Oliviero Antonio, Tecchio Franca, Zappasodi Filippo, Pasqualetti Patrizio, Salustri Carlo, Lupoi Domenico, Ercolani Matilde, Romani Gian Luca, Rossini Paolo Maria
AFaR, Ospedale Fatebenefratelli, Dipartimento di Neuroscienze, Isola Tiberina, Rome, Italy.
Neuroimage. 2004 Oct;23(2):542-50. doi: 10.1016/j.neuroimage.2004.06.040.
An understanding of the functional readjustments that the brain undergoes during the early days after a stroke would give us a major insight into how and how much neurons are capable to react to an insult. Thirty-two patients affected by an acute monohemispheric ischemic stroke were enrolled in the study. Magnetoencephalography was used to record the somatosensory-evoked fields (SEF) generated in response to median nerve stimulation. Latency, strength, and position of the related early cortical components (M20 and M30) were studied both separately within each hemisphere, and in terms of interhemispheric differences. Interhemispheric cross-correlations among SEF waveshapes in the two hemispheres were also investigated. Overall, except for some source displacement possibly induced by the perilesional edema, results did not demonstrate any unusual neural recruitment. The severity of the clinical picture was found related to the sources' strengths (both as absolute values and as interhemispheric differences), to excessive interhemispheric differences in SEF waveshapes and in the M30 latencies. Signs of an enhanced excitability were present in the affected hemisphere (AH) following a cortical lesion, usually in combination with preserved hand functionality. An enhanced excitability of the unaffected hemisphere (UH) was paired with larger lesions with cortical involvement; signs compatible with an abnormal transcallosal transmission and intracortical function of inhibitory GABAergic interneurons in the AH were found subtending UH enhancement. Spared responsiveness from Brodmann's area (BA) 2 and posterior parietal areas despite an altered response from BA 3b was found in six patients, combined to high hand functionality. Present results in acute phase increase the knowledge of the mechanisms governing brain adaptation/reaction capabilities, for future efforts to establish therapeutic and rehabilitative procedures.
了解中风后早期大脑所经历的功能重新调整，将使我们深入了解神经元对损伤的反应方式和程度。32例急性单半球缺血性中风患者纳入本研究。采用脑磁图记录正中神经刺激诱发的体感诱发电场（SEF）。分别研究每个半球内相关早期皮质成分（M20和M30）的潜伏期、强度和位置，以及半球间差异。还研究了两个半球SEF波形之间的半球间互相关性。总体而言，除了可能由病灶周围水肿引起的一些源移位外，结果未显示任何异常的神经募集。发现临床症状的严重程度与源的强度（绝对值和半球间差异）、SEF波形和M30潜伏期的过度半球间差异有关。皮质损伤后，患侧半球（AH）出现兴奋性增强的迹象，通常与手部功能保留相结合。未患侧半球（UH）兴奋性增强与累及皮质的较大病灶相关；发现与AH中抑制性GABA能中间神经元的胼胝体异常传递和皮质内功能相符的体征是UH增强的基础。6例患者尽管Brodmann区（BA）3b反应改变，但BA2区和顶叶后部区域仍有保留的反应性，且手部功能良好。急性期的目前结果增加了对大脑适应/反应能力控制机制的认识，为今后建立治疗和康复程序的努力提供了依据。
