Functional impact of dendritic branch-point morphology.
Cortical pyramidal cells store multiple features of complex synaptic input in individual dendritic branches and independently regulate the coupling between dendritic and somatic spikes. Branch points in apical trees exhibit wide ranges of sizes and shapes, and the large diameter ratio between trunk and oblique dendrites exacerbates impedance mismatch. The morphological diversity of dendritic bifurcations could thus locally tune neuronal excitability and signal integration. However, these aspects have never been investigated. Here, we first quantified the morphological variability of branch points from two-photon images of rat CA1 pyramidal neurons. We then investigated the geometrical features affecting spike initiation, propagation, and timing with a computational model validated by glutamate uncaging experiments. The results suggest that even subtle membrane readjustments at branch points could drastically alter the ability of synaptic input to generate, propagate, and time action potentials.
Center for Neural Informatics, Structures, and Plasticity, and Molecular Neuroscience Department, Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA.
Michele
M
Ferrante
Michele
M
Migliore
Giorgio A
GA
Ascoli
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D048430:Cell Shape / Q000502:physiology*; D003712:Dendrites / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D008297:Male; D008959:Models, Neurological; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley