title: Relation between regional functional MRI activation and vascular reactivity to carbon dioxide during normal aging.
abstract: Recent blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging studies have shown a reduction of cerebral activation during aging, which may be associated with age-related changes of the cerebral vascular system. The authors used a global hypercapnic breath-holding challenge to define nonneuronal contributions to a significantly reduced activation in the primary sensorimotor cortex during finger tapping in a group of old (n = 6; mean age 65 years) compared with a group of young (n = 6; mean age 27 years) subjects. Within significantly activated voxels in both groups during finger tapping, the mean BOLD signal amplitudes were significantly smaller in the group of older subjects for both tasks. In those voxels showing significant activation only in young subjects during finger tapping, the response to hypercapnia was also greatly diminished in older subjects. The attenuated hypercapnic BOLD signal response in older subjects within this region suggests that age-dependent changes of the cerebral vasculature may alter the neuronal-vascular coupling. In older subjects, cerebral vessels may not react as effectively in response to a vasodilating stimulus, which will lead to differences in the number of voxels that pass a criterion threshold despite similar neuronal activation.
authors.affiliation: Department of Neurology, University of Tübingen, Tübingen, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Riecker
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Grodd
authors.forename: Uwe
authors.initials: U
authors.lastname: Klose
authors.forename: Jörg B
authors.initials: JB
authors.lastname: Schulz
authors.forename: Klaus
authors.initials: K
authors.lastname: Gröschel
authors.forename: Michael
authors.initials: M
authors.lastname: Erb
authors.forename: Hermann
authors.initials: H
authors.lastname: Ackermann
authors.forename: Andreas
authors.initials: A
authors.lastname: Kastrup
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D013003:Somatosensory Cortex / Q000098:blood supply / Q000378:metabolism*
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen