Human topographical orientation: individual variability and neural mechanisms

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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.