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Default mode network abnormalities during state switching in attention deficit hyperactivity disorder.
Psychol Med. 2016 Feb;46(3):519-28
Authors: Sidlauskaite J, Sonuga-Barke E, Roeyers H, Wiersema JR
Abstract
BACKGROUND: Individuals 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.
METHOD: These 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.
RESULTS: Against 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.
CONCLUSIONS: Rest-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.
PMID: 26456561 [PubMed – indexed for MEDLINE]
via https://www.ncbi.nlm.nih.gov/pubmed/26456561?dopt=Abstract