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Different roles of alpha and beta band oscillations in anticipatory sensorimotor gating.

Buchholz VN, Jensen O, Medendorp WP - Front Hum Neurosci (2014)

Bottom Line: Both frequency bands showed different lateralization profiles at central vs. posterior sensors, indicating anticipation of somatosensory and oculomotor processing.Furthermore, beta band power in somatosensory cortex correlated positively with saccade reaction time (SRT), with correlation values that were significantly higher with contralateral vs. ipsilateral activation.In contrast, alpha band power in parietal cortex correlated negatively with SRT, with correlation values that were significantly more negative with ipsilateral than contralateral activation.

View Article: PubMed Central - PubMed

Affiliation: Cognition and Behaviour, Donders Institute for Brain, Radboud University Nijmegen Nijmegen, Netherlands ; Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf Hamburg, Germany.

ABSTRACT
Alpha (8-12 Hz) and beta band (18-30 Hz) oscillations have been implicated in sensory anticipation and motor preparation. Here, using magneto-encephalography, we tested whether they have distinct functional roles in a saccade task that induces a remapping between sensory and motor reference frames. With a crossed hands posture, subjects had to saccade as fast and accurate as possible toward a tactile stimulus delivered to one of two non-visible index fingers, located to the left or right of gaze. Previous studies have shown that this task, in which the somatotopic stimulus must be remapped to activate oculomotor system in the opposing hemisphere, is occasionally preceded by intrahemispheric remapping, driving a premature saccade into the wrong direction. To test whether the brain could anticipate the remapping, we provided auditory predictive cues (80% validity), which indicated which finger is most likely to be stimulated. Both frequency bands showed different lateralization profiles at central vs. posterior sensors, indicating anticipation of somatosensory and oculomotor processing. Furthermore, beta band power in somatosensory cortex correlated positively with saccade reaction time (SRT), with correlation values that were significantly higher with contralateral vs. ipsilateral activation. In contrast, alpha band power in parietal cortex correlated negatively with SRT, with correlation values that were significantly more negative with ipsilateral than contralateral activation. These results suggest distinct functional roles of beta and alpha band activity: (1) somatosensory gating by beta oscillations, increasing excitability in contralateral somatosensory cortex (positive correlation); and (2) oculomotor gating by posterior alpha oscillations, inhibiting gaze-centered oculomotor regions involved in generating the saccade to the wrong direction (negative correlation). Our results show that low frequency rhythms gate upcoming sensorimotor transformations.

No MeSH data available.


Related in: MedlinePlus

Prestimulus modulations in alpha and beta bands. (A) Scalp topography in the beta band (averaged across 18–30 Hz, and at time −0.3 s). Cooler colors, lower power for anticipating contralateral hand stimuli; warmer colors, lower power for stimuli on the ipsilateral hand. (B) Data combined across hemispheres. (C) Source reconstruction of the relative beta suppression contralateral to the expected hand stimulation. (D–F) Scalp topography and source reconstructions of the alpha oscillations (10 Hz, and time −0.3 s) in the same format as A–C. CS, Central sulcus; IPS, intraparietal sulcus.
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Figure 2: Prestimulus modulations in alpha and beta bands. (A) Scalp topography in the beta band (averaged across 18–30 Hz, and at time −0.3 s). Cooler colors, lower power for anticipating contralateral hand stimuli; warmer colors, lower power for stimuli on the ipsilateral hand. (B) Data combined across hemispheres. (C) Source reconstruction of the relative beta suppression contralateral to the expected hand stimulation. (D–F) Scalp topography and source reconstructions of the alpha oscillations (10 Hz, and time −0.3 s) in the same format as A–C. CS, Central sulcus; IPS, intraparietal sulcus.

Mentions: Figure 2A shows the scalp topography of power in the beta band (averaged across 18–30 Hz) in the 500 ms prestimulus period, comparing log-transformed power when subjects were expecting a stimulus on the contralateral hand as compared to the ipsilateral hand. Thus, for the left hemisphere we compare right-hand (RH)—LH stimulation, and for the right hemisphere: LH—RH. Regions with cooler colors indicate lower power values for anticipating contralateral hand stimuli, while regions with warmer colors signify lower power values for stimuli on the ipsilateral hand. The scalp topography shows lower beta-band power for contralateral hand stimuli than for ipsilateral stimuli (cooler colors), most prominently over central regions. This is consistent with increased excitability in the hemisphere contralateral to the hand in a body-centered (somatotopic) representation format, or a decreased excitability in the hemisphere ipsilateral to the hand. To examine consistent effects across hemispheres, and improve the signal-to-noise ratio, data were combined by averaging across the two halves, resulting in a cleaner topography of the lower power for anticipated stimuli to the contralateral hand (Figure 2B). As shown, opposite modulations across hemispheres, which are inconsistent with either reference frame, and just reflect a general spatial bias have cancelled out. The observed lateralization was significantly different between central and posterior sensors (indicated by dots; t = 3.55, P = 0.0019). In fact, there was a clear lateralization at central sensors, but not at posterior sensors, which is consistent with sensory anticipation at central regions by beta band activity in a somatotopic reference frame.


Different roles of alpha and beta band oscillations in anticipatory sensorimotor gating.

Buchholz VN, Jensen O, Medendorp WP - Front Hum Neurosci (2014)

Prestimulus modulations in alpha and beta bands. (A) Scalp topography in the beta band (averaged across 18–30 Hz, and at time −0.3 s). Cooler colors, lower power for anticipating contralateral hand stimuli; warmer colors, lower power for stimuli on the ipsilateral hand. (B) Data combined across hemispheres. (C) Source reconstruction of the relative beta suppression contralateral to the expected hand stimulation. (D–F) Scalp topography and source reconstructions of the alpha oscillations (10 Hz, and time −0.3 s) in the same format as A–C. CS, Central sulcus; IPS, intraparietal sulcus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4060639&req=5

Figure 2: Prestimulus modulations in alpha and beta bands. (A) Scalp topography in the beta band (averaged across 18–30 Hz, and at time −0.3 s). Cooler colors, lower power for anticipating contralateral hand stimuli; warmer colors, lower power for stimuli on the ipsilateral hand. (B) Data combined across hemispheres. (C) Source reconstruction of the relative beta suppression contralateral to the expected hand stimulation. (D–F) Scalp topography and source reconstructions of the alpha oscillations (10 Hz, and time −0.3 s) in the same format as A–C. CS, Central sulcus; IPS, intraparietal sulcus.
Mentions: Figure 2A shows the scalp topography of power in the beta band (averaged across 18–30 Hz) in the 500 ms prestimulus period, comparing log-transformed power when subjects were expecting a stimulus on the contralateral hand as compared to the ipsilateral hand. Thus, for the left hemisphere we compare right-hand (RH)—LH stimulation, and for the right hemisphere: LH—RH. Regions with cooler colors indicate lower power values for anticipating contralateral hand stimuli, while regions with warmer colors signify lower power values for stimuli on the ipsilateral hand. The scalp topography shows lower beta-band power for contralateral hand stimuli than for ipsilateral stimuli (cooler colors), most prominently over central regions. This is consistent with increased excitability in the hemisphere contralateral to the hand in a body-centered (somatotopic) representation format, or a decreased excitability in the hemisphere ipsilateral to the hand. To examine consistent effects across hemispheres, and improve the signal-to-noise ratio, data were combined by averaging across the two halves, resulting in a cleaner topography of the lower power for anticipated stimuli to the contralateral hand (Figure 2B). As shown, opposite modulations across hemispheres, which are inconsistent with either reference frame, and just reflect a general spatial bias have cancelled out. The observed lateralization was significantly different between central and posterior sensors (indicated by dots; t = 3.55, P = 0.0019). In fact, there was a clear lateralization at central sensors, but not at posterior sensors, which is consistent with sensory anticipation at central regions by beta band activity in a somatotopic reference frame.

Bottom Line: Both frequency bands showed different lateralization profiles at central vs. posterior sensors, indicating anticipation of somatosensory and oculomotor processing.Furthermore, beta band power in somatosensory cortex correlated positively with saccade reaction time (SRT), with correlation values that were significantly higher with contralateral vs. ipsilateral activation.In contrast, alpha band power in parietal cortex correlated negatively with SRT, with correlation values that were significantly more negative with ipsilateral than contralateral activation.

View Article: PubMed Central - PubMed

Affiliation: Cognition and Behaviour, Donders Institute for Brain, Radboud University Nijmegen Nijmegen, Netherlands ; Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf Hamburg, Germany.

ABSTRACT
Alpha (8-12 Hz) and beta band (18-30 Hz) oscillations have been implicated in sensory anticipation and motor preparation. Here, using magneto-encephalography, we tested whether they have distinct functional roles in a saccade task that induces a remapping between sensory and motor reference frames. With a crossed hands posture, subjects had to saccade as fast and accurate as possible toward a tactile stimulus delivered to one of two non-visible index fingers, located to the left or right of gaze. Previous studies have shown that this task, in which the somatotopic stimulus must be remapped to activate oculomotor system in the opposing hemisphere, is occasionally preceded by intrahemispheric remapping, driving a premature saccade into the wrong direction. To test whether the brain could anticipate the remapping, we provided auditory predictive cues (80% validity), which indicated which finger is most likely to be stimulated. Both frequency bands showed different lateralization profiles at central vs. posterior sensors, indicating anticipation of somatosensory and oculomotor processing. Furthermore, beta band power in somatosensory cortex correlated positively with saccade reaction time (SRT), with correlation values that were significantly higher with contralateral vs. ipsilateral activation. In contrast, alpha band power in parietal cortex correlated negatively with SRT, with correlation values that were significantly more negative with ipsilateral than contralateral activation. These results suggest distinct functional roles of beta and alpha band activity: (1) somatosensory gating by beta oscillations, increasing excitability in contralateral somatosensory cortex (positive correlation); and (2) oculomotor gating by posterior alpha oscillations, inhibiting gaze-centered oculomotor regions involved in generating the saccade to the wrong direction (negative correlation). Our results show that low frequency rhythms gate upcoming sensorimotor transformations.

No MeSH data available.


Related in: MedlinePlus