Yuan B, Morrow T J, Casey K L
J Neurosci. 1986 Dec;6(12):3611-7. doi: 10.1523/JNEUROSCI.06-12-03611.1986.
Corticofugal influences on the responses of 39 ventrobasal (VB) thalamic neurons to repetitive stimuli were studied in awake rats by focally suppressing the evoked and spontaneous electrocortical activity of the primary (S1) somatosensory cortex with magnesium or lidocaine plus magnesium. Suppression of the S1 cortex reduced the number of spikes discharged by 19 (66%) of 29 VB units in response to each of 25 electrical stimuli delivered to the medial lemniscus; 9 units were unaffected and 1 showed an increased response to 1-10 Hz stimuli. The responses of 6 (38%) of 16 VB units to electrical somatic stimuli were also reduced following S1 cortical suppression; 9 units were unaffected and 1 showed an increased response to 20-40 Hz stimuli. A comparison of the reduced responsiveness of 5 units studied during medial lemniscal and somatic stimulation did not reveal any additional response attenuation attributable to subthalamic corticofugal influences. We conclude that, in the awake rat, somatosensory transmission to VB thalamic neurons is primarily facilitated by S1 corticothalamic neurons.
在清醒大鼠中，通过用镁或利多卡因加镁局部抑制初级躯体感觉皮层（S1）诱发的和自发的电皮层活动，研究了皮质离心投射对39个腹侧基底（VB）丘脑神经元对重复刺激反应的影响。S1皮层的抑制减少了29个VB单位中19个（66%）对传递到内侧丘系的25个电刺激中每个刺激的放电峰值数量；9个单位不受影响，1个单位对1 - 10Hz刺激的反应增强。S1皮层抑制后，16个VB单位中有6个（38%）对躯体电刺激的反应也降低；9个单位不受影响，1个单位对20 - 40Hz刺激的反应增强。对在内侧丘系和躯体刺激期间研究的5个单位反应性降低的比较未发现任何可归因于丘脑底核皮质离心投射影响的额外反应减弱。我们得出结论，在清醒大鼠中，躯体感觉向VB丘脑神经元的传递主要由S1皮质丘脑神经元促进。
