Wilson, D. E., Whitney, D. E., Scholl, B., & Fitzpatrick, D. (2016). Orientation
selectivity and the functional clustering of synaptic inputs in primary visual cortex. Nature
neuroscience, 19(8), 1003-1009. https://www.nature.com/articles/nn.4323
Sparse expression of GCaMP6 and two-photon calcium imaging. Measured
individual receptive field tuning properties of hundreds dendritic spines on a single neuron along
with the soma’s tuning to moving grating stimuli.
Layer 2/3 ferret visual cortex
Paper addresses a central question in neuroscience: “How does the tuning of an
individual neuron relate to the tuning of its synaptic inputs?” Authors show that the orientation
preference of a visual neuron is predictable from its summed synaptic input. But they show that
the cell’s selectivity is narrower than this summed input and suggest that ‘orientation-specific
clustering of synaptic inputs’ may be a key determiner of selectivity.
“[W]e used in vivo two-photon calcium imaging to characterize the orientation tuning and
spatial arrangement of synaptic inputs to the dendritic spines of individual pyramidal neurons in
layer 2/3 of ferret visual cortex. The summed synaptic input to individual neurons reliably
predicted the neuron’s orientation preference… Dendritic branches with more co-tuned synaptic
clusters exhibited greater rates of local dendritic calcium events, supporting a prominent role for
functional clustering of synaptic inputs in dendritic nonlinearities that shape orientation
selectivity.”