現(xiàn)在,，采用功能磁共振成像和計(jì)算模型，科學(xué)家已經(jīng)可以通過分析大腦,，“重現(xiàn)”人們觀看到的電影畫面,。好萊塢不少科幻片里的場(chǎng)面正一步步成為現(xiàn)實(shí)。
美國(guó)加州大學(xué)伯克利分校的科學(xué)家們采用這種先進(jìn)技術(shù),，已成功解碼并重現(xiàn)了人們大腦的動(dòng)態(tài)視覺感受,。在9月22日發(fā)表于《當(dāng)代生物學(xué)》中的一篇研究成果報(bào)告中，科學(xué)家們稱他們重現(xiàn)了志愿者看過的一段好萊塢電影預(yù)告片,。他們希望,，有一天能通過這一技術(shù)看到昏迷患者腦中的想法，或是通過視頻看到某人所做的夢(mèng)境到底是什么,。
加州大學(xué)的神經(jīng)科學(xué)家杰克·格拉特說,，志愿者在磁共振成像儀中必須保持靜止幾個(gè)小時(shí)去觀看一段視頻。然后研究者對(duì)志愿者大腦各個(gè)部位的活躍度進(jìn)行測(cè)試,，大腦每一秒的活躍度都被采樣,，并且所觀看過視頻的每一個(gè)片段都被獨(dú)立地重構(gòu)。
用腦掃描技術(shù)重建人們看到的畫面,，其難點(diǎn)在于,，要觀測(cè)的大腦中血流情況比編碼電影中動(dòng)態(tài)信息的神經(jīng)信號(hào)速度要慢得多。因此過去多數(shù)類似嘗試用的都是靜態(tài)圖像,。(生物谷 Bioon.com)
doi:10.1016/j.cub.2011.08.031
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Reconstructing Visual Experiences from Brain Activity Evoked by Natural Movies
Shinji Nishimoto, An T. Vu, Thomas Naselaris, Yuval Benjamini, Bin Yu, Jack L. Gallant
Quantitative modeling of human brain activity can provide crucial insights about cortical representations and can form the basis for brain decoding devices. Recent functional magnetic resonance imaging (fMRI) studies have modeled brain activity elicited by static visual patterns and have reconstructed these patterns from brain activity.However, blood oxygen level-dependent (BOLD) signals measured via fMRI are very slow ,so it has been difficult to model brain activity elicited by dynamic stimuli such as natural movies. Here we present a new motion-energy encoding model that largely overcomes this limitation. The model describes fast visual information and slow hemodynamics by separate components. We recorded BOLD signals in occipitotemporal visual cortex of human subjects who watched natural movies and fit the model separately to individual voxels. Visualization of the fit models reveals how early visual areas represent the information in movies. To demonstrate the power of our approach, we also constructed a Bayesian decoder by combining estimated encoding models with a sampled natural movie prior. The decoder provides remarkable reconstructions of the viewed movies. These results demonstrate that dynamic brain activity measured under naturalistic conditions can be decoded using current fMRI technology.
