New Paper

[Arjen van Ooyen]

New Paper:

Development of Nerve Connections under the Control
of Neurotrophic Factors: Parallels with
Consumer-Resource Systems in Population Biology.

Arjen van Ooyen & David J. Willshaw, 
J. Theor. Biol. (2000) 206: 195-210.

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Abstract
--------

We show that a recently formulated model of axonal competition can be
rewritten as a general consumer-resource system. 
This allows neurobiological phenomena to be interpreted in population
biological terms and, conversely, results from population biology 
(where competition is better understood) to be applied to neurobiology. 
Using findings from population biology, we study two extensions of our
axonal competition model. In the first extension, the spatial dimension 
of the target is explicitly taken into account. We show that distance
between axons on their target mitigates competition and permits the
coexistence of axons. The model can account for the fact that, in many
types of neurons, a positive correlation exists between the size of the 
dendritic tree and the number of innervating axons surviving into
adulthood. In the second extension, axons are allowed to respond to more
than one neurotrophic factor. We show that this permits competitive 
exclusion within one type of axons, while at the same time there is 
coexistence with a different type of axons innervating the same target. 
The model offers an explanation for the innervation pattern found on
cerebellar Purkinje cells, where climbing fibres compete with each 
other until only a single one remains, which coexists with parallel 
fibre input to the same Purkinje cell. 




-- 
Arjen van Ooyen, Netherlands Institute for Brain Research,
Meibergdreef 33, 1105 AZ Amsterdam, The Netherlands.
email: A.van.Ooyen at nih.knaw.nl 
website: http://www.anc.ed.ac.uk/~arjen
phone: +31.20.5665483  fax: +31.20.6961006