"... We examined the relationship between dendritic arborization and the coupling between somatic and dendritic action potential (AP) initiation sites in layer 5 (L5) neocortical pyramidal neurons. Coupling was defined as the relative reduction in threshold for initiation of a dendritic calcium AP due to a coincident back-propagating AP. Simulations based on reconstructions of biocytin-filled cells showed that addition of oblique branches of the main apical dendrite in close proximity to the soma (d < 140 um) increases the coupling between the apical and axosomatic AP initiation zones, whereas incorporation of distal branches decreases coupling. ... We conclude that variation in dendritic arborization may be a key determinant of variability in coupling (49+-17%; range 19-83%; n = 37) and is likely to outweigh the contribution made by variations in active membrane properties. Thus coincidence detection of inputs arriving from different cortical layers is strongly regulated by differences in dendritic arborization."

Model Type: Neuron or other electrically excitable cell

Cell Type(s): Neocortex L5/6 pyramidal GLU cell

Currents: I Na,t; I A; I K; I M; I K,Ca; I Calcium

Model Concept(s): Action Potential Initiation; Coincidence Detection

Simulation Environment: NEURON

Implementer(s): Schaefer, Andreas T [andreas.schaefer at crick.ac.uk]

References:

Schaefer AT, Larkum ME, Sakmann B, Roth A. (2003). Coincidence detection in pyramidal neurons is tuned by their dendritic branching pattern. Journal of neurophysiology. 89 [PubMed]