Top-down processing and perceptual learning: role of the lateromedial secondary visual cortex in a mouse model of visual perceptual learning

Perceptual learning refers to any change in perceptual ability as a result of experience and practice. In the visual system, visual perceptual learning (vPL) occurs in response to a wide range of tasks, including grating, texture, vernier or stereoscopic discriminations. Even though several studies proved that vPL is associated with morphological and functional changes in primary visual neurons, it is currently under debate whether, and to what extent, these changes are also mediated by top-down processing. With the aim of providing an answer to this open issue, I chemogenetically interfered with the activity of the lateromedial cortex (LM), a higher-order visual area, employing the mouse as experimental model. To this end, I adapted a perceptual task previously developed to study vPL in rats and human subjects. This task requires the discrimination between two visual gratings of progressively close spatial frequencies until a perceptual plateau is reached. The results obtained in the present thesis suggest that LM activity is crucially required for vPL.