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Hum Brain Mapp. 2015 Jul;36(7):2719-31. doi: 10.1002/hbm.22802. Epub 2015 Apr 2.

Interactions between default mode and control networks as a function of increasing cognitive reasoning complexity.

Author information

1
Queensland Brain Institute, The University of Queensland, Brisbane, Australia.
2
Melbourne Neuropsychiatry Centre and Melbourne School of Engineering, The University of Melbourne, Melbourne, Australia.
3
School of Psychology, The University of Queensland, Brisbane, Australia.

Abstract

Successful performance of challenging cognitive tasks depends on a consistent functional segregation of activity within the default-mode network, on the one hand, and control networks encompassing frontoparietal and cingulo-opercular areas on the other. Recent work, however, has suggested that in some cognitive control contexts nodes within the default-mode and control networks may actually cooperate to achieve optimal task performance. Here, we used functional magnetic resonance imaging to examine whether the ability to relate variables while solving a cognitive reasoning problem involves transient increases in connectivity between default-mode and control regions. Participants performed a modified version of the classic Wason selection task, in which the number of variables to be related is systematically varied across trials. As expected, areas within the default-mode network showed a parametric deactivation with increases in relational complexity, compared with neural activity in null trials. Critically, some of these areas also showed enhanced connectivity with task-positive control regions. Specifically, task-based connectivity between the striatum and the angular gyri, and between the thalamus and right temporal pole, increased as a function of relational complexity. These findings challenge the notion that functional segregation between regions within default-mode and control networks invariably support cognitive task performance, and reveal previously unknown roles for the striatum and thalamus in managing network dynamics during cognitive reasoning.

KEYWORDS:

cognitive control; connectivity; default-mode; networks; reasoning; relational complexity

PMID:
25833189
DOI:
10.1002/hbm.22802
[Indexed for MEDLINE]

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