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bioRxiv · 10.1101/2023.05.29.542696

Asymmetric spread of excitatory synaptic potentialin hippocampal neuronal dendrites revealed by voltage imaging

Morita, M.·Higashi, R.·Kawaguchi, S.-y.
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Abstract

Processing of synaptic signals in somatodendritic compartments determines the neuronal computation. Although amplification of excitatory signals by local voltage-dependent cation channels has been extensively studied, its spatio-temporal dynamics in elaborate dendritic branches remains obscure because of technical limitation. Using fluorescent voltage imaging throughout dendritic arborizations in hippocampal pyramidal neurons, here we demonstrate a unique Cl--dependent remote computation mechanism equipped in distal branches. Local laser photolysis of caged-glutamate triggered excitatory postsynaptic potentials spreading along dendrites with gradual amplification toward the distal end whereas with attenuation toward the soma. Tour-de-force subcellular patch-clamp recordings from thin branches complemented with biophysical model simulation revealed that the asymmetric augmentation of excitation relies on the TTX-resistant Na+ channels and Cl--conductances accompanied with deeper dendritic resting potential. Taken together, the present study unveils cooperative voltage-dependent actions of cation and anion conductances for dendritic supralinear computation which can locally decode the spatio-temporal context of synaptic inputs.

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Morita, M., Higashi, R., Kawaguchi, S.-y.. 2023-05-29. Asymmetric spread of excitatory synaptic potentialin hippocampal neuronal dendrites revealed by voltage imaging. https://doi.org/10.1101/2023.05.29.542696

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