When one learns a novel motor skill, retention of that skill requires consolidation of motor learning. Previous reports have shown that preceding sessions of motor learning can interfere with the acquisition of new tasks and that new motor learning can disrupt previously retained skills. A recent study by Caithness et al. (2004) shows that new learning, even after long delays, can totally disrupt prior retention. This finding is consistent with the idea that re-activated memories become labile and subject to displacement. However the result is difficult to reconcile with day-to-day experience in which skills improve with repetition and are not disrupted by unrelated activities. In this experiment, we show that when subjects learn new dynamics the influence of one task on another depends on the similarity of the force fields involved. We used a robotic manipulandum to define environments in which subjects learned to move. We used an AB design in which subjects learned field A on day one and B on day 2. We show that the effect of having learned environment A 24-hours prior to learning B varies along a continuum from facilitation when they are identical, through little effect when they are unrelated, to total interference when they are opposite. These findings thus indicate that the nervous system encodes information about dynamics in a fashion that is predictable on the basis of the similarity between the initial and final training environments. One month following their initial training, we tested subjects environment C, whose dynamics were opposite to B. Performance on this task suggests that the nervous system retained neither discrete instances of past training nor solely the most recent motor learning, but instead constructed a running average of learned dynamics to build an individual's motor repertoire.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.84060 |
| Date | January 2005 |
| Creators | Mattar, Andrew A. G. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002293368, proquestno: AAIMR22752, Theses scanned by UMI/ProQuest. |
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