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Rápida plasticidad extragranular en ausencia de plasticidad talamocortical en el desarrollo de la corteza visual
J T Trachtenberg1, C Trepel, M P Stryker
1W. M. Keck Foundation Center for Integrative Neuroscience and Department of Physiology, University of California, San Francisco, CA 94143-0444, USA.
Science (New York, N.Y.)
|March 17, 2000
Resumen
La privación visual temprana remodela la corteza visual del cerebro, haciendo que las neuronas respondan menos al ojo privado. Este estudio revela que la plasticidad ocurre en las capas corticales superiores, no en la sinapsis talamocortical.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Neurociencia del desarrollo neurológico.
- Plasticidad del sistema visual Plasticidad del sistema visual
Sus antecedentes:
- La privación monocular durante el desarrollo temprano altera los circuitos de la corteza visual primaria (V1).
- Las neuronas suelen mostrar una respuesta reducida a los estímulos del ojo privado después de este período.
- Este cambio fisiológico está relacionado con la pérdida anatómica de la entrada del ojo privado, potencialmente comenzando en la sinapsis talamocortical.
Objetivo del estudio:
- Para investigar la plasticidad de la dominación ocular en la corteza visual primaria después de una breve privación monocular (24 horas).
- Para determinar las capas específicas dentro de la corteza visual donde se produce esta plasticidad.
- Para probar la hipótesis de que la organización talamocortical es guiada por cambios en etapas corticales superiores.
Principales métodos:
- Se empleó imágenes ópticas de señal intrínseca para analizar la actividad de la corteza visual.
- Se utilizaron grabaciones específicas de unidades extracelulares para evaluar las respuestas neuronales.
- Estos métodos permitieron el examen de los cambios de dominación ocular a nivel celular.
Principales resultados:
- La respuesta al ojo privado se perdió significativamente en las capas extragranulares de la corteza visual primaria.
- La binocularidad normal, particularmente en la capa IV, se conservó a pesar de la privación monocular.
- Estos hallazgos indican un efecto específico de capa de la experiencia visual temprana.
Conclusiones:
- La plasticidad observada en las capas extragranulares, en lugar de la sinapsis talamocortical, desafía las hipótesis anteriores.
- Esto sugiere que las etapas de procesamiento cortical de nivel superior pueden guiar la organización de las entradas talamocorticales.
- La experiencia visual temprana moldea críticamente los circuitos corticales de una manera dependiente de las capas.
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