運(yùn)動(dòng)輔助區(qū)
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運(yùn)動(dòng)輔助區(qū)(英:Supplementary Motor Area, SMA)是大腦皮質(zhì)的一個(gè)主要與運(yùn)動(dòng)功能相關(guān)的區(qū)域。在解剖位置上來說,SMA位于腦半球的內(nèi)側(cè)面,和初級(jí)運(yùn)動(dòng)皮層的前方。從細(xì)胞結(jié)構(gòu)分區(qū)上來說,SMA位于Brodmann 6區(qū)。但是Brodmann 6區(qū)除了包含SMA,還包含位于腦半球外側(cè)面的前運(yùn)動(dòng)皮層。在進(jìn)化歷史上,該區(qū)域出現(xiàn)較晚。
目錄 |
結(jié)構(gòu)
研究表明輔助運(yùn)動(dòng)區(qū)(SMA)可分為結(jié)構(gòu)和功能上都有差異的兩個(gè)區(qū)域,包括運(yùn)動(dòng)輔助區(qū)本部(SMA Proper,或稱后運(yùn)動(dòng)輔助區(qū),Caudal SMA)和前運(yùn)動(dòng)輔助區(qū)(或稱前SMA,Pre-SMA)。[1] 在非人類靈長(zhǎng)類,SMA本部大約對(duì)應(yīng)于F3區(qū),而前SMA對(duì)應(yīng)于F6區(qū)。[2]
功能
運(yùn)動(dòng)輔助區(qū)(SMA)的功能與運(yùn)動(dòng)的計(jì)劃有關(guān)。與前運(yùn)動(dòng)皮層不同,SMA主要參與動(dòng)物體自身產(chǎn)生和控制的運(yùn)動(dòng),而不是在外界刺激下所產(chǎn)生的運(yùn)動(dòng)。例如SMA參與從記憶中產(chǎn)生的序列運(yùn)動(dòng)。[3]
前運(yùn)動(dòng)輔助區(qū)(Pre-SMA)的功能與學(xué)習(xí)新運(yùn)動(dòng)序列有關(guān)。該區(qū)域中的神經(jīng)活動(dòng)在動(dòng)物執(zhí)行較新的運(yùn)動(dòng)序列時(shí)較高,而在該運(yùn)動(dòng)序列被學(xué)習(xí)完后,前運(yùn)動(dòng)輔助區(qū)中的神經(jīng)活動(dòng)降低。運(yùn)動(dòng)輔助區(qū)本部(SMA Proper)與前運(yùn)動(dòng)輔助區(qū)不同,它在執(zhí)行學(xué)習(xí)好的運(yùn)動(dòng)序列時(shí)激活。 有些SMA本部中的神經(jīng)元在執(zhí)行特定的動(dòng)作序列時(shí)發(fā)放沖動(dòng),其他一些SMA本部中的神經(jīng)元在準(zhǔn)備特定位次的動(dòng)作時(shí)發(fā)放沖動(dòng)。比如,有些神經(jīng)元在動(dòng)物準(zhǔn)備執(zhí)行某個(gè)序列的第三個(gè)動(dòng)作時(shí)激活,而與這個(gè)動(dòng)作具體為何無關(guān)。
參考文獻(xiàn)
- ↑ Y. Matsuzaka; H. Aizawa; J. Tanji. A motor area rostral to the supplementary motor area (presupplementary motor area) in the monkey: neuronal activity during a learned motor task. Journal of Neurophysiology. 1992, 68: 653-662.
- ↑ Giuseppe Luppino; Massimo Matelli; Rosolino Camarda; Giacomo Rizzolatti. Corticocortical connections of area F3 (SMA-proper) and area F6 (pre-SMA) in the macaque monkey. The Journal of Comparative Neurology. December 1993, 338 (1): 114-140. doi:10.1002/cne.903380109.
- ↑ Shima K.; Tanji J.. Both supplementary and presupplementary motor areas are crucial for the temporal organization of multiple movements. Journal of Neurophysiology. 1998, 80: 3247-3260.
更多閱讀材料
- Principles of Neural Science (2000), 4th ed., Kandel et al.
- Debaere,-F; Wenderoth,-N; Sunaert,-S; Van-Hecke,-P; Swinnen,-S-P (2003). Internal vs external generation of movements: differential neural pathways involved in bimanual coordination performed in the presence or absence of augmented visual feedback. Neuroimage. 2003 Jul; 19(3): 764-76
- Nachev, P, Kennard, C & Husain M (2008) Functional role of the supplementary and pre-supplemenatary motor areas. Nature Reviews Neuroscience 9: 856-869.
- Vorobiev et al. (1998) Parcellation of human mesial area 6: cytoarchitectonic evidence for three separate areas. Eur J Neurosci. 10(6):2199-203.
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