Florence S L, Wall J T, Kaas J H
Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240.
J Comp Neurol. 1991 Sep 22;311(4):563-78. doi: 10.1002/cne.903110410.
Central termination patterns of afferents from the hands of squirrel monkeys were studied after subdermal injections of wheat germ agglutinin conjugated with horseradish peroxidase (WGA-HRP) or cholera toxin subunit B conjugated to HRP (BHRP). WGA-HRP more effectively labeled axons terminating in the superficial dorsal horn of the spinal cord, while BHRP more effectively labeled axons terminating in the deeper layers. Injections of both tracers, when restricted to parts of glabrous digits, palm, or dorsal hand, revealed somatotopic patterns in the spinal cord and pars rotunda of the cuneate nucleus that were, in some respects, similar and, in other respects, quite different from those previously reported for macaque monkey (Florence et al., J. Comp. Neurol. 286:48-70, '89). As in macaques, injections in digits 1-5 produced a rostrocaudal sequence of foci of terminations in the cervical spinal cord. However, inputs from the palm were located medial to those from the digits, whereas the palm is represented lateral to the digits in macaque monkeys. Since inputs from the palm is also medial in the dorsal horn in cats (Nyberg and Blomqvist, J. Comp. Neurol. 242:28-39, '85), the condition in squirrel monkeys may be similar to the generalized state. In the cuneate nucleus, single injections in the hand produced dense label in the pars rotunda, and sparse label in the rostral and caudal poles. As in macaque monkeys, inputs from specific parts of the hand related to rostrocaudal clusters of cells that are cytochrome oxidase dense. The representation of the digits differed from macaques in that the digits were represented dorsal to the palm, rather that ventral to the palm as in macaques. Again, comparisons with cats suggest that squirrel monkeys have the more generalized pattern. Finally, inputs from the hair, dorsal surfaces of the digits terminated on the same clusters as the inputs from the glabrous, ventral surfaces, apparently overlapping somewhat. The proximity of these terminations from dorsal and ventral surfaces of the digits may be related to observations that cortical representations of the glabrous surfaces of digits become responsive to dorsal surfaces of the same digits when inputs from glabrous skin are chronically deactivated (e.g., Merzenich et al., Neuroscience 3:33-55, '83).
在皮下注射与辣根过氧化物酶（WGA-HRP）偶联的小麦胚芽凝集素或与HRP偶联的霍乱毒素亚基B（BHRP）后，研究了松鼠猴手部传入神经的中枢终末模式。WGA-HRP更有效地标记终止于脊髓浅表背角的轴突，而BHRP更有效地标记终止于深层的轴突。当两种示踪剂的注射局限于无毛手指、手掌或手背的部分区域时，在脊髓和楔状核圆形部显示出躯体定位模式，这些模式在某些方面相似，而在其他方面与先前报道的猕猴的模式有很大不同（Florence等人，《比较神经学杂志》286:48-70，'89）。与猕猴一样，在手指1-5进行注射会在颈髓中产生一个从尾到头的终止灶序列。然而，来自手掌的传入神经位于来自手指的传入神经的内侧，而在猕猴中手掌位于手指的外侧。由于在猫中手掌的传入神经在背角中也是内侧的（Nyberg和Blomqvist，《比较神经学杂志》242:28-39，'85），松鼠猴的情况可能与一般状态相似。在楔状核中，手部单次注射在圆形部产生密集标记，在头端和尾端产生稀疏标记。与猕猴一样，手部特定部位的传入神经与细胞色素氧化酶密集的头尾细胞簇相关。手指的表征与猕猴不同，因为手指在手掌的背侧而不是像猕猴那样在手掌的腹侧。同样，与猫的比较表明松鼠猴具有更普遍的模式。最后，来自手指背侧毛发表面的传入神经与来自无毛腹侧表面的传入神经终止于相同的细胞簇，显然有一定程度的重叠。手指背侧和腹侧表面这些终止的接近程度可能与以下观察结果有关：当来自无毛皮肤的输入长期失活时，手指无毛表面的皮层表征会对同一手指的背侧表面产生反应（例如，Merzenich等人，《神经科学》3:33-55，'83）。
