Schoenbaum Geoffrey, Nugent Summer, Saddoris Michael P, Gallagher Michela
Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 North Charles Street, 25 Ames Hall, Baltimore, MD 21218, USA.
Neurobiol Aging. 2002 Jul-Aug;23(4):555-64. doi: 10.1016/s0197-4580(01)00343-8.
Recent work suggests that normal aging may be associated with decline in different brain systems. In the present study, young and aged Long-Evans rats were tested in a spatial version of the Morris water maze dependent on medial temporal lobe function and also on an odor discrimination reversal task previously used to investigate orbitofrontal function. Aged rats acquired the odor discrimination problems normally but were impaired in acquiring subsequent reversals of the problems. A subset of the aged rats also exhibited impaired spatial learning in the water maze. There was no correlation between reversal performance and spatial learning in the aged rats, indicating that the reversal learning impairment was not related to decline in medial temporal lobe function. Instead the performance of the aged rats on the odor discrimination task resembled that of young rats with neurotoxic lesions of orbitofrontal cortex. These data indicate that rats show independent decline of different brain systems during normal aging and suggest orbitofrontal cortex as one prefrontal area where changes may be localized for further study.
近期研究表明，正常衰老可能与不同脑系统的衰退有关。在本研究中，对年轻和老年的Long-Evans大鼠进行了两项测试，一项是依赖内侧颞叶功能的空间版莫里斯水迷宫测试，另一项是先前用于研究眶额叶功能的气味辨别反转任务。老年大鼠能够正常习得气味辨别问题，但在随后的问题反转学习中表现受损。一部分老年大鼠在水迷宫中的空间学习能力也受损。老年大鼠的反转学习表现与空间学习之间没有相关性，这表明反转学习障碍与内侧颞叶功能衰退无关。相反，老年大鼠在气味辨别任务上的表现类似于眶额叶皮质有神经毒性损伤的年轻大鼠。这些数据表明，大鼠在正常衰老过程中不同脑系统会出现独立衰退，并表明眶额叶皮质是前额叶的一个区域，其变化可能是进一步研究的重点。
