Burke Sarah N, Wallace Jenelle L, Hartzell Andrea L, Nematollahi Saman, Plange Kojo, Barnes Carol A
Evelyn F. McKnight Brain Institute, Division of Neural Systems Memory and Aging, University of Arizona, Tucson, AZ 85724, USA.
Behav Neurosci. 2011 Dec;125(6):836-47. doi: 10.1037/a0026238.
Normal aging causes a decline in object recognition. Importantly, lesions of the perirhinal cortex produce similar deficits and also lead to object discrimination impairments when the test objects share common features, suggesting that the perirhinal cortex participates in perceptual discrimination. The current experiments investigated the ability of young and aged animals to distinguish between objects that shared features with tasks with limited mnemonic demands. In the first experiment, young and old rats performed a variant of the spontaneous object recognition task in which there was a minimal delay between the sample and the test phase. When the test objects did not share any features ("Easy" perceptual discrimination) both young and aged rats correctly identified the novel object. When the test objects contained overlapping features, however, only the young rats showed an exploratory preference for the novel object. In Experiment 2, young and aged monkeys were tested on an object discrimination task. When the object pairs were dissimilar, both the young and aged monkeys learned to select the rewarded object quickly. In contrast, when LEGOs® were used to create object pairs with overlapping features, the aged monkeys took significantly longer than did the young animals to learn to discriminate between the rewarded and the unrewarded object. Together, these data indicate that behaviors requiring the perirhinal cortex are disrupted in advanced age, and suggest that at least some of these impairments may be explained by changes in high-level perceptual processing in advanced age.
正常衰老会导致物体识别能力下降。重要的是，鼻周皮质受损会产生类似的缺陷，并且当测试物体具有共同特征时也会导致物体辨别障碍，这表明鼻周皮质参与了感知辨别。当前的实验研究了年轻和老年动物区分与记忆需求有限的任务具有共同特征的物体的能力。在第一个实验中，年轻和老年大鼠执行了自发物体识别任务的一个变体，其中样本和测试阶段之间的延迟最小。当测试物体没有任何共同特征时（“简单”感知辨别），年轻和老年大鼠都能正确识别新物体。然而，当测试物体包含重叠特征时，只有年轻大鼠对新物体表现出探索偏好。在实验2中，年轻和老年猴子接受了物体辨别任务测试。当物体对不同时，年轻和老年猴子都能快速学会选择得到奖励的物体。相比之下，当使用乐高积木制作具有重叠特征的物体对时，老年猴子比年轻动物需要长得多的时间来学会区分得到奖励和未得到奖励的物体。总之，这些数据表明，需要鼻周皮质参与的行为在老年时会受到干扰，并且表明这些损伤中至少有一些可能是由老年时高级感知处理的变化所解释的。
