Scientists have provided physiological evidence that a comprehensive neuromodulation system —
The neuromodulator acetylcholine may even help the brain's main auditory circuit differentiate speech from noise.
“Although the phenomenon of the influence of these modulators has been studiedat the level of the neocortex, where the brain's most complex computations occur, it has rarely been studied at more fundamental levels of the brain,” said study author R. Michael Burger of Lehigh University in the US.
Research published in JNeurosci:The Journal of Neuroscience is likely to draw new attention in the field to how circuits like this, which are widely considered “simple,” are in fact very complex and subject to modulatory influences just like the ones above. areas of the brain.
Scientists conducted electrophysiologicalexperiments and data analysis to demonstrate that input of the neurotransmitter acetylcholine, a common neuromodulator in the brain, influences 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 thought to be computationally simple, driven by a single large excitatory synapse and influenced by local inhibitory inputs.
Scientists have demonstrated that in additionTo these inputs, acetylcholine modulation enhances neural discrimination of tones from noise stimuli, which may facilitate the processing of important acoustic signals such as speech.
In addition, they describe new anatomical projections that mediate acetylcholine entry into the MNTB.
Burger studies a chain of neurons that are "wired together" to perform the specialized function of calculating the locations from which sounds come in space.
He described neuromodulators as broader, less specific circuits that overlap more highly specialized ones.
"This modulation appears to help theseneurons to detect weak signals in noise. You can think of this modulation as shifting the position of the antenna to eliminate static electricity for your favorite radio station,' explains Burger.
Modulatory circuits have a profound effect on neurons in sound localization circuits at a very low base level of the auditory system, the researchers emphasize.
The study authors are confident that these discoverieswill shed new light on the contribution of neuromodulation to fundamental computational processes in the auditory circuits of the brain stem, as well as on understanding how other sensory information is processed in the brain.
Read also
Check out the most beautiful pictures of Hubble. What has the telescope seen in 30 years?
Research: Crops in Chernobyl are still contaminated with radiation
Scientists take the first high-quality pictures of coronavirus thorns