Adoff, M. D., Climer, J. R., Davoudi, H., Marvin, J. S., Looger, L. L., & Dombeck, D.
A. (2021). The functional organization of excitatory synaptic input to place cells. Nature
communications, 12(1), 1-15. https://www.nature.com/articles/s41467-021-23829-y
Two-photon microscopy to record glutamate input onto individual dendritic regions
(1 μm length ROIs tiling the length of each dendritic segment) using the membrane-targeted
genetically encoded glutamate reporter iGluSnFR. “Evoked iGluSnFR fluorescence transients
were highly localized along the dendrites, with increased change in fluorescence (ΔF/F) over ~1
μm. Based on the spatial extent and the stochastic nature of the evoked responses, we
presume that these ΔF/F transients originate from glutamate released at single synapses,
consistent with previous characterization.”
Hippocampal CA1 place cells in awake behaving (virtual reality) mouse
There are now several studies in primary sensory cortical regions exploring how a
neuron’s receptive field is build up from the receptive fields of the cells providing it synaptic
input. This study is the first (that I know of) that attempts to do the same for a neuron in a highlevel brain area (hippocampus). The results are thus relevant to understanding how high-level
representations are formed.
“Using iGluSnFR in the hippocampus during spatial behaviors in virtual reality (VR), we
found that the dendrites of individual place cells received significant excitatory input at track
locations both inside and outside of the somatic place field. Many micron-scale dendritic regions
of interest (ROIs) received highly spatially tuned excitatory input (place-ROIs)… The total
excitatory input was greater in the somatic place field versus outside, and this increased
excitation mainly arose from place-ROIs with spatial tuning overlapping the somatic field.”