Output Properties of the Cortical Hindlimb Motor Area in Spinal Cord-Injured Rats
Output Properties of the Cortical Hindlimb Motor Area in Spinal Cord-Injured Rats
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DOI：
10.1089/neu.2015.3961
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发表时间：
2015-11-01
影响因子：
4.2
通讯作者：
Nudo, Randolph J.
中科院分区：
文献类型：
--
作者：
Frost, Shawn B.;Dunham, Caleb L.;Nudo, Randolph J.
本研究的目的是检测脊髓损伤后大鼠后肢运动皮质区的神经元活动水平，并与正常大鼠的测量结果进行比较。15只雄性fisher -344大鼠在T9-T10水平处接受200 Kdyn的胸索挫伤。脊髓损伤后至少4周，在氯胺酮麻醉下对前肢和后肢运动区（FLA， HLA）进行皮质内微刺激（ICMS）和单单元记录技术。虽然在相对较低的电流水平下，ICMS可以在前肢区域引起运动，但在任何受伤的大鼠HLA中，ICMS都不能引起运动或肌电反应。在相同的程序中，电生理记录用单柄，16通道密歇根探针（Neuronexus）获得，以监测活动。利用主成分分析法对神经尖峰进行了判别。神经活动（动作电位）的采集和数字化持续5min。尽管脊髓损伤大鼠的后肢运动皮层无法通过刺激引起运动，但可以可靠地记录到强大的单单元活动。脊髓损伤大鼠运动皮质的活动明显高于未损伤大鼠，后肢和前肢运动皮质的活动也有相似程度的增加。这些结果表明，在大鼠胸椎脊髓损伤模型中，损伤后数周内可以可靠地记录到单单位皮质活动的增加。
The purpose of this study was to examine neuronal activity levels in the hindlimb area of motor cortex following spinal cord injury (SCI) in rats and compare the results with measurements in normal rats. Fifteen male Fischer-344 rats received a 200 Kdyn contusion injury in the thoracic cord at level T9-T10. After a minimum of 4 weeks following SCI, intracortical microstimulation (ICMS) and single-unit recording techniques were used in both the forelimb and hindlimb motor areas (FLA, HLA) under ketamine anesthesia. Although movements could be evoked using ICMS in the forelimb area with relatively low current levels, no movements or electromyographical responses could be evoked from ICMS in the HLA in any of the injured rats. During the same procedure, electrophysiological recordings were obtained with a single-shank, 16-channel Michigan probe (Neuronexus) to monitor activity. Neural spikes were discriminated using principle component analysis. Neural activity (action potentials) was collected and digitized for a duration of 5min. Despite the inability to evoke movement from stimulation of cortex, robust single-unit activity could be recorded reliably from hindlimb motor cortex in SCI rats. Activity in the motor cortex of SCI rats was significantly higher compared with uninjured rats, and increased in hindlimb and forelimb motor cortex by similar amounts. These results demonstrate that in a rat model of thoracic SCI, an increase in single-unit cortical activity can be reliably recorded for several weeks post-injury.