Human topographical orientation: individual variability and neural mechanisms

在环境中定向的能力是人类最复杂的行为之一。一些研究表明，这种复杂性依赖于环境因素，例如环境中有意义的地标的密度。其他研究表明，除了环境因素外，个体在使用某些环境信息时所表现出的自发偏见也导致了这一现象的复杂性，从而导致个体在采用不同定向策略时的高度变异性。虽然这两个因素可能有助于在人类的复杂性方向，有证据表明，个人在他们的定向技能不同，无论他们移动的环境和他们可能使用的战略方向。在目前的研究计划中，我们的目标是调查的假设，这种变化在个人的方向技能可能部分取决于功能和完整性的大脑区域已知负责在人类的方向。为了实现这一目标，我们将利用虚拟现实环境，年轻健康的参与者将通过使用不同的方向策略执行不同的导航任务。这将使我们能够选择在使用选择性定向策略方面技能较差或较好的个人群体。然后，这些个人团体将参加一系列神经成像项目，包括功能性磁共振成像（fMRI）和扩散张量成像（DTI）研究。功能磁共振成像研究将评估当个体使用选择性定向策略时所涉及的不同大脑区域的神经活动，以及神经活动如何与个体的定向技能相关。DTI研究将调查参与定向的那些大脑区域的分子特性，以及它们的结构组织如何与个体在利用不同定向策略的能力中观察到的变异性相关。行为的变异性和神经机制的变异性之间存在密切关系的证据，将成为解释人类定向的基本机制的重要信息来源。

The ability to orient in the surrounding is one of the most complex human behaviors. Some studies suggest that this complexity relies on environmental factors, such as the density of meaningful landmarks available within the environment. Other studies suggest that in addition to environmental factors, the spontaneous bias that individuals show in using certain environmental information contributes to the complexity of the phenomenon, resulting in a high variability across individuals in adopting different orientation strategies. Although both of these factors may contribute to the complexity of orientation in humans, there is evidence that individuals vary in their orientation skills irrespective of both the environment in which they move and the strategies that they may use for orientation. In the present research program, we aim to investigate the hypothesis that such variability in individual orientation skills may depend in part on the functionality and integrity of those brain regions known to be responsible for orientation in humans. To achieve this objective, we will make use of virtual reality environments in which young healthy participants will perform different navigational tasks by using different orientation strategies. This will allow us to select groups of individuals with poor or good skills in using selective orientation strategies. These groups of individuals will then participate in a series of neuroimaging projects including functional Magnetic Resonance Imaging (fMRI) and Diffusion Tensor Imaging (DTI) studies. The fMRI studies will assess the neural activity of different brain regions involved while individuals make use of selective orientation strategies, and how that neural activity relates to the individuals' orientation skills. The DTI studies will investigate the molecular properties of those brain regions involved in orientation, and how their structural organization relates to the variability observed across individuals in their ability to make use of different orientation strategies. The evidence of a strong relationship between variability in behavior and variability in neural mechanisms will be a critical source of information to explain the basic fundamental mechanisms of orientation in humans.