Neural Activations during Visual Sequence Learning Leave a Trace in Post-Training Spontaneous EEG

Abstract

Recent EEG studies have shown that implicit learning involving specific cortical circuits results in an enduring local trace manifested as local changes in spectral power. Here we used a well characterized visual sequence learning task and high density-(hd-)EEG recording to determine whether also declarative learning leaves a post-task, local change in the resting state oscillatory activity in the areas involved in the learning process. Thus, we recorded hd-EEG in normal subjects before, during and after the acquisition of the order of a fixed spatial target sequence (VSEQ) and during the presentation of targets in random order (VRAN). We first determined the temporal evolution of spectral changes during VSEQ and compared it to VRAN. We found significant differences in the alpha and theta bands in three main scalp regions, a right occipito-parietal (ROP), an anterior-frontal (AFr), and a right frontal (RFr) area. The changes in frontal theta power during VSEQ were positively correlated with the learning rate. Further, post-learning EEG recordings during resting state revealed a significant increase in alpha power in ROP relative to a pre-learning baseline. We conclude that declarative learning is associated with alpha and theta changes in frontal and posterior regions that occur during the task, and with an increase of alpha power in the occipito-parietal region after the task. These post-task changes may represent a trace of learning and a hallmark of use-dependent plasticity.

Practice changes beta power at rest and its modulation during movement in healthy subjects but not in patients with Parkinson's disease

“…Also, we have previously found that alpha and theta modulation changed during the learning of a visual sequence (Moisello et al. ). Interestingly, the changes in movement‐related beta modulation reported in this study were not clearly associated with improved performance: although movement speed increased in the 40‐minute practice in both groups, we did not find significant correlation between ERS beta changes and the decrease in movement time, in agreement with the results of recent studies (Tan et al.…”

“…In other words, they were interpreted as signs of use‐dependent plasticity, possibly independent from learning outcomes (Moisello et al. ).…”

“…) and learning of visual sequences (Moisello et al. ). In particular, we found that, after a 40‐minute visual learning, the EEG changes at rest were confined to the regions active during learning and were task‐specific, as they did not occur after performance of the same duration with other tasks.…”

Tracking neural correlates of successful learning over repeated sequence observations

“…To minimize trial rejection from frequent blinks, data were segmented into relatively short epochs extending from −100 ms to 800 ms relative to stimulus onset, spanning just half of the inter-stimulus interval. Changes in spectral power during learning and signatures of prior learning in resting-state data recorded after completion of the task in Experiment I have been reported in a separate article (Moisello et al, 2013). The present study focused on event-related potentials elicited by the sequence elements.…”

“…Rushby et al, 2002; Wiswede et al, 2007). Some studies have examined spectral changes exhibited after versus before learning (Moisello et al, 2013), or more finely over the course of repeated presentations (Madhaven et al, 2015; Zhuang et al, 1997), in the latter cases linking the changes to motor execution (Zhuang et al, 1997), or memory retrieval (Madhaven et al, 2015) rather than memory formation. To our knowledge, however, no study has yet fully exploited the possibilities outlined above, and tracked neural correlates of memory formation on an element-by-element basis as they develop through discrete learning state transitions.…”