Age-related deficits in voluntary control over saccadic eye movements: consideration of electrical brain stimulation as a therapeutic strategy.
Sudden changes in our visual environment trigger reflexive eye movements, so automatically they often go unnoticed. Consequently, voluntary control over reflexive eye movements entails considerable effort. In relation to frontal-lobe deterioration, adult aging adversely impacts voluntary saccadic eye movement control in particular, which compromises effective performance of daily activities. Here, we review the nature of age-related changes in saccadic control, focusing primarily on the antisaccade task because of its assessment of 2 key age-sensitive control functions: reflexive saccade inhibition and voluntary saccade generation. With an ultimate view toward facilitating development of therapeutic strategies, we systematically review the neuroanatomy underpinning voluntary control over saccadic eye movements and natural mechanisms that kick in to compensate for age-related declines. We then explore the potential of noninvasive electrical brain stimulation to counteract aging deficits. Based on evidence that anodal transcranial direct current stimulation can confer a range of benefits specifically relevant to aging brains, we put forward this neuromodulation technique as a therapeutic strategy for improving voluntary saccadic eye movement control in older adults.
Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
Po Ling
PL
Chen
Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand. Electronic address: liana@psy.otago.ac.nz.
Liana
L
Machado
D000375:Aging / Q000473:pathology / Q000502:physiology*; D004599:Electric Stimulation Therapy / Q000379:methods*; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D015835:Ocular Motility Disorders / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D012438:Saccades
Aging; Antisaccades; Compensation; Oculomotor control; Saccades; tDCS