Slow Cholinergic Modulation of Spike Probability in Ultra-Fast Time-Coding Sensory Neurons

What is it about?

It has long been thought, that the way our brain processes sounds in the lower part of the hearing system was pretty fixed and not easily modulated. However, this part of the brain receives signals not just from the ears but also from other parts of the brain through a neurotransmitter called acetylcholine. So, we decided to see how acetylcholine affects a type of nerve cell in the brain called spherical bushy cells (SBCs) in gerbils. We did this by recording their activity and adding acetylcholine-like chemicals. We found that about 55-72% of these cells are more susceptible to neuronal activation when exposed to acetylcholine. This effect happens over different time scales, from fractions of a second to several minutes. We also discovered that this effect was caused by specific receptors for acetylcholine and when blocking these receptors, nerve cells became harder to excite. This suggests that acetylcholine can change how our brain processes sound by making it more responsive and accurate, thanks to signals from other parts of the brain.

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