Takatsuru Yusuke, Fukumoto Dai, Yoshitomo Miki, Nemoto Tomomi, Tsukada Hideo, Nabekura Junichi
Japan Science and Technology Agency, Kawaguchi, Japan.
J Neurosci. 2009 Aug 12;29(32):10081-6. doi: 10.1523/JNEUROSCI.1638-09.2009.
Recent advances in functional imaging of human brain activity in stroke patients, e.g., functional magnetic resonance imaging, have revealed that cortical hemisphere contralateral to the infarction plays an important role in the recovery process. However, underlying mechanisms occurring in contralateral hemisphere during functional recovery have not been elucidated. We experimentally induced a complete infarction of somatosensory cortex in right hemisphere of mice and examined the neuronal changes in contralateral (left) somatosensory cortex during recovery. Both basal and ipsilateral somatosensory stimuli-evoked neuronal activity in left (intact) hemisphere transiently increased 2 d after stroke, followed by an increase in the turnover rate of usually stable mushroom-type synaptic spines at 1 week, observed by using two-photon imaging in vivo. At 4 weeks after stroke, when functional recovery had occurred, a new pattern of electrical circuit activity in response to somatosensory stimuli was established in intact ipsilateral hemisphere. Thus, the left somatosensory cortex can compensate for the loss of the right somatosensory cortex by remodeling neuronal circuits and establishing new sensory processing. This finding could contribute to establish the effective clinical treatments targeted on the intact hemisphere for the recovery of impaired functions and to achieve better quality of life of patients.
近期，针对中风患者大脑活动的功能成像技术取得了进展，例如功能磁共振成像，这些技术揭示出，梗死灶对侧的皮质半球在恢复过程中发挥着重要作用。然而，功能恢复期间对侧半球所发生的潜在机制尚未阐明。我们通过实验诱导小鼠右半球体感皮层发生完全梗死，并在恢复过程中检查对侧（左）体感皮层的神经元变化。使用双光子活体成像观察到，中风后2天，左（完整）半球的基础及同侧体感刺激诱发的神经元活动短暂增加，随后在1周时，通常稳定的蘑菇型突触棘的更新率增加。中风后4周，当功能恢复发生时，完整的同侧半球建立了一种新的响应体感刺激的电路活动模式。因此，左体感皮层可以通过重塑神经回路和建立新的感觉处理来补偿右体感皮层的缺失。这一发现有助于确立针对完整半球的有效临床治疗方法，以恢复受损功能，提高患者生活质量。
