[Comp-neuro] new paper

Arjen van Ooyen arjen.van.ooyen at falw.vu.nl
Wed May 26 14:20:24 CEST 2010


Impact of dendritic size and dendritic topology on burst firing in 
pyramidal cells

Van Elburg, R. A. J., and Van Ooyen, A. (2010). PloS Computational 
Biology 6(5): e1000781. doi:10.1371/journal.pcbi.1000781.

To download full text, go to my website: http://www.bio.vu.nl/enf/vanooyen


Abstract

Neurons display a wide range of intrinsic firing patterns. A 
particularly relevant pattern for neuronal signaling and synaptic 
plasticity is burst firing, the generation of clusters of action 
potentials with short interspike intervals. Besides ion-channel 
composition, dendritic morphology appears to be an important factor 
modulating firing pattern. However, the underlying mechanisms are poorly 
understood, and the impact of morphology on burst firing remains 
insufficiently known.
    Dendritic morphology is not fixed but can undergo significant 
changes in many pathological conditions. Using computational models of 
neocortical pyramidal cells, we here show that not only the total length 
of the apical dendrite but also the topological structure of its 
branching pattern markedly influences inter- and intraburst spike 
intervals and even determines whether or not a cell exhibits burst 
firing. We found that there is only a range of dendritic sizes that 
supports burst firing, and that this range is modulated by dendritic 
topology. Either reducing or enlarging the dendritic tree, or merely 
modifying its topological structure without changing total dendritic 
length, can transform a cell’s firing pattern from bursting to tonic 
firing. Interestingly, the results are largely independent of whether 
the cells are stimulated by current injection at the soma or by synapses 
distributed over the dendritic tree.
   By means of a novel measure called mean electrotonic path length, we 
show that the influence of dendritic morphology on burst firing is 
attributable to the effect both dendritic size and dendritic topology 
have, not on somatic input conductance, but on the average spatial 
extent of the dendritic tree and the spatiotemporal dynamics of the 
dendritic membrane potential.
   Our results suggest that alterations in size or topology of pyramidal 
cell morphology, such as observed in Alzheimer’s disease, mental 
retardation, epilepsy, and chronic stress, could change neuronal burst 
firing and thus ultimately affect information processing and cognition.


-- 
Dr. Arjen van Ooyen
Computational Neuroscience Group
Department of Integrative Neurophysiology
Center for Neurogenomics and Cognitive Research
VU University Amsterdam
De Boelelaan 1085
1081 HV Amsterdam
The Netherlands

E-mail: arjen.van.ooyen at cncr.vu.nl
Phone:  +31.20.5987090
Fax:    +31.20.5987112
Room:   B-451
Web:    http://www.bio.vu.nl/enf/vanooyen




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