Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Neurosciences, Neurosciences & Neurology, hippocampus, mouse, Purkinje cell, pyramidal cell, signal transduction, synaptic plasticity, ANOMALOUS DIFFUSION, CALCIUM DYNAMICS, PARVALBUMIN, AXONS, Animals, Computer Simulation, Dendrites, Dendritic Spines, Diffusion, Hippocampus, Mice, Models, Molecular, Models, Neurological, Patch-Clamp Techniques, Purkinje Cells, Pyramidal Cells, Signal Transduction, 1109 Neurosciences, 1701 Psychology, 1702 Cognitive Sciences, Neurology & Neurosurgery, 3209 Neurosciences, 5202 Biological psychology, 5204 Cognitive and computational psychology

Abstract:

We combined computational modeling and experimental measurements to determine the influence of dendritic structure on the diffusion of intracellular chemical signals in mouse cerebellar Purkinje cells and hippocamal CA1 pyramidal cells. Modeling predicts that molecular trapping by dendritic spines causes diffusion along spiny dendrites to be anomalous and that the value of the anomalous exponent (d(w) ) is proportional to spine density in both cell types. To test these predictions we combined the local photorelease of an inert dye, rhodamine dextran, with two-photon fluorescence imaging to track diffusion along dendrites. Our results show that anomalous diffusion is present in spiny dendrites of both cell types. Further, the anomalous exponent is linearly related to the density of spines in pyramidal cells and d(w) in Purkinje cells is consistent with such a relationship. We conclude that anomalous diffusion occurs in the dendrites of multiple types of neurons. Because spine density is dynamic and depends on neuronal activity, the degree of anomalous diffusion induced by spines can dynamically regulate the movement of molecules along dendrites.