Neural Substrates of Contextual Interference during Motor Learning Support a Model of Active Preparation

Abstract

Abstract& When individuals acquire new skills, initial performance is typically better and tasks are judged to be easier when the tasks are segregated and practiced by block, compared to when different tasks are randomly intermixed in practice. However, subsequent skill retention is better for a randomly practiced group, an effect known as contextual interference (CI). The present study examined the neural substrates of CI using functional magnetic resonance imaging (fMRI). Individuals learned a set of three 4-element sequences with the left hand according to a block or random practice schedule. Behavioral retest for skill retention confirmed the presence of a typical CI effect with the random group outperforming the block group. Using a go/no-go fMRI paradigm, sequence preparation during the premovement study period was separated from movement execution.

Consolidating behavioral and neurophysiologic findings to explain the influence of contextual interference during motor sequence learning

“…For example, activity in regions crucial to recognition of objects in complex scenes (e.g., parahippocampal gyri, medial and inferior temporal lobe) as well as color coding and recognition were more prevalent during random practice, which would be expected given that each motor sequence used in Lin et al was assigned a unique combination of colored stimuli. Finally, the dorsal premotor area and SMA as well as the postcentral gyrus (i.e., S1), all previously described as critical for the orderly planning of sequential actions, were again recruited more extensively during the high CI practice case (Cross et al, 2007;. A significant contribution from contra-lateral dorsolateral prefrontal cortex for younger adults during random practice, not highlighted in previous work (Lin et al, 2011), was noted in a subsequent study (Lin et al, 2012).…”

“…The neurophysiologic findings that have recently accompanied studies addressing CI during motor learning provide support for the core claim of the elaboration and reconstruction accounts that incorporating greater CI during practice results in a broader recruitment of neural sites that were identified previously as important contributors to successful longterm implementation of motor sequences (Cross et al, 2007;Dayan & Cohen, 2011;Doyon et al, 2009;Lin et al, 2012;Lin et al, 2011;Penhune & Steele, 2012;. Despite this, the findings of Lin et al (2011Lin et al ( , 2012 in conjunction with those of Grafton and colleagues (Cross et al, 2007;) do little in the way of uncovering a specific neural profile that might act as a signature to differentiate low and high CI training, if such a profile exists. Nonetheless, in the few studies that examined the neural underpinnings of the CI effect directly (Cross et al, 2007;Lin et al, 2011;), a few sites consistently emerged revealing more activity during random rather than blocked practice (see Table 1).…”

“…Initial neurophysiologic evidence was reported by Wymbs and Grafton (2009) from a study that involved executing multiple motor sequences in a random or blocked format using a go/no-go paradigm designed to separate preparatory (i.e., those of primary interest) and execution process during practice only (Cross, Schmitt, & Grafton, 2007). As expected, the behavioral data revealed the expected effect of CI during acquisition and test (Shea & Morgan, 1979).…”

“…Storing motor chunks developed during random practice might be one outcome that reduces the need to recruit such an elaborate set of motor planning sites to support motor sequence production during delayed tests (Immink & Wright, 2001;Lin et al, 2011;Wright et al, 2004). The neurophysiologic findings that have recently accompanied studies addressing CI during motor learning provide support for the core claim of the elaboration and reconstruction accounts that incorporating greater CI during practice results in a broader recruitment of neural sites that were identified previously as important contributors to successful longterm implementation of motor sequences (Cross et al, 2007;Dayan & Cohen, 2011;Doyon et al, 2009;Lin et al, 2012;Lin et al, 2011;Penhune & Steele, 2012;. Despite this, the findings of Lin et al (2011Lin et al ( , 2012 in conjunction with those of Grafton and colleagues (Cross et al, 2007;) do little in the way of uncovering a specific neural profile that might act as a signature to differentiate low and high CI training, if such a profile exists.…”

“…Despite this, the findings of Lin et al (2011Lin et al ( , 2012 in conjunction with those of Grafton and colleagues (Cross et al, 2007;) do little in the way of uncovering a specific neural profile that might act as a signature to differentiate low and high CI training, if such a profile exists. Nonetheless, in the few studies that examined the neural underpinnings of the CI effect directly (Cross et al, 2007;Lin et al, 2011;), a few sites consistently emerged revealing more activity during random rather than blocked practice (see Table 1). Specifically, there is a frequent, and reliable, presence of heightened activation in the medial PM region, including pSMA-a neural region reported to be important in the acquisition of discrete motor sequences (Kennerley, Sakai, & Rushworth, 2004).…”