Sharma Greeshma, Gramann Klaus, Chandra Sushil, Singh Vijander, Mittal Alok Prakash
Biomedical Engineering Department, INMAS, DRDO, Delhi, 110054, India.
Biological Psychology and Neuroergonomics, Institute of Technology, University of Berlin, 10587, Berlin, Germany.
Brain Inform. 2017 Sep;4(3):207-217. doi: 10.1007/s40708-017-0066-6. Epub 2017 May 16.
Emerging evidence suggests that the variations in the ability to navigate through any real or virtual environment are accompanied by distinct underlying cortical activations in multiple regions of the brain. These activations may appear due to the use of different frame of reference (FOR) for representing an environment. The present study investigated the brain dynamics in the good and bad navigators using Graph Theoretical analysis applied to low-density electroencephalography (EEG) data. Individual navigation skills were rated according to the performance in a virtual reality (VR)-based navigation task and the effect of navigator's proclivity towards a particular FOR on the navigation performance was explored. Participants were introduced to a novel virtual environment that they learned from a first-person or an aerial perspective and were subsequently assessed on the basis of efficiency with which they learnt and recalled. The graph theoretical parameters, path length (PL), global efficiency (GE), and clustering coefficient (CC) were computed for the functional connectivity network in the theta and alpha frequency bands. During acquisition of the spatial information, good navigators were distinguished by a lower degree of dispersion in the functional connectivity compared to the bad navigators. Within the groups of good and bad navigators, better performers were characterised by the formation of multiple hubs at various sites and the percentage of connectivity or small world index. The proclivity towards a specific FOR during exploration of a new environment was not found to have any bearing on the spatial learning. These findings may have wider implications for how the functional connectivity in the good and bad navigators differs during spatial information acquisition and retrieval in the domains of rescue operations and defence systems.
新出现的证据表明，在任何真实或虚拟环境中导航能力的差异都伴随着大脑多个区域明显的潜在皮质激活。这些激活可能是由于使用了不同的参照系（FOR）来表征环境而出现的。本研究使用应用于低密度脑电图（EEG）数据的图论分析方法，研究了优秀和较差导航者的脑动力学。根据在基于虚拟现实（VR）的导航任务中的表现对个体的导航技能进行评分，并探讨了导航者对特定参照系的倾向对导航性能的影响。向参与者介绍了一个新的虚拟环境，他们从第一人称视角或鸟瞰视角学习该环境，随后根据他们学习和回忆的效率进行评估。计算了θ和α频段功能连接网络的图论参数，路径长度（PL）、全局效率（GE）和聚类系数（CC）。在获取空间信息的过程中，与较差的导航者相比，优秀的导航者在功能连接方面的分散程度较低。在优秀和较差导航者组中，表现较好的人的特征是在不同位置形成多个枢纽以及连接百分比或小世界指数。在探索新环境时对特定参照系的倾向未被发现与空间学习有任何关联。这些发现可能对救援行动和防御系统领域中优秀和较差导航者在空间信息获取和检索过程中的功能连接差异具有更广泛的意义。
