Loud Noise, Potassium Channels in the Dorsal Cochlear Nucleus and Tinnitus

by Neil Bauman, Ph.D.

© February, 2013

In the past few years, scientists have discovered that tinnitus can arise in various areas of the brain when too much spontaneous neuronal activity takes place, and, for whatever reason, the normal inhibiting mechanisms fail to suppress it.

As time goes by, researchers are more and more zeroing in on the specific areas of the brain and the specific mechanisms that can lead to tinnitus. For example, Dr. Martine Hamann of the University of Leicester in the UK recently discovered that exposing your ears to loud sounds can trigger uncontrolled activity in the neurons of the dorsal cochlear nucleus. (The dorsal cochlear nucleus is the area of your brain that relays signals from your ears to other parts of your brain that decode and make sense of the sounds you are hearing.)

According to Dr. Hamann, normally neurons receive a sound signal, fire and then return to a state of rest. This happens because potassium channels help “drag down the cellular electrical activity to its resting state”. (1) This allows neurons to function in regular patterns in response to sound signals.

However, loud noises inhibit the potassium channels’ ability to properly regulate excess neuronal activity. This means these neurons do not return to their resting state. Instead, they “fire continuously in random bursts, creating the sensation of constant noise where none exists.” (1) We call this resulting noise tinnitus.

Now you know one reason why it is so important to protect your ears from loud sounds. You do not want to inhibit the function of the potassium channels or else some of the neurons in your dorsal cochlear nucleus may begin to fire erratically, and you could be left with loud tinnitus.

For researchers, the next step is to find ways to quickly get the potassium channels working properly again. The thinking is that when the potassium channels do their jobs properly, they will suppress all this extra neuronal activity, and this will greatly reduce or even eliminate tinnitus from this cause.
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(1) Smith, Graham. May 11, 2012. A cure for tinnitus? Hope for millions tormented by ringing in ears as scientists edge closer to developing first drug treatments. Mail Online.