Ojemann George A
Department of Neurological Surgery, University of Washington, P.O. Box 356470, Seattle, WA 98195, USA.
Int J Psychophysiol. 2003 May;48(2):141-6. doi: 10.1016/s0167-8760(03)00051-5.
Neurosurgical operations under local anesthesia provide a unique opportunity to investigate the neurobiology of human cognition. We have studied the cortical organization of language and verbal memory in this setting, using two different techniques: electrical stimulation mapping and extracellular microelectrode recording of activity of individual neurons. The two techniques provide very different perspectives. Stimulation mapping identifies brain areas that are essential for a behavior, while changes in neuronal activity can occur in non-essential regions. Stimulation mapping identifies multiple discrete areas in perisylvian cortex of the dominant hemisphere as essential for a function, with separation of areas for different aspects of language including naming in two languages, different semantic classes, naming compared to reading, and language from verbal memory. There is substantial individual variation in the location of these essential areas, variability that in part relates to subjects age, gender and verbal abilities. Neurons changing activity with language or verbal memory are widely distributed, in both hemispheres. However, individual neurons usually change activity with only one function, including naming in only one of two languages, only naming or reading, or with recent verbal memory encoding but not identification of similar items. A few lateralized changes in neuronal activity have been identified, including a predominance of inhibition in dominant hemisphere with naming, and polymodal memory responses in dominant hemisphere, unimodal in nondominant. Specific neuronal populations have been identified that are related to different aspects of memory, that differentiate correct from incorrect identification or memory performance and differentiate learned from unlearned associations, with some evidence of differences in neuronal activity related to subjects' ability.
在局部麻醉下进行神经外科手术为研究人类认知的神经生物学提供了独特的机会。我们在这种情况下，使用两种不同的技术研究了语言和言语记忆的皮质组织：电刺激图谱和单个神经元活动的细胞外微电极记录。这两种技术提供了截然不同的视角。刺激图谱可识别对某种行为至关重要的脑区，而神经元活动的变化可能发生在非关键区域。刺激图谱确定优势半球颞周皮质中的多个离散区域对某种功能至关重要，不同语言方面（包括两种语言的命名、不同语义类别、命名与阅读的比较以及语言与言语记忆的区分）的区域相互分离。这些关键区域的位置存在很大的个体差异，这种差异部分与受试者的年龄、性别和语言能力有关。随语言或言语记忆改变活动的神经元广泛分布于两个半球。然而，单个神经元通常仅随一种功能改变活动，包括仅在两种语言中的一种语言中命名、仅命名或阅读，或仅与近期言语记忆编码有关，而与相似项目的识别无关。已确定了一些神经元活动的单侧化变化，包括优势半球在命名时抑制占主导，以及优势半球的多模态记忆反应，非优势半球为单模态。已确定了与记忆不同方面相关的特定神经元群体，这些群体可区分正确与错误的识别或记忆表现，并区分已学习与未学习的关联，有证据表明神经元活动的差异与受试者的能力有关。
