Differential expressions of task responsive neural inhibition and regulation across competing sensory and cognitive systems

Nelson, Wilf (2022). Differential expressions of task responsive neural inhibition and regulation across competing sensory and cognitive systems. University of Birmingham. Ph.D.

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Abstract

Inhibition is a fundamental property of neural communication with widespread, uncontrolled activity being one of the defining features of an epileptic seizure. Healthy brain function requires a constant interplay between activity, of many different sorts, rest, and at times inhibition. Two major methods of measuring inhibition through modern-day neuroscience are Negative BOLD Responses (NBR) for fMRI experiments and the alpha oscillation in EEG/MEG experiments. In this thesis, the aim is to explore current theories regarding how different sensory and cognitive modalities interact with non-task-relevant regions (NTRRs) during tasks and measure inhibition. In the Introduction a review of the current literature and its gaps will be provided as well as a discussion on how similar NBRs and alpha oscillations are in representing a common neural signal. Chapter 2 will focus on studying multiple stimulated modalities at once and measuring inhibitory responses across the whole brain using fMRI. In Chapter 3 the same experimental paradigm is used as in Chapter 2 but with EEG to instead measure how sustained alpha synchronisation does and does not occur during trials which require inhibition for periods of 4 seconds and larger instead of the current focus on time periods only a few hundred milliseconds long. Chapter 4 uses MEG to explore the expression of posterior alpha power synchronisation during stimulation as a marker of two different inhibitory scenarios; comparing between proactive inhibition of a distracting, non-task-relevant sensory modality and more reactive inhibition of unexpected distraction. The final experiment of Chapter 5 studies positive and negative BOLD responses during a large sample of cognitive tests in the Human Connectome Project dataset. This experiment studies whether the inhibitory NBRs in NTRRs are a function of the cognitive systems being used or instead are just a function of the sensory modalities being stimulated. The thesis concludes with a discussion that highlights the key findings as they pertain to multiple chapters and also areas for future studies including higher levels of alpha power variability across the population than was reported in the literature review in the Introduction.

Type of Work:	Thesis (Doctorates > Ph.D.)
Award Type:	Doctorates > Ph.D.
Licence:	All rights reserved
College/Faculty:	Colleges (2008 onwards) > College of Life & Environmental Sciences
School or Department:	School of Psychology
Funders:	None/not applicable
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
URI:	http://etheses.bham.ac.uk/id/eprint/12623

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