A model of thalamocortical relay cells.
J Physiol
; 565(Pt 3): 765-81, 2005 Jun 15.
Article
em En
| MEDLINE
| ID: mdl-15613378
ABSTRACT
It is well established that the main intrinsic electrophysiological properties of thalamocortical relay cells, production of a low threshold burst upon release from hyperpolarized potential and production of a train of single spikes following stimulation from depolarized potentials, can be readily modelled using a single compartment. There is, however, another less well explored intrinsic electrophysiological characteristic of relay cells for which models have not yet accounted at somatic potentials near spike threshold, relay cells produce a fast ragged high threshold oscillation in somatic voltage. Optical [Ca(2+)] imaging and pharmacological tests indicate that this oscillation correlates with a high threshold Ca(2+) current in the dendrites. Here we present the development of a new compartment model of the thalamic relay cell guided by the simultaneous constraints that it must produce the familiar regular spiking relay mode and low threshold rebound bursts which characterize these cells, as well as the less-studied fast oscillation occurring at near-threshold somatic potentials. We arrive at a model cell which is capable of the production of isolated high threshold Ca(2+) spikes in distal branch segments, driven by a rapidly inactivating intermediate threshold Ca(2+) channel. Further, the model produces the low threshold spike behaviour of the relay cell without requiring high T-current density in the distal dendritic segments. The results thus support a new picture of the dendritic tree of relay cells which may have implications for the manner in which thalamic relay cells integrate descending input from the cortex.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tálamo
/
Potenciais de Ação
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Córtex Cerebral
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Modelos Neurológicos
/
Neurônios
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Physiol
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Estados Unidos