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认识程度，还取决于一个人对新信息和以前接触过的信息的区分程度。这种能力是必要的，以防止人们相信他们知道的事情或人，实际上他们从未见过。在认知科学领域，将新刺激与已知刺激混淆的错误称为错误识别。错误认知主要发生在新刺激与已知刺激相似的时候。一旦检测到两种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已经有了相对较好的记录。然而，关于回忆和错配检测参与正确拒绝的大脑机制知之甚少。目前的研究计划旨在研究这些机制的框架涉及四个大脑区域：前额叶皮层（PFC），前扣带皮层（ACC），颞叶皮层和视觉皮层。这些大脑区域对纠正排斥反应的作用各不相同。首先，当感知到一个新的刺激时，类似刺激的记忆表征在颞叶皮层被重新激活。由于内存限制，通常只有少数特征的表示被重新激活。因此，调节特定特征（如颜色）的视觉区域也应该被重新激活。PFC将表象与感知刺激进行比较，ACC监测不匹配的信息。本研究计划的目的是用物体和面孔来测试这个模型。道格拉斯研究所最近获得的三种神经成像技术将用于提供涉及错误识别和正确拒绝的大脑动力学的完整图像。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.