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Dopaminergic modulation of motor network dynamics in Parkinson's disease.

Michely J, Volz LJ, Barbe MT, Hoffstaedter F, Viswanathan S, Timmermann L, Eickhoff SB, Fink GR, Grefkes C - Brain (2015)

Bottom Line: Preserved performance during external cueing was associated with enhanced connectivity between prefrontal cortex and lateral premotor cortex OFF medication, compatible with a context-dependent compensatory role of the lateral premotor loop in the hypodopaminergic state.Dopaminergic medication significantly improved finger tapping speed in patients, which correlated with a drug-induced coupling increase of prefrontal cortex with the supplementary motor area, i.e. the mesial premotor loop.In contrast, medication did not improve internal motor control deficits concurrent to missing effects at the connectivity level.

View Article: PubMed Central - PubMed

Affiliation: 1 Department of Neurology, Cologne University Hospital, Kerpener Str. 62, 50937 Cologne, Germany 2 Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany.

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Functional MRI paradigm. Each block of trials started with the presentation of a fixation cross. Tapping condition: On appearance of a white arrow pointing to the left or right side, subjects were instructed to start tapping movements with maximum speed with the respective index finger as long as the respective arrow was shown (periods of 3 s), tapping periods were followed by a 2.5-s break again indicated by the fixation cross. In each block, four tapping periods were recorded. Free condition: On appearance of the fixation cross, subjects were instructed to press the left or right button with the respective index finger at any self-chosen time. Every response was followed by a visual feedback pointing to the side of the button-press. Thereafter, the fixation cross reappeared until the next response was given by the subject. Thus, subjects were free in terms of both movement lateralization and timing. Intern condition: Subjects were instructed to react as fast as possible and press the left or right button upon appearance of a double-headed arrow pointing to both sides. Hence, subjects were restricted to the time point of movement initiation but free in terms of movement lateralization. The fixation cross appeared for the time between stimuli. Extern condition: Subjects were instructed to react as fast as possible and press the left button upon appearance of an arrow pointing to the left or the right button upon appearance of an arrow pointing to the right. Thus, subjects were restricted to both time point and movement lateralization.
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awu381-F1: Functional MRI paradigm. Each block of trials started with the presentation of a fixation cross. Tapping condition: On appearance of a white arrow pointing to the left or right side, subjects were instructed to start tapping movements with maximum speed with the respective index finger as long as the respective arrow was shown (periods of 3 s), tapping periods were followed by a 2.5-s break again indicated by the fixation cross. In each block, four tapping periods were recorded. Free condition: On appearance of the fixation cross, subjects were instructed to press the left or right button with the respective index finger at any self-chosen time. Every response was followed by a visual feedback pointing to the side of the button-press. Thereafter, the fixation cross reappeared until the next response was given by the subject. Thus, subjects were free in terms of both movement lateralization and timing. Intern condition: Subjects were instructed to react as fast as possible and press the left or right button upon appearance of a double-headed arrow pointing to both sides. Hence, subjects were restricted to the time point of movement initiation but free in terms of movement lateralization. The fixation cross appeared for the time between stimuli. Extern condition: Subjects were instructed to react as fast as possible and press the left button upon appearance of an arrow pointing to the left or the right button upon appearance of an arrow pointing to the right. Thus, subjects were restricted to both time point and movement lateralization.

Mentions: We used a computerized motor task to probe basic motor functions as well as executive functions engaged in movement preparation and selection (Fig. 1). In all conditions, subjects responded via button presses on a MRI compatible response device using the right or left index finger. Visual stimuli were generated using the ‘Presentation’ software package (Version 10.3, Neurobehavioral Systems Inc.). The task comprised four conditions [slightly modified version of the task used in Michely et al. (2012)]. Each condition was presented in blocks of 20 s duration separated by resting baselines of 16 s during which subjects watched a blank screen. Each block was introduced by a one-word instruction presented for 2.5 s, informing the subject about which of the four conditions followed next.


Dopaminergic modulation of motor network dynamics in Parkinson's disease.

Michely J, Volz LJ, Barbe MT, Hoffstaedter F, Viswanathan S, Timmermann L, Eickhoff SB, Fink GR, Grefkes C - Brain (2015)

Functional MRI paradigm. Each block of trials started with the presentation of a fixation cross. Tapping condition: On appearance of a white arrow pointing to the left or right side, subjects were instructed to start tapping movements with maximum speed with the respective index finger as long as the respective arrow was shown (periods of 3 s), tapping periods were followed by a 2.5-s break again indicated by the fixation cross. In each block, four tapping periods were recorded. Free condition: On appearance of the fixation cross, subjects were instructed to press the left or right button with the respective index finger at any self-chosen time. Every response was followed by a visual feedback pointing to the side of the button-press. Thereafter, the fixation cross reappeared until the next response was given by the subject. Thus, subjects were free in terms of both movement lateralization and timing. Intern condition: Subjects were instructed to react as fast as possible and press the left or right button upon appearance of a double-headed arrow pointing to both sides. Hence, subjects were restricted to the time point of movement initiation but free in terms of movement lateralization. The fixation cross appeared for the time between stimuli. Extern condition: Subjects were instructed to react as fast as possible and press the left button upon appearance of an arrow pointing to the left or the right button upon appearance of an arrow pointing to the right. Thus, subjects were restricted to both time point and movement lateralization.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4339773&req=5

awu381-F1: Functional MRI paradigm. Each block of trials started with the presentation of a fixation cross. Tapping condition: On appearance of a white arrow pointing to the left or right side, subjects were instructed to start tapping movements with maximum speed with the respective index finger as long as the respective arrow was shown (periods of 3 s), tapping periods were followed by a 2.5-s break again indicated by the fixation cross. In each block, four tapping periods were recorded. Free condition: On appearance of the fixation cross, subjects were instructed to press the left or right button with the respective index finger at any self-chosen time. Every response was followed by a visual feedback pointing to the side of the button-press. Thereafter, the fixation cross reappeared until the next response was given by the subject. Thus, subjects were free in terms of both movement lateralization and timing. Intern condition: Subjects were instructed to react as fast as possible and press the left or right button upon appearance of a double-headed arrow pointing to both sides. Hence, subjects were restricted to the time point of movement initiation but free in terms of movement lateralization. The fixation cross appeared for the time between stimuli. Extern condition: Subjects were instructed to react as fast as possible and press the left button upon appearance of an arrow pointing to the left or the right button upon appearance of an arrow pointing to the right. Thus, subjects were restricted to both time point and movement lateralization.
Mentions: We used a computerized motor task to probe basic motor functions as well as executive functions engaged in movement preparation and selection (Fig. 1). In all conditions, subjects responded via button presses on a MRI compatible response device using the right or left index finger. Visual stimuli were generated using the ‘Presentation’ software package (Version 10.3, Neurobehavioral Systems Inc.). The task comprised four conditions [slightly modified version of the task used in Michely et al. (2012)]. Each condition was presented in blocks of 20 s duration separated by resting baselines of 16 s during which subjects watched a blank screen. Each block was introduced by a one-word instruction presented for 2.5 s, informing the subject about which of the four conditions followed next.

Bottom Line: Preserved performance during external cueing was associated with enhanced connectivity between prefrontal cortex and lateral premotor cortex OFF medication, compatible with a context-dependent compensatory role of the lateral premotor loop in the hypodopaminergic state.Dopaminergic medication significantly improved finger tapping speed in patients, which correlated with a drug-induced coupling increase of prefrontal cortex with the supplementary motor area, i.e. the mesial premotor loop.In contrast, medication did not improve internal motor control deficits concurrent to missing effects at the connectivity level.

View Article: PubMed Central - PubMed

Affiliation: 1 Department of Neurology, Cologne University Hospital, Kerpener Str. 62, 50937 Cologne, Germany 2 Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany.

Show MeSH
Related in: MedlinePlus