DifferenceNeuronVSTransistor

Transistors vs. Neurons

I'll start with transistors because they're simpler. A transistor has three terminals and works by utilizing a small control signal in one terminal to control a larger signal flowing between the other two. When the control receives the right voltage, it allows electricity to flow, turning the switch on, otherwise it is off. In between, on and off, transistors can be considered to be in the analog range of continuous signals. But by ignoring these in-between levels, we consider a circuit to be digital.

Now, switching to biology, the neuron receives inputs from other neurons through its branching dendrites. While digital gates will typically have a few inputs, neurons can have thousands. These inputs receive chemical messengers called neurotransmitters, and these neurotransmitters open ion channels in the membrane of the synapse, which allows ions to enter the neuron and change its internal voltage, also called the membrane potential or activation level. Without any more input, this activation level will just leak away. But if enough signals arrive close together, the neuron reaches a threshold and fires an electrical spike, also called an action potential, which travels down the axon.

Compare this, though, with a NAND gate (transistor/neuron?) which uses about a million times less energy and is about 500 million times faster.

• Source: 2025-06-24 Why isn't AI SMARTER if Transistors are SO FAST?