人們學習某項運動技能的時候，有時學得快忘得也快,，而有時雖然學得慢,，卻能長久不忘，這種現(xiàn)象并非偶然,，而是有其生理基礎,。據(jù)美國物理學家組織網(wǎng)近日報道，南加利福尼亞大學科學家首次揭示了在運動記憶形成過程中,，短期記憶和長期記憶共同作用但卻互相競爭的生理機制,。該發(fā)現(xiàn)不僅有助于制定科學合理的個人訓練計劃，也為中風病人康復帶來了希望,。相關論文發(fā)表在近期出版的《神經(jīng)生理學雜志》上,。
該項目由加利福尼亞大學生物運動機能學與物理療法分部的尼古拉斯-斯格威霍夫領導。研究小組在對中風患者進行空間工作記憶測試時發(fā)現(xiàn),，中風后病人的短期記憶被破壞,，長期記憶卻更好地保留下來，這是因為他們不得不依賴長期記憶的緣故,。研究人員由此發(fā)現(xiàn),，運動記憶現(xiàn)象是由兩個過程組成，對某項技能建立起記憶,，是長期記憶和短期記憶共同作用的結果,。
研究人員解釋說，假如你在學習某些運動技能,，比如兩種上手投球,，分別學這兩種,，可能會掌握得很快，但一段時間后,，卻很可能把這兩種動作都忘了,。但如果你把時間輪流分配在多種運動技能訓練上，比如同時學習兩種不同的投球,，你或許學得更慢,，但在以后卻可能將這兩種都記住。這一現(xiàn)象稱為“背景干擾效應”,。
斯格威霍夫解釋說,，“背景干擾效應”是短期運動記憶和長期運動記憶競爭的結果，雖然人們早就知道存在這種效應,，但新研究首次揭示了這種效應背后的生理機制,。
“不斷地清除運動短期記憶有助于更新長期記憶。”斯格威霍夫說,，如果大腦是靠短期記憶去記住一項運動任務,，記住了之后，該任務卻還沒能建立起長期記憶,。如果人們在此時不停下來,，繼續(xù)學習另一項任務，并在兩項任務之間交替輪換地學習,，將會進一步建立起長期記憶,。雖然這要花更長時間，但以后不會忘記,。“學習兩種運動技能更加困難,。但在無序訓練中，我們還沒發(fā)現(xiàn)忘記的情況,。”
斯格威霍夫表示,，從長遠來看，該發(fā)現(xiàn)有助于為中風病人找到最優(yōu)的康復療法,，以及為每個人制定最有效的訓練方案,。(生物谷 Bioon.com)
doi:10.?1152/?jn.?00399.?2011
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Mechanisms of the contextual interference effect in individuals post-stroke
Nicolas Schweighofer, Jeong-Yoon Lee, Hui-Ting Goh, Younggeun Choi, Sungshin Kim, Jill C Stewart, Rebecca Lewthwaite, and Carolee J. Winstein
Although intermixing different motor learning tasks via random schedules enhances long-term retention compared to "blocked" schedules, the mechanism underlying this contextual interference effect has been unclear. Furthermore, previous studies have reported inconclusive results in individuals post-stroke. We instructed participants to learn to produce three grip force patterns in either random or blocked schedules, and measured the contextual interference effect by long-term forgetting: the change in performance between immediate and 24-hour post-tests. Non-disabled participants exhibited the contextual interference effect: no forgetting in the random condition, but forgetting in the blocked condition. Participants at least 3 months post-stroke exhibited no forgetting in the random condition, but marginal forgetting in the blocked condition. However, in participants post-stroke, the integrity of visuo-spatial working memory modulated long-term retention after blocked schedule training: participants with poor visuo-spatial working memory exhibited little forgetting at 24 hours. These counter-intuitive results were predicted by a computational model of motor memory that contains a common fast process and multiple slow processes, which are competitively updated by motor errors. In blocked schedules, the fast process quickly improved performance, therefore reducing error-driven update of the slow processes, and thus poor long-term retention. In random schedules, interferences in the fast process led to slower change in performance, therefore increasing error-driven update of slow processes and thus good long-term retention. Increased forgetting rates in the fast process, as would be expected in individuals with visuo-spatial working memory deficits, led to small updates of the fast process during blocked schedules, and thus better long-term retention.
