AMPA receptor mobility shapes synaptic plasticity
Short-term synaptic plasticity (STP), the rapid modulation of synaptic efficiency during closely spaced neuronal activity, has long been considered primarily presynaptic in origin. In a study published in Neuron(1), Daniel Choquet’s team (IINS, Neurocampus Bordeaux) demonstrates, using several advanced microscopy approaches implemented at the Bordeaux Imaging Center (France-BioImaging Bordeaux node), that postsynaptic AMPA receptor mobility plays a decisive role in this regulation.
Visualizing receptor dynamics in real time
To investigate this mechanism, researchers used primarily lattice light-sheet (LLS) microscopy, a high spatiotemporal resolution system enabling the characterization of AMPA receptor mobility at individual synapses. This approach revealed that AMPA receptors are not static but undergo lateral diffusion within the postsynaptic membrane.
By combining LLS with Fluorescence Recovery After Photobleaching (FRAP) experiments, AMPA receptor mobile fraction can be quantified. The team also used targeted 1P and 2P photo-manipulation, to demonstrate the link between potentiation or depression and receptor mobility. When AMPA receptors are immobilized, synaptic depression increases.
Super-resolution STORM microscopy was also employed to examine the static nano-organization of AMPA receptor subunits. The results show that their nanoscale organization is not altered when immobilizing AMPA by crosslinking agent. Only the mobility is affected as revealed with LLS single particle tracking.
Figure 2 Differential AMPAR biophysics and mobility define synapse-type-specific STP (E) LLSM-FRAP in acute slices. AP-GluA2 labeled with mSA-ALFA and αALFA nanobody. Representative images show spine regions of interest (ROIs) (dashed circles) at baseline (−1 s), after photobleaching (+0.5 s), and diffusion-dependent recovery (+250 s). Scale bar, 2 μm. Kymographs illustrate ROI fluorescence recovery (dashed line; ∼250 s). Mean recovery curves and fraction (CA1 = 23, S1 = 18 spines; unpaired t test: F(17,22) = 1.939, ∗p = 0.024).
From single synapses to neuronal networks
Finally, two-photon microscopy enabled the study of the impact of AMPA receptor mobility at the network level. The findings indicate that receptor dynamics influence collective neuronal activity and contribute to maintaining appropriate synaptic gain.
These findings establish AMPA receptor mobility as a functional component of short-term plasticity. By directly visualizing and manipulating receptor dynamics, advanced microscopy demonstrates that postsynaptic receptor motion actively shapes synaptic strength regulation.
(1) Agata Nowacka, Angela M. Getz, Hanna L. Zieger, Maxime Malivert, Diogo Bessa-Neto, Elisabete Augusto, Christelle Breillat, Sophie Daburon, Cécile Lemoigne, Sébastien Marais, Mathieu Ducros, Alexandre Favereaux, Andrew C. Penn, Richard Naud, Matthieu Sainlos, Daniel Choquet, Synapse-specific and plasticity-regulated AMPA receptor mobility tunes synaptic integration, Neuron, 2026, ISSN 0896-6273, https://doi.org/10.1016/j.neuron.2025.12.004.
