北京大學(xué)心理學(xué)系和機(jī)器感知與智能教育部重點(diǎn)實(shí)驗(yàn)室，香港大學(xué)心理學(xué)系,，明尼蘇達(dá)州大學(xué)的研究人員利用功能性核磁共振技術(shù)研究視皮層可塑性取得的新進(jìn)展,。這一研究成果公布在Current Biology雜志上,。
人類通過多個(gè)感覺通道接受外界信息，包括視覺,、聽覺,、觸覺、嗅覺等,。這些信息被大腦整合,、解釋以達(dá)到還原外部世界的目的。各個(gè)通道之間不僅存在合作,，也存在競(jìng)爭(zhēng)，比如早期研究發(fā)現(xiàn)盲人的“視”皮層被用于加工觸覺信息,。
在這篇文章中,，研究人員報(bào)道了一個(gè)特殊病人的個(gè)案研究，該病人由于眼球病變而導(dǎo)致弱視,，只能看見低頻空間信息（模糊信息）,，而看不見高頻空間信息（精確信息），但他的觸覺能力遠(yuǎn)超正常人,，可以快速準(zhǔn)確的閱讀盲文和精確識(shí)別觸覺刺激,。利用功能性核磁共振掃描該病人的大腦，發(fā)現(xiàn)他的視皮層中對(duì)應(yīng)外周視野的區(qū)域被用來加工視覺信息,，而對(duì)應(yīng)中央視野的區(qū)域被用來加工觸覺信息,。一般認(rèn)為，對(duì)應(yīng)外周視野的視覺區(qū)被用來加工低頻模糊信息,，而對(duì)應(yīng)中央視野的視覺區(qū)被用來加工高頻精確信息,。由于該病人看不見高頻空間信息，他的大腦中對(duì)應(yīng)中央視野的視覺區(qū)就被觸覺加工“占用”了,。視皮層的這種特異性重組反映了,，大腦可以適應(yīng)性的利用有限的神經(jīng)資源,，對(duì)多模態(tài)信息進(jìn)行高效處理。這對(duì)于理解皮層可塑性有重要意義,，同時(shí)對(duì)于弱視病人的治療與康復(fù)也有重要指導(dǎo)意義和臨床借鑒意義,。（生物谷Bioon.com）
生物谷推薦原始出處：
Current Biology,09 April 2009 doi:10.1016/j.cub.2009.02.063
Retinotopically Specific Reorganization of Visual Cortex for Tactile Pattern Recognition
Sing-Hang Cheung1,2,4,,,Fang Fang3,4,,,Sheng He2andGordon E. Legge2
1 Department of Psychology, The University of Hong Kong, Hong Kong, China
2 Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA
3 Department of Psychology and Key Laboratory of Machine Perception (Ministry of Education), Peking University, Beijing 100871, China
4 These authors contributed equally to this work
Summary
Although previous studies have shown that Braille reading and other tactile discrimination tasks activate the visual cortex of blind and sighted people [1,2,3,4,5], it is not known whether this kind of crossmodal reorganization is influenced by retinotopic organization. We have addressed this question by studying S, a visually impaired adult with the rare ability to read print visually and Braille by touch. S had normal visual development until 6 years of age, and thereafter severe acuity reduction due to corneal opacification, but no evidence of visual-field loss. Functional magnetic resonance imaging revealed that, in S's early visual areas, tactile information processing activated what would be the foveal representation for normally sighted individuals, and visual information processing activated what would be the peripheral representation. Control experiments showed that this activation pattern was not due to visual imagery. S's high-level visual areas, which correspond to shape- and object-selective areas in normally sighted individuals, were activated by both visual and tactile stimuli. The retinotopically specific reorganization in early visual areas suggests an efficient redistribution of neural resources in the visual cortex.
