van Ekert Janneke, Wegman Joost, Jansen Clemens, Takashima Atsuko, Janzen Gabriele
Radboud University Nijmegen Behavioural Science Institute, P.O. Box 9104, 6500 HE, Nijmegen, The Netherlands.
Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
Hippocampus. 2017 Apr;27(4):393-404. doi: 10.1002/hipo.22698. Epub 2017 Jan 16.
Navigating through space is fundamental to human nature and requires the ability to retrieve relevant information from the remote past. With the passage of time, some memories become generic, capturing only a sense of familiarity. Yet, others maintain precision, even when acquired decades ago. Understanding the dynamics of memory consolidation is a major challenge to neuroscientists. Using functional magnetic resonance imaging, we systematically examined the effects of time and spatial context on the neural representation of landmark recognition memory. An equal number of male and female subjects (males N = 10, total N = 20) watched a route through a large-scale virtual environment. Landmarks occurred at navigationally relevant and irrelevant locations along the route. Recognition memory for landmarks was tested directly following encoding, 24 h later and 30 days later. Surprisingly, changes over time in the neural representation of navigationally relevant landmarks differed between males and females. In males, relevant landmarks selectively engaged the parahippocampal gyrus (PHG) regardless of the age of the memory. In females, the response to relevant landmarks gradually diminished with time in the PHG but strengthened progressively in the inferior frontal gyrus (IFG). Based on what is known about the functioning of the PHG and IFG, the findings of this study suggest that males maintain access to the initially formed spatial representation of landmarks whereas females become strongly dependent on a verbal representation of landmarks with time. Our findings yield a clear objective for future studies. © 2017 Wiley Periodicals, Inc.
在空间中导航是人类本性的基本需求，并且需要从遥远的过去检索相关信息的能力。随着时间的推移，一些记忆变得模糊，只留下一种熟悉感。然而，其他记忆即使是在几十年前获得的，仍能保持精确性。理解记忆巩固的动态过程是神经科学家面临的一项重大挑战。我们使用功能磁共振成像技术，系统地研究了时间和空间背景对地标识别记忆的神经表征的影响。同等数量的男性和女性受试者（男性N = 10，总N = 20）观看了一条穿过大规模虚拟环境的路线。地标出现在路线上与导航相关和不相关的位置。在编码后、24小时后和30天后直接测试对地标的识别记忆。令人惊讶的是，男性和女性在与导航相关的地标的神经表征随时间的变化上存在差异。在男性中，无论记忆的时长如何，相关地标都选择性地激活海马旁回（PHG）。在女性中，海马旁回对相关地标的反应随时间逐渐减弱，但在额下回（IFG）中则逐渐增强。基于对海马旁回和额下回功能的了解，本研究结果表明，男性能够持续获取最初形成的地标的空间表征，而女性则随着时间的推移强烈依赖于地标的语言表征。我们的研究结果为未来的研究明确了一个目标。© 2017威利期刊公司
