Mechanisms of excitatory-inhibitory functions and neural oscillations in human sensor-motor cortex

1)观察硬脑膜下电极直接记录的体感诱发电位（SEPs）高频振荡（HFOs），探讨初级体感皮层与HFOs的关系。对3例顽固性癫痫患者术前植入硬脑膜下电极，直接记录脑膜下电位，进行临床评价。由于硬脑膜下电极记录的hfo分布与体感诱发电位N20-P20组分的分布一致，因此认为初级感觉皮层（36区）是体感hfo的来源。体感hfo显示出严格的体位源排列。hfo的前期分量和N20-P20分量在中央沟两侧呈极性反转。然而，在hfo的后半部分，阶段是同步的。我们提出hfo的早期和后期的起源是不同的，并且有一个更明确的躯体解剖。2)观察自发性运动时皮质图的事件相关同步和非同步，评价负运动区与自发性运动的关系。记录4例顽固性部分性癫痫患者硬脑膜下电极植入后的皮质图。负运动区在运动开始前和运动后存在与事件相关的α去同步。皮层活动分析表明，负运动区在准备自主运动中起着重要作用。3)通过配对脉冲刺激模式评估皮质脊髓神经元早期和晚期抑制的局灶性。我们对4例难治性部分性癫痫患者进行硬脑膜下电极植入的成对电脉冲刺激研究。以阈下条件反射刺激对手运动皮层（M1）进行脉冲配对刺激，在条件反射测试间隔1 ~ 6 ms之间获得了第一背骨间肌运动诱发电位的抑制作用。当条件反射刺激被转移到感觉皮层（S1）或手臂M1时，这种早期抑制被消除。在所有3例患者中，50 ~ 300 ms的阈上条件刺激对手M1的脉冲刺激也产生抑制作用。当将条件反射刺激移至手部S1时，仅在3例患者中有1例患者仍能识别出这种晚期抑制。早期抑制发生在M1的很小区域，但在某些情况下，S1可能与晚期抑制的产生有关。少

1) To examine high frequency oscillations (HFOs) of somatosensory evoked potentials (SEPs) recorded directly from subdural electrodes to investigate the relationship between the primary somatosensory cortex and HFOs. SEPs were recorded directly from subdural electrodes previously implanted in 3 patients for clinical evaluation prior to surgical treatment of intractable epilepsy. The primary sensory cortex (area 36) was proposed as the source of somatosensory HFOs, because the distribution of HFOs recorded from the subdural electrodes agreed with the distribution of the N20-P20 components of the somatosensory evoked potential. The somatosensory HFOs showed a strictly somatotopic source arrangement. There was a polarity inversion of the prophase component and also the N20-P20 component of HFOs across the central sulcus. However, the phase was synchronized in the latter part of the HFOs. We proposed that the origins of the early and latter parts of HFOs are different, and that there was a … More clear somatotopy.2) To examine event-related synchronization and desynchronization of corticogram during voluntary movement to evaluate the relationship between the negative motor area and voluntary movement. Corticograms were recorded from subdural electrodes implanted in 4 patients with intractable partial epilepsy. Negative motor area had event-related alpha desynchronization preceding the onset of movement and post-movement beta synchronization. The analysis of cortical activity suggested that the negative motor area had a important role for preparation of voluntary movement.3) To evaluated the focal nature of the early and late inhibition of corticospinal neurons demonstrated by a paired-pulse stimulation paradigm. We performed paired-electric pulse stimulation studies using subdural electrodes implanted in 4 patients with intractable partial epilepsy. Inhibition of motor evoked potentials in the first dorsal interosseous muscle was obtained by paired-pulse stimulation of the hand motor cortex (M1) with a subthreshold conditioning stimulus at conditioning-test intervals between 1 and 6 ms. This early inhibition was abolished when the conditioning stimulus was moved to the sensory cortex (S1) or the arm M1. The inhibition was also produced by paired-pulse stimulation of the hand M1 with a suprathreshold conditioning stimulus between 50 and 300 ms in all 3 patients. This late inhibition was still recognized when moving the conditioning stimulus to the hand S1 only in one of 3 patients. The early inhibition arises from very small areas in the M1 but the S1 may be related to the generation of the late inhibition in some cases. Less