Mossy cell loss and mossy fiber sprouting are two characteristic
consequences of repeated seizures and head trauma. However, their
precise contributions to the hyperexcitable state are not well
understood. Because it is difficult, and frequently impossible, to
independently examine using experimental techniques whether it is the
loss of mossy cells or the sprouting of mossy fibers that leads to
dentate hyperexcitability, we built a biophysically realistic and
anatomically representative computational model of the dentate gyrus
to examine this question. The 527-cell model, containing granule,
mossy, basket, and hilar cells with axonal projections to the
perforant-path termination zone, showed that even weak mossy fiber
sprouting (10-15% of the strong sprouting observed in the pilocarpine
model of epilepsy) resulted in the spread of seizure-like activity to
the adjacent model hippocampal laminae after focal stimulation of the
perforant path. See reference for more and details.
Reference:
1 .
Santhakumar V, Aradi I, Soltesz I (2005) Role of mossy fiber sprouting and mossy cell loss in hyperexcitability: a network model of the dentate gyrus incorporating cell types and axonal topography. J Neurophysiol 93:437-53 [PubMed]
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