Figure 2

T ime-frequency wavelet plots and event related desynchronizations Wavelet analysis of the parietal and parieto-occipital areas and changes in the beta-frequency-band during swallowing execution. a) In the first MEG measurement (persisting severe dysphagia) no activation in the somatosensory system can be seen with the chosen threshold. Instead distinct activation of the PPC is found, wavelet analysis shows no systematic activation in either brain region. b) four days later after clinical recovery of swallowing ability distinct activation of the somatosensory cortex with a left hemispheric lateralization was found in wavelet analysis, a distinct beta desynchronisation in the parietal cortex is found in SAM data, while no systematic activation can be seen in the parieto-occipital areas. c) The wavelet results of a healthy control group are similar to those found in the second measurement. Also SAM results reveal distinct beta desynchronization in the parietal cortex. For SAM data the color bar represents the t-value. For wavelet data time 0 on the x-axis corresponds to the individually set markers. Colors represent the level of frequency power, with lower numbers (blue) indicating a decrease in power (ERD) and higher numbers (red) an increase in power (ERS).