):  
Daniella J. Furman ◽  
Zhihao Zhang ◽  
Christopher H. Chatham ◽  
Maxwell Good ◽  
David Badre ◽  
...  
Keyword(s):  
Working Memory ◽  
Premotor Cortex ◽  
Memory Task ◽  
Resting State Fmri ◽  
Double Blind ◽  
Stimulus Response ◽  
Gating Mechanisms ◽  
The Face ◽  
Improved Performance ◽  
Maintenance Requirements

The contents of working memory must be maintained in the face of distraction, but updated when appropriate. To manage these competing demands of stability and flexibility, maintained representations in working memory are complemented by distinct gating mechanisms that selectively transmit information into and out of memory stores. The operations of such dopamine-dependent gating systems in the midbrain and striatum and their complementary dopamine-dependent memory maintenance operations in the cortex may therefore be dissociable. If true, selective increases in cortical dopamine tone should preferentially enhance maintenance over gating mechanisms. To test this hypothesis, tolcapone, a catechol- O-methyltransferase inhibitor that preferentially increases cortical dopamine tone, was administered in a randomized, double-blind, placebo-controlled, within-subject fashion to 49 participants who completed a hierarchical working memory task that varied maintenance and gating demands. Tolcapone improved performance in a condition with higher maintenance requirements and reduced gating demands, reflected in a reduction in the slope of RTs across the distribution. Resting-state fMRI data demonstrated that the degree to which tolcapone improved performance in individual participants correlated with increased connectivity between a region important for first-order stimulus response mappings (left dorsal premotor cortex) and cortical areas implicated in visual working memory, including the intraparietal sulcus and fusiform gyrus. Together, these results provide evidence that augmenting cortical dopamine tone preferentially improves working memory maintenance.

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