Allison T, McCarthy G, Nobre A, Puce A, Belger A
Neuropsychology Laboratory, VA Medical Center, West Haven, Connecticut 06516.
Cereb Cortex. 1994 Sep-Oct;4(5):544-54. doi: 10.1093/cercor/4.5.544.
Electrophysiological correlates of the processing of visual information were studied in epileptic patients with electrodes chronically implanted on the surface of striate and extrastriate cortex. In separate experiments patients viewed faces, letter strings (words and non-words), numbers, and control stimuli. A negative potential, N200, was evoked by faces, letter strings, and numbers, but not by the control stimuli. N200 was recorded bilaterally from discrete regions of the fusiform and inferior temporal gyri. These category-specific face, letter-string, and number "modules" vary in location. In most cases there was no overlap in the location of face and letter-string modules, suggesting a mosaic of functionally discrete regions. In some cases letter-string and number N200s were recorded from the same location, suggesting that these modules may be less spatially and functionally discrete. Face N200-like potentials can be recorded from temporal scalp, allowing the possibility of studying early face processing in normal subjects. Longer-latency face-specific potentials were recorded from the inferior surface of the anterior temporal lobe. Potentials evoked by colored checkerboards were recorded from a region of the fusiform gyrus posterior to the fusiform region from which category-specific N200s were recorded. These results suggest that there are several processing streams in inferior extrastriate cortex. In addition to object recognition systems previously proposed for faces and words, our preliminary results suggest a separate system dealing with numbers. Postulated systems dealing with larger manipulable objects and animals have not been detected.
对电极长期植入纹状和纹状外皮层表面的癫痫患者视觉信息处理的电生理相关性进行了研究。在单独的实验中，患者观看面部、字母串（单词和非单词）、数字和对照刺激。面部、字母串和数字能诱发一种负电位，即N200，但对照刺激不能。N200在双侧梭状回和颞下回的离散区域记录到。这些特定类别的面部、字母串和数字“模块”位置不同。在大多数情况下，面部和字母串模块的位置没有重叠，表明存在功能上离散区域的镶嵌。在某些情况下，字母串和数字N200从同一位置记录到，表明这些模块在空间和功能上可能不那么离散。类似面部N200的电位可从颞部头皮记录到，这使得研究正常受试者早期面部处理成为可能。从前颞叶下表面记录到潜伏期更长的面部特异性电位。彩色棋盘诱发的电位从梭状回中记录特定类别N200的梭状区域后方的一个区域记录到。这些结果表明，纹状外皮层下部存在多个处理流。除了先前提出的用于面部和单词的物体识别系统外，我们的初步结果表明存在一个单独处理数字的系统。尚未检测到处理更大可操作物体和动物的假定系统。
