The Effects of Medication on Default Mode Network (DMN) Connectivity in Attention Deficit-hyperactivity Disorder (ADHD): Bibliographic Review

Author(s):  
Victor Pereira
2016 ◽  
Vol 33 (S1) ◽  
pp. S357-S357 ◽  
Author(s):  
V. Pereira ◽  
P. de Castro-Manglano ◽  
C. Soutullo Esperon

IntroductionAttention deficit hyperactivity disorder (ADHD) is a challenge in child and adolescent psychiatry. In the recent decades many studies with longitudinal designs have used neuroimaging with ADHD patients, suggesting its neurodevelopmental origin.ObjectivesStudy the findings of neuroimaging (MRI, fMRI, DTI, PET) techniques on ADHD patients from a longitudinal point of view, looking also for the potential influence of treatments and other predictors (i.e. genetics).AimsTo provide a global perspective of all the recent findings on ADHD patients with the neuroimaging technics, focusing on longitudinal measurements of the changes in brain development.MethodsWe conducted a review of the literature in the databases Pubmed and ScienceDirect (terms ADHD, neuroimaging, MRI, fMRI, DTI, PET, functional connectivity, metilphenidate and cortical thickness). We focused on studies using neuroimaging techniques with ADHD patients, looking at their populations, methodologies and results.ResultsThe studies found abnormalities in the structure of grey matter, activity and brain connectivity in many neural networks, with particular involvement of the fronto-parietal and Default Mode Network. There is also convergent evidence for white matter pathology and disrupted anatomical connectivity in ADHD. In addition, dysfunctional connectivity during rest and during cognitive tasks has been demonstrated.ConclusionsThis evidence describe ADHD as a brain development disorder, with delays and disruptions in the global development of the central nervous system that compromises grey and white matters, most evident in the prefrontal cortex, parietal and posterior cingulate cortices, as well as basal ganglia, damaging activity and structural and functional connectivity of various brain networks, especially the fronto-striato-parietal and default mode network.Disclosure of interestThe authors have not supplied their declaration of competing interest.


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Xuan Bu ◽  
Kaili Liang ◽  
Qingxia Lin ◽  
Yingxue Gao ◽  
Andan Qian ◽  
...  

Abstract Attention-deficit/hyperactivity disorder has been identified to involve the impairment of large-scale functional networks within grey matter, and recent studies have suggested that white matter, which also encodes neural activity, can manifest intrinsic functional organization similar to that of grey matter. However, the alterations in white matter functional networks in attention-deficit/hyperactivity disorder remain unknown. We recruited a total of 99 children, including 66 drug-naive patients and 33 typically developing controls aged from 6 to 14, to characterize the alterations in functional networks within white matter in drug-naive children with attention-deficit/hyperactivity disorder. Using clustering analysis, resting-state functional MRI data in the white matter were parsed into different networks. Intrinsic activity within each network and connectivity between networks and the associations between network activity strength and clinical symptoms were assessed. We identified eight distinct white matter functional networks: the default mode network, the somatomotor network, the dorsal attention network, the ventral attention network, the visual network, the deep frontoparietal network, the deep frontal network and the inferior corticospinal-posterior cerebellum network. The default mode, somatomotor, dorsal attention and ventral attention networks showed lower spontaneous neural activity in patients. In particular, the default mode network and the somatomotor network largely showed higher connectivity with other networks, which correlated with more severe hyperactive behaviour, while the dorsal and ventral attention networks mainly had lower connectivity with other networks, which correlated with poor attention performance. In conclusion, there are two distinct patterns of white matter functional networks in children with attention-deficit/hyperactivity disorder, with one being the hyperactivity-related hot networks including default mode network and somatomotor network and the other being inattention-related cold networks including dorsal attention and ventral attention network. These results extended upon our understanding of brain functional networks in attention-deficit/hyperactivity disorder from the perspective of white matter dysfunction.


2015 ◽  
Vol 124 (1) ◽  
pp. 208-214 ◽  
Author(s):  
Baris Metin ◽  
Ruth M. Krebs ◽  
Jan R. Wiersema ◽  
Tom Verguts ◽  
Roos Gasthuys ◽  
...  

2015 ◽  
Vol 46 (3) ◽  
pp. 519-528 ◽  
Author(s):  
J. Sidlauskaite ◽  
E. Sonuga-Barke ◽  
H. Roeyers ◽  
J. R. Wiersema

BackgroundIndividuals with attention deficit hyperactivity disorder (ADHD) display excess levels of default mode network (DMN) activity during goal-directed tasks, which are associated with attentional disturbances and performance decrements. One hypothesis is that this is due to attenuated down-regulation of this network during rest-to-task switching. A second related hypothesis is that it may be associated with right anterior insula (rAI) dysfunction – a region thought to control the actual state-switching process.MethodThese hypotheses were tested in the current fMRI study in which 19 adults with ADHD and 21 typically developing controls undertook a novel state-to-state switching paradigm. Advance cues signalled upcoming switches between rest and task periods and switch-related anticipatory modulation of DMN and rAI was measured. To examine whether rest-to-task switching impairments may be a specific example of a more general state regulation deficit, activity upon task-to-rest cues was also analysed.ResultsAgainst our hypotheses, we found that the process of down-regulating the DMN when preparing to switch from rest to task was unimpaired in ADHD and that there was no switch-specific deficit in rAI modulation. However, individuals with ADHD showed difficulties up-regulating the DMN when switching from task to rest.ConclusionsRest-to-task DMN attenuation seems to be intact in adults with ADHD and thus appears unrelated to excess DMN activity observed during tasks. Instead, individuals with ADHD exhibit attenuated up-regulation of the DMN, hence suggesting disturbed re-initiation of a rest state.


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