The role of modelling and computer simulations at various levels of brain organisation

Krzeminski, Dominik 2021. The role of modelling and computer simulations at various levels of brain organisation. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Computational modelling and simulations are critical analytical tools in contemporary neuroscience. Models at various levels of abstraction, corresponding to levels of organisation of the brain, attempt to capture different neuronal or cognitive phenomena. This thesis discusses several models and applies them to behavioural and electrophysiological data. First, we model a voluntary decision process in a task where two available options carry the same probability of a reward for the outcome. Trial-by-trial accumulation rates are modulated by single-trial EEG features. Hierarchical Bayesian parameter estimation shows that the probability of reward is associated with changes in the speed of accumulation of evidence. Second, we use a pairwise Maximum Entropy Model (pMEM) to quantify irregularities in the MEG resting-state networks between juvenile myoclonic epilepsy (JME) patients and healthy controls. The JME group exhibited on average fewer local minima of the pMEM energy landscape than controls in the fronto-parietal network. Our results show the pMEM to be descriptive, generative model for characterising atypical functional network properties in brain disorders. Next, we use a hierarchical drift-diffusion model (HDDM) to study the integration of information from multiple sources. We observe a non-perfect integration in the case of the accumulation of both congruent and incongruent evidence. Based on fitting the HDDM parameters, we hypothesise about the neuronal implementation by extending a biologically plausible neuronal mass model of decision making. Finally, we propose a spiking neuron model that unifies various components of inferential decision-making systems. The model includes populations corresponding to anatomical regions, e.g. the dorsolateral prefrontal cortex, orbitofrontal cortex, and basal ganglia. It consists of 8000 neurons and realises dedicated cognitive operations such as weighted valuation of inputs, competition between potential actions, and urgency-mediated modulation. Overall, this work paves the way for closer integration of theoretical models with behavioural and neuroimaging data

Item Type:	Thesis (PhD)
Date Type:	Acceptance
Status:	Unpublished
Schools:	Psychology
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
Funders:	EPSRC
Date of First Compliant Deposit:	26 May 2021
Date of Acceptance:	24 May 2021
Last Modified:	04 Aug 2022 01:37
URI:	https://orca.cardiff.ac.uk/id/eprint/141576

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