The Electric Brain
An action potential is an electric pulse that travels down the length of a neuron and, if it reaches the synapse, causes the release of chemicals to send a signal to the next neuron. If the synapse is excitatory then once the receiving neuron gets enough messages from the sending neuron, it fires its own action potential, forwarding the message to the next neuron. If the synapse is inhibitory then the messages sent to the receiving neuron say to do nothing, thereby inhibiting an action potential… and this is how everything in the brain happens!
Where Communication Happens
Synapses are the meeting points where neurons communicate with each other. The neurons aren’t physically connected, though — instead, there’s a space between them (the “synaptic cleft”) where chemicals are released by one neuron and detected by the next neuron.
Changing How Neurons Connect
At any synapse there is always one neuron sending a signal and one neuron receiving it. Synapses can strengthen or weaken depending on the amount and type of communication that happens at them. The ability to change the strength of synapses is called synaptic plasticity.