352 — A Distance-Dependent Distribution of Presynaptic Boutons Tunes Frequency-Dependent Dendritic Integration

While researching this paper, I found @BrainPost’s post about it here. If you want a much better synopsis than mine, go check that page out!

In this paper, the researchers look at the enormous, extensive dendritic arbors of pyramidal CA1 neurons in mouse hippocampus. In particular, they ask how the shape and size of bouton-dendrite synapses’ active zones vary with relation to distance from the soma. They find (in agreement with previous research) that the further a bouton is from the soma of the target neuron, the smaller the active zone of the corresponding synapse. And so — somethingsomethingsomething probabilities and somethingsomethingsomething SNARE — the closer a bouton is to the soma, the higher the probability of release given an equal stimulus. But the functional behavior of the synapses along this gradient also vary with distance: Short-term facilitation (the probability that a synapse will be influenced by prior pulses) increases along that same distance, suggesting a mitigatory mechanism that makes up for the lesser influence of distal synapses on the more proximal neuronal compartments.

This relates closely to this paper that discusses synapse sorting along a neurite. Clearly, neurites are not synapsing serendiptiously. There is a strong heuristic that drives where and when neurons communicate.