NEURAL BASIS OF ENDOGENOUS POTENTIALS IN HUMANS

流经活跃的大脑突触的电流可能会产生 诱发电位（EP）和磁场，可以记录在一个 距离 因此，认知EP成分可用于监测 正常和患病受试者脑突触的非侵入性活动 就像他们想的那样。 最终，认知EP可以用来识别 信息处理的性质、顺序、持续时间和强度 涉及知觉、记忆和语言的阶段。 目前，此类 认知EP的应用受到限制，因为它们的突触 发电机未知。 定位EP的唯一明确方法 generators是直接从生成结构中记录。 目前的补助金建议对患有以下疾病的患者进行此类记录： 癫痫发作在多年的抗惊厥药物治疗后仍然无法控制 治疗 植入电极以定位 致癫痫组织，从而指导其手术切除。 而 等待自发性癫痫发作，患者可以同意进行 认知任务，同时监测他们的脑内脑电图。 深度 将从植入的宏电极获得记录， 枕叶，顶叶，颞叶，罗兰和额叶皮质，以及 边缘系统（杏仁核、海马结构和扣带回）， 在任务期间唤起各种认知EP成分，包括：（1） N1abc/P2/MMN/N2/P3a/P3b/SW由不常见的听觉、视觉或 躯体感觉刺激;（2）P75/N125/P170/N230/N310/N460/P620/慢 由面孔和词语及其组成部分引起的波。 任务 变体将被用来区别地唤起面部的连续阶段， 以及用于描述相关EP的文字识别 件. 对于每个组件，记录部位将分为： (1)焦点发生器，其中组件相对于相邻组件较大 结构，并且其振幅在连续的 导致，并可能极性反转;（2）可能的扩散发生器，其中 电压梯度可能很小但在灰质中明显较大 比直接subjable白色的问题，（3）远离 生成结构 层流记录将用于更好地定义 焦点发生器内的电流源和电流汇。 的可能性 本地产生的EP传播到头皮将被测试， 在治疗性皮质边缘切除术之前和之后进行记录。 所有 将使用基于MRI的有限差分法解释记录， EP传播的计算模型。 总体而言，拟议的研究 将加深和拓宽我们对人类认知EP的认识。 这 将允许：可使用头皮测试的集成神经认知模型 正常受试者的记录;动物的精确验证标准 认知EP的模型，导致基本的神经生理学研究; 使用头皮EP对特定突触系统进行直接功能测试， 患有神经或精神疾病的患者。

Current flowing across active brain synapses may summate to produce Evoked Potentials (EPs) and magnetic fields which can be recorded at a distance. Thus, cognitive EP components may be used to monitor the activity of brain synapses noninvasively in normal and diseased subjects as they think. Eventually, cognitive EPs may be used to identify the nature, sequence, duration and intensity of the information-processing stages involved in perception, memory, and language. Currently, such applications of cognitive EPs are limited because their synaptic generators are unknown. The only unambiguous method for localizing EP generators is to directly record from within the generating structure. The present grant proposes to perform such recordings in patients with epileptic seizures that remain uncontrolled after years of anticonvulsant treatment. Electrodes are implanted in order to localize the epileptogenic tissue, and thus direct its surgical removal. While awaiting spontaneous seizure onset, the patient may consent to perform cognitive tasks while their intracerebral EEG is monitored. Depth recordings will be obtained from macroelectrodes implanted in the occipital, parietal, temporal, rolandic and frontal cortices, and in the limbic system (amygdala, hippocampal formation and cingulate gyrus), during tasks evoking various cognitive EP components, including: (1) the N1abc/P2/MMN/N2/P3a/P3b/SW evoked by infrequent auditory, visual or somaesthetic stimuli; and (2) the P75/N125/P170/N230/ N310/N460/P620/slow wave evoked by faces and words, and their constituent parts. Task variants will be used to differentially evoke successive stages of face and word recognition for characterization of the associated EP components. For each component, recording sites will be classified into: (1) focal generators, where the component is large relative to adjacent structures, and where its amplitude changes rapidly between successive leads, and may polarity-invert; (2) possible diffuse generators, where the voltage gradient may be small but clearly larger in the grey matter than in immediately subjacent white matter, and (3) distant from the generating structure. Laminar recordings will be used to better define the current sources and sinks within focal generators. The possibility that the locally generated EPs propagate to the scalp will be tested by recording before and after therapeutic cortico-limbic excisions. All recordings will be interpreted using an MRI-based finite difference computational model for EP propagation. Overall, the proposed studies will deepen and broaden our knowledge of cognitive EPs in humans. This will permit: integrated neurocognitive models testable using scalp recordings in normal subjects; precise validation criteria for animal models of cognitive EPs, leading to basic neurophysiological studies; and direct functional tests for specific synaptic systems using scalp EPs in patients with neurological or psychiatric disease.