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

1)检测直接从硬膜下电极记录的体感诱发电位(SEP)的高频振荡(HFO)，以探讨初级体感皮质与高频振荡的关系。3例患者在手术治疗顽固性癫痫前，直接从硬膜下电极记录SEP，用于临床评估。由于从硬膜下电极记录到的HFO的分布与体感诱发电位N20-P20成分的分布一致，初步认为初级感觉皮层(36区)是体感HFO的来源。体感HFO显示出严格的体视源排列。Hfos的前期成分和N20-P20成分在中央沟均有极性反转。然而，在HFO的后期，这一阶段是同步的。我们认为…的早期和晚期的起源是不同的，并且存在一个HFO更清晰的躯体动作。2)检查自愿运动时皮质图的事件相关同步化和去同步化，以评估负运动区与自愿运动之间的关系。对4例顽固性部分性癫痫患者植入硬膜下电极进行皮质醇描记。负性运动区在运动开始前有事件相关的α去同步化，运动后有β同步化。皮层活动分析表明，负运动区对自主运动的准备有重要作用。3)评估双脉冲刺激范式显示的皮质脊髓神经元早期和晚期抑制的局灶性。我们使用植入硬膜下电极的配对电脉冲刺激研究4例顽固性部分性癫痫患者。在条件反射测试间隔为1~6ms的条件刺激下，双脉冲刺激手部运动皮质(M1)，获得对第一骨间背侧肌肉运动诱发电位的抑制。当条件性刺激被移到感觉皮质(S1)或臂M1时，这种早期的抑制被取消。在所有3名患者中，用阈值上的条件性刺激50-300ms的配对脉冲刺激手部M1也产生了抑制。当将条件性刺激移到手S1时，仅有3名患者中的1名患者仍能识别这种晚期抑制。早期抑制来自M1中非常小的区域，但在某些情况下，S1可能与晚期抑制的产生有关。较少

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