Exciting new publication from the lab on miniature neurotransmission and ageing led by Soumya. In the paper we describe a new adult Drosophila motor synaptic terminal NMJ preparation, genetic tools and electrophysiology methods. We use the prep to examine the effects of ageing on motor synapses. We find that synaptic terminal boutons fragment into smaller units as ageing progresses accompanied by reduced evoked and miniature neurotransmission (affectionately known as ‘minis’ or sometimes spontaneous release). Surprisingly, we found that reducing all vesicular neurotransmission is sufficient to induce synaptic structural fragmentation in young animals similar to that of old animals. Even more surprisingly, we find that minis alone are critical to maintain synaptic structures – specifically decreasing mini frequency induces fragmentation of young synapses while increasing minis alone can delay fragmentation AND prolong the motor ability of ageing animals. Our results establish that miniature neurotransmission, formerly viewed as ‘noise’, is necessary for the long-term stability of synaptic connections.
