Garraghty P E, Hanes D P, Florence S L, Kaas J H
Department of Psychology, Indiana University, Bloomington 47405.
Somatosens Mot Res. 1994;11(2):109-17. doi: 10.3109/08990229409028864.
Previous experiments have shown that the reorganization of the hand representations in areas 3b and 1 of somatosensory cortex of monkeys can be extensive or limited, depending on the pattern of peripheral sensory loss. After the loss of two or more digits, the deprived zones of cortex are not fully reactivated by remaining inputs from the hand (Merzenich et al., 1984). In contrast, after deafferentation of the entire glabrous surface of the hand, the deprived cortex becomes responsive throughout its extent to cutaneous stimulation of the dorsal hairy surface of the hand (Garraghty and Kaas, 1991). To test the hypothesis that it is the pattern of sensory loss and not the deprivation procedure that results in these differences, we mimicked multiple-digit amputation by deafferenting corresponding parts of the dorsal and ventral hand. We then recorded from areas 3b and 1 of 3 squirrel monkeys 3-11 months after the deafferentation. In each case, much of the cortex normally activated by the removed inputs remained unresponsive to cutaneous stimulation of skin surfaces of the hand with intact innervation. Thus, the reorganization that can occur in somatosensory cortex following peripheral sensory loss is constrained by the precise content of the stimulus deprivation; that is, there is a limit to the set of new receptive fields cortical neurons can acquire.
先前的实验表明，猴子体感皮层3b区和1区手部表征的重组程度可大可小，这取决于外周感觉丧失的模式。在丧失两个或更多手指后，手部剩余输入无法完全重新激活皮层的剥夺区（Merzenich等人，1984年）。相反，在手部整个无毛表面去传入后，被剥夺的皮层在其整个范围内对手背多毛表面的皮肤刺激产生反应（Garraghty和Kaas，1991年）。为了验证导致这些差异的是感觉丧失模式而非剥夺程序这一假设，我们通过对手背和手掌相应部位进行去传入来模拟多指截肢。然后，在去传入3至11个月后，我们对3只松鼠猴的3b区和1区进行了记录。在每种情况下，通常由被去除的输入激活的大部分皮层，对具有完整神经支配的手部皮肤表面的皮肤刺激仍无反应。因此，外周感觉丧失后体感皮层可能发生的重组受到刺激剥夺的精确内容的限制；也就是说，皮层神经元能够获得的新感受野集合是有限的。
