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Timing Matters? Learning of Complex Spatiotemporal Sequences in Left-hemisphere Stroke Patients.

During rehabilitation after stroke motor sequence learning is of particular importance since considerable effort is devoted to (re-)acquiring lost motor skills. Previous studies suggest that implicit motor sequence learning is preserved in stroke patients but were restricted to the spatial dimension, although the timing of single action components is as important as their spatial order. As the left parietal cortex is known to play a critical role in implicit timing and spatio-temporal integration, in the present study we applied an adapted version of the serial reaction time task designed to assess both spatial (different stimulus locations) and temporal (different response-stimulus intervals) aspects of motor learning to 24 right-handed patients with a single left-hemispheric stroke and 24 age-matched healthy controls. Implicit retrieval of sequence knowledge was tested both at Day 1 and after 24 hours (Day 2). Additionally, voxel-based lesion symptom mapping (VLSM) was used to investigate the neurobiological substrates of the behavioural effects.


Although LH stroke patients showed a combined spatio-temporal learning effect that was comparable to that observed in controls, LH stroke patients did not show learning effects for the learning probes in which only one type of sequence information was maintained while the other one was randomized. Particularly on Day 2 patients showed significantly smaller learning scores for these two learning probes than controls. VLSM analyses revealed for all learning probes that diminished learning scores on Day 2 were associated with lesions of the striatum. This might be attributed to its role in motor chunking and off-line consolidation as group differences occurred on Day 2 only. The current results suggest that LH stroke patients rely on multimodal information (here: temporal and spatial information) when retrieving motor sequence knowledge and are very sensitive to any disruption of the learnt sequence information as they seem to build very rigid chunks preventing them from forming independent spatial and temporal sequence representations.

Dovern et al (Paper of the month October 2015)

Results of the voxel-based lesion-symptom mapping (VLSM) analyses. VLSMs were calculated for the three different learning scores (i.e., SS-TS, SS-TR, SR-TS). Diminished learning scores in the SS-TS condition were associated with lesions of the putamen and caudate nucleus (A), while diminished learning scores in the learning probes maintaining only one type of sequence information (i.e., SS-TR and SR-TS) were associated with lesions of the caudate nucleus only (B,C).

Originalpublikation:

Dovern, A., Fink, G. R., Timpert, D. C., Saliger, J., Karbe, H., Weiss, P. H., & Koch, I. (2015). Timing Matters? Learning of Complex Spatiotemporal Sequences in Left-hemisphere Stroke Patients. Journal of Cognitive Neuroscience, 1–14.

Ansprechpartner:

Dr. Anna Dovern
Tel. 02461 61-6184
a.dovern@fz-juelich.de


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