Rahmati Masih, Curtis Clayton E, Sreenivasan Kartik K
Department of Psychology, New York University, New York, NY, United States.
Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
Front Behav Neurosci. 2023 May 10;17:1094226. doi: 10.3389/fnbeh.2023.1094226. eCollection 2023.
There is a growing appreciation for the role of the thalamus in high-level cognition. Motivated by findings that internal cognitive state drives activity in feedback layers of primary visual cortex (V1) that target the lateral geniculate nucleus (LGN), we investigated the role of LGN in working memory (WM). Specifically, we leveraged model-based neuroimaging approaches to test the hypothesis that human LGN encodes information about spatial locations temporarily encoded in WM. First, we localized and derived a detailed topographic organization in LGN that accords well with previous findings in humans and non-human primates. Next, we used models constructed on the spatial preferences of LGN populations in order to reconstruct spatial locations stored in WM as subjects performed modified memory-guided saccade tasks. We found that population LGN activity faithfully encoded the spatial locations held in memory in all subjects. Importantly, our tasks and models allowed us to dissociate the locations of retinal stimulation and the motor metrics of memory-guided saccades from the maintained spatial locations, thus confirming that human LGN represents true WM information. These findings add LGN to the growing list of subcortical regions involved in WM, and suggest a key pathway by which memories may influence incoming processing at the earliest levels of the visual hierarchy.
人们越来越认识到丘脑在高级认知中的作用。受内部认知状态驱动初级视觉皮层(V1)反馈层(靶向外侧膝状体核(LGN))活动这一发现的启发,我们研究了LGN在工作记忆(WM)中的作用。具体而言,我们利用基于模型的神经成像方法来检验人类LGN编码WM中临时编码的空间位置信息这一假设。首先,我们在LGN中定位并得出了一个详细的地形组织,这与之前在人类和非人类灵长类动物中的发现非常吻合。接下来,我们使用基于LGN群体空间偏好构建的模型,以便在受试者执行改良的记忆引导扫视任务时重建WM中存储的空间位置。我们发现,所有受试者的LGN群体活动都忠实地编码了记忆中的空间位置。重要的是,我们的任务和模型使我们能够将视网膜刺激的位置和记忆引导扫视的运动指标与维持的空间位置区分开来,从而证实人类LGN代表了真正的WM信息。这些发现将LGN添加到参与WM的越来越多的皮层下区域列表中,并暗示了一条记忆可能在视觉层次结构的最早层面影响传入处理的关键途径。