Grant: DRA : Canada Graduate Research Scholarship - Doctoral Program (CGRS D)

Bipolar Disorder (BD) is a mental health condition that causes extreme mood swings, from high-energy mania to deep depression. Some people with BD also experience symptoms such as hearing voices, known as auditory hallucinations (AHs). In other conditions like schizophrenia, hearing voices has been linked to differences in how the brain is shaped (i.e., its structure). AHs in schizophrenia have also been associated with changes in how the brain responds to unexpected sounds. One way scientists measure this is through a brain response called mismatch negativity (MMN). MMN helps us notice changes in sounds, and when it's weaker, it suggests the brain has trouble detecting those changes, which can affect everyday life. While we know a lot about these brain changes in schizophrenia, we know much less about how hearing voices affects the brains of people with BD. This study will explore whether people with BD who hear voices have differences in brain shape compared to those without AHs, using structural magnetic resonance imaging (MRI), which takes detailed pictures of the brain. We will also examine whether people with BD who hear voices have weaker MMN responses compared to those who don't, using electroencephalography (EEG), which captures brain waves (i.e., electrical brain activity). Finally, we will use functional MRI (fMRI), which visually maps out brain activity in different brain regions, to see whether these activity differences are linked to changes in specific brain areas. We will work with 80 participants: 40 people with BD who hear voices and 40 who don't. They will complete a simple task to measure their brain's MMN response using EEG and fMRI, as well as a structural MRI scan to take pictures of the brain. This research will provide new knowledge about how the brains of people with BD work, particularly for those who hear voices. Understanding these differences can help develop better, more personalized treatments for BD in the future.