Vision Research Laboratory, School of Life Science, University of Science and Technology of China, Hefei, Anhui 230027, PR China.
Neurobiol Aging. 2010 May;31(5):863-73. doi: 10.1016/j.neurobiolaging.2008.06.013. Epub 2008 Aug 1.
The ability to accurately perceive the direction and speed of moving objects declines during normal aging. This is likely due to functional degradation of cortical neurons. Most neurons in the primate middle temporal area (MT) are direction-selective and their activity is closely linked to the perception of coherent motion. We investigated the mechanisms that underlie this age-related decline by comparing the proportions of direction-selective MT cells in old and young macaque monkeys, using in vivo single-cell recording techniques. Our results showed that the proportion of such cells was lower in old than in young monkeys. Moreover, one type of direction-sensitive cells, pattern cells, was especially sensitive to aging and was affected more severely than another class, component cells. We also found that direction selectivity was affected more severely in MT than in V1 of senescent monkeys. Thus, the functional degradation of MT and V1 cells may mediate perceptual decline in visual motion tasks in old primates.
随着正常衰老，准确感知移动物体方向和速度的能力会下降。这可能是由于皮质神经元功能退化所致。灵长类动物中颞中区（MT）的大多数神经元对方向具有选择性，其活动与连贯运动的感知密切相关。我们通过比较老年和年轻猕猴的 MT 细胞中具有方向选择性的细胞比例，利用体内单细胞记录技术，研究了这种与年龄相关的下降的机制。结果表明，老年猕猴中具有这种细胞的比例低于年轻猕猴。此外，一种对衰老特别敏感的方向敏感细胞，即模式细胞，比另一种细胞，即组成细胞，受影响更严重。我们还发现，在衰老猕猴的 MT 中，方向选择性比 V1 更受影响。因此，MT 和 V1 细胞的功能退化可能介导了老年灵长类动物在视觉运动任务中的感知下降。
