Lueschow A, Miller E K, Desimone R
Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, Maryland 20892.
Cereb Cortex. 1994 Sep-Oct;4(5):523-31. doi: 10.1093/cercor/4.5.523.
The specific size and retinal location of an object are readily perceived, yet recognition of an object's identity is hardly affected by transformations of its size or location. To explore how such stimulus transformations are treated by known mechanisms for visual short-term memory in inferior temporal (IT) cortex, IT cells were recorded in monkeys performing a delayed matching-to-sample task. The stimuli were pictures of complex objects, and the monkeys ignored differences in size and retinal location when matching the test items to the sample held in memory. The sensory information communicated by cells was assessed in their responses to the sample stimuli, and mnemonic information was assessed in their responses to the test stimuli. In the sensory domain, the ordering of relative stimulus preferences for nearly all cells was invariant over changes in size or location; however, some cells nonetheless preferred stimuli of a given size or location. In the mnemonic domain, the responses of many cells were modulated according to whether the test stimulus matched the sample held in memory, and these memory effects were invariant over the relative sizes and locations of the stimuli. Thus, IT neuronal populations may mediate not only the recognition and memory of object identity, which are invariant over size and location, but also the perception of the transformations themselves.
物体的具体大小和在视网膜上的位置很容易被感知，然而物体身份的识别却几乎不受其大小或位置变化的影响。为了探究颞下（IT）皮质中已知的视觉短期记忆机制如何处理这种刺激变化，在执行延迟样本匹配任务的猴子身上记录了IT细胞。刺激物是复杂物体的图片，猴子在将测试项目与记忆中的样本进行匹配时忽略了大小和视网膜位置的差异。通过细胞对样本刺激的反应来评估细胞传递的感觉信息，通过细胞对测试刺激的反应来评估记忆信息。在感觉领域，几乎所有细胞相对刺激偏好的排序在大小或位置变化时是不变的；然而，一些细胞仍然偏好给定大小或位置的刺激。在记忆领域，许多细胞的反应根据测试刺激是否与记忆中的样本匹配而受到调节，并且这些记忆效应在刺激的相对大小和位置上是不变的。因此，IT神经元群体可能不仅介导物体身份的识别和记忆，这在大小和位置上是不变的，而且还介导对变化本身的感知。
