Neurophysiological measures of task-set switching: effects of working memory and aging.
We investigated age-related differences in task-switching performance by using behavioral measures and event-related brain potentials. We tested younger and older adults, and we separated older adults into groups with high and low working memory (WM); that is, we separated them into old-high-WM and old-low-WM groups. On average, all participants responded more slowly in mixed-task than in single-task blocks (i.e., reaction time or RT mixing cost). Younger adults and old-high-WM participants had equivalent RT mixing costs and showed larger posterior negative slow-wave activity when preparing for mixed trials than for single-task trials, suggesting that mixed-task trials required trial-to-trial preparation. Old-high-WM participants also showed frontally distributed activity on mixed-task trials, suggesting their use of executive control to offset age-related differences in mixed-task preparation. In contrast, old-low-WM participants had large RT mixing costs and large posterior event-related brain potential negativities during single-task trials, suggesting that they prepare during single- and mixed-task blocks. High WM, therefore, may help older adults offset the age-related difficulties often observed when they are task switching.
Goffaux
Philippe
P
Department of Psychology, Centre for Research in Human Development, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, Canada.
Phillips
Natalie A
NA
Sinai
Marco
M
Pushkar
Dolores
D
D000368:Aged; D000375:Aging / Q000502:physiology*; D001288:Attention / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology* / Q000503:physiopathology*; D008570:Memory, Short-Term / Q000502:physiology*; D015995:Prevalence; D011597:Psychomotor Performance / Q000502:physiology*; D012720:Severity of Illness Index; D014888:Wechsler Scales