Filippi M M, Oliveri M, Vernieri F, Pasqualetti P, Rossini P M
AFaR CRCCS Ospedale Fatebenefratelli, Isola Tiberina, 39-00100, Rome, Italy.
Brain Res. 2000 Oct 27;881(2):159-64. doi: 10.1016/s0006-8993(00)02837-7.
In order to investigate the role of visceral afferent inputs flowing along autonomic fibers on corticospinal tract excitability, the variability of Motor Evoked Potentials (MEPs), elicited by Transcranial Magnetic Stimulation (TMS), was analysed during simultaneous monitoring of electrocardiogram (EKG) phases, breathing phases and sudomotor skin responses (SSRs) in a group of 10 healthy subjects. A cascade of at least 60 consecutive magnetic stimuli, with an interstimulus interval randomly varying between 20 and 40 s, was acquired. At the end of the recording session, the subject was asked to make at random five not consecutive self-paced forced inspirations. TMS was carried out at an intensity 10% above motor threshold excitability via a circular coil placed over the motor area of the right hemisphere. MEPs were recorded from the contralateral abductor digiti minimi muscle (ADM). Sudomotor Skin Responses (SSRs) were recorded on both hand palms. MEPs latency and amplitude did not show significant correlation with any of the EKG and respiratory phases. During forced inspiration, a significant latency shortening was found. TMS elicited SSRs, whose amplitudes were not correlated with MEP parameters. During forced inspiration a significant SSR amplitude increment, not correlated with MEP latency shortening, was also observed. These results assign a minor if any role to the considered autonomic parameters in modulating corticospinal motor excitability.
为了研究沿自主神经纤维传导的内脏传入输入对皮质脊髓束兴奋性的作用，在对10名健康受试者同步监测心电图（EKG）阶段、呼吸阶段和汗腺运动皮肤反应（SSR）的过程中，分析了经颅磁刺激（TMS）诱发的运动诱发电位（MEP）的变异性。采集了至少60个连续的磁刺激序列，刺激间隔在20至40秒之间随机变化。在记录结束时，要求受试者随机进行五次不连续的自主控制的强制吸气。通过放置在右半球运动区上方的圆形线圈，以高于运动阈值兴奋性10%的强度进行TMS。从对侧小指展肌（ADM）记录MEP。在双手手掌记录汗腺运动皮肤反应（SSR）。MEP潜伏期和波幅与任何EKG和呼吸阶段均无显著相关性。在强制吸气期间，发现潜伏期显著缩短。TMS诱发了SSR，其波幅与MEP参数无关。在强制吸气期间，还观察到SSR波幅显著增加，且与MEP潜伏期缩短无关。这些结果表明，所考虑的自主神经参数在调节皮质脊髓运动兴奋性方面即使有作用也是很小的。
