The relationship between working memory capacity and cortical activity during performance of a novel motor task

Objectives: This study assessed whether individual differences in working memory capacity influenced verbal-analytical processes when performing a novel motor skill. Design: Participants performed a tennis-hitting task in two conditions: no pressure and high-pressure. Methods: Eighteen young adults participated in the study. EEG coherence between the T3-F3 and T4-F4 regions in the Beta1 and Alpha2 frequencies was recorded during performance in each condition. Verbal and visuo-spatial working memory capacity were assessed using the Automated Working Memory Assessment. Results: No differences were found between the two conditions for hitting performance and EEG activity. However, across both conditions, verbal and visuo-spatial working memory were significant predictors of EEG coherence between the T3-F3 and T4-F4 regions in the Beta1 and Alpha2 frequencies. Larger verbal working memory capacity was associated with greater coherence while the opposite trend was observed for visuo-spatial working memory capacity. Conclusions: These results indicate that larger verbal working memory capacity is associated with a greater tendency to use explicit processes during motor performance, whereas larger visuo-spatial working memory capacity is associated more with implicit processes. The findings are discussed with relevance to the theory of implicit motor learning. © 2015 Elsevier Ltd. All rights reserved. The process of consciously updating movement patterns on the basis of performance outcome requires working memory involvement (Maxwell, Masters,& Eves, 2003). Information about previous performances must be held actively in (working) memory so that it can be used to adjust subsequent movement strategies. Thus, working memory can be considered to be involved when a person is consciously engaged in motor performance. Working memory is limited by its capacity to hold information and this capacity differs for everyone (Daneman& Carpenter,1980). Indeed, individual differences in working memory capacity (WMC) consistently reflect differences in conscious control mechanisms, namely attention control. For example, high WMC individuals outperform lowWMC individuals in tasks that require the restraint of attention, such as antisaccade tasks (Kane, Bleckley, Conway, & Engle, 2001; Unsworth, Redick, Spillers, & Brewer, 2012; Unsworth, Schrock, & Engle, 2004) and Stroop tasks (Kane & Engle, 2003; Long & Prat, 2002; Unsworth et al., 2012). Similarly, high WMC individuals perform better in tasks that demand the constraint of attention in the presence of distracting information, such as flanker tasks (Heitz & Engle, 2007; Redick & Engle, 2006; Unsworth et al., 2012). As such, we argue that individual differences in WMC may also reflect differences in the ability to control attention during motor performance, thereby influencing the propensity to be consciously engaged in motor performance. A series of studies by Anguera and colleagues highlighted the significance of WMC during motor performance with specific reference to visuo-motor adaptations (Anguera et al., 2012; Anguera, Reuter-Lorenz, Willingham, & Seidler, 2010, 2011). In these studies, greater (spatial)WMCwas linkedwith faster learning * Corresponding author. Institute of Sport, Exercise and Active Living (ISEAL), College of Sport and Exercise Science, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia. E-mail addresses: [email protected] (T. Buszard), [email protected]. au (D. Farrow), [email protected] (F.F. Zhu), [email protected] (R.S.W. Masters).