Professor Juan Burrone, in collaboration with researchers at the Centre for Ultastructural Imaging (CUI) at KCL and the Sainsbury Wellcome Centre at UCL, has uncovered a novel arrangement for how synapses in the brain are distributed along dendrites. Their findings, published in this issue of Neuron, have important implication for understanding how neurons bring together information from the thousands of connections they receive.
The main findings from the study (led by Federico Grillo and Guilherme Neves) show that presynaptic terminals are arranged in a biased manner along dendrites: the further away from the soma, the smaller they become. This morphological distribution was found to be matched by a decrease in neurotransmitter release probability and an increase in facilitation to a stimulus burst. Distal inputs were therefore better able to amplify signals that arrive in high frequency bursts. As a result, the integration of inputs along a dendrite appear to be preferentially tuned to increasing frequencies with distance along a dendrite, away from the soma.
These findings show that dendrites are surprisingly specialised units of integration that organise the type of information they receive into spatially segregated domains. The location along a dendrite will therefore determine the type of computation performed locally. The article, entitled ‘A distance-dependent distribution of presynaptic boutons tunes frequency-dependent dendritic integration’ was published in Neuron on 25 July 2018 (Volume 99, Issue 2, p275-282).