Offline consolidation in implicit sequence learning

Abstract

The goal of this study was to investigate offline memory consolidation with regard to general motor skill learning and implicit sequence-specific learning. We trained young adults on a serial reaction time task with a retention interval of either 24 hours (Experiment 1) or 1 week (Experiment 2) between two sessions. We manipulated sequence complexity (deterministic vs. probabilistic) and motor responses (unimanual or vs. bimanual). We found no evidence of offline memory consolidation for sequencespecific learning with either interval (in the sense of no deterioration over the interval but no further improvement either). However, we did find evidence of offline enhancement of general motor skill learning with both intervals, independent of kind of sequence or kind of response. These results suggest that general motor skill learning, but not sequence-specific learning, appears to be enhanced during offline intervals in implicit sequence learning.Keywords: implicit learning, motor skill learning, retention interval OFFLINE CONSOLIDATION 3 IntroductionThere have been a vast number of studies on sequence learning, but only recently has there been much interest in how it relates to memory consolidation. The term consolidation usually refers to the stabilization, and even enhancement, of memory traces after their initial acquisition. For example, it has been demonstrated that the performance of some procedures can be significantly improved after a "silent" or offline interval subsequent to training. During this interval, there is no further practice, or even mention, of the procedure, and learning remains largely tacit or implicit (Brown & Robertson, 2007;Hallgato, Gyori-Dani, Pekar, Janacsek, & Nemeth, 2013;Krakauer & Shadmehr, 2006;Németh et al., 2010). Consolidation is also sometimes referred to as resistance to interference and forgetting (Ghilardi, Moisello, Silvestri, Ghez, & Krakauer, 2009;Goedert & Willingham, 2002; Stephan, Meier, Orosz, Cattapan-Ludewig, & KaelinLang, 2009). In the present study, we use the first definition (i.e., further improvement or enhancement). For related reviews see Doyon et al. (2009) Offline consolidation of sequence learning may depend on a variety of factors, such as training session intervals (Albouy et al., 2008;Press, Casement, Pascual-Leone, & Robertson, 2005;, practice (Korman, Raz, Flash, & Karni, 2003;Shanks & Cameron, 2000;Steele & Penhune, 2010), sleep vs.,wakefulness and time of day (Brawn, Fenn, Nusbaum, & Margoliash, 2010;Cajochen et al., 2004;Della-Maggiore, 2005;Doyon et al., 2009;Fischer, Hallschmid, Elsner, & Born, 2002;Keisler, Ashe, & Willingham, 2007;Kuriyama, Stickgold, & Walker, 2004;Manoach et al., 2004;Maquet, Schwartz, Passingham, & Frith, 2003 The purpose of the present study was to investigate the separate contributions of general motor skill learning and sequence-specific memory consolidation in implicit sequence learning. General motor skill learning refers to faster responses as a result of practice. Sequence-specific learning refers to faster ...

Statistical learning leads to persistent memory: Evidence for one-year consolidation

“…The retention of statistical knowledge after the long delay extends the findings of Nemeth and Janacsek 14 and Meier and Cock 16 , who found comparable retention of sequential memory across 12-hour, 24-hour, and one-week delay intervals. It is conceivable that those processes related specifically to the retention of statistical knowledge do not change already after 12-hour delay (see also refs 29 and 48), which is also in line with our finding that the acquired statistical knowledge was equally robust to interference both after 24 hours and one year.…”

“…Previous studies 14, 16 found improved general skills both after 24 hours and one week compared to the end of the training session, but the degree of improvement did not differ between the two delay intervals. Moreover, retained general skills were also found after one year 25 .…”

Age-Dependent Effect of Transcranial Alternating Current Stimulation on Motor Skill Consolidation

“…Here, the GMS score represents the RT difference between block 7 of the first SRTT run and block 2 of the subsequent SRTT run. We used block 2 rather than block 1 of the next SRTT run because block 1 was random and the RT difference between block 7 and block 1 might underestimate the extent of GMS consolidation (Meier and Cock, 2014). Three GMS scores were determined: the RT difference before stimulation (block 7) and immediately after stimulation (block 2); immediately after (block 7) and 60 min after stimulation (block 2); 60 min after (block 7) and 120 min after stimulation (block 2).…”

“…Improved performance is indicated by the gradual increase in GMS scores which is due to the reduction of RTs because of the participant's growing expertise on the movement component of the sequence. GMS consolidation is assumed to be accompanied by several processes such as stabilization and enhancement of motor memories, as well as resistance to interference (Meier and Cock, 2014). Sequential trials require a stable motor memory of sequential (repeating) finger movements.…”

Intention to learn differentially affects subprocesses of procedural learning and consolidation: Evidence from a probabilistic sequence learning task

“…Second, beyond focusing on how the mode of learning affects the acquisition of statistical and sequence knowledge, we also aimed to test its effect on the consolidation of these subprocesses. Consolidation refers to the changes in the acquired knowledge during the post-learning offline periods (Krakauer & Shadmehr, 2006;Meier & Cock, 2014;Robertson, 2009;Robertson, Pascual-Leone, & Miall, 2004). Typically, incidentally acquired (statistical 5 or sequence) knowledge is retained during the offline period (Hallgató, Győri-Dani, Pekár, Janacsek, & Nemeth, 2013;Janacsek & Nemeth, 2012;Kim, Seitz, Feenstra, & Shams, 2009;Kóbor et al, 2019;Rickard et al, 2008;Song, Howard, & Howard, 2007b).…”