Medial temporal lobe error signaling during navigation tracks developmental differences in spatial representation

• In Event: Poster Session 06
  In Poster Session: PS 06 Topic - Biological Processes: Neuroscience and Genetics

Abstract

As we navigate, we build spatial maps of our environment. Moving to a new city, we learn routes from our new home to the grocery store. On the first trip, a wrong turn, down a wrong street may mean back tracking to reach the goal. But after multiple trips, we can update our navigation to a more efficient path based on the previously learned relationships between landmarks, streets and locations. Such updating may be supported by brain regions in the medial temporal lobe (MTL) and parietal cortex that track location and orientation within an environment. For instance, hippocampus (HPC) and entorhinal cortex (ERC) spatial codes integrate novel route information with prior spatial knowledge (Doeller et al., 2008, 2010; Suthana et al., 2009). The parahippocampal cortex (PHC), and the retrosplenial cortex (RSC) supports orientation to stable landmarks in the environment (Epstein et al., 2007; Marchette et al., 2014). Together, this network of brain regions updates our spatial knowledge to support efficient future navigation.

Across development, spatial learning shows a protracted behavioral trajectory (Julian et al., 2019), in which children may have coarser maps of their world. This reduced spatial mapping could be linked to the functional maturity of brain regions that support updating spatial knowledge. Here, we hypothesize that developmental differences in spatial memory precision arise from age-related differences in spatial mapping refinement based on error-driven learning. Children (6-12 years) and adults (18-33 years) completed a virtual navigation task, which required learning the location of different objects within a virtual arena. During test trials, participants were cued with an object and had to navigate to its remembered location. Immediately following navigation, participants received feedback as to the object’s actual location and had to navigate from their selected location to the correct goal location. This active feedback phase provided participants with the opportunity to update previously learned object-location mappings.

Behaviorally, spatial memory improved with age, measured by an age-related increase in path efficiency as well as age-related decreases in distance error and angular error. To quantify neural signals that refines object-location mappings, we focused on the neural response during feedback. Specifically, we performed a trial-by-trial parametric analysis, in which feedback response was modulated by the participant’s behavioral improvement on the next trial (change in distance error from trial n to trial n+1). We found that increased HPC, ERC, PHC, and RSC response during feedback was associated with greater improvement in spatial memory performance on the next trial. Furthermore, the relationship between error-related medial temporal lobe signals and performance were age-dependent, with adults showing a tighter coupling between brain responses and behavior relative to children. These results indicate that the functional development of these spatial mapping regions play a key role in age-related differences in spatial memory precision. Children may be less likely to learn from their navigational mistakes, failing to use feedback signals as a means to refine their spatial maps across learning.

Authors

• Hannah Elizabeth Roome, University of Texas at Austin
  Presenting Author

• Katherine R. Sherrill, University of Texas at Austin
  Non-Presenting Author

• Alison Preston, University of Texas at Austin
  Non-Presenting Author