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Neural activation and functional connectivity during motor imagery of bimanual everyday actions.

Szameitat AJ, McNamara A, Shen S, Sterr A - PLoS ONE (2012)

Bottom Line: We conclude that in MI of everyday actions intermanual coordination demands are primarily met by changes in connectivity between areas and only moderately, if at all, by changes in the amount of neural activity.These results are the first characterization of the neuroanatomical correlates of bimanual coordination demands in MI.The findings extent our understanding of the motor system and may aid the development of clinical neurorehabilitation approaches based on mental practice.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Ludwig Maximilians University, Munich, Germany. szameitat@psy.lmu.de

ABSTRACT
Bimanual actions impose intermanual coordination demands not present during unimanual actions. We investigated the functional neuroanatomical correlates of these coordination demands in motor imagery (MI) of everyday actions using functional magnetic resonance imaging (fMRI). For this, 17 participants imagined unimanual actions with the left and right hand as well as bimanual actions while undergoing fMRI. A univariate fMRI analysis showed no reliable cortical activations specific to bimanual MI, indicating that intermanual coordination demands in MI are not associated with increased neural processing. A functional connectivity analysis based on psychophysiological interactions (PPI), however, revealed marked increases in connectivity between parietal and premotor areas within and between hemispheres. We conclude that in MI of everyday actions intermanual coordination demands are primarily met by changes in connectivity between areas and only moderately, if at all, by changes in the amount of neural activity. These results are the first characterization of the neuroanatomical correlates of bimanual coordination demands in MI. Our findings support the assumed equivalence of overt and imagined actions and highlight the differences between uni- and bimanual actions. The findings extent our understanding of the motor system and may aid the development of clinical neurorehabilitation approaches based on mental practice.

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Related in: MedlinePlus

Behavioral data.White bars and left axis denote raw force values averaged across both hands. Gray bars and right axis denote quality of imagination (QoI) rating (rating scale ranged from 1–7). Black bars and right axis denote estimated difficulty of overt performance of the actions (rating scale ranged from 1–5). Note that Difficulty values for the Bimanual condition were derived from an independent sample (see Methods). For illustration purposes interval scale level was assumed for the Difficulty and QoI rating values and means and SEMs are displayed. Error bars denote SEM.
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pone-0038506-g001: Behavioral data.White bars and left axis denote raw force values averaged across both hands. Gray bars and right axis denote quality of imagination (QoI) rating (rating scale ranged from 1–7). Black bars and right axis denote estimated difficulty of overt performance of the actions (rating scale ranged from 1–5). Note that Difficulty values for the Bimanual condition were derived from an independent sample (see Methods). For illustration purposes interval scale level was assumed for the Difficulty and QoI rating values and means and SEMs are displayed. Error bars denote SEM.

Mentions: Before the experiment started participants were asked to rate how difficult it would be to overtly perform perform the movements used in the present experiment. Participants rated the perceived difficulty for each movement when performed with the left and right hand, respectively, using a scale ranging from 1 (“very easy”) to 5 (“very hard”). Ratings of different unimanual tasks were significantly different for complex and simple actions (non-parametric Wilcoxon tests (N = 17), see Fig. 1, black bars). Imagination of left hand actions was perceived to be more difficult than right hand actions for both categories of complexity (Simple: Z = 2.640, p<.01; Complex: Z = 3.720, p<.001). In addition, Simple tasks were easier than Complex tasks when performed with the left hand (Z = 3.743, p<.001), but not when performed with the right hand (Z = 1, p = .317). Compared to unimanual conditions (derived from the study sample), Biman actions were easier than Complex-L actions (Z = 5.141, p<.001), showed a trend to be more difficult than Simple-R actions (Z = 2.659; p = .079), and were equivalent to Simple-L and Complex-R (both p>.15). Therefore, the bimanual actions were rated to be in the same difficulty range as the unimanual actions.


Neural activation and functional connectivity during motor imagery of bimanual everyday actions.

Szameitat AJ, McNamara A, Shen S, Sterr A - PLoS ONE (2012)

Behavioral data.White bars and left axis denote raw force values averaged across both hands. Gray bars and right axis denote quality of imagination (QoI) rating (rating scale ranged from 1–7). Black bars and right axis denote estimated difficulty of overt performance of the actions (rating scale ranged from 1–5). Note that Difficulty values for the Bimanual condition were derived from an independent sample (see Methods). For illustration purposes interval scale level was assumed for the Difficulty and QoI rating values and means and SEMs are displayed. Error bars denote SEM.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368848&req=5

pone-0038506-g001: Behavioral data.White bars and left axis denote raw force values averaged across both hands. Gray bars and right axis denote quality of imagination (QoI) rating (rating scale ranged from 1–7). Black bars and right axis denote estimated difficulty of overt performance of the actions (rating scale ranged from 1–5). Note that Difficulty values for the Bimanual condition were derived from an independent sample (see Methods). For illustration purposes interval scale level was assumed for the Difficulty and QoI rating values and means and SEMs are displayed. Error bars denote SEM.
Mentions: Before the experiment started participants were asked to rate how difficult it would be to overtly perform perform the movements used in the present experiment. Participants rated the perceived difficulty for each movement when performed with the left and right hand, respectively, using a scale ranging from 1 (“very easy”) to 5 (“very hard”). Ratings of different unimanual tasks were significantly different for complex and simple actions (non-parametric Wilcoxon tests (N = 17), see Fig. 1, black bars). Imagination of left hand actions was perceived to be more difficult than right hand actions for both categories of complexity (Simple: Z = 2.640, p<.01; Complex: Z = 3.720, p<.001). In addition, Simple tasks were easier than Complex tasks when performed with the left hand (Z = 3.743, p<.001), but not when performed with the right hand (Z = 1, p = .317). Compared to unimanual conditions (derived from the study sample), Biman actions were easier than Complex-L actions (Z = 5.141, p<.001), showed a trend to be more difficult than Simple-R actions (Z = 2.659; p = .079), and were equivalent to Simple-L and Complex-R (both p>.15). Therefore, the bimanual actions were rated to be in the same difficulty range as the unimanual actions.

Bottom Line: We conclude that in MI of everyday actions intermanual coordination demands are primarily met by changes in connectivity between areas and only moderately, if at all, by changes in the amount of neural activity.These results are the first characterization of the neuroanatomical correlates of bimanual coordination demands in MI.The findings extent our understanding of the motor system and may aid the development of clinical neurorehabilitation approaches based on mental practice.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Ludwig Maximilians University, Munich, Germany. szameitat@psy.lmu.de

ABSTRACT
Bimanual actions impose intermanual coordination demands not present during unimanual actions. We investigated the functional neuroanatomical correlates of these coordination demands in motor imagery (MI) of everyday actions using functional magnetic resonance imaging (fMRI). For this, 17 participants imagined unimanual actions with the left and right hand as well as bimanual actions while undergoing fMRI. A univariate fMRI analysis showed no reliable cortical activations specific to bimanual MI, indicating that intermanual coordination demands in MI are not associated with increased neural processing. A functional connectivity analysis based on psychophysiological interactions (PPI), however, revealed marked increases in connectivity between parietal and premotor areas within and between hemispheres. We conclude that in MI of everyday actions intermanual coordination demands are primarily met by changes in connectivity between areas and only moderately, if at all, by changes in the amount of neural activity. These results are the first characterization of the neuroanatomical correlates of bimanual coordination demands in MI. Our findings support the assumed equivalence of overt and imagined actions and highlight the differences between uni- and bimanual actions. The findings extent our understanding of the motor system and may aid the development of clinical neurorehabilitation approaches based on mental practice.

Show MeSH
Related in: MedlinePlus