Thalamic circuit diversity for active visual processing

Descripción del proyecto

Estudio del efecto de la diversidad de los circuitos talámicos en el procesamiento visual

La percepción consciente de imágenes depende del núcleo geniculado dorsolateral (NGDL) del tálamo, que recibe y procesa las señales de la retina y las envía a la corteza visual primaria. En este contexto, aún no se comprenden bien muchos de los mecanismos del NGDL. En el proyecto ActiVisTha, financiado por el Consejo Europeo de Investigación, se pretende dilucidar el papel de la diversidad de circuitos talámicos en el procesamiento visual y su modulación mediante tecnologías avanzadas en un modelo murino. Se investigará cómo las diversas aferencias retinianas se transforman en características visuales talamocorticales variadas y cuál es el impacto de las interneuronas locales sobre las eferencias talamocorticales. Además, se explorará cómo las aferencias extrarretinianas modulan el procesamiento visual durante la conducta activa. Los resultados principales de la investigación incluirán matrices de transformación retino-talámicas, un modelo de los mecanismos de inhibición local y un modelo espacial y de causalidad para las diferentes aferencias extrarretinianas.

Objetivo

Conscious image perception depends on the dorsolateral geniculate nucleus (dLGN) of the thalamus. The dLGN receives signals from the retina and sends its outputs to the primary visual cortex. Already at this first central stage, the brain actively modulates vision by attention and arousal. Yet, the circuit mechanisms for processing and actively modulating visual information in the dLGN are largely not known. Cells and circuits in the dLGN show diverse specializations, which can only partially be explained by known parallel streams of information. I here propose to explore the role of thalamic circuit diversity for visual processing and its active modulation, using cutting-edge technologies at multiple scales, from synapses to long-range connections, that will dissect and interrogate thalamic circuits at unprecedented resolution in the mouse model. I propose novel approaches that will advance beyond the current state of the art.

First, we investigate how retinal input diversity functionally transforms into thalamocortical visual feature diversity. Second, we study how diverse modes of inhibition by local interneurons – powerful key players with supposedly multifaceted roles – contribute to the diversity of thalamocortical outputs. Third, we explore how diverse extraretinal inputs influence visual processing and interact during active behavior. Key outcomes will be: (1) the retino-thalamic transformation matrices, (2) a multi-mechanistic model of local inhibition, (3) a spatial map and causality model of different extraretinal inputs. These approaches will provide missing links between input and output diversity that can redefine the role of thalamus.

Beyond approaching the question how cognition is implemented, ActiVisTha will have translational and technological impact: understanding the circuits for early visual processing and its active modulation will promote the development of advanced visual prostheses for the blind as well as machine learning technologies.