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Dependencia de la eficacia de EPSP en la ubicación de la sinapsis en las neuronas piramidal neocortical
Stephen R Williams1, Greg J Stuart
1Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, ACT 0200, Australia.
Science (New York, N.Y.)
|March 9, 2002
Resumen
Las entradas sinápticas distantes a las neuronas son débiles, pero pueden desencadenar potenciales de acción cuando se activan simultáneamente. Esta detección de coincidencia pone de relieve un papel de señalización transitorio para los potenciales postsinápticos excitatorios distales (EPSP).
Área de la Ciencia:
- La neurociencia es la neurociencia.
- La neurociencia computacional es una neurociencia computacional.
- La neurociencia celular es la neurociencia celular.
Sus antecedentes:
- Las neuronas integran miles de entradas sinápticas a través de complejos árboles dendríticos.
- Comprender cómo las entradas sinápticas en diferentes ubicaciones dendríticas influyen en la salida neuronal es crucial.
Objetivo del estudio:
- Investigar el impacto somático de los potenciales postsinápticos excitatorios (EPSP) generados en sitios dendríticos específicos en las neuronas piramidal neocorticales.
- Determinar las condiciones bajo las cuales las entradas sinápticas distales pueden influir en la activación neuronal.
Principales métodos:
- Registros electrofisiológicos de las neuronas piramidal neocorticales.
- Estimulación de las entradas sinápticas en ubicaciones dendríticas conocidas.
- Análisis de la amplitud somática EPSP y potenciales de acción de salida.
Principales resultados:
- La amplitud somática EPSP disminuyó significativamente con el aumento de la distancia de entrada desde el soma.
- La depresión dependiente del uso de EPSP aumentó para las entradas más distales.
- Activación coincidente de EPSP distales dentro de una ventana de tiempo estrecha (aprox. 10 ms) podría conducir directamente la salida del potencial de acción, a pesar de una marcada atenuación (>40 veces).
- Se observó la generación de picos dendríticos después de una activación de entrada distal coincidente.
Conclusiones:
- Los EPSP distales son fuentes ineficientes de excitación somática de fondo.
- La detección de coincidencias de EPSP distales permite un poderoso papel de señalización transitorio en la generación de potenciales de acción.
- La integración dendrítica y la generación de picos juegan un papel crítico en la traducción de las entradas distales a la salida neuronal.
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