Gonsalves Brian D, Kahn Itamar, Curran Tim, Norman Kenneth A, Wagner Anthony D
Department of Psychology and Neurosciences Program, Stanford University, Stanford, California 94305, USA.
Neuron. 2005 Sep 1;47(5):751-61. doi: 10.1016/j.neuron.2005.07.013.
Declarative memory permits an organism to recognize stimuli that have been previously encountered, discriminating them from those that are novel. One basis for recognition is item memory strength, which may support the perception of stimulus familiarity. Though the medial temporal lobes are known to be critical for declarative memory, at present the neural mechanisms supporting perceived differences in memory strength remain poorly specified. Here, functional MRI (fMRI) and anatomically constrained magnetoencephalography (MEG) indexed correlates of graded memory strength in the human brain, focusing on medial temporal cortex. fMRI revealed a decrease in medial temporal cortical activation that tracked parametric levels of perceived memory strength. Anatomically constrained MEG current estimates revealed that strength-dependent signal reductions onset within 150-300 ms. Memory strength appears to be rapidly signaled by medial temporal cortex through repetition suppression (activation reductions), providing a basis for the subjective perception of stimulus familiarity or novelty.
陈述性记忆使生物体能够识别先前遇到的刺激，并将它们与新的刺激区分开来。识别的一个基础是项目记忆强度，它可能支持对刺激熟悉度的感知。尽管已知内侧颞叶对陈述性记忆至关重要，但目前支持记忆强度感知差异的神经机制仍不明确。在这里，功能磁共振成像（fMRI）和解剖学约束脑磁图（MEG）对人类大脑中分级记忆强度的相关性进行了索引，重点关注内侧颞叶皮质。fMRI显示内侧颞叶皮质激活减少，该减少跟踪感知记忆强度的参数水平。解剖学约束的MEG电流估计显示，强度依赖性信号减少在150 - 300毫秒内开始。记忆强度似乎通过重复抑制（激活减少）由内侧颞叶皮质快速发出信号，为刺激熟悉度或新颖性的主观感知提供了基础。
