What are the different roles of synapses in the nervous system?

When discussing synapses we tend to think of a typical cholinergic (uses an acetylcholine neurotransmitter) synapse, which transmits an action potential from the synaptic bulb of the presynaptic neurone to the post synaptic membrane of the next neurone. However, there are multiple other way a signal is transmitted across the nervous system, such as: Convergent transmission: several presynaptic neurones converge to one post synaptic neurone, meaning multiple different stimuli can cause one response. Divergent transmission: one presynaptic neurone diverges to multiple post synaptic neurones, meaning one stimulus can cause multiple different responses. Summation: the amplification of low-level signals. The combination of multiple low level signals allows the threshold potential to be exceeding, causing the transmission of an action potential. Acclimatisation: extensive repeated stimulation of the same synapse results in the synaptic bulb running out of the neurotransmitter (acetylcholine). This means the synapse is 'fatigued', so can no longer transmit the action potential. An example of this is getting used to the sensation of clothing on your skin, you feel the clothing when you first put it on but become acclimatised and are unaware of the sensation for the rest of the day.