Dissecting the neurocomputational mechanisms of auditory verbal hallucinations
Supervisors:
Dr Filippo Queirazza, School of Health & Wellbeing
Prof Marios Philiastides, School of Psychology & Neuroscience
Summary:
Auditory verbal hallucinations (AVH) are the hallmark feature of psychosis. AVH have been linked to excessive dopamine in the striatum and their treatment of choice is antipsychotic medications, which reduce dopamine transmission in the brain. Yet, a comprehensive mechanistic understanding of AVH has been elusive.
While perceptual decisions are primarily influenced by sensory evidence, our sensory system also leverages prior knowledge to make optimal perceptual judgements. Such perceptual priors can bias perceptual inference and, under certain conditions such as excess striatal dopamine, even give rise to perceptual disturbances including AVH. Preliminary empirical evidence has linked dopamine-dependent baseline activity in the (dorsal) striatum to the encoding of perceptual priors. In this project we plan to use advanced computational and neuroimaging (i.e., fMRI) techniques to characterize the mechanisms underpinning auditory perceptual biases and ensuing AVH in both healthy subjects and psychotic patients. Moreover, we aim to leverage pharmacological manipulations of striatal dopaminergic tone to establish a causal link between dopamine and perceptual biases, thus bridging the gap between AVH phenomenology and neurobiology. Using state-of-the-art machine learning classification algorithms, we aim to capitalize on the identified neurocomputational signatures of auditory perceptual biases to predict response to antipsychotic treatment in patients with a psychotic disorder.