Format

Send to

Choose Destination

See 1 citation found by title matching your search:

Neuroimage. 2015 Jan 1;104:21-34. doi: 10.1016/j.neuroimage.2014.09.056. Epub 2014 Oct 2.

Age trajectories of functional activation under conditions of low and high processing demands: an adult lifespan fMRI study of the aging brain.

Author information

1
Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA. Electronic address: Kristen.kennedy1@utdallas.edu.
2
Center for Vital Longevity, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, TX 75235, USA.
3
Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA.

Abstract

We examined functional activation across the adult lifespan in 316 healthy adults aged 20-89years on a judgment task that, across conditions, drew upon both semantic knowledge and ability to modulate neural function in response to cognitive challenge. Activation in core regions of the canonical semantic network (e.g., left IFG) were largely age-invariant, consistent with cognitive aging studies that show verbal knowledge is preserved across the lifespan. However, we observed a steady linear increase in activation with age in regions outside the core network, possibly as compensation to maintain function. Under conditions of increased task demands, we observed a stepwise reduction across the lifespan of modulation of activation to increasing task demands in cognitive control regions (frontal, parietal, anterior cingulate), paralleling the neural equivalent of "processing resources" described by cognitive aging theories. Middle-age was characterized by decreased modulation to task-demand in subcortical regions (caudate, nucleus accumbens, thalamus), and very old individuals showed reduced modulation to task difficulty in midbrain/brainstem regions (ventral tegmental, substantia nigra). These novel findings suggest that aging of activation to demand follows a gradient along the dopaminergic/nigrostriatal system, with earliest manifestation in fronto-parietal regions, followed by deficits in subcortical nuclei in middle-age and then to midbrain/brainstem dopaminergic regions in the very old.

KEYWORDS:

Aging; Cognitive control; Lifespan; Nigrostriatal system; Semantic judgment; fMRI

PMID:
25284304
PMCID:
PMC4252495
DOI:
10.1016/j.neuroimage.2014.09.056
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center