Decoding Spatial Memory Retrieval in Cubical Space Using fMRI Signals.

Jiahe Guo,Rui Zhao,Jianyu Zhang,Shengping Yu,Kai Zhang,Wen Qin,Yu Lin,Xuejun Yang,Yibo Liang

doi:10.3389/fncir.2021.624352

Abstract

The way spatial memory retrieval is represented in the brain remains unclear to date. Previous studies have displayed a hippocampus-centered navigation network using functional magnetic resonance imaging (fMRI) analysis. There have been some studies on the representation of navigation behavior by signal distribution patterns, but only in the hippocampus and adjacent structures. In this study, we aimed to determine (1) the brain regions that represent information in both intensity and distribution patterns during spatial memory retrieval and (2) whether the patterns of neural responses represent spatial memory retrieval behavior performance. Both univariate analysis [general linear model (GLM)] and multivariate pattern analysis (MVPA) were employed to reveal the spatial distributions of brain responses elicited by spatial memory retrieval. Correlation analyses were performed to detect the correspondences between brain responses and behavior performance. We found that spatial memory retrieval occurred in widespread brain regions, including the bilateral hippocampi, bilateral superior frontal gyrus, bilateral superior parietal lobules, bilateral occipital lobes, and cerebellum. The amplitude of activation in the left hippocampus showed a significant negative correlation (r = −0.46, p = 0.039) with the number of task completions. Additionally, within-subject classification accuracies based on the blood oxygenation level-dependent (BOLD) signal patterns of the right middle temporal gyrus (rMTG) rostral areas in the Brainnetome Atlas showed a significant positive correlation (r = 0.78, p < 0.0001) with retrieval accuracy. In summary, our findings have implications for understanding the separation between navigational and non-navigational states and emphasizing the utility of MVPA in the whole brain.

Highlights

Spatial memory is the storage of information about orientation and location
Using a voxelwise general linear model (GLM) analysis model to determine the effect of spatial memory retrieval, we found that the amplitude of functional magnetic resonance imaging (fMRI) responses was associated with spatial memory retrieval in widespread brain areas, including the bilateral hippocampi, bilateral frontal superior gyri, bilateral superior parietal lobule (SPL), bilateral occipital lobe, and cerebellum
Significantly activated brain regions were the core parts often elicited by spatial memory retrieval (Nilsson et al, 2013; Reynolds et al, 2019)

Summary

Introduction

Spatial memory is the storage of information about orientation and location. The way spatial memory is represented in the brain has been a motivating question for decades (Eichenbaum et al, 1999; Buzsaki and Llinas, 2017; Bellmund et al, 2018). Roland’s hometown walking task has frequently been used in neuroimaging studies to assess patients’ spatial memory function (e.g., anterior temporal lobe resection, temporal lesions) (Avila et al, 2004, 2006; Janszky et al, 2005; Bonelli et al, 2010; Strandberg et al, 2017) Despite congruent findings, such a free-behaving experiment remained a niche due to uncontrollability and unnecessary complexity, resulting in essentially uninterpretable data (Maguire, 2012). The bridge between the MTL and other cortices associated with spatial memory has not yet been fully built (Maviel et al, 2004; Vann and Albasser, 2011; Moscovitch et al, 2016; Sekeres et al, 2018)

Objectives

Methods

Results

Conclusion