Spatial orienting in naturalistic conditions: mapping the contribution stimulus-related and endogenous signals
Functional imaging in healthy participants has been extensively used to study regions of the brain involved in the processing of stimulus- and task-related signals that contribute to spatial orienting. Previous studies consistently highlighted the central role of the dorsal and ventral fronto-parietal cortices that appear to preferentially process endogenous vs. stimulus-related signals, respectively. Nonetheless, the vast majority of these investigations made use of very artificial paradigms (e.g. using repeated presentations of simple geometrical shapes) that may not generate the same type of signals that occur naturally in real-life situations. Here I will present a series of experiments that sought to bridge the gap between standard laboratory paradigms and spatial orienting in real-life. Across studies, we made use of pictures of natural scenes, short videos, full length movies, and - more recently - active navigation in virtual environments. We combined computational analyses of the sensory input (saliency maps) and measures of overt spatial orienting (eye-movements during free viewing) with the aim of mapping signals relevant for orienting in naturalistic conditions. We found that dorsal parietal regions engage when the participants orient towards externally salient locations, while the ventral parietal cortex activates primarily when internal knowledge contributes to spatial orienting. Overall our results confirm the central role of the fronto-parietal networks for spatial orienting, but also highlight that distinctive constraints govern the functioning of these systems in naturalistic, life-like conditions.
Suggested reading (pdfs available at www.brainreality.eu/publications)
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