Functional correlates of likelihood and prior representations in a virtual distance task

Abstract

Spatial navigation is an imperative cognitive function, in which individuals must interact with their environment in order to accurately reach a destination. Previous research has demonstrated that, when traveling a predetermined distance, humans must balance between noise in the measurement process and the prior history of traveled distances. This tradeoff has recently been formally described using Bayesian estimation; however, the neural correlates of Bayesian estimation during distance reproduction have yet to be investigated. Here, human subjects performed a virtual reality distance reproduction task during functional Magnetic Resonance Imaging (fMRI), in which they were required to reproduce various traveled distances in the absence of overt navigational cues. As previously demonstrated, subjects exhibited a central tendency effect, wherein reproduced distances gravitated to the mean of the stimulus set. fMRI activity during this task revealed distance-sensitive activity in a network of regions, including prefrontal and hippocampal regions. Using a computational index of central tendency, we found that activity in the retrosplenial cortex, a region highly implicated in spatial navigation, negatively covaried between subjects with the degree of central tendency observed; conversely, we found that activity in the anterior hippocampus/amygdala complex was positively correlated with the central tendency effect of gravitating to the average reproduced distance. These findings suggest dissociable roles for the retrosplenial cortex and hippocampal complex during distance reproduction, with both regions coordinating with the prefrontal cortex the influence of prior history of the environment with present experience. Hum Brain Mapp 37:3172-3187, 2016. © 2016 Wiley Periodicals, Inc.

Multiplexing of EEG signatures for temporal and spatial distance estimates

“…One possibility here is that frontal beta oscillations underlie proximity to a memory standard used for judging relative duration (Wiener, et al 2018;Mendoza, et al 2018), whereas posterior alpha oscillations underlie the encoding of spatial distances in memory (Khader, et al 2010;Sauseng, et al 2005;Sutterer, et al 2019). Notably, in an fMRI version of the distance reproduction task used here, greater hippocampal activation was observed as subjects completed distance reproductions, which further correlated with the degree of central tendency between subjects (Wiener, et al 2016).…”

“…Task: Subjects performed temporal and spatial reproduction tasks within a virtual reality environment. The environment for the task was modified from an earlier version employed in our lab (Robinson, et al 2019;Wiener, Michaelis, & Thompson, 2016), based on a paradigm devised by Petzschner and Glasauer (2011) and designed using the Python-based software Vizard 5.0 (Worldviz). The VR environment resembled a desert with a textured ground, 20 scattered rocks in the distance, and a clear, sunny sky.…”

“…In the present study, we sought to disentangle time and space processing during the estimation and reproduction of intervals from each dimension. We employed a task in which subjects walked for randomized distances in an environment lacking landmarks, crucially relying on path integration mechanisms (Wiener et al, 2016). Concurrently recorded EEG was used to measure the CNV across encoding and reproduction of both dimensions.…”

A Bayesian Perspective on Accumulation in the Magnitude System

“…Additional studies using neuroimaging techniques such as M/EEG need to investigate the neural correlates underpinning accumulation processes in the brain when estimating magnitudes (Centro-Parietal Positivity, for example, see [64,65]), to fully explain the behavioral results obtained in these two experiments. Further, fMRI studies must be conducted to elucidate the neural circuits for memory representations of different magnitudes [47]. Bayesian approaches may provide interesting perspectives on magnitudes estimations, and additional studies need to be performed to understand to which extent these models can be applied to explain the variety of results observed in the literature.…”

Spatially periodic activation patterns of retrosplenial cortex encode route sub-spaces and distance travelled

“…The existence of a RSC distance code is consistent with detriments to path integration following damage to the region 47,48 . Further, recent fMRI work has demonstrated strong RSC correlates with virtual distance integration [49][50][51] .…”