Mild Physical Activity Does Not Improve Spatial Learning in a Virtual Environment.

Tavor Ben-Zeev,Inbal Weiss,Yuval Heled,Saar Ashri,Itay Ketko,Ran Yanovich,Eitan Okun

doi:10.3389/fnbeh.2020.584052

Abstract

It is well-established that physical exercise in humans improves cognitive functions, such as executive functions, pattern separation, and working memory. It is yet unknown, however, whether spatial learning, long known to be affected by exercise in rodents, is also affected in humans. In order to address this question, we recruited 20 healthy young male adults (18–30 years old) divided into exercise and control groups (n = 10 in each group). The exercise group performed three sessions per week of mild-intensity aerobic exercise for 12 weeks, while the control group was instructed not to engage in any physical activity. Both groups performed maximal oxygen uptake (VO2max) tests to assess their cardiovascular fitness at baseline and every 4 weeks through the 12 weeks of the training program. The effects of mild aerobic exercise were tested on performance in two different virtual reality (VR)-based spatial learning tasks: (1) virtual Morris water maze (VMWM) and (2) virtual Radial arm water maze (VRAWM). Subjects were tested in both tasks at baseline prior to the training program and at the end of 12 weeks training program. While the mild-intensity aerobic exercise did not affect subjects' VO2max parameters, mean time to anaerobic threshold increased for the exercise group compared with control. No effect was observed, however, on performance in the VMWM or VRAWM between the two groups. Based on these results, we suggest that mild-intensity aerobic exercise does not improve spatial learning and memory in young, healthy adults.

Highlights

Aerobic exercise is well-known to improve long-term spatial learning and memory tasks in rodents (Lee et al, 2012)
The aim of this study was to address whether aerobic physical activity improves long-term spatial learning and memory in humans
While extensive data connects between physical activity and spatial learning and memory in rodents, the link in humans has not yet been causally established. To establish such a link in humans, we first generated and calibrated the virtual reality task analogous to the MWM (VMWM) and the VRAWM Since the MWM and RAWM spatial learning tasks were originally designed for rodents, we first conducted calibration tests to fit human subjects

Summary

Introduction

Aerobic exercise is well-known to improve long-term spatial learning and memory tasks in rodents (Lee et al, 2012). The theory suggests lateralization of hippocampal function, with the right hippocampus encoding spatial relationships and the left hippocampus storing relationships between linguistic entities (Iglói et al, 2010). One or both hippocampi incorporate temporal information derived from the frontal lobes, which serves to timestamp each visit to a location, providing the basis for a spatial short-term working memory system (which can hold information from seconds and up to several minutes) (Burgess et al, 2002)

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