Voice Adaptation and Vocal Learning

According to control theory, internal models play a decisive role in how our brain operates at an optimum level. By extracting sensory information from the environment and integrating it across domains, the brain is constantly updating its modus operandi, thereby using sensory resources as efficiently as possible. An essential prerequisite for this efficiency is the ability to form sensory predictions, which entails a repeatedly encountered stimulus to become less salient and thus, more predictable. With the extension of a well-established somatosensory model into the auditory domain, our focus lies on elucidating individual differences in auditory sensory prediction by using behavioral and neuroimaging techniques (EEG & fMRI).

Researchers:

Lisa Goller, Joseph Johnson and Xanthate Duggirala

Project I: I predict, therefore I do not hallucinate: a new protocol for testing the neurocognitive underpinnings of auditory hallucinations

This project investigates auditory verbal hallucinations (AVH) in non-clinical populations. As relevant differences between clinical and non-clinical voice hearers have been fathomed in regards to the experience of AVH, we now think it is crucial to scrutinize the actual mechanism of AVH by shifting our attention to a not clinically diagnosed population.  By using the EEG, we aim to find out about early identifiable differences in voice perception (own voice vs. someone else’s voice) in respect to the N100 component, which has been associated with stimulus salience and prediction in the past. Our goal is to find out about modulations in measured signals across a continuum of individuals, who vary in the degree of hallucinatory proneness.

Project II: Sensory gating and executive control: two sides of the same coin in non-clinical voice hearing?

It is evidenced that one of the prominent differences between healthy voice hearers and their pathological counterparts is the emotional valence of the content. Studies have shown that majority of voices are negatively affected, and these voices could accurately predict the presence of pathology and thus, help to differentiate between clinical and non-clinical voice hearers. In this context, the current project has two broad goals. 1) To examine the saliency effects of neutral and negatively affected self-generated and externally generated auditory stimuli as a function of proneness to voice hearing in non-clinical (otherwise healthy) population. 2) To investigate if this altered voice processing in voice hearers in non-clinical population is an impairment at the sensory level or a more general executive attention impairment.

Project III: Structural Alterations in voice hearers

Owing to the paucity of research probing altered voice processing in voice hearers, we aim to clarify how the underlying neural architecture and circuits may be altered in a non-clinical voice-hearers. In this project, we use different methods (voxel-based morphometry, cortical thickness, diffusion tensor imaging) to analyze structural data in a non-clinical sample and correlate results with neuropsychological test scores.