Bimanual Interference in Rapid Discrete Movements Is Task Specific and Occurs at Multiple Levels of Processing

Abstract

Obhi, Sukhvinder S. and Melvyn A. Goodale. Bimanual interference in rapid discrete movements is task specific and occurs at multiple levels of processing . J Neurophysiol 94: 1861-1868, 2005. First published May 25, 2005 10.1152/jn.00320.2005. It has been suggested that interference in symbolically cued bimanual reaction time tasks is caused primarily by the perceptual processing of stimuli and not by motor preparation of the required movements. Here subjects made movements of the right and left index fingers that varied in their spatial and motor congruence. Spatial congruence was manipulated by presenting symbolic cues (i.e., pairs of letters) on a computer screen cueing the required movement directions. Motor congruence was manipulated by altering hand orientation. Results showed that interference occurs at both the stage of stimulus processing and the stage of motor preparation. These effects were reflected in the latencies of the different bimanual movements with both motor incongruence and spatial incongruence causing significant increases in reaction time. However, spatially incongruent movements that were made in response to incongruent visual cues demonstrated changes in reaction time that were more than double those of movements that required simultaneous activation of nonhomologous muscles. Therefore in symbolically cued bimanual reaction-time tasks, although both motor and spatial constraints operate, there is a clear dominance of spatial incongruence on performance. While motor congruence effects are likely due to cross-facilitation in corticospinal pathways, spatial incongruence effects are probably due to interference between the mechanisms that identify incongruent stimuli and translate these cues into the appropriate movements.

Interference effects in bimanual coordination are independent of movement type.

“…The frequency dependency of the RT and MT is consistent with research that has shown that either or both slow down the more in the presence of a second task, the more the latter differs from the first in terms of movement amplitude and/or accuracy, movement direction or peak force (Heuer & Klein, 2006;Kelso, Southard, & Goodman, 1979;Marteniuk & MacKenzie, 1980;Marteniuk, MacKenzie, & Baba, 1984;Obhi & Goodale, 2005;Spijkers & Heuer, 2004;Weigelt, 2007). Although the movements here studied did not significantly differ in amplitude 7 across frequencies and positions, they were distinct in terms of their underlying dynamics as well as in terms of their time scale of operation.…”

Visual layout modulates Fitts’s law: The importance of first and last positions

“…This notion of a special status of end positions in an array, which may act as natural spatial anchors that facilitate spatial processing, is supported by the well-known finding that a masking stimulus has less effect on location information at end positions than at middle positions of an array of letters (e.g., Mewhort & Campbell, 1978). In addition, Obhi and Goodale (2005) recently made a similar point by showing that landmarks, once encoded, facilitate pointing movements and reduce error variability. The outcome of this particularly salient spatial coding of end positions is that movements can be made more rapidly to such locations without a corresponding change in accuracy.…”

Personality and intentional binding: an exploratory study using the narcissistic personality inventory

“…Whereas there is large body of research on the production and control of human action, there is less work devoted to understanding the subjective experience of action (Rosenbaum, 1991 ; Haggard, 2001 ; Obhi and Goodale, 2005 ). The sense of agency refers to the feeling of control over self-produced actions and, as a consequence, the feeling of being a causal agent capable of effecting change in the environment (Gallagher, 2012 ; Moore and Obhi, 2012 ).…”