Abstract
Dendritic spines are the primary sites of excitatory transmission in the mammalian brain. Spines of cerebellar Purkinje Cells (PCs) are plastic, but they differ from forebrain spines in a number of important respects, and the mechanisms of spine plasticity differ between forebrain and cerebellum. Our previous studies indicate that in hippocampal spines cortactin—a protein that stabilizes actin branch points—resides in the spine core, avoiding the spine shell. To see whether the distribution of cortactin differs in PC spines, we examined its subcellular organization using quantitative preembedding immunoelectron microscopy. We found that cortactin was enriched in the spine shell, associated with the non-synaptic membrane, and was also situated within the postsynaptic density (PSD). This previously unrecognized distribution of cortactin within PC spines may underlie structural and functional differences in excitatory spine synapses between forebrain, and cerebellum.
Highlights
Dendritic spines are the primary sites of excitatory transmission in the mammalian brain
To ensure that Purkinje neurons express cortactin, we performed high-resolution laserscanning confocal microscopy on cerebellar sections double labelled with the Purkinje Cells (PCs)-specific marker calbindin (Fig. 2)
We confirmed that PCs are expressing cortactin in their dendritic tree, and in puncta associated with their dendritic branchlets, suggesting that spines are enriched in cortactin
Summary
Dendritic spines are the primary sites of excitatory transmission in the mammalian brain. We found that cortactin was enriched in the spine shell, associated with the non-synaptic membrane, and was situated within the postsynaptic density (PSD) This previously unrecognized distribution of cortactin within PC spines may underlie structural and functional differences in excitatory spine synapses between forebrain, and cerebellum. Cerebellar learning arises from the temporal pairing of signals from MFs onto PC spines with activation of the associated CF, leading to LTD at the PF-PC synapse that is mechanistically quite different from forebrain synaptic plasticity. According to the currently accepted view, LTD and LTP play a complementary role in cerebellar motor learning These long-lasting changes in synaptic efficacy are tightly coupled to changes in spine morphology, at least in the forebrain 16. One might presume a similar organization of cortactin in PCs as in the Scientific Reports | (2021) 11:1375
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
