Monday, October 07, 2013

Better memory with less default mode activity

I've done a number of posts on our default mode versus attentional networks (a review is here, for example). Here is the summary and abstract for some interesting work in NeuroImage by Chai et al. on the relationship of these modes to memory:

-Children, adolescents and adults studied scenes during fMRI.
-Default-mode network (DMN) deactivation was examined during memory encoding.
-DMN deactivation was associated with successful memory encoding in adults.
-In children, deactivation of the DMN did not predict memory outcome. 
Task-induced deactivation of the default-mode network (DMN) has been associated in adults with successful episodic memory formation, possibly as a mechanism to focus allocation of mental resources for successful encoding of external stimuli. We investigated developmental changes of deactivation of the DMN (posterior cingulate, medial prefrontal, and bilateral lateral parietal cortices) during episodic memory formation in children, adolescents, and young adults (ages 8–24), who studied scenes during functional magnetic resonance imaging (fMRI). Recognition memory improved with age. We defined DMN regions of interest from a different sample of participants with the same age range, using resting-state fMRI. In adults, there was greater deactivation of the DMN for scenes that were later remembered than scenes that were later forgotten. In children, deactivation of the default-network did not differ reliably between scenes that were later remembered or forgotten. Adolescents exhibited a pattern of activation intermediate to that of children and adults. The hippocampal region, often considered part of the DMN, showed a functional dissociation with the rest of the DMN by exhibiting increased activation for later remembered than later forgotten scene that was similar across age groups. These findings suggest that development of memory ability from childhood through adulthood may involve increased deactivation of the neocortical DMN during learning.

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