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Brain oscillatory activity during motor preparation: effect of directional uncertainty on beta, but not alpha, frequency band.

Tzagarakis C, West S, Pellizzer G - Front Neurosci (2015)

Bottom Line: During cue presentation, the reduction of power of the alpha-band in the occipital lobe showed a brief differentiation of condition: the wider the visual cue, the more the power of the alpha-band decreased.However, during motor preparation, only the power of the beta-band was dependent on directional uncertainty: the less the directional uncertainty, the more the power of the beta-band decreased.In conclusion, the results indicate that the power in the alpha-band is associated briefly with cue size, but is otherwise an undifferentiated indication of neural activation, whereas the power of the beta-band reflects the level of motor preparation.

View Article: PubMed Central - PubMed

Affiliation: Brain Sciences Center, Veterans Affairs Health Care Service Minneapolis, MN, USA ; Department of Neuroscience, University of Minnesota Minneapolis, MN, USA.

ABSTRACT
In time-constraint activities, such as sports, it is advantageous to be prepared to act even before knowing precisely what action will be needed. Here, we studied the relation between neural oscillations during motor preparation and amount of uncertainty about the direction of the upcoming target. Ten right-handed volunteers participated in a cued center-out task. A brief visual cue identified the region of space in which the target would appear. Three cue sizes were used to vary the amount of information about the direction of the upcoming target. The target appeared at a random location within the region indicated by the cue, and the participants moved a joystick-controlled cursor toward it. Time-frequency analyses showed phasic increases of power in low (delta/theta: <7 Hz) and high (gamma: >30 Hz) frequency-bands in relation to the onset of visual stimuli and of the motor response. More importantly in regard to motor preparation, there was a tonic reduction of power in the alpha (8-12 Hz) and beta (14-30 Hz) bands during the period between cue presentation and target onset. During motor preparation, the main source of change of power of the alpha band was localized over the contralateral sensorimotor region and both parietal cortices, whereas for the beta-band the main source was the contralateral sensorimotor region. During cue presentation, the reduction of power of the alpha-band in the occipital lobe showed a brief differentiation of condition: the wider the visual cue, the more the power of the alpha-band decreased. However, during motor preparation, only the power of the beta-band was dependent on directional uncertainty: the less the directional uncertainty, the more the power of the beta-band decreased. In conclusion, the results indicate that the power in the alpha-band is associated briefly with cue size, but is otherwise an undifferentiated indication of neural activation, whereas the power of the beta-band reflects the level of motor preparation.

No MeSH data available.


Multidimensional scaling analysis of the time-series of alpha and beta relative power from each voxel within the significant brain regions. (A) Projection of each data point in the 3-D MDS space. The data for alpha- (blue) and beta- (red) bands were colored differently to identify them in the MDS space. (B,C) Projection of the alpha-band and the beta-band data points, respectively. The data from the clusters obtained with the cluster analysis are identified by different colors (same as in Figure 4). These results illustrate that each cluster was located in a specific region within the MDS space, but data points varied continuously between those regions.
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Figure 5: Multidimensional scaling analysis of the time-series of alpha and beta relative power from each voxel within the significant brain regions. (A) Projection of each data point in the 3-D MDS space. The data for alpha- (blue) and beta- (red) bands were colored differently to identify them in the MDS space. (B,C) Projection of the alpha-band and the beta-band data points, respectively. The data from the clusters obtained with the cluster analysis are identified by different colors (same as in Figure 4). These results illustrate that each cluster was located in a specific region within the MDS space, but data points varied continuously between those regions.

Mentions: We analyzed the power time-series to examine whether the clusters identified above correspond to discrete groups of time-series profiles or whether they correspond to subdivisions within a continuum of variations of profiles. The MDS analysis was performed to achieve reduction of the multidimensional representation of time-series to 2 or 3 dimensions. The SStress value for two dimensions was 0.152, whereas it was 0.088 for three dimensions. SStress values < 0.1 indicate that the MDS dimensions provide a good representation of the data (Johnson and Wichern, 1998). For this reason, the 3-D MDS representation was selected for examination. The results are displayed in Figure 5. The MDS analysis showed that data from the alpha- and beta-band were well-separated (Figure 5A), whereas data from different clusters within band represented specific regions along a continuum of profiles of power time-series (Figures 5B,C).


Brain oscillatory activity during motor preparation: effect of directional uncertainty on beta, but not alpha, frequency band.

Tzagarakis C, West S, Pellizzer G - Front Neurosci (2015)

Multidimensional scaling analysis of the time-series of alpha and beta relative power from each voxel within the significant brain regions. (A) Projection of each data point in the 3-D MDS space. The data for alpha- (blue) and beta- (red) bands were colored differently to identify them in the MDS space. (B,C) Projection of the alpha-band and the beta-band data points, respectively. The data from the clusters obtained with the cluster analysis are identified by different colors (same as in Figure 4). These results illustrate that each cluster was located in a specific region within the MDS space, but data points varied continuously between those regions.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508519&req=5

Figure 5: Multidimensional scaling analysis of the time-series of alpha and beta relative power from each voxel within the significant brain regions. (A) Projection of each data point in the 3-D MDS space. The data for alpha- (blue) and beta- (red) bands were colored differently to identify them in the MDS space. (B,C) Projection of the alpha-band and the beta-band data points, respectively. The data from the clusters obtained with the cluster analysis are identified by different colors (same as in Figure 4). These results illustrate that each cluster was located in a specific region within the MDS space, but data points varied continuously between those regions.
Mentions: We analyzed the power time-series to examine whether the clusters identified above correspond to discrete groups of time-series profiles or whether they correspond to subdivisions within a continuum of variations of profiles. The MDS analysis was performed to achieve reduction of the multidimensional representation of time-series to 2 or 3 dimensions. The SStress value for two dimensions was 0.152, whereas it was 0.088 for three dimensions. SStress values < 0.1 indicate that the MDS dimensions provide a good representation of the data (Johnson and Wichern, 1998). For this reason, the 3-D MDS representation was selected for examination. The results are displayed in Figure 5. The MDS analysis showed that data from the alpha- and beta-band were well-separated (Figure 5A), whereas data from different clusters within band represented specific regions along a continuum of profiles of power time-series (Figures 5B,C).

Bottom Line: During cue presentation, the reduction of power of the alpha-band in the occipital lobe showed a brief differentiation of condition: the wider the visual cue, the more the power of the alpha-band decreased.However, during motor preparation, only the power of the beta-band was dependent on directional uncertainty: the less the directional uncertainty, the more the power of the beta-band decreased.In conclusion, the results indicate that the power in the alpha-band is associated briefly with cue size, but is otherwise an undifferentiated indication of neural activation, whereas the power of the beta-band reflects the level of motor preparation.

View Article: PubMed Central - PubMed

Affiliation: Brain Sciences Center, Veterans Affairs Health Care Service Minneapolis, MN, USA ; Department of Neuroscience, University of Minnesota Minneapolis, MN, USA.

ABSTRACT
In time-constraint activities, such as sports, it is advantageous to be prepared to act even before knowing precisely what action will be needed. Here, we studied the relation between neural oscillations during motor preparation and amount of uncertainty about the direction of the upcoming target. Ten right-handed volunteers participated in a cued center-out task. A brief visual cue identified the region of space in which the target would appear. Three cue sizes were used to vary the amount of information about the direction of the upcoming target. The target appeared at a random location within the region indicated by the cue, and the participants moved a joystick-controlled cursor toward it. Time-frequency analyses showed phasic increases of power in low (delta/theta: <7 Hz) and high (gamma: >30 Hz) frequency-bands in relation to the onset of visual stimuli and of the motor response. More importantly in regard to motor preparation, there was a tonic reduction of power in the alpha (8-12 Hz) and beta (14-30 Hz) bands during the period between cue presentation and target onset. During motor preparation, the main source of change of power of the alpha band was localized over the contralateral sensorimotor region and both parietal cortices, whereas for the beta-band the main source was the contralateral sensorimotor region. During cue presentation, the reduction of power of the alpha-band in the occipital lobe showed a brief differentiation of condition: the wider the visual cue, the more the power of the alpha-band decreased. However, during motor preparation, only the power of the beta-band was dependent on directional uncertainty: the less the directional uncertainty, the more the power of the beta-band decreased. In conclusion, the results indicate that the power in the alpha-band is associated briefly with cue size, but is otherwise an undifferentiated indication of neural activation, whereas the power of the beta-band reflects the level of motor preparation.

No MeSH data available.