This proposal focuses on the role of auditory perception, a subconstruct within the cognitive systems domain of the Research Domain Criteria (RDoC), in the pathophysiology of auditory perceptual disturbances in health and across traditional (DSM-IV and DSM-V) disease categories. The overall aim is to characterize the neurobiological and neurocomputational basis of auditory sensory learning to identify pathophysiological mechanisms leading to auditory perceptual disturbances and, specifically, auditory verbal hallucinations (AVH).
We aim to recruit the following groups: schizophrenia and schizoaffective disorder with low- and high-severity AVH (n=15 and n=15, respectively), delusional disorder (delusional psychosis without AVH; n=15), tinnitus (auditory perceptual disturbances without AVH; n=15), and matched healthy controls (varying degrees of subclinical perceptual disturbances; n=30). We will obtain extensive clinical, neurocognitive, and genetic characterization, and multimodal imaging in all subjects: (1) PET measures of D2/3 receptors and DA storage/release capacity within the thalamus, striatum, and the midbrain, using [11C]PHNO and the amphetamine paradigm; (2) Model-based fMRI measures of sensory prediction-error signals in auditory regions during a probabilistic, auditory discrimination task; 3) MR spectroscopy measures of glutamate concentration in the auditory cortex; (4) Task-based and resting- state fMRI connectivity measures in sensory thalamo-cortical projections; (5) Whole genome sequencing based on blood DNA samples. We will test in the overall sample across diagnostic groups if auditory PE deficits predict AVH (SA1) and correlate with altered DA in striatum and thalamus (SA2) and with increased glutamate in the auditory cortex (SA3). We will also explore the relationship within the same subjects between DA and glutamate (EA1) and the relationships of auditory PE to connectivity between auditory thalamus and auditory cortex (EA2) and identify a set of candidate genes associated with auditory PE deficits (EA3). This RDoC proposal will lead to further understanding of the mechanisms of sensory learning and their perturbations in conditions associated with auditory perceptual alterations.
We will use a multidisciplinary approach to identify molecular and neural correlates of auditory perceptual disturbances in health and across traditional (DSM-IV and DSM-V) disease categories, in line with the NIMH's RDoC initiative.
