Visual plasticity and exercise revisited: no evidence for a “cycling lane”

Abstract

Experiments using enriched environments have shown that physical exercise modulates visual plasticity in rodents. A recent study (Lunghi & Sale, 2015, doi: 10.1016/j.cub.2015.026) investigated whether exercise also affects visual plasticity in adult humans. The plastic effect they measured was the shift in ocular dominance caused by 2 hours of monocular deprivation (e.g. by an eye patch). They used a binocular rivalry task to measure this shift. They found that the magnitude of the shift was increased by exercise during the deprivation period. This effect of exercise was later disputed by a study that used a different behavioural task (Zhou et al., 2017(Zhou et al., , doi: 10.1155(Zhou et al., /2017. Our goal was to determine whether the difference in task was responsible for that study's failure to find an exercise effect. We set out to replicate Lunghi & Sale (2015). We measured ocular dominance with a rivalry task before and after 2 hours of deprivation. We measured data from two conditions in 30 subjects. On two separate days they either performed exercise or rested during the deprivation period. Contrary to the previous study, we find no significant effect of exercise. We hypothesise that exercise may affect rivalry dynamics in a way that interacts with the measurement of the deprivation effect.

Some psychophysical tasks measure ocular dominance plasticity more reliably than others

“…Data of 88 adults (age range = 18–33 years) with normal or corrected-to-normal vision were included in this study. The data from 62 subjects have already been reported in publications ( Baldwin & Hess, 2018 ; Finn, Baldwin et al, 2019 ; Min, Baldwin et al, 2018 ; Min, Baldwin et al, 2019 ). For this study alone, we recruited 26 additional subjects.…”

“…Each task is described in detail in this section. Moreover, we extracted a subset of data from four published studies ( Baldwin & Hess, 2018 ; Finn, Baldwin et al, 2019 ; Min, Baldwin et al, 2018 ; Min, Baldwin et al, 2019 ). We additionally recruited 26 unique subjects for three experimental tasks (see Figures 1 and 2 ; n = 15 per task).…”

“…Here, we refer to this neuroplastic change in ocular dominance as a result of short-term monocular deprivation as the patching effect . The patching effect lasts for 30 to 90 minutes ( Finn, Baldwin et al, 2019 ; Lunghi, Burr et al, 2011 ; Min, Baldwin et al, 2018 ). It can be induced by both opaque and translucent patches, and by dichoptic video presentation ( Bai, Dong et al, 2017 ; Zhou, Reynaud et al, 2014 ).…”

“…Furthermore, the site of action is believed to be at an early stage (i.e., striate) in cortical processing by some groups ( Begum and Tso 2016 ; Reynaud, Roux et al, 2018 ; Tso, Miller et al, 2017 ; Zhou, Reynaud et al, 2014 ) and at a later stage (i.e., extrastriate) by others ( Bai, Dong et al, 2017 ; Kim, Kim et al, 2017 ; Ramamurthy & Blaser 2018 ). Second, the test–retest variability of one method might yield inconsistent data ( Finn, Baldwin et al, 2019 ; Lunghi & Sale 2015 ). Third, the patching effect itself in the same subject might fluctuate across separate days or experimental sessions.…”

Visual plasticity and exercise revisited: No evidence for a “cycling lane”

“…An early version of this work was presented in poster form at the 2017 European Conference on Visual Perception (Finn, Zhou, Baldwin, Reynaud, & Hess, 2017). A presubmission version of this manuscript has been made available on the bioRviv preprint system (Finn, Baldwin, Reynaud, & Hess, 2018). Data…”