Yakovlev Volodya, Amit Daniel J, Romani Sandro, Hochstein Shaul
Life Sciences Institute & Neural Computation Center, Hebrew University, Jerusalem 91904, Israel.
J Neurosci. 2008 Jan 2;28(1):239-48. doi: 10.1523/JNEUROSCI.4799-07.2008.
Macaque monkeys were tested on a delayed-match-to-multiple-sample task, with either a limited set of well trained images (in randomized sequence) or with never-before-seen images. They performed much better with novel images. False positives were mostly limited to catch-trial image repetitions from the preceding trial. This result implies extremely effective one-shot learning, resembling Standing's finding that people detect familiarity for 10,000 once-seen pictures (with 80% accuracy) (Standing, 1973). Familiarity memory may differ essentially from identification, which embeds and generates contextual information. When encountering another person, we can say immediately whether his or her face is familiar. However, it may be difficult for us to identify the same person. To accompany the psychophysical findings, we present a generic neural network model reproducing these behaviors, based on the same conservative Hebbian synaptic plasticity that generates delay activity identification memory. Familiarity becomes the first step toward establishing identification. Adding an inter-trial reset mechanism limits false positives for previous-trial images. The model, unlike previous proposals, relates repetition-recognition with enhanced neural activity, as recently observed experimentally in 92% of differential cells in prefrontal cortex, an area directly involved in familiarity recognition. There may be an essential functional difference between enhanced responses to novel versus to familiar images: The maximal signal from temporal cortex is for novel stimuli, facilitating additional sensory processing of newly acquired stimuli. The maximal signal for familiar stimuli arising in prefrontal cortex facilitates the formation of selective delay activity, as well as additional consolidation of the memory of the image in an upstream cortical module.
猕猴在延迟匹配多样样本任务中接受测试，样本要么是一组有限的经过充分训练的图像（以随机顺序呈现），要么是从未见过的图像。它们对新图像的表现要好得多。误报大多仅限于前一次试验中捕获试验图像的重复。这一结果意味着极其有效的一次性学习，类似于斯坦丁的发现，即人们能识别出10000张只看过一次的图片（准确率达80%）（斯坦丁，1973年）。熟悉度记忆可能与识别本质上不同，识别会嵌入并生成情境信息。当遇到另一个人时，我们能立刻说出他或她的脸是否熟悉。然而，我们可能很难识别出同一个人。为了配合这些心理物理学发现，我们提出了一个通用神经网络模型，该模型基于产生延迟活动识别记忆的相同保守赫布突触可塑性来再现这些行为。熟悉度成为建立识别的第一步。添加试验间重置机制可限制前一次试验图像的误报。与之前的提议不同，该模型将重复识别与增强的神经活动联系起来，正如最近在前额叶皮层92%的差异细胞中通过实验观察到的那样，前额叶皮层是直接参与熟悉度识别的区域。对新图像与熟悉图像的增强反应之间可能存在本质的功能差异：来自颞叶皮层的最大信号针对新刺激，有助于对新获取刺激进行额外的感觉处理。前额叶皮层中产生的熟悉刺激的最大信号有助于形成选择性延迟活动，以及在上游皮层模块中对图像记忆进行额外的巩固。
