Reduced haemodynamic response in the ageing visual cortex measured by absolute fNIRS

Ward, L. M. , Aitchison, R. T., Tawse, M., Simmers, A. J. and Shahani, U. (2015) Reduced haemodynamic response in the ageing visual cortex measured by absolute fNIRS. PLoS ONE, 10(4), e0125012. (doi:10.1371/journal.pone.0125012) (PMID:25909849) (PMCID:PMC4409147)

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Abstract

The effect of healthy ageing on visual cortical activation is still to be fully explored. This study aimed to elucidate whether the haemodynamic response (HDR) of the visual cortex altered as a result of ageing. Visually normal (healthy) participants were presented with a simple visual stimulus (reversing checkerboard). Full optometric screening was implemented to identify two age groups: younger adults (n = 12, mean age 21) and older adults (n = 13, mean age 71). Frequency-domain Multi-distance (FD-MD) functional Near-Infrared Spectroscopy (fNIRS) was used to measure absolute changes in oxygenated [HbO] and deoxygenated [HbR] haemoglobin concentrations in the occipital cortices. Utilising a slow event-related design, subjects viewed a full field reversing checkerboard with contrast and check size manipulations (15 and 30 minutes of arc, 50% and 100% contrast). Both groups showed the characteristic response of increased [HbO] and decreased [HbR] during stimulus presentation. However, older adults produced a more varied HDR and often had comparable levels of [HbO] and [HbR] during both stimulus presentation and baseline resting state. Younger adults had significantly greater concentrations of both [HbO] and [HbR] in every investigation regardless of the type of stimulus displayed (p<0.05). The average variance associated with this age-related effect for [HbO] was 88% and [HbR] 91%. Passive viewing of a visual stimulus, without any cognitive input, showed a marked age-related decline in the cortical HDR. Moreover, regardless of stimulus parameters such as check size, the HDR was characterised by age. In concurrence with present neuroimaging literature, we conclude that the visual HDR decreases as healthy ageing proceeds.

Item Type:Articles (Other)
Additional Information:LMW is funded by a Glasgow Caledonian University studentship for a 3 year PhD.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Ward, Dr Laura
Authors: Ward, L. M., Aitchison, R. T., Tawse, M., Simmers, A. J., and Shahani, U.
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > Mental Health and Wellbeing
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2015 Ward et al.
First Published:First published in PLoS ONE 10(4): e0125012
Publisher Policy:Reproduced under a Creative Commons license

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