Developmental refinement of visual cortex function through cortico-thalamic feedback

• Applicants: Professorin Julijana Gjorgjieva, Ph.D.; Professor Dr. Knut Kirmse
• Subject Area: Experimental and Theoretical Network Neuroscience
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 562183930

Spontaneous neuronal activity in the developing visual system commences long before the onset of patterned vision. It is widely assumed that such pre-sensory activity serves as a training signal which instructs the developmental refinement of nascent neuronal circuits, including those in the primary visual cortex (V1). However, the impact of pre-sensory activity on the proper maturation of sensory abilities and network dynamics underlying adult visual computations and behaviors in vivo remains largely unknown. The developing visual system has classically been analyzed and modeled as a feedforward circuit, in which visual stimuli are received by the retina and synaptically transmitted to the visual thalamus and V1. This view is incomplete, however, as cortico-thalamic feedback is already functional at early developmental stages. Focusing on the developing mouse visual system in vivo, we here propose that (i) V1 neurons learn their receptive field properties and mature network dynamics on spontaneous activity before eye opening and that (ii) cortico-thalamic projection neurons crucially contribute to this developmental learning by providing feedback amplification to V1. We will examine these hypotheses in an integrated experimental-theoretical approach. Specifically, we will combine neuronal population imaging and cell type-specific manipulations in mouse models with computational data analysis and neural network modeling in a mutually dependent manner. We expect that our study will provide novel insights into the causal mechanisms of cortico-thalamic feedback loops during visual system development.

• DFG Programme: Research Grants