Department of Psychology, Vanderbilt University, Nashville, TN, USA.
Exp Neurol. 2013 Nov;249:132-43. doi: 10.1016/j.expneurol.2013.08.013. Epub 2013 Sep 7.
After disruption of dorsal column afferents at high cervical spinal levels in adult monkeys, somatosensory cortical neurons recover responsiveness to tactile stimulation of the hand; this reactivation correlates with a recovery of hand use. However, it is not known if all neuronal response properties recover, and whether different cortical areas recover in a similar manner. To address this, we recorded neuronal activity in cortical area 3b and S2 in adult squirrel monkeys weeks after unilateral lesion of the dorsal columns. We found that in response to vibrotactile stimulation, local field potentials remained robust at all frequency ranges. However, neuronal spiking activity failed to follow at high frequencies (≥15 Hz). We suggest that the failure to generate spiking activity at high stimulus frequency reflects a changed balance of inhibition and excitation in both area 3b and S2, and that this mismatch in spiking and local field potential is a signature of an early phase of recovering cortex (<two months).
在成年猕猴的高颈段背柱传入纤维被阻断后，躯体感觉皮层神经元对手部触觉刺激的反应能力得到恢复；这种再激活与手功能的恢复相关。然而，尚不清楚所有神经元的反应特性是否都能恢复，以及不同的皮层区域是否以相似的方式恢复。为了解决这个问题，我们在成年松鼠猴单侧背柱损伤后数周，在皮层 3b 和 S2 区记录神经元的活动。我们发现，在对振动触觉刺激的反应中，局部场电位在所有频率范围内仍然很强。然而，神经元的放电活动未能跟上高频（≥15Hz）。我们认为，高频刺激时不能产生放电活动反映了 3b 区和 S2 区抑制和兴奋之间平衡的改变，而这种放电和局部场电位的不匹配是恢复皮层的早期阶段（<两个月）的特征。
