Inhibition Shapes Acoustic Responsiveness in Spherical Bushy Cells

What is it about?

In some parts of our brain that process sound, there is a complex interaction between nerve cell activation (excitation) and suppression (inhibition). We still do not fully understand how these two factors work together to process sound information effectively and with precise timing. One group of nerve cells called spherical bushy cells (SBCs), receives their main excitatory signal from auditory nerve fibers through special connections called endbulbs of Held. They also receive inhibitory signals that suppress their activity from other cells. SBCs are crucial for sending sound information to other parts of the brain that help us figure out where sounds are coming from. To study the role of excitation/inhibition at SBCs, we recorded the activity of these cells in gerbils while playing them sounds. We found that, for some sounds, the inhibitory signals from other cells were strong enough to stop SBCs from firing. These inhibitory signals took a bit longer to kick in and fade away, and they got stronger when the sounds were louder. However, this inhibition also changed how well SBCs responded to sounds, making them more precise in their timing. This means that inhibition is a crucial part of how our brain processes sound information as it travels through different parts of the auditory system.

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