Related Experiment Video
Updated: Jul 16, 2025

Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury
Published on: November 19, 2012
Depolarization shift in the resting membrane potential of inferior colliculus neurons explains their hyperactivity
Chun-Jen Hsiao1, Alexander V Galazyuk1
1Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States.
Introduction:
Neuronal hyperactivity has been associated with many brain diseases. In the auditory system, hyperactivity has been linked to hyperacusis and tinnitus. Previous research demonstrated the development of hyperactivity in inferior colliculus (IC) neurons after sound overexposure, but the underlying mechanism of this hyperactivity remains unclear. The main goal of this study was to determine the mechanism of this hyperactivity.
Methods:
Experiments were performed on CBA/CaJ mice in a restrained, unanesthetized condition using intracellular recordings with sharp microelectrodes. Recordings were obtained from control (unexposed) and unilaterally sound overexposed groups of mice.
Results:
Our data suggest that sound exposure-induced hyperactivity was due to a depolarizing shift of the resting membrane potential (RMP) in the hyperactive neurons. The half width of action potentials in these neurons was also decreased after sound exposure. Surprisingly, we also found an RMP gradient in which neurons have more hyperpolarized RMPs with increasing depth in the IC. This gradient was altered in the overexposed animals.
Related Concept Videos
The Cochlea
Auditory Pathway
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking...
Hair Cells

