Changes in Neural Activity Underlying Working Memory after Computerized Cognitive Training in Older Adults

Abstract

Computerized cognitive training (CCT) may counter the impact of aging on cognition, but both the efficacy and neurocognitive mechanisms underlying CCT remain controversial. In this study, 35 older individuals were randomly assigned to Cogmed adaptive working memory (WM) CCT or an active control CCT, featuring five weeks of five ∼40 min sessions per week. Before and after the 5-week intervention, event-related potentials were measured while subjects completed a visual n-back task with three levels of demand (0-back, 1-back, 2-back). The anterior P3a served as an index of directing attention and the posterior P3b as an index of categorization/WM updating. We hypothesized that adaptive CCT would be associated with decreased P3 amplitude at low WM demand and increased P3 amplitude at high WM demand. The adaptive CCT group exhibited a training-related increase in the amplitude of the anterior P3a and posterior P3b in response to target stimuli across n-back tasks, while subjects in the active control CCT group demonstrated a post-training decrease in the anterior P3a. Performance did not differ between groups or sessions. Larger overall P3 amplitudes were strongly associated with better task performance. Increased post-CCT P3 amplitude correlated with improved task performance; this relationship was especially robust at high task load. Our findings suggest that adaptive WM training was associated with increased orienting of attention, as indexed by the P3a, and the enhancement of categorization/WM updating processes, as indexed by the P3b. Increased P3 amplitude was linked to improved performance; however. there was no direct association between adaptive training and improved performance.

Open- and Closed-Skill Exercise Interventions Produce Different Neurocognitive Effects on Executive Functions in the Elderly: A 6-Month Randomized, Controlled Trial

“…This suggests that not only closed- but also open-skill exercise could facilitate the memory-related neural processing which is involved in categorizing incoming information and updating the context of the working memory (e.g., encoding, rehearsal, recognition, and retrieval), due to the greater efficiency by which cognitive resources are allocated (Duncan-Johnson and Donchin, 1977 ; Donchin and Coles, 1988 ; Rugg, 1995 ). Although there were no significant between-group AR differences post-exercise among the three groups, the increase in exercise-induced P3 amplitudes observed in the two exercise groups after the 6-month interventions, as compared with the figures seen before training, could reveal that they allocated more resources for target classification and evaluation, which might result in higher ARs in the working memory task since larger overall P3 amplitudes during the N-back could be associated with better task performance in older adults (Tusch et al, 2016 ). However, the P3 amplitude could be influenced by a greater latency jitter of P3 in the high than in the low memory condition (Kok, 2001 ), and regular exercise could change P3 latency in the older adults (see review, Hillman et al, 2003 ), the potential response jitter thus needs to be clarified in further investigations, since different conditions in the two cognitive tasks are involved in different cognitive loads in the present study.…”

“…The effects of the two cognitive tasks on the P3 component in the elderly were clearly visible in the frontal-parietal regions of the scalp in the current study (see also Kieffaber and Hetrick, 2005 ; Friedman et al, 2008 ; Baskin-Sommers et al, 2014 ). Three electrodes (Fz, Cz, Pz) were thus analyzed in the present work (Themanson et al, 2006 ; Tusch et al, 2016 ). P3 mean amplitudes were calculated for the time-window between 300 and 600 ms post stimulus.…”

Task-Irrelevant Novel Sounds have Antithetical Effects on Visual Target Processing in Young and Old Adults

“…Mean reaction time (RT) was measured and ratios of target stimuli correctly responded to (target hits) and stimuli incorrectly identified as targets (false alarms) were calculated. Oddball performance was characterized by the nonparametric discrimination index (e.g., sensitivity) A’ and the A’ composite with RT have been used in studies of cognitive aging (Tusch et al, 2016b ; Vermeij et al, 2017 ). A’ is a behavioral performance variable derived from signal detection theory (Grier, 1971 ; Hannay, 1986 ) and ranges from 0.5 (chance level) to 1 (perfect discrimination between targets and non-targets).…”

“…The target P3 in the task-relevant modality was measured, which indexes the process of categorizing an event (Squires et al, 1973 ; Kok, 2001 ) or updating memory after an event has been categorized (Donchin, 1981 ; Donchin and Coles, 1988 ; Polich, 1996 , 2007 ). Larger P3 amplitude indicates more cognitive resources committed to stimulus processing (Wickens et al, 1983 ; Polich, 1996 ) and has been shown to correlate with task performance in some studies (Walhovd and Fjell, 2003 ; Tusch et al, 2016b ). Of particular interest is the difference in P3 amplitude to visual targets preceded by auditory novels compared to visual targets preceded by repetitive auditory standards or no auditory stimuli.…”

Interventional programmes to improve cognition during healthy and pathological ageing: Cortical modulations and evidence for brain plasticity

“…The authors reported improved performance at a low difficulty level after the training period. Overall, current research on CIs is focusing on identifying more effective training parameters (Brehmer et al, 2011;Styliaidis et al, 2015), maintaining long-term persistence of the obtained benefits (Boyke et al, 2008;Lövdén et al, 2012), and studying transfer effects to untrained abilities (Anguera et al, 2013;Berry et al, 2010;Dahlin et al, 2008;Tusch et al, 2016;Wolf et al, 2014).…”