Abstract
We have examined the effects of theta burst on the neuronal activity of oculomotor cortex during eye movements. By combining fMRI and theta TMS, we studied the effect of theta TMS on not only performance, but also measured neuronal activity at the same time. This approach allowed us to investigate whether neuronal activity of an area is suppressed after theta burst TMS; whether the activity level of remote areas (i.e. non stimulated areas) is influenced; and whether effects on neuronal activity are task dependent. We applied theta burst TMS just before the start of the fMRI part. Subjects particpated in three session. Subjects received theta TMS targeting either the Right, or Left Frontal Eye Field (FEF), or a sham control side. After the TMS, subjects were moved into the MRI scanner. Blocks of voluntary saccades, reflexive saccades, and a manual key press task were presented in the MRI. The data suggests (N=4) that TMS over the right, but not the left FEF resulted in a reduced BOLD response. Interestingly, this was true only during voluntary saccades. In other words, the effect seemed to be task dependent. The other striking finding was that there was a trend towards a reduced activity level throughout the whole oculomotor cortical network.
We now seek to confirm this finding in a larger group of subjects.
This research was supported by the Wellcome Trust [079886].