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Causal connectivity between the human anterior intraparietal area and premotor cortex during grasp.

Davare M, Rothwell JC, Lemon RN - Curr. Biol. (2010)

Bottom Line: At rest, AIP virtual lesions did not modify PMv-M1 interactions.In contrast, the usual muscle-specific PMv-M1 interactions that appeared during grasp preparation were significantly reduced following AIP cTBS without directly modifying corticospinal excitability.Behaviorally, disruption of AIP was also associated with a relative loss of the grasp-specific pattern of digit muscle activity.

View Article: PubMed Central - PubMed

Affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK. mdavare@ion.ucl.ac.uk

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Effect of Anterior Intraparietal Area cTBS on PMv-M1 Interactions and on the Muscle Pattern(A) Relative amplitude of motor-evoked potentials (MEPs) (± standard deviation [SD]) recorded from the 1DI and ADM when preparing to grasp either the pen or the disc (left: before cTBS; right: after cTBS). y axis values represent the relative MEP amplitudes resulting from a suprathreshold test (T) stimulus applied over M1 preceded by a subthreshold conditioning (C) stimulus applied over PMv at different C-T intervals (x axis). Note that the facilitation of the 1DI when grasping the pen and of the ADM when grasping the disc (∗p < 0.05) decreased following cTBS (∗∗p < 0.05).(B) Z score normalized electromyographic (EMG) activity (±SD) measured during grasp of the pen or the disc (left: before cTBS; right: after cTBS). EMG activity was measured between the time at which subjects left the hand pad and 100 ms before the object liftoff. The 1DI was more active when grasping the pen compared to the disc and, conversely, the ADM was more active when grasping the disc compared to the pen (∗p < 0.05). Note the less-selective muscle pattern following AIP cTBS (∗∗p < 0.05).(C) Correlation between the effect of AIP cTBS on the MEP size and on the muscle pattern. The axes represent the effect of AIP cTBS in reducing the EMG activity (x axis) and the MEP facilitation (y axis) expressed in percent of values measured before the AIP cTBS. Left: 1DI values when grasping the pen; right: ADM values when grasping the disc. Note that the greater the disruptive effect of cTBS on MEP facilitation, the more the muscle pattern during grasp was disturbed.
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fig2: Effect of Anterior Intraparietal Area cTBS on PMv-M1 Interactions and on the Muscle Pattern(A) Relative amplitude of motor-evoked potentials (MEPs) (± standard deviation [SD]) recorded from the 1DI and ADM when preparing to grasp either the pen or the disc (left: before cTBS; right: after cTBS). y axis values represent the relative MEP amplitudes resulting from a suprathreshold test (T) stimulus applied over M1 preceded by a subthreshold conditioning (C) stimulus applied over PMv at different C-T intervals (x axis). Note that the facilitation of the 1DI when grasping the pen and of the ADM when grasping the disc (∗p < 0.05) decreased following cTBS (∗∗p < 0.05).(B) Z score normalized electromyographic (EMG) activity (±SD) measured during grasp of the pen or the disc (left: before cTBS; right: after cTBS). EMG activity was measured between the time at which subjects left the hand pad and 100 ms before the object liftoff. The 1DI was more active when grasping the pen compared to the disc and, conversely, the ADM was more active when grasping the disc compared to the pen (∗p < 0.05). Note the less-selective muscle pattern following AIP cTBS (∗∗p < 0.05).(C) Correlation between the effect of AIP cTBS on the MEP size and on the muscle pattern. The axes represent the effect of AIP cTBS in reducing the EMG activity (x axis) and the MEP facilitation (y axis) expressed in percent of values measured before the AIP cTBS. Left: 1DI values when grasping the pen; right: ADM values when grasping the disc. Note that the greater the disruptive effect of cTBS on MEP facilitation, the more the muscle pattern during grasp was disturbed.

Mentions: Subjects were presented with two different objects, a pen or a disc (Figure 1B), which they had to lift with a precision grip or whole-hand grasp, respectively. The precision grip required more activity in the first dorsal interosseous (1DI) muscle than the whole-hand grasp; conversely, there was more abductor digiti minimi (ADM) muscle activity for the whole-hand grasp than the precision grip (repeated-measure analysis of variance [RM-ANOVA] grasp main effect: both F > 11.35, both p < 0.001; Figure 2B). This pattern was expected because 1DI is a prime mover in precision grip, whereas the ADM abducts the little finger to open the hand in the whole-hand grasp [21].


Causal connectivity between the human anterior intraparietal area and premotor cortex during grasp.

Davare M, Rothwell JC, Lemon RN - Curr. Biol. (2010)

Effect of Anterior Intraparietal Area cTBS on PMv-M1 Interactions and on the Muscle Pattern(A) Relative amplitude of motor-evoked potentials (MEPs) (± standard deviation [SD]) recorded from the 1DI and ADM when preparing to grasp either the pen or the disc (left: before cTBS; right: after cTBS). y axis values represent the relative MEP amplitudes resulting from a suprathreshold test (T) stimulus applied over M1 preceded by a subthreshold conditioning (C) stimulus applied over PMv at different C-T intervals (x axis). Note that the facilitation of the 1DI when grasping the pen and of the ADM when grasping the disc (∗p < 0.05) decreased following cTBS (∗∗p < 0.05).(B) Z score normalized electromyographic (EMG) activity (±SD) measured during grasp of the pen or the disc (left: before cTBS; right: after cTBS). EMG activity was measured between the time at which subjects left the hand pad and 100 ms before the object liftoff. The 1DI was more active when grasping the pen compared to the disc and, conversely, the ADM was more active when grasping the disc compared to the pen (∗p < 0.05). Note the less-selective muscle pattern following AIP cTBS (∗∗p < 0.05).(C) Correlation between the effect of AIP cTBS on the MEP size and on the muscle pattern. The axes represent the effect of AIP cTBS in reducing the EMG activity (x axis) and the MEP facilitation (y axis) expressed in percent of values measured before the AIP cTBS. Left: 1DI values when grasping the pen; right: ADM values when grasping the disc. Note that the greater the disruptive effect of cTBS on MEP facilitation, the more the muscle pattern during grasp was disturbed.
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Related In: Results  -  Collection

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fig2: Effect of Anterior Intraparietal Area cTBS on PMv-M1 Interactions and on the Muscle Pattern(A) Relative amplitude of motor-evoked potentials (MEPs) (± standard deviation [SD]) recorded from the 1DI and ADM when preparing to grasp either the pen or the disc (left: before cTBS; right: after cTBS). y axis values represent the relative MEP amplitudes resulting from a suprathreshold test (T) stimulus applied over M1 preceded by a subthreshold conditioning (C) stimulus applied over PMv at different C-T intervals (x axis). Note that the facilitation of the 1DI when grasping the pen and of the ADM when grasping the disc (∗p < 0.05) decreased following cTBS (∗∗p < 0.05).(B) Z score normalized electromyographic (EMG) activity (±SD) measured during grasp of the pen or the disc (left: before cTBS; right: after cTBS). EMG activity was measured between the time at which subjects left the hand pad and 100 ms before the object liftoff. The 1DI was more active when grasping the pen compared to the disc and, conversely, the ADM was more active when grasping the disc compared to the pen (∗p < 0.05). Note the less-selective muscle pattern following AIP cTBS (∗∗p < 0.05).(C) Correlation between the effect of AIP cTBS on the MEP size and on the muscle pattern. The axes represent the effect of AIP cTBS in reducing the EMG activity (x axis) and the MEP facilitation (y axis) expressed in percent of values measured before the AIP cTBS. Left: 1DI values when grasping the pen; right: ADM values when grasping the disc. Note that the greater the disruptive effect of cTBS on MEP facilitation, the more the muscle pattern during grasp was disturbed.
Mentions: Subjects were presented with two different objects, a pen or a disc (Figure 1B), which they had to lift with a precision grip or whole-hand grasp, respectively. The precision grip required more activity in the first dorsal interosseous (1DI) muscle than the whole-hand grasp; conversely, there was more abductor digiti minimi (ADM) muscle activity for the whole-hand grasp than the precision grip (repeated-measure analysis of variance [RM-ANOVA] grasp main effect: both F > 11.35, both p < 0.001; Figure 2B). This pattern was expected because 1DI is a prime mover in precision grip, whereas the ADM abducts the little finger to open the hand in the whole-hand grasp [21].

Bottom Line: At rest, AIP virtual lesions did not modify PMv-M1 interactions.In contrast, the usual muscle-specific PMv-M1 interactions that appeared during grasp preparation were significantly reduced following AIP cTBS without directly modifying corticospinal excitability.Behaviorally, disruption of AIP was also associated with a relative loss of the grasp-specific pattern of digit muscle activity.

View Article: PubMed Central - PubMed

Affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK. mdavare@ion.ucl.ac.uk

Show MeSH
Related in: MedlinePlus