Distinguishing false from true memories

记忆的准确性不仅取决于一个人对过去事件的识别程度，还取决于一个人对新信息和以前暴露的信息的区分程度。这种能力是必要的，以防止人们认为他们知道一些他们实际上从未见过的事情或人。在认知科学领域，将新的刺激与已知的刺激混淆的错误称为错误识别。错误识别主要发生在新的刺激与已知的刺激相似的时候。一旦检测到两个刺激之间的差异或不匹配，它通常被避免或正确地拒绝作为新的刺激。错误识别的大脑机制已经得到了广泛的研究，记忆在这一现象中的作用现在也得到了较好的证明。然而，人们对正确拒绝所涉及的记忆和错配检测的大脑机制知之甚少。本研究的目的是在一个涉及四个脑区的框架内研究这些机制：前额叶皮质(PFC)、前扣带回皮质(ACC)、颞叶皮质和视觉皮质。这些大脑区域中的每一个对纠正拒绝的作用都不同。首先，当感觉到新的刺激时，相似刺激的助记表征在颞叶皮质中被重新激活。由于内存的限制，通常只重新激活表示的几个特征。因此，调节特定特征(例如，颜色)的可视区域也应重新激活。PFC在表征和感知刺激之间进行比较，而ACC监控不匹配的信息。本研究计划的目的是用物体和人脸来检验这个模型。道格拉斯研究所最近获得的三种神经成像技术将被用来提供涉及错误识别和纠正拒绝的大脑动力学的完整图景。功能磁共振成像(FMRI)将有助于识别大脑结构，事件相关电位(ERPs)将用于定义过程的时空大脑特征，经颅磁刺激(TMS)将用于测试已识别过程的功能作用。

Memory accuracy does not only depend on how well one recognizes past events, but also on how well one distinguishes new information from previously exposed information. This ability is necessary to prevent people believing that they know something or someone that in fact they have never encountered. In the field of cognitive science, the mistake bringing one to confound a new stimulus with a known one is called false recognition. False recognition occurs mainly when a new stimulus resembles a known one. It is generally avoided or correctly rejected as a new stimulus, once a difference or mismatch is detected between the two stimuli. The brain mechanisms of false recognition have been widely studied and the role of recollection in this phenomenon is now relatively well documented. However, less is known about the brain mechanisms of recollection and mismatch detection involved in correct rejection. The present research program aims at studying these mechanisms within a framework involving four brain areas: the prefrontal cortex (PFC), the anterior cingulated cortex (ACC), the temporal cortex, and the visual cortex. Each of these brain areas contributes differently to correct rejection. First, when perceiving a new stimulus, mnemonic representations of resembling stimuli are reactivated in the temporal cortex. Due to memory limitations, only few features of the representation are generally reactivated. Visual areas mediating the specific features (e.g., colour) should thus also be reactivated. The PFC makes a comparison between the representation and the perceived stimulus and the ACC monitors mismatching information. The purpose of the present research program is to test this model with objects and faces. Three neuroimaging techniques recently acquired by the Douglas Institute will be used to provide a complete picture of the brain dynamics involved in false recognition and correct rejection. Functional magnetic resonance imagery (fMRI) will help identify the brain structures, event-related potentials (ERPs) will be used to define the spatio-temporal brain signature of the processes, and transcranial magnetic stimulation (TMS) will be used to test the functional role of the identified processes.