Neural patterns underlying the effect of negative distractors on working memory in older adults

Publication date: Available online 3 February 2017
Source:Neurobiology of Aging
Author(s): Noga Oren, Elissa L. Ash, Ricardo Tarrasch, Talma Hendler, Nir Giladi, Irit Shapira-Lichter
Working memory (WM) declines with age. Older adults, however, perform similar to younger adults in WM tasks with negative distractors at low WM load. To clarify the neural basis of this phenomenon, older (n=28) and younger (n=24) adults performed an emotional n-back task during an fMRI scan, and activity in task-related regions was examined. Comparing negative to neutral distraction at low WM load, older adults demonstrated shorter reaction times (RT) and reduced activation in fronto-parietal regions: bilateral middle frontal gyrus (MFG) and left parietal cortex. They also had greater coherence within the fronto-parietal network, as well as greater deactivation of the ventromedial prefrontal cortex and the amygdala. These patterns probably contributed to the older adults' diminished distractibility by negative task-irrelevant stimuli. Since recruitment of control mechanisms was less required, the fronto-parietal network was less activated and performance was improved. Faster RT during the negative condition was related to lesser activation of the MFG in both age groups, corroborating the functional significance of this region to WM across the lifespan.



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