Computational model explains the role of neurotransmitters

The researchers mapped the density and spatial distribution of the fibers that deliver these chemical signals across all layers of the rat’s somatosensory cortex. They found that the cholinergic system (acetylcholine) dominates. The density of varicose veins, which release the substance, is 2.3 times higher than that of the serotonergic system. These findings were integrated into a biophysical model to simulate, for the first time, how the activation of these three systems affects the rhythmic activity of an entire cortical microcircuit.

It has been found that acetylcholine effectively suppresses the slow delta waves characteristic of deep sleep and maintains a state of wakefulness. According to the model, its action is mediated through precise synaptic transmission rather than diffuse propagation, which helps to resolve a long-standing scientific debate. Dopamine and serotonin also reduce the synchronization of activity and weaken the slow oscillations in sensory areas, which were previously underestimated outside the prefrontal cortex. Serotonin is additionally capable of triggering faster theta rhythms, which opens up new perspectives for understanding the effects of antidepressants targeting the serotonin system. Dopamine, on the other hand, covers all layers of the cortex, affecting both excitatory and inhibitory neurons, and likely plays a key role in adjusting the overall state of the neural network.

All experimental data and the complete computational model are available in open repositories. Since disturbances in these systems underlie conditions such as Alzheimer’s disease, Parkinson’s disease, depression, and schizophrenia, the work creates a foundation for developing more precise therapeutic approaches. In addition, the principles obtained can be used in neuromorphic artificial intelligence, as quantitative models of neuromodulation can form the basis for new AI architectures inspired by the brain’s structure.