Pause time alters the preparation of two-component movements
Michael C Bajema1, Colum D MacKinnon, Michael J Carter
1Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.
Experimental Brain Research
|August 15, 2013
Summary
Movement preparation depends on timing. A loud acoustic stimulus revealed that longer pauses in reciprocal aiming tasks are pre-planned, with the return movement becoming more independent as pause duration increases.
Area of Science:
- Motor control
- Human movement science
- Cognitive neuroscience
Background:
- Reciprocal aiming movements are essential for daily activities.
- The impact of timing parameters on motor preparation for these movements remains unclear.
Purpose of the Study:
- To investigate how varying pause times in reciprocal aiming tasks influence motor preparation.
- To examine the effect of startling acoustic stimuli (SAS) on movement timing and planning.
Main Methods:
- Participants performed visually guided wrist extension-flexion tasks with 50, 200, or 500 ms pauses.
- A loud (124 dB) startling acoustic stimulus (SAS) was presented before movement components.
- Movement onsets were analyzed to assess motor preparation and pre-planning.
Main Results:
- SAS before the outward movement significantly shortened reaction times for both outward and return components, regardless of pause duration.
- For longer pauses (200, 500 ms), SAS before the return component triggered earlier return movements.
- The 50 ms pause condition suggested a single, pre-planned action.
Conclusions:
- Motor preparation for reciprocal aiming is influenced by pause duration.
- Shorter pauses (50 ms) are likely pre-planned as a single motor act.
- Longer pauses involve pre-planning of the initial movement and pause timing, with a more independent return phase.
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