Brain Mapping Guided Electrophysiology with Applications in Hearing and Noise Pollution Research

Project: ResearchECS

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The brain’s function is closely related to electrical activity. During hearing, sound enters the ears and the information is transformed into brain electrical activity. Electrophysiology studies the electrical properties of cells and tissues and is important for hearing research and neuroscience in general. Electrophysiology using methods such as extracellular recordings measures the activity of single or multiple cells in vivo. Such recordings require placing fine electrodes into sound processing centers in the brain. One significant challenge in recordings is placing the electrode precisely within a center as the brain is large. This challenge is common to related methods such as those using electrode arrays, optogenetics, site-targeted injections, and deep brain stimulation. Electrode placement is typically guided by atlases of the brain. This method has several limitations: (1) Precise placement depends on close agreement between the atlas and the subject’s brain. Many factors can affect agreement, such as age and inter-species differences. (2) Brain injury, or plasticity, can also change the precise size, shape, location, and function of sound processing centers. Unfortunately, the changes are known only after extensive research, which significantly complicates electrode placement for performing that research. Brain mapping using noninvasive imaging has guided surgical procedures, including electrode placement. Guidance has typically been provided by anatomical images acquired with technology such as magnetic resonance imaging (MRI) and computed tomography. For in vivo recordings from sound processing centers, functional images are also required to precisely locate the centers, especially in situations such as (2) above. This project will develop novel anatomical and functional imaging guided electrode placement methods for rat hearing models. Rats are widely used in hearing research and our group recently developed functional MRI (fMRI) for rat hearing models. Noninvasive MRI and fMRI images will be acquired of the living brain with sound stimulation. State-of- the-art MRI sequences will be employed that significantly reduce the impact of scanner acoustic noise. The locations of sound processing centers and anatomical landmarks, visible in images and during surgery, will be determined with 500 µm precision. These locations will set subject-specific coordinates, using which the electrode will be precisely placed in the target center. This imaging guided electrophysiology method will be applied to study the impact of long-term, low sound level noise on sound processing in the brain. Noise pollution is a serious health concern and the resulting multi-modality imaging and electrophysiology data will significantly advance our understanding of the impact on hearing. ?


Effective start/end date1/01/18 → …