Researchers have presented evidence for the first time that the system of pervasive neuromodulation – groups of neurons that regulate more specialized neurons – strongly influence sound processing in an important auditory region of the brain. A neuromodulator, acetylcholine, may even help the brain’s auditory system distinguish speech from noise.
Scientists have provided physiological evidence that the overarching neuromodulation system – a group of neurons that regulate more specialized neurons – strongly affects sound processing in an important auditory region of the brain.
A neuromodulator – acetylcholine – may even help the brain’s main auditory circuitry distinguish speech from noise.
“”While the effects of these modulators have been studied at the neocortex, where the brain’s most complex computations take place, it has rarely been studied at the more fundamental levels of the brain,” said study author R. Michael Burger of Lehigh University in the US.
The study, published in JNeurosci: The Journal of Neuroscience, is likely to draw new attention in this area to how circuits like this, which are widely considered “simple,” are actually very complex and modulating as above. Areas of the brain.
Scientists conducted electrophysiological experiments and data analysis to demonstrate that the input of the neurotransmitter acetylcholine, a common neuromodulator in the brain, affects the encoding of acoustic information by the medial nucleus of the trapezius body (MNTB), the most prominent source of inhibition of several key nuclei in the lower auditory system.
MNTB neurons were previously considered computationally simple, controlled by one large excitatory synapse, and influenced by local inhibitory inputs.
Scientists have demonstrated that, in addition to these input signals, modulation of acetylcholine enhances neural tone discrimination from noise stimuli, which can aid in processing important acoustic signals such as speech. Also, they describe new anatomical views that allow acetylcholine to enter the MNTB.
Burger studies a chain of neurons that are “wired together” to perform a specialized function of calculating the locations from which sounds emanate in space.
He described neuromodulators as broader, less specific circuits overlapping more highly specialized ones.
“This modulation appears to help these neurons detect weak signals in noise. You can think of this modulation as offsetting the antenna position to eliminate static electricity for your favorite radio station, ”explains Burger.
The researchers emphasize that modulating circuits have a profound effect on neurons in sound localization circuits at a very low baseline in the auditory system.
The study authors are confident that these discoveries will shed new light on the contribution of neuromodulation to fundamental computational processes in the auditory circuits of the brain stem and understand how other sensory information is processed in the brain.