Activity of Somatosensory-Responsive Neurons in High Subdivisions of SI Cortex during Locomotion
Activity of Somatosensory-Responsive Neurons in High Subdivisions of SI Cortex during Locomotion
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DOI：
10.1523/jneurosci.3545-14.2015
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发表时间：
2015-05-20
影响因子：
5.3
通讯作者：
Beloozerova, Irina N.
中科院分区：
文献类型：
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作者：
Favorov, Oleg V.;Nilaweera, Wijitha U.;Beloozerova, Irina N.
运动过程中初级躯体感觉皮层神经元的反应知之甚少，即使是在平面上行走这样简单的任务中也是如此。在这项研究中，我们分析了神经元的尖峰放电的喙银行的柄沟（1-2区）在2只猫，而猫走在一个平面上或水平的梯子，一个复杂的任务，需要准确的步进。所有的神经元（n = 82），对侧前肢感受野（RF）表现出频率调制的活动，锁定在简单的运动过程中的步幅周期。神经元与近端RF（上臂/肩膀）和锥体束投射神经元（PTNs）与快速传导轴突往往在中间的摆动阶段的发射率达到峰值，而神经元与RF的远端肢体（手腕/爪子）和慢传导PTNs通常表现出峰值发射摆动和站立阶段之间的过渡。11的12个神经元与触觉RF掌前爪开始发射到摆动结束，峰值活动发生在脚与地板接触的那一刻，从而之前从触摸感受器诱发的感觉齐射。要求准确地踩在梯子上影响了91%的神经元，这表明它们参与了控制踩的准确性。在这两项任务中，神经元表现出各种各样的尖峰分布在步幅周期内，这表明，无论是简单的或阶梯运动，他们代表了循环体感事件在他们的活动预测之前和反射后，这些事件发生。
Responses of neurons in the primary somatosensory cortex during movements are poorly understood, even during such simple tasks as walking on a flat surface. In this study, we analyzed spike discharges of neurons in the rostral bank of the ansate sulcus (areas 1-2) in 2 cats while the cats walked on a flat surface or on a horizontal ladder, a complex task requiring accurate stepping. All neurons (n = 82) that had receptive fields (RFs) on the contralateral forelimb exhibited frequency modulation of their activity that was phase locked to the stride cycle during simple locomotion. Neurons with proximal RFs (upper arm/shoulder) and pyramidal tract-projecting neurons (PTNs) with fast-conducting axons tended to fire at peak rates in the middle of the swing phase, whereas neurons with RFs on the distal limb (wrist/paw) and slow-conducting PTNs typically showed peak firing at the transition between swing and stance phases. Eleven of 12 neurons with tactile RFs on the volar forepaw began firing toward the end of swing, with peak activity occurring at the moment of foot contact with floor, thereby preceding the evoked sensory volley from touch receptors. Requirement to step accurately on the ladder affected 91% of the neurons, suggesting their involvement in control of accuracy of stepping. During both tasks, neurons exhibited a wide variety of spike distributions within the stride cycle, suggesting that, during either simple or ladder locomotion, they represent the cycling somatosensory events in their activity both predictively before and reflectively after these events take place.