Investigating the effects of neuromodulatory training on autistic traits: a multi-methods psychophysiological study. Tania K. García Vite A thesis submitted for the degree of Doctor of Philosophy (PhD) Department of Psychology University of Essex April 2020 ii Declaration I declare that this thesis, ‘Investigating the effects of neuromodulatory training on autistic traits: a multi-methods psychophysiological study.’, represents my own work, except where otherwise stated. None of the work referred to in this thesis has been accepted in any previous application for a higher degree at this or any other University or institution. All quotations have been distinguished by quotation marks and the sources of information specifically acknowledged. Submitted by Tania K. García Vite Signature of Candidate: Date: iii Table of Contents Declaration……………………. .............................................................................................. ii Acknowledgements…… .......................................................................................................... x Abstract……………….. ......................................................................................................... xi Foreword………………. ......................................................................................................... 1 1. Theoretical overview ......................................................................................................... 6 1.1. Autism ..................................................................................................................... 6 1.1.1.Definition and classifications ................................................................................. 6 1.1.2.Brief overview of Autism theories .........................................................................10 1.1.3.Broader Autistic Phenotype (BAP) and Autistic traits in the normal developing population… ..................................................................................................................12 1.1.4.Neural systems implicated .....................................................................................14 1.1.4.1.The limbic system ..............................................................................................15 1.1.4.1.1.Temporo-amygdala- orbitofrontal circuit. ........................................................16 1.1.4.1.2.Dorso-medial limbic circuit .............................................................................16 1.1.4.2.The face processing system ................................................................................19 1.1.4.2.1.The superior temporal sulcus ...........................................................................19 1.1.4.2.2.The fusiform face area .....................................................................................20 1.1.4.2.3.The amygdala ..................................................................................................21 1.1.4.3.The mirror neuron system ..................................................................................23 1.2. Mirror neurons ........................................................................................................24 iv 1.2.1.Overview and historical findings ...........................................................................24 1.2.1.1.Classification .....................................................................................................29 1.2.1.1.1.Strictly congruent ............................................................................................29 1.2.1.1.2.Broadly congruent ...........................................................................................30 1.2.1.1.3.Logically related .............................................................................................30 1.2.2.The Human Mirror Neuron System (hMNS) .........................................................31 1.2.2.1.Overview ...........................................................................................................31 1.2.2.2.Mu Rhythms and mirror neurons ........................................................................43 1.2.2.3.ASD and the hMNS ...........................................................................................52 1.2.2.4.Considerations and limitations............................................................................54 1.3. Neurofeedback ........................................................................................................58 1.3.1.Overview and basic concepts ................................................................................58 1.3.2.Historical background ...........................................................................................60 1.3.3.Protocols ...............................................................................................................62 1.3.3.1.General considerations .......................................................................................62 1.3.3.2.Low vs high frequency protocols ........................................................................64 1.3.4.Applications ..........................................................................................................67 1.3.4.1.Performance enhancement (sports, music, cognition) .........................................68 1.3.4.2.Cognition in elderly............................................................................................70 1.3.4.3.NFT as a treatment for disorders (ADHD, Epilepsy, Depression) .......................71 1.3.5.NFT and ASD .......................................................................................................74 v 2. Resting state EEG (rEEG) in autistic traits .......................................................................77 2.1. Aims and overview .................................................................................................77 2.2. Methods ..................................................................................................................80 2.2.1.Participants ...........................................................................................................80 2.2.2.Materials ...............................................................................................................81 2.2.2.1.Pre-screening .....................................................................................................81 2.2.2.2.Protocol..............................................................................................................82 2.2.3.Experimental Design .............................................................................................82 2.2.4.Procedure ..............................................................................................................82 2.2.4.1.EEG data preparation .........................................................................................83 2.2.5.Results ..................................................................................................................83 2.2.6.Discussion........................................................................................................... 104 2.2.7.Conclusion .......................................................................................................... 108 3. EEG protocols on hMNS activation (mu suppression) and its difference according to self- reported traits of autism in neurotypical individuals. ............................................................. 110 3.1. Aims and overview ............................................................................................... 110 3.2. Methods ................................................................................................................ 116 3.2.1.Participants ......................................................................................................... 116 3.2.2.Materials ............................................................................................................. 117 3.2.2.1.Scales ............................................................................................................... 117 3.3. Mu multiple repetitions protocol (MMR) .............................................................. 117 vi 3.3.1.Stimuli ................................................................................................................ 117 3.3.2.Experimental design ............................................................................................ 119 3.3.2.1.EEG ................................................................................................................. 119 3.3.2.2.Eye-tracking ..................................................................................................... 119 3.3.3.Research Hypotheses .......................................................................................... 120 3.3.4.Procedure ............................................................................................................ 120 3.3.4.1.EEG data preparation ....................................................................................... 121 3.3.5.Results ................................................................................................................ 122 3.3.5.1.EEG ................................................................................................................. 122 3.3.5.2.Eye-tracking ....................................................................................................