TY - CONF
T1 - Distinct roles for alpha and beta-band oscillations during construction of goal-directed action plans
AU - Brinkman, Loek
AU - de Lange, Floris P.
AU - Stolk, Arjan
AU - Dijkerman, Chris
AU - Leijten, F.S.S.
AU - Toni, Ivan
PY - 2014
Y1 - 2014
N2 - Action plans can be regarded as simulations of movements which are used to issue motor commands to the muscles and predict the sensory consequences of our actions. In order to construct an action plan, specific neuronal populations controlling particular features of that movement need to be selected, while other neuronal populations need to be suppressed. Neuronal oscillations in the alpha (8 - 12 Hz) and beta (15 - 25 Hz) band frequency range provide a possible mechanism for implementing these processes of activation and suppression in the sensorimotor system. However, their relevance and specificity for selecting neuronal ensembles remain unclear. Here we use magnetoencephalography (MEG, n = 24) and electrocorticography (ECoG, n = 9) to investigate the relative contribution of these rhythms to the construction of action plans. Changes in oscillatory power were measured while participants imagined grasping a cylinder whose orientation changed from trial to trial. This paradigm allowed us to study the neuronal processes that underlie the construction of an action plan in the absence of signals related to motor execution and sensory reafference. Given human biomechanical constraints, some object orientations evoke consistent over-hand or under-hand grasping movements, whereas other orientations are compatible with both movements. These task features allowed us to experimentally manipulate movement selection demands and to behaviourally validate motor imagery performance. Source-reconstructed MEG data revealed a dissociation between the alpha and beta band activity evoked during the imagery process. Alpha-band oscillatory power increased in the ipsilateral sensorimotor cortex, whereas beta-band power concurrently decreased in the contralateral sensorimotor cortex. These findings emerged both when movement selection demands were modulated within the imagery condition and when imagery trials were compared to trials of a control condition. These observations indicate that neural oscillations in the alpha-band mediate the allocation of computational resources, disengaging task-irrelevant cortical regions. In contrast, a reduction of neural oscillations in the beta-band may be directly related to the computations of movement parameters. We are currently analyzing ECoG data of patients implanted with subdural electrodes performing the same motor imagery task, to validate and spatially define these observations.
AB - Action plans can be regarded as simulations of movements which are used to issue motor commands to the muscles and predict the sensory consequences of our actions. In order to construct an action plan, specific neuronal populations controlling particular features of that movement need to be selected, while other neuronal populations need to be suppressed. Neuronal oscillations in the alpha (8 - 12 Hz) and beta (15 - 25 Hz) band frequency range provide a possible mechanism for implementing these processes of activation and suppression in the sensorimotor system. However, their relevance and specificity for selecting neuronal ensembles remain unclear. Here we use magnetoencephalography (MEG, n = 24) and electrocorticography (ECoG, n = 9) to investigate the relative contribution of these rhythms to the construction of action plans. Changes in oscillatory power were measured while participants imagined grasping a cylinder whose orientation changed from trial to trial. This paradigm allowed us to study the neuronal processes that underlie the construction of an action plan in the absence of signals related to motor execution and sensory reafference. Given human biomechanical constraints, some object orientations evoke consistent over-hand or under-hand grasping movements, whereas other orientations are compatible with both movements. These task features allowed us to experimentally manipulate movement selection demands and to behaviourally validate motor imagery performance. Source-reconstructed MEG data revealed a dissociation between the alpha and beta band activity evoked during the imagery process. Alpha-band oscillatory power increased in the ipsilateral sensorimotor cortex, whereas beta-band power concurrently decreased in the contralateral sensorimotor cortex. These findings emerged both when movement selection demands were modulated within the imagery condition and when imagery trials were compared to trials of a control condition. These observations indicate that neural oscillations in the alpha-band mediate the allocation of computational resources, disengaging task-irrelevant cortical regions. In contrast, a reduction of neural oscillations in the beta-band may be directly related to the computations of movement parameters. We are currently analyzing ECoG data of patients implanted with subdural electrodes performing the same motor imagery task, to validate and spatially define these observations.
M3 - Poster
ER -