Chapados Catherine, Petrides Michael
Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, 3801 University, Montreal, Quebec, Canada H3A 2B4 Department of Psychology, McGill University, 1205 Doctor Penfield Avenue, Montreal Quebec, Canada H3A 1B1.
Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, 3801 University, Montreal, Quebec, Canada H3A 2B4 Department of Psychology, McGill University, 1205 Doctor Penfield Avenue, Montreal Quebec, Canada H3A 1B1
Proc Biol Sci. 2015 Feb 22;282(1801):20142555. doi: 10.1098/rspb.2014.2555.
The prefrontal cortex appears to contribute to the mnemonic retrieval of the context within which stimuli are experienced, but only under certain conditions that remain to be clarified. Patients with lesions to the frontal cortex, the temporal lobe and neurologically intact individuals were tested for context memory retrieval when verbal stimuli (words) had been experienced across multiple (unstable context condition) or unique (stable context condition) contexts; basic recognition memory of these words-in-contexts was also tested. Patients with lesions to the right ventrolateral prefrontal cortex (VLPFC) were impaired on context retrieval only when the words had been seen in multiple contexts, demonstrating that this prefrontal region is critical for active retrieval processing necessary to disambiguate memory items embedded across multiple contexts. Patients with lesions to the left dorsomedial prefrontal region were impaired on both context retrieval conditions, regardless of the stability of the stimulus-to-context associations. Conversely, prefrontal lesions sparing the ventrolateral and dorsomedial regions did not impair context retrieval. Only patients with temporal lobe excisions were impaired on basic recognition memory. The results demonstrate a basic contribution of the left dorsomedial frontal region to mnemonic context retrieval, with the VLPFC engaged, selectively, when contextual relations are unstable and require disambiguation.
前额叶皮层似乎有助于对经历刺激的情境进行记忆提取，但仅在某些尚待阐明的条件下才会如此。对额叶皮层、颞叶有损伤的患者以及神经功能正常的个体进行了测试，以考察当言语刺激（单词）在多个（不稳定情境条件）或单一（稳定情境条件）情境中被经历时，他们对情境记忆的提取能力；同时也测试了这些情境中单词的基本识别记忆。右侧腹外侧前额叶皮层（VLPFC）有损伤的患者，只有当单词在多个情境中出现时，其情境提取能力才会受损，这表明该前额叶区域对于区分嵌入在多个情境中的记忆项目所需的主动提取处理至关重要。左侧背内侧前额叶区域有损伤的患者，无论刺激与情境关联的稳定性如何，在两种情境提取条件下都会受损。相反，未损伤腹外侧和背内侧区域的前额叶损伤患者，其情境提取能力并未受损。只有颞叶切除术患者的基本识别记忆受损。结果表明，左侧背内侧额叶区域对记忆情境提取有基本贡献，当情境关系不稳定且需要区分时，VLPFC会选择性地参与其中。
