A fNIRS investigation of switching and inhibition during the modified Stroop task in younger and older adults

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2013-01, Vol.64, p.485-495
• Main Authors: Laguë-Beauvais, Maude, Brunet, Julie, Gagnon, Louis, Lesage, Frédéric, Bherer, Louis
• Format: Article
• Language: English
• Subjects: Adult; Aging; Aging - physiology; Attention; Attention - physiology; Biological and medical sciences; Brain; Brain Mapping - methods; Executive Function - physiology; Executive functions; Female; fNIRS; Functional Neuroimaging - methods; Fundamental and applied biological sciences. Psychology; Humans; Inhibition (Psychology); Male; Neuroimaging; Older people; Prefrontal cortex; Prefrontal Cortex - physiology; Spectroscopy, Near-Infrared - methods; Stroop Test; Studies; Vertebrates: nervous system and sense organs; Young Adult
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2012.09.042

Brain imaging studies have reported age-related differences in brain activation for attentional control functions, such as inhibition and task-switching. However, age-related differences in brain activation patterns in more than one attentional control task have rarely been studied in the same group of participants. In this study, younger and older adults completed a modified Stroop task with interference and switching conditions, using functional near infra-red spectroscopy. While interference did not reveal any significant activation of the prefrontal cortex in younger adults, switching produced an increased activation bilaterally in both the anterior dorsolateral prefrontal cortex (DLPFC) and the anterior ventrolateral prefrontal cortex (VLPFC). In older adults, an isolated right and left anterior DLPFC activation was observed even in the non-executive conditions of the Stroop task (color denomination) and the interference condition revealed activation mostly in the posterior left DLPFC and bilateral VLPFC with a small right anterior DLPFC component. Specific to older adults, switching induced an increased activation spread out bilaterally over the prefrontal cortex in the bilateral anterior DLPFC, the posterior left DLPFC and bilateral VLPFC. These results suggest that for both older and younger adults, inhibition and switching are associated with distinct patterns of prefrontal activation and that age-related differences exist in these patterns such that prefrontal activation seems to be more spread out at different sites in older adults. ► Frontal activation for inhibition and task-switching was compared in a single task. ► Younger and older adults were compared. ► Distinct patterns of frontal activation during inhibition and switching were found. ► There is functional dissociation between the two executive functions. ► Age-related differences emerged with spread out activation in older adults.