Neural plasticity underlying visual perceptual learning in aging

Abstract

Healthy aging is associated with a decline in basic perceptual abilities, as well as higher-level cognitive functions such as working memory. In a recent perceptual training study using moving sweeps of Gabor stimuli, Berry et al. (2010) observed that older adults significantly improved discrimination abilities on the most challenging perceptual tasks that presented paired sweeps at rapid rates of 5 & 10 Hz. Berry et al. further showed that this perceptual training engendered transfer-of-benefit to an untrained working memory task. Here, we investigated the neural underpinnings of the improvements in these perceptual tasks, as assessed by event-related potential (ERP) recordings. Early visual ERP components time-locked to stimulus onset were compared pre- and post- training, as well as relative to a no-contact control group. The visual N1 and N2 components were significantly enhanced after training, and the N1 change correlated with improvements in perceptual discrimination on the task. Further, the change observed for the N1 and N2 was associated with the rapidity of the perceptual challenge; the visual N1 (120–150 ms) was enhanced post-training for 10 Hz sweep pairs, while the N2 (240–280 ms) was enhanced for the 5 Hz sweep pairs. We speculate that these observed post-training neural enhancements reflect improvements by older adults in the allocation of attention that is required to accurately dissociate perceptually overlapping stimuli when presented in rapid sequence.

Intensive Working Memory Training Produces Functional Changes in Large-scale Frontoparietal Networks

“…It is unclear why connectivity (and activation) changes were modest in the 3-back condition given the robust behavioral improvements in that condition for the N-Back group. The training-induced relations between brain plasticity as measured by connectivity and gains in WM performance are consistent with EEG studies examining the WM benefits of visual-perceptual (Berry et al, 2010; Mishra, Rolle, & Gazzaley, 2015) and distractor training (Mishra, de Villers-Sidani, Merzenich, & Gazzaley, 2014). …”

Prefrontal Modulation of Visual Processing and Sustained Attention in Aging, a tDCS–EEG Coregistration Approach

“…Early visual evoked electrophysiological responses in older adults are malleable in nature. Behavioral interventions, such as visual discrimination training protocols, have been shown to alter early visual ERPs with corresponding improvements in both early visual attention processes and higher cognitive operations (Mishra, Rolle, & Gazzaley, 2015;Berry, Zanto, Clapp, Hardy, & Delahunt, 2010). The results presented in this article complement these earlier findings and show that increasing top-down control from PFC can potentiate electrophysiological markers of visual attention.…”

Adaptive Training Diminishes Distractibility in Aging across Species

“…In prior studies that failed to remediate distractibility, individuals were trained to discriminate progressively more challenging task-relevant target stimuli, but not to manage more challenging distractors. These studies, performed both in older humans (Berry et al, 2010, Mishra et al, 2014) and rats (de Villers-Sidani et al, 2010), show robust neural enhancement of relevant information, but find no impact on distractor suppression. This selectivity is expected, as supported by neuroscience evidence showing that neural enhancement and suppression have distinct neural networks (Chadick and Gazzaley, 2011) and are differentially impacted in aging (Gazzaley et al, 2005; 2008; Clapp and Gazzaley, 2012; Chadick et al, 2014).…”