Thesis defense Verena Buchholz (Donders Series 118)

15 May, 2013

Promotor: Prof.dr. P. Medendorp, copromotor, Dr. O. Jensen

Oscillatory activity in tactile remapping

This thesis explores the role of neural synchronization during movement planning to tactile stimuli. Tactile information about the outer world enters our brain through the skin. To guide movements, this somatotopic information must be transformed into other representations, with coding formats (i.e. reference frames) that vary for different effector systems. In several experiments, we test the hypothesis that oscillations in different frequency bands reflect sensorimotor processes operating in parallel in different reference frames. We show that both the planning of eye and reaching movements to tactile stimuli involved a remapping for this information into sensory and non-sensory reference frames, including a gaze-centered reference frame. This is seen in alpha and gamma band activity in posterior parietal regions. Beta band activity merely shows sensory, somatotopic processing in central and posterior regions. In a further study, we also investigate how multisensory integration is implemented in various reference frames. We further show that the neural oscillations reflect the anticipation of tactile stimuli in both sensory and motor reference frames, thereby preventing errors in the tactile remapping. In summary, the results show that cortical rhythms provide spectral channels for distributed and parallel processing of spatial information in different formats.