Mechanisms of the contextual interference effect in individuals poststroke

Area of Science:

• Motor learning
• Neurorehabilitation
• Cognitive neuroscience

Background:

• Intermixing motor learning tasks (random schedules) enhances long-term retention over blocked schedules, a phenomenon known as the contextual interference effect.
• The underlying neural mechanisms and effectiveness in individuals poststroke remain incompletely understood.

Purpose of the Study:

• To investigate the contextual interference effect in motor learning among non-disabled individuals and individuals poststroke.
• To explore the role of visuospatial working memory in modulating motor memory retention after different training schedules in the poststroke population.

Main Methods:

• Participants learned three grip force patterns under either random or blocked practice schedules.
• Long-term forgetting was quantified by comparing performance between immediate and 24-hour posttests.
• Visuospatial working memory capacity was assessed in participants poststroke.

Main Results:

• Non-disabled participants showed no forgetting with random schedules but forgetting with blocked schedules.
• Participants poststroke also exhibited no forgetting with random schedules and only marginal forgetting with blocked schedules.
• In individuals poststroke, poorer visuospatial working memory correlated with less forgetting after blocked schedule training.

Conclusions:

• The study confirms the contextual interference effect in motor learning for both healthy individuals and those poststroke.
• Visuospatial working memory integrity significantly influences long-term motor memory retention, particularly after blocked training in individuals poststroke.
• Computational modeling supports these findings, suggesting a dual-process model of motor memory consolidation affected by practice schedule and working memory capacity.