根據(jù)一項研究,，探測回憶活動引發(fā)的神經(jīng)活動的大腦掃描可能讓科學(xué)家——還可能讓執(zhí)法官員——確定一個人是否認出了一張?zhí)囟ǖ拿婵住＠霉δ艽殴舱癯上瘢╢MRI）,，Jesse Rissman及其同事發(fā)現(xiàn)了與受試者識別面容有關(guān)的神經(jīng)活動的模式,，這些受試者研究了一個圖像數(shù)據(jù)庫中的數(shù)以百計的面容，然后看了一系列的照片,，這些照片包括了一些來自這個數(shù)據(jù)庫的面容,，而另一些面容是新的。
這組科學(xué)家在受試者表明他們是否識別出了每一個面容的時候進行了掃描,。這組作者報告說,，模式識別軟件在大腦掃描中分離出了一種記憶的“神經(jīng)特征”， 而且這種特征在各個受試者身上是一致的,。然而,，這組作者指出，fMRI掃描在知識檢測方面有嚴重的限制,。特別是這種技術(shù)無法可靠地區(qū)分正確地報告識別出了一幅圖像和錯誤地聲稱識別出了此前沒有見過的面容的受試者,。盡管這些發(fā)現(xiàn)提示fMRI可以探測記憶，這組作者強調(diào)說,，這種技術(shù)可能無法在一些情況下工作,，而且“假陽性”可能帶來嚴重的法律后果。（生物谷Bioon.com）
生物谷推薦原文出處：
PNAS doi: 10.1073/pnas.1001028107
Detecting individual memories through the neural decoding of memory states and past experience
Jesse Rissmana,1, Henry T. Greelyb, and Anthony D. Wagnera,c,1
a Department of Psychology,
b Law School, and
c Neurosciences Program, Stanford University, Stanford, CA 94305
A wealth of neuroscientific evidence indicates that our brains respond differently to previously encountered than to novel stimuli. There has been an upswell of interest in the prospect that functional MRI (fMRI), when coupled with multivariate data analysis techniques, might allow the presence or absence of individual memories to be detected from brain activity patterns. This could have profound implications for forensic investigations and legal proceedings, and thus the merits and limitations of such an approach are in critical need of empirical evaluation. We conducted two experiments to investigate whether neural signatures of recognition memory can be reliably decoded from fMRI data. In Exp. 1, participants were scanned while making explicit recognition judgments for studied and novel faces. Multivoxel pattern analysis (MVPA) revealed a robust ability to classify whether a given face was subjectively experienced as old or new, as well as whether recognition was accompanied by recollection, strong familiarity, or weak familiarity. Moreover, a participant's subjective mnemonic experiences could be reliably decoded even when the classifier was trained on the brain data from other individuals. In contrast, the ability to classify a face's objective old/new status, when holding subjective status constant, was severely limited. This important boundary condition was further evidenced in Exp. 2, which demonstrated that mnemonic decoding is poor when memory is indirectly (implicitly) probed. Thus, although subjective memory states can be decoded quite accurately under controlled experimental conditions, fMRI has uncertain utility for objectively detecting an individual's past experiences.
