Publications [#252073] of Ahmad Hariri

Journal Articles

1. Mattay, VS; Fera, F; Tessitore, A; Hariri, AR; Das, S; Callicott, JH; Weinberger, DR (2002). Neurophysiological correlates of age-related changes in human motor function.. Neurology, 58(4), 630-635. [11865144], [doi]
   (last updated on 2024/04/16)

   Abstract:
   

   Background

   There are well-defined and characteristic age-related deficits in motor abilities that may reflect structural and chemical changes in the aging brain.

   Objective

   To delineate age-related changes in the physiology of brain systems subserving simple motor behavior.

   Methods

   Ten strongly right-handed young (<35 years of age) and 12 strongly right-handed elderly (>50 years of age) subjects with no evidence of cognitive or motor deficits participated in the study. Whole-brain functional imaging was performed on a 1.5-T MRI scanner using a spiral pulse sequence while the subjects performed a visually paced "button-press" motor task with their dominant right hand alternating with a rest state.

   Results

   Although the groups did not differ in accuracy, there was an increase in reaction time in the elderly subjects (mean score plus minus SD, young subjects = 547 +/- 97 ms, elderly subjects = 794 +/- 280 ms, p < 0.03). There was a greater extent of activation in the contralateral sensorimotor cortex, lateral premotor area, supplementary motor area, and ipsilateral cerebellum in the elderly subjects relative to the young subjects (p < 0.001). Additional areas of activation, absent in the young subjects, were seen in the ipsilateral sensorimotor cortex, putamen (left > right), and contralateral cerebellum of the elderly subjects.

   Conclusions

   The results of this study show that elderly subjects recruit additional cortical and subcortical areas even for the performance of a simple motor task. These changes may represent compensatory mechanisms invoked by the aging brain, such as reorganization and redistribution of functional networks to compensate for age-related structural and neurochemical changes.