How are messages transmitted between synapses?

Messages are transmitted between synapses electrochemically, which refers to the process involving both electrical and chemical signals. When a neuron sends a signal, it releases neurotransmitters from its axon terminals into the synaptic cleft, the gap between neurons. These neurotransmitters then bind to receptors on the postsynaptic neuron's membrane, leading to changes in the electrical state of that neuron. This combination of electrical activity (the action potential traveling down the neuron) and the chemical interaction (neurotransmitter release and receptor binding) allows for communication between neurons.

The other methods of transmission mentioned do not accurately describe how synapses function. Visual transmission would imply that messages are communicated through sight, which is not how neurons connect. Mechanical transmission suggests that signals might be conveyed through physical movement, which does not occur in neural communication. Magnetic transmission does not apply in this context since synaptic communication relies on electrochemical processes rather than magnetic fields. Thus, the correct choice accurately reflects the biological mechanisms at play in the nervous system.