El-Boustani, S., Ip, J. P., Breton-Provencher, V., Knott, G. W., Okuno, H., Bito, H.,
& Sur, M. (2018). Locally coordinated synaptic plasticity of visual cortex neurons in vivo.
Science, 360(6395), 1349-1354.
https://science.sciencemag.org/content/360/6395/1349.abstract
2P calcium imaging of dendritic spine receptive fields; Serial BlockFace EM
Mouse visual cortex
The authors use 2P calcium imaging of a visual neuron’s dendritic spines to
determine the receptive field properties of upstream neurons. Then they use optogenetics to
train that visual neuron to have a different receptive field. Using 2P fluorescence microscopy
they track changes in spine volume across this training and show that the synapses that grow
(i.e. that increase their strength) are precisely those that would have undergone LTP during the
training based on Hebbian theory. They thus demonstrate that the receptive field of a visual
neuron is determined by the synapses it receives and by the structural size of these synapses.
“We used dendritic spine volume changes as a structural proxy for long-term
potentiation [sLTP = structural long-term potentiation]…We hypothesized that sLTP spines
should have their receptive field centers overlapping the visual target because of Hebbian
plasticity… Spines with receptive fields overlapping the target stimulus indeed increased in
volume…EM spine volume was highly correlated with synaptic surface area, consistent with the
hypothesis that synaptic weight is reflected in spine volume.”
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