Retrosplenial complex represents the broader spatial environment during the active experience of navigation Open Access
Suzuki, Shosuke (Spring 2020)
Successfully navigating the world requires not only being able to find one’s way through the immediately visible environment, but also situating the immediately visible environment to a broader spatial environment. Two scene systems are thought to support these different navigational processes, with the occipital place area (OPA) supporting navigation through the immediate environment (“visually-guided navigation”) and the retrosplenial complex (RSC) supporting navigation of the broader environment (“map-based navigation”). However, the precise roles of these systems are still not well understood, especially since most studies use only static displays and/or passive-viewing tasks, rather than studying responses within these regions during the active, first-person perspective experience of navigating. Moreover, a widespread and intuitive hypothesis in the spatial learning literature is that such active experience is critical for spatial processing, raising the possibility that active processing may also be critical for scene navigation; although the role of active vs. passive viewing has never been tested in the cortical navigation regions. Here we address these two hypotheses using fMRI and a novel maze-navigation paradigm. While in the scanner, participants navigated either simple or complex mazes (testing representation of the broader spatial environment) and did so while either controlling their own movement via button presses (i.e., “active”) or by being ferried through the maze (i.e., “passive”) (testing the active experience hypothesis). Consistent with the hypothesized division of labor within navigation between OPA and RSC, we indeed found that RSC responded significantly more to complex than simple mazes, while OPA did not. Surprisingly, however, we further found a specific effect of active processing in RSC only, showing greater processing of the broader environment in the active than passive condition (no effect was found in OPA). Taken together, these findings suggest the novel hypothesis that map-based navigation in RSC is relatively deliberate, whereas visually-guided navigation in OPA is relatively automatic, shedding new light on the dissociable functions of these systems.
Table of Contents
Table of Contents
Introduction ······································ 1
Materials and Methods ··················· 4
Participants ······································· 4
Experimental Design ······················ 5
Training and Calibration ················ 7
Data Acquisition & Analysis ········· 8
Results ·············································· 10
Discussion ······································· 12
References ······································· 17
Figures ·············································· 21
List of Figures
Figure 1. Schematic representation of a single trial of the maze-navigation task.
Figure 2. Localization of scene-selective regions (RSC, OPA, and PPA) in a sample participant.
Figure 3. Effect of navigation condition and maze structure in RSC, OPA, and PPA.
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|Retrosplenial complex represents the broader spatial environment during the active experience of navigation ()||2020-04-11 01:47:39 -0400||