Hölscher Christian, Rolls Edmund T, Xiang Jianzhong
University of Oxford, Department of Experimental Psychology, South Parks Road, Oxford OX1 3UD, UK.
Eur J Neurosci. 2003 Oct;18(7):2037-46. doi: 10.1046/j.1460-9568.2003.02903.x.
Lesion studies suggest that the perirhinal cortex plays a role in object recognition memory. To analyse its role, the activity of single neurons in the perirhinal cortex was recorded in three rhesus monkeys (Macaca mulatta) performing a delayed matching-to-sample task with up to three intervening stimuli. A set of familiar visual stimuli was used. Some neurons had activity related to working memory, in that they responded more to the sample than to the match image within a trial, as shown previously. However, when a novel set of stimuli was introduced, the neuronal responses were on average only 47% of the magnitude of the responses to the familiar set of stimuli. Moreover, it was shown in eight different replications in three monkeys that the responses of the perirhinal cortex neurons gradually increased over hundreds of presentations of the new set of (initially novel) stimuli to become as large as with the already familiar stimuli. The mean number of 1.3-s presentations to induce this effect was 400 occurring over 7-13 days. These results show that perirhinal cortex neurons represent the very long-term familiarity of visual stimuli. A representation of the long-term familiarity of visual stimuli may be important for many aspects of social behaviour, and part of the impairment in temporal lobe amnesia may be related to the difficulty of building representations of the degree of familiarity of stimuli.
损伤研究表明，嗅周皮层在物体识别记忆中发挥作用。为了分析其作用，在三只恒河猴（猕猴）执行延迟样本匹配任务（最多有三个中间刺激）时，记录了嗅周皮层单个神经元的活动。使用了一组熟悉的视觉刺激。如先前所示，一些神经元的活动与工作记忆有关，即在一次试验中，它们对样本的反应比对匹配图像的反应更强烈。然而，当引入一组新的刺激时，神经元反应的幅度平均仅为对熟悉刺激组反应幅度的47%。此外，在三只猴子的八次不同重复实验中表明，嗅周皮层神经元的反应在新的（最初是新颖的）刺激组经过数百次呈现后逐渐增加，变得与已经熟悉的刺激时一样大。诱导这种效应的1.3秒呈现的平均次数为400次，发生在7至13天内。这些结果表明，嗅周皮层神经元代表了视觉刺激的非常长期的熟悉度。视觉刺激长期熟悉度的表征可能对社会行为的许多方面都很重要，颞叶失忆症的部分损伤可能与构建刺激熟悉度程度表征的困难有关。
