Sridhar S. Kannurpatti1, Michael A. Motes2, Bart Rypma2, Bharat B. Biswal1
1Radiology, UMDNJ-New Jersey Medical School, Newark, NJ, USA; 2School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
Vascular reactivity and resting CBF levels lead to inter-subject variability in fMRI-BOLD contrast during a neural task. This variability is exacerbated in an aging population. fMRI-BOLD studies were conducted in older and younger subject groups using a motor, cognitive and a breath hold task. Inter-subject BOLD signal response variability during motor task performance was largely vascular and may exacerbate BOLD signal amplitude variability in the elderly. However, cognitive task induced a BOLD signal amplitude variability that was largely neural, in both younger and older groups. These results suggest that age-related differences in BOLD signal during cognitive task performance, is principally a consequence of neural variability.