Spatial and state-dependent effects of transcranial magnetic stimulation of prefrontal cortex in non-human primates

.............................................................................................................................. ii Keywords ............................................................................................................................ ii Co-Authorship Statement ................................................................................................... iii Acknowledgments .............................................................................................................. iv Table of Content ................................................................................................................. v List of Figures ................................................................................................................... vii List of Appendices ............................................................................................................ vii List of Abbreviations ....................................................................................................... viii List of Symbols ................................................................................................................ viii Chapter 1 – Introduction .................................................................................................. 1 1.1 Transcranial Magnetic Stimulation ................................................................ 1 1.2 The Oculomotor System ................................................................................ 5 1.3 Superior Colliculus and Brainstem ................................................................ 7 1.4 Frontal Cortex ................................................................................................ 9 1.5 Lateral Intraparietal Area ............................................................................. 10 1.6 TMS in the Human Oculomotor System ..................................................... 11 1.7 TMS in the Monkey Oculomotor System .................................................... 14 1.8 Hypothesis and Predictions .......................................................................... 15 Chapter 2 – Methods ...................................................................................................... 16 2.1 Animal Preparation ...................................................................................... 16 2.2 Transcranial Magnetic Stimulation .............................................................. 18 2.3 Behavioral Paradigm .................................................................................... 19 2.4 Data Acquisition .......................................................................................... 23 Chapter 3 – Results ........................................................................................................ 25 3.1 Single Pulse TMS ........................................................................................ 26 3.2 Change in Response Over Frontal Cortex ................................................... 28 3.3 TMS-M1 MEP Response ............................................................................. 30 3.4 Change in Response with TMS intensity ..................................................... 31 3.5 TMS During Memory Guided Saccade Task ............................................... 31 3.6 Increase in EMG activity Only for Contralateral Saccades ......................... 33 3.7 Decrease in Contralateral Saccade Reaction Time ...................................... 39 3.8 Increase in EMG Response Correlates in Decrease in Reaction Time ........ 41 Chapter 4 – Discussion .................................................................................................. 43 4.1 TMS Over PFC Evoked Contralateral Head Turning Synergy ................... 43 4.2 Contralateral Head Turning Synergy Evoked Only Over PFC .................... 44 4.3 TMS-PFC Affects Multiple Cortical Regions of Oculomotor System ........ 46 4.4 General Conclusion ...................................................................................... 47