At the confluence of the senses Cortical processing of multisensory stimuli and context

We sample the world through multiple senses – vision, touch, audition and more – each entering the brain through physically separate pathways, yet merging into a unified experience. This thesis aims to investigate how the brain integrates multiple senses and how multisensory context shapes sensory processing.
In Chapter 2, we show that mice can linearly combine visual and auditory cues. Chapter 3 examines the mouse posterior parietal cortex as a site for integration visual and tactile evidence and, although no multisensory-specific neuronal activity was found, we identified detection-related signals and demonstrated this region’s causal role in visuotactile decision-making, independent of sensory modality. In Chapter 4, we report that adding an additional relevant sensory modality extended the period during which the primary visual cortex contributed to visual perception, revealing that multisensory context modulates cortical activity and dynamics. Finally, Chapter 5 focuses on neuron-level mechanisms: layer 5 pyramidal tract neurons in the rat somatosensory cortex encode touch through bursting activity, unlike other cell types, highlighting their unique role in tactile encoding.
Together, these findings advance our understanding of the neural principles that support multisensory processing, from behavior to circuits to single-cell function.