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

Project: Research

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The brain’s function is closely related to electrical activity. During hearing, sound entersthe ears and the information is transformed into brain electrical activity.Electrophysiology studies the electrical properties of cells and tissues and is importantfor hearing research and neuroscience in general. Electrophysiology using methods suchas extracellular recordings measures the activity of single or multiple cells in vivo. Suchrecordings require placing fine electrodes into sound processing centers in the brain. Onesignificant challenge in recordings is placing the electrode precisely within a center asthe brain is large. This challenge is common to related methods such as those usingelectrode arrays, optogenetics, site-targeted injections, and deep brain stimulation.Electrode placement is typically guided by atlases of the brain. This method has severallimitations:(1) Precise placement depends on close agreement between the atlas and the subject’sbrain. 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, andfunction of sound processing centers. Unfortunately, the changes are known only afterextensive research, which significantly complicates electrode placement for performingthat research.Brain mapping using noninvasive imaging has guided surgical procedures, includingelectrode placement. Guidance has typically been provided by anatomical imagesacquired with technology such as magnetic resonance imaging (MRI) and computedtomography. For in vivo recordings from sound processing centers, functional images arealso required to precisely locate the centers, especially in situations such as (2) above.This project will develop novel anatomical and functional imaging guided electrodeplacement methods for rat hearing models. Rats are widely used in hearing research andour group recently developed functional MRI (fMRI) for rat hearing models. NoninvasiveMRI 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 ofscanner acoustic noise. The locations of sound processing centers and anatomicallandmarks, visible in images and during surgery, will be determined with 500µmprecision. These locations will set subject-specific coordinates, using which the electrodewill be precisely placed in the target center. This imaging guided electrophysiologymethod will be applied to study the impact of long-term, low sound level noise on soundprocessing in the brain. Noise pollution is a serious health concern and the resultingmulti-modality imaging and electrophysiology data will significantly advance ourunderstanding of the impact on hearing.?


Project number9048098
Grant typeECS
Effective start/end date1/01/1824/11/21