Neuron signals digital and analog simultaneously
Researchers at the Yale School of Medicine found that brain cells use a mixture of analog and digital signals. Neurons communicate with each other by sending neurotransmitters through axons (output) and synapses (input). When a cell receives transmitters through a synapse, the voltage inside the cell fluctuates. If there is enough voltage to pass a certain threshold, it generates an action potential, sending a specialized waveform out the axon, thus releasing a transmitter to the next neuron in the chain, which sends one to the next, and so on until the power runs out. This helps overturn the old belief that signals between neurons were sent solely through rate and timing of the action potentials, digitally.
Moreover, they found that the analog signal already present in a nuron is also sent down the axon, further influencing the synaptic transmission. So, the sent waveform is altered with each neuron it passes through. As the voltage of the sending signal becomes more positive, the amplitude of future transmissions is enhanced. This explains in part how neuron nets that store our experiences are formed. David McCormick, neurobiology professor at Yale and senior author of the study, says: "It’s as if everyone thought communication in the brain was like a telegraph, but actually it turned out to be more similar to a telephone."
Brain Communicates in Analog and Digital Modes Simultaneously, Yale.edu
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