Capturing Complex Behavior in Brain Imaging: Strategies and Instrumentation

Functional neuroimaging investigates the human brain through non-invasive recordings of brain signals or non-invasive stimulation. Traditionally, neuroimaging practitioners attempted to restrict the subject's behavior throughout the experiment to the point where it could be completely characterized by a few simple variables. Although this approach has its merits, it considerably limits the possibilities for investigating neural mechanisms underlying the organism's function under natural conditions. To overcome this limitation, researchers have increasingly focused on neuroimaging studies of subjects involved in complex ecologically-valid behavioral tasks. The shift from simple to complex behavior in neuroimaging studies brings along the demand for: (1) new instrumentation for handling the behavioral aspect of the experiment, and (2) new experimental designs that exploit the complexity of the participant's behavior instead of trying to suppress it. The thesis comprises four publications that examine the capacity of video technology to provide new instrumentation and explore possibilities for new experimental designs utilizing rich behavioural information provided by video, in the context of magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS) methods. Additionally, it introduces the Helsinki VideoMEG Project an open-source collaborative effort aimed at providing MEG practitioners with video recording and analysis tools. The first part of the thesis (Publications I and II) examines the feasibility of augmenting TMS and MEG experiments with simultaneous synchronized video and audio recordings of the participant. The second part of the thesis (Publications III and IV) explores the possibility of using audio and video to link the participants in an MEG hyperscanning experiment simultaneous recording of MEG signals from two interacting subjects. The results presented in this thesis demonstrate the feasibility of augmenting TMS and MEG experiments with synchronized video and audio recordings