高等動(dòng)物（包括人類）的大腦演化出一套功能各不相同的感覺(jué)通道,，用于接收和處理來(lái)自外界的各種不同的信息,。通常一個(gè)外界事件往往包含多種感覺(jué)模態(tài)信息，為能夠真實(shí)地反映和編碼外界事物,，大腦需要對(duì)來(lái)自不同通道的信息進(jìn)行整合,。已有的研究表明，神經(jīng)系統(tǒng)許多區(qū)域都存在著能夠會(huì)聚和整合多種感覺(jué)信息的神經(jīng)元,，它們能增強(qiáng)源于對(duì)同一事件不同模態(tài)的刺激反應(yīng),，抑制對(duì)無(wú)關(guān)刺激的反應(yīng)，構(gòu)成腦信息處理的一種最佳協(xié)同形式,。然而,，這種在發(fā)育中形成的多感覺(jué)整合模式和規(guī)則，在成年后還能夠改變嗎,？
俞黎平等人的最新研究成果《多感覺(jué)整合可塑性：上丘多感覺(jué)神經(jīng)元短時(shí)經(jīng)驗(yàn)——依賴的改變》,，給出了肯定的回答。他們?cè)诔赡曦埖难芯恐邪l(fā)現(xiàn),，上丘多感覺(jué)神經(jīng)元仍然具有很大的信息整合可塑性,，只要接受幾分鐘短暫的序列視覺(jué)和聽覺(jué)的組合刺激訓(xùn)練，就可誘導(dǎo)神經(jīng)元對(duì)相應(yīng)刺激信息的整合,。實(shí)驗(yàn)中發(fā)現(xiàn),，隨著序列信號(hào)的重復(fù)刺激，神經(jīng)元很快適應(yīng)了這種帶有事件性質(zhì)的刺激組合,，使前后兩種刺激信號(hào)所引起的反應(yīng)開始靠近,，逐漸融合，具體表現(xiàn)為前一個(gè)反應(yīng)的時(shí)程被延長(zhǎng)了,，后一個(gè)反應(yīng)的潛伏期縮短了,，表現(xiàn)出神經(jīng)元能整合這種新異序列的多感覺(jué)信息了，整合效應(yīng)在序列訓(xùn)練停止后仍然存在,。
這項(xiàng)研究說(shuō)明,，經(jīng)過(guò)訓(xùn)練，成年后的多感覺(jué)神經(jīng)元仍然能夠快速地適應(yīng)外界環(huán)境變化,，從而在一個(gè)更寬廣的范圍內(nèi)實(shí)現(xiàn)對(duì)多模態(tài)信息的整合,，這可能是多感覺(jué)信息加工的另一個(gè)重要規(guī)則。同時(shí),，該項(xiàng)研究還對(duì)人們理解腦的“預(yù)測(cè)”和“注意”等高級(jí)認(rèn)知功能提供了新思維,。（生物谷Bioon.com）
生物谷推薦原始出處：
The Journal of Neuroscience, December 16, 2009, 29(50):15910-15922; doi:10.1523/JNEUROSCI.4041-09.2009
Adult Plasticity in Multisensory Neurons: Short-Term Experience-Dependent Changes in the Superior Colliculus
Liping Yu,1 Barry E. Stein,2 and Benjamin A. Rowland2
1East China Normal University, School of Life Sciences, Institute of Cognitive Neuroscience, Shanghai, China, and 2Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1010
Multisensory neurons in the superior colliculus (SC) have the capability to integrate signals that belong to the same event, despite being conveyed by different senses. They develop this capability during early life as experience is gained with the statistics of cross-modal events. These adaptations prepare the SC to deal with the cross-modal events that are likely to be encountered throughout life. Here, we found that neurons in the adult SC can also adapt to experience with sequentially ordered cross-modal (visual-auditory or auditory-visual) cues, and that they do so over short periods of time (minutes), as if adapting to a particular stimulus configuration. This short-term plasticity was evident as a rapid increase in the magnitude and duration of responses to the first stimulus, and a shortening of the latency and increase in magnitude of the responses to the second stimulus when they are presented in sequence. The result was that the two responses appeared to merge. These changes were stable in the absence of experience with competing stimulus configurations, outlasted the exposure period, and could not be induced by equivalent experience with sequential within-modal (visual-visual or auditory-auditory) stimuli. A parsimonious interpretation is that the additional SC activity provided by the second stimulus became associated with, and increased the potency of, the afferents responding to the preceding stimulus. This interpretation is consistent with the principle of spike-timing-dependent plasticity, which may provide the basic mechanism for short term or long term plasticity and be operative in both the adult and neonatal SC.
