Sex differences in age-related motor slowing in the rhesus monkey: behavioral and neuroimaging data

• Published in: Neurobiology of aging Vol. 26; no. 4; pp. 543 - 551
• Main Authors: Lacreuse, Agnès, Diehl, Maria M., Goh, Mark Y., Hall, Marisa J., Volk, Alyssa M., Chhabra, Rashmeet K., Herndon, James G.
• Format: Journal Article
• Language: English
• Published: London Elsevier Inc 01.04.2005; Elsevier Science
• Subjects: Aging; Aging - physiology; Animals; Basal ganglia; Behavior, Animal - physiology; Biological and medical sciences; Brain - pathology; Brain - physiopathology; Brain Mapping; Development. Senescence. Regeneration. Transplantation; Female; Fundamental and applied biological sciences. Psychology; Image Processing, Computer-Assisted - methods; Macaca mulatta - physiology; Macaque; Magnetic Resonance Imaging; Magnetic Resonance Imaging - methods; Male; Motor Activity - physiology; Motor Skills Disorders - pathology; Motor Skills Disorders - physiopathology; Psychomotor Performance - physiology; Reaction Time - physiology; Sex Characteristics; Vertebrates: nervous system and sense organs; Aging; Magnetic Resonance Imaging; Macaque; Basal ganglia; Senescence; Central nervous system; Monkey; Basal ganglion; Nuclear magnetic resonance imaging; Encephalon; Vertebrata; Mammalia; Primates; Behavior; Sexual dimorphism; Age
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2004.05.007

The nigrostriatal system is critical for fine motor function and its deterioration during aging is thought to underlie the decline in fine manual ability of old persons. Because estrogen has a neuroprotective effect on this system, one might expect women's motor function to be less vulnerable to the detrimental effects of aging than that of men. We examined this hypothesis in the rhesus monkey, which has been established as an excellent model of human age-related motor impairment. We tested 28 young and old rhesus monkeys of both sexes in a task involving the retrieval of a Life Saver ® candy from rods of different complexity to determine whether fine motor ability (1) is sexually dimorphic, (2) declines with age and (3) declines differently in males and females. In addition, we measured the whole brain volume, the volumes of the caudate, putamen, hippocampal formation and the area of the corpus callosum in a subset of the monkeys ( n = 15) for which magnetic resonance images of the brain were available. All monkeys performed similarly in the test with the simplest rod. In the test with complex rods; however, age-related slowing of motor function was evident in males, but not in females. Age-related decreases in the normalized caudate and putamen volumes were similar in males and in females. In addition, motor speed was not significantly correlated to any of the neuroanatomical measures under study. Further studies will be necessary to uncover the neurohormonal bases of the differential age-related motor decline between males and females.