Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys.
Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys.
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DOI：
10.1016/j.neuroimage.2016.08.015
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发表时间：
2016-11-15
期刊：
影响因子：
5.7
通讯作者：
Avison MJ
中科院分区：
文献类型：
--
作者：
Qi HX;Wang F;Liao CC;Friedman RM;Tang C;Kaas JH;Avison MJ
在躯体感觉背柱(DC)通路损伤后，皮质手部表征可以对触觉刺激失去反应，但在损伤后数周恢复相当大的反应性。这种重新激活表明，保留下来的阈值下感觉输入会得到加强，轴突会随着时间的推移而萌发，以调节恢复。在这里，我们研究了3只松鼠猴子的恢复过程，使用高分辨率fMRI CBV-fMRI映射对侧躯体感觉皮层对低水平和高水平电刺激(ES)刺激远端指垫(ES)的反应，在高水平的对侧DC损伤前以及2、4和6周后。低强度和高强度的手指ES都揭示了损毁前猴子3b区手部表征的预期体位，而在1区和3a区，高强度刺激在激活体位模式方面更有效。损伤后6周，无论DC直接输入丢失的严重程度(98%，79%，40%)，所有三种动物的体感皮层3b区在体感和对低强度和高强度ES的反应性方面都显示出接近完全恢复。然而，动物内部和动物之间的个体指域重新激活的模式和幅度存在显著差异，反映了损伤后2周初级DC和次级输入的永久性和/或暂时性沉默程度的差异，以及它们在2至6周之间恢复的时空轨迹。3a区和1区躯体复制的沉默和恢复以及对高强度电刺激的反应的相似变化与次级(如脊髓丘脑)通路的附带损伤和恢复的个体差异一致。因此，皮层失活和随后的再激活不仅取决于DC损伤的程度，还取决于低强度和高强度ES所揭示的次级和初级输入丧失的严重程度和持续时间。
After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution fMRI CBV-fMRI mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6 weeks after a high cervical level contralateral DC lesion. Both low and high intensity ES of digits revealed the expected somatotopy of the area 3b hand representation in pre-lesion monkeys, while in areas 1 and 3a, high intensity stimulation was more effective in activating somatotopic patterns. Six weeks post-lesion, and irrespective of the severity of loss of direct DC inputs (98%, 79%, 40%), somatosensory cortical area 3b of all three animals showed near complete recovery in terms of somatotopy and responsiveness to low and high intensity ES. However there was significant variability in the patterns and amplitudes of reactivation of individual digit territories within and between animals, reflecting differences in the degree of permanent and/or transient silencing of primary DC and secondary inputs 2 weeks post-lesion, and their spatio-temporal trajectories of recovery between 2 and 6 weeks. Similar variations in the silencing and recovery of somatotopy and responsiveness to high intensity ES in areas 3a and 1 are consistent with inter-individual differences in collateral damage to and recovery of secondary (e.g. spinothalamic) pathways. Thus, cortical deactivation and subsequent reactivation depends not only on the degree of DC lesion, but also on the severity and duration of loss of secondary as well as primary inputs revealed by low and high intensity ES.
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影响因子：
64.8
作者：
Florence, SL;Jain, N;Kaas, JH
通讯作者：
Kaas, JH
影响因子：
9.2
作者：
Frey, Scott H.;Bogdanov, Sergei;Breidenbach, Warren C.
通讯作者：
Breidenbach, Warren C.
DOI：
10.1073/pnas.96.14.7705
发表时间：
1999-07-06
影响因子：
11.1
作者：
Bushnell, MC;Duncan, GH;Carrier, B
通讯作者：
Carrier, B
DOI：
10.1177/1073858408331372
发表时间：
2009-04
期刊：
The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry
影响因子：
--
作者：
Darian-Smith C
通讯作者：
Darian-Smith C
影响因子：
2.5
作者：
Churchill, James D.;Garraghty, Preston E.
通讯作者：
Garraghty, Preston E.