Differential innervation within a transverse plane of spinal gray matter by sensorimotor cortices, with special reference to the somatosensory cortices
Differential innervation within a transverse plane of spinal gray matter by sensorimotor cortices, with special reference to the somatosensory cortices
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DOI：
10.1002/cne.24626
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发表时间：
2019-06-01
影响因子：
2.5
通讯作者：
Sakurai, Masaki
中科院分区：
文献类型：
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作者：
Kameda, Hiroshi;Murabe, Naoyuki;Sakurai, Masaki
投射到颈髓的皮质脊髓(CS)神经元不仅分布在运动相关的皮质区域，而且也分布在躯体感觉区域，包括初级躯体感觉皮质(S1)。然而，这些广泛分布的CS神经元的确切功能在很大程度上是未知的。在这项研究中，我们给小鼠注射了编码膜结合荧光蛋白的腺相关病毒，以研究CS神经元在广泛皮质区域内不同区域的轴突分布。我们发现，来自初级运动皮质(M1)、S1吻侧部分(S1r)和S1尾侧部分(S1c)的CS轴突分别投射到第七颈髓段脊髓灰质内的特定区域：(A)M1主要投射到中间和腹侧区域，(B)S1r投射到内侧区域，(C)S1c投射到背外侧区域。我们还发现，来自S1r的投射与前肢区域相对应，与背角内来自前爪(手)的皮肤传入终末大部分重叠，S1c与躯干之间也有类似的关系。我们的发现表明，在背角内存在相当精细的躯体视区域，它处理躯体感觉和下行信息，这主要由S1CS神经元提供，有助于在运动产生过程中对感觉信息进行精细控制。
The corticospinal (CS) neurons projecting to the cervical cord distribute not only in motor-related cortical areas, but also in somatosensory areas, including the primary somatosensory cortex (S1). The exact functions of these widely distributed CS neurons are largely unknown, however. In this study, we injected mice with adeno-associated virus encoding membrane-binding fluorescent proteins to investigate the distribution of axons from CS neurons in different regions within a broad cortical area. We found that CS axons from the primary motor cortex (M1), the rostral part of S1 (S1r), and the caudal part of S1 (S1c) differentially project to specific compartments within the spinal gray matter of the seventh cervical cord segment: (a) M1 projects mainly to intermediate and ventral areas, (b) S1r to the mediodorsal area, and (c) S1c to the dorsolateral area. We also found that the projection from S1r, which corresponds to the forelimb area, largely overlaps the cutaneous afferent terminals from the forepaw (hand) in the dorsal horn, and we detected a similar relation between S1c and the trunk. Our findings suggest the existence of considerably fine somatotopic compartments within the dorsal horn that process somatosensation and descending information, which is provided mainly by S1 CS neurons and contribute to delicate control of sensory information in generation of movement.