PhD Defence Alessandra Pizzuti

Keywords: Human Brain, Ultra-high field 7 Tesla (f)MRI, Visual Illusion
 

"Distinct and Complementary: Insights on Bistable Perception in Humans Using Ultra-high Field MRI Across Multiple Spatial Scales"

This thesis investigates how the human brain shapes conscious experience from ambiguous visual input, like when a single image seems to flip between two interpretations. Using cutting-edge magnetic resonance imaging (MRI) at ultra-high field strength (7 Tesla), the researcher mapped how brain activity unfolds as perception changes, even though the stimulus remains the same. To study this phenomenon in unprecedented detail, the research combined MRI data across multiple spatial resolutions—including submillimeter precision, known as the mesoscale. This required the development of novel analysis tools tailored to the complexity of high-resolution brain data. By integrating experiments across different levels of brain organization, the work offers a new multi-scale perspective on how perception is constructed in real time. The findings reveal that not only large-scale brain networks, but also very local interactions at the mesoscale between specific brain areas are key to resolving visual ambiguity. These insights deepen our understanding of conscious perception and open new directions for neuroscience research. 

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