Landmark sequencing and route knowledge: An fMRI study

IntroductionThe ability to navigate in a familiar environment mainly relies on route knowledge, that is, a mental representation of relevant locations along a way, sequenced according to a navigational goal. Despite the clear ecological validity of this issue, route navigation and route knowledge have been scarcely investigated and little is known about the neural and cognitive bases of this navigational strategy. Using functional magnetic resonance imaging (fMRI) we tested the validity of the predictions based on the main cognitive models of spatial knowledge acquisition about route-based navigation.MethodsAn order judgment task was used with two conditions (route and activity). Subjects were required to detect potential mismatches between a current sensory input and expectations deriving from route and activity knowledge.ResultsA medial occipto-temporal (e.g., lingual gyrus, calcarine cortex, fusiform gyrus, parahippocampal cortex) network was found activated during the route task, whereas a temporo-parietal (temporo-parietal junction) and frontal (e.g., Broca's area) network was related to the activity task.ConclusionsFunctional data are congruent with cognitive models of route-based navigation. The route task activated areas related to both landmark identity and landmark order. Data are discussed in view of route-based navigation models.