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La selectividad de la dirección cortical surge en la convergencia de las sinapsis tálamicas
Anthony D Lien1,2,3, Massimo Scanziani4,5,6,7
1Neurosciences Graduate Program, University of California San Diego, La Jolla, CA, USA. anthony.d.lien@gmail.com.
Nature
|May 26, 2018
Resumen
Las neuronas de la corteza visual logran la selectividad de la dirección del movimiento mediante la integración de las entradas de las neuronas del tálamo con una sincronización precisa. Esta integración espacio-temporal permite la detección de la dirección del movimiento del objeto, una tarea de procesamiento visual fundamental.
Área de la Ciencia:
- La neurociencia
- Neurociencia computacional
- Procesamiento visual
Sus antecedentes:
- La selectividad de dirección es crucial para el procesamiento visual en la corteza visual de los mamíferos.
- Se cree que las neuronas corticales logran la selectividad de dirección mediante la integración de entradas con retrasos espaciotemporales específicos.
- Los mecanismos celulares precisos y los orígenes de este desplazamiento espacio-temporal siguen sin estar claros.
Objetivo del estudio:
- Investigar cómo las entradas talamicas contribuyen a la selectividad de la dirección en las neuronas corticales visuales del ratón.
- Para aclarar el papel de la integración espacio-temporal de las entradas del tálamo en el cálculo de la dirección del movimiento.
Principales métodos:
- Registro de la actividad de aproximadamente 80-100 neuronas talamicas que se proyectan a la corteza visual en ratones.
- Estimulando la corteza visual del ratón con estímulos visuales para observar las respuestas neuronales.
- Analizando las características de respuesta temporal de las neuronas tálamicas a los estímulos en diferentes lugares.
Principales resultados:
- Las neuronas tálamicas exhibieron perfiles de respuesta temporales distintos a estímulos en diferentes ubicaciones espaciales.
- Estas neuronas tálamicas excitaron las neuronas corticales visuales durante la estimulación visual.
- La integración de estas entradas tálamicas con compensaciones espaciotemporales apropiadas confería un sesgo para la selectividad de dirección en las neuronas corticales.
Conclusiones:
- Las neuronas tálamicas proporcionan entradas espaciales y temporales diversas a la corteza visual.
- Las neuronas corticales aprovechan la diversidad espaciotemporal de las entradas tálamicas para lograr la selectividad de dirección.
- Este mecanismo demuestra cómo las características visuales fundamentales como la dirección del movimiento se extraen de los circuitos neuronales.
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