Wenqing Wei: Emergence of feature selectivity in thalamo-cortical circuits of the rodent visual system

Abstract 

 
Vision is one of the fundamental senses that allow us to see and interact with the environment. It is not simply the detection of light, but a series of complex processes involving transformation, integration and processing of the visual stimuli. Through a cascade of neural mechanism, the visual system transforms raw visual information into finely tuned representations. One of the key mechanism is associated with feature selectivity, which refers to the ability of neurons to respond to specific features of visual stimuli, such as orientation, direction of motion and spatial frequency.

 Our research focuses on studying feature selectivity in the thalamo-cortical circuits in three steps. Firstly, neurons in the rodent visual cortex respond selectively to the stimulus orientations already at eye opening. For past decades, several models have been proposed to study the emergence of orientation selectivity in the thalamocortical pathway. However, there is currently no agreement on which thalamocortical transformation leads to neuronal tuning curves observed in experiments. Here we present a new model of thalamocortical pathway where orientation selectivity emerges and describe in detail the underlying neural mechanism. Secondly, although the corticothalamic feedback connections outnumber the feedforward projections, the exact role of CT feedback remains unclear. We extend our feedforward model with feedback connections to investigate the contribution of CT feedback on the orientation selectivity of V1 neurons, which is currently hard to study in experiments. Lastly, we use the plaid pattern, which is the superposition of two simple sinusoidal gratings, to study the directional selectivity of V1 neurons.  

 About the speaker and her research

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