Bottom-up and top-down modulation of multisensory integration.

Sensory perception in the real world requires proper integration of different modality inputs. Process of multisensory integration is not uniform. It varies from individual to individual and changes at different behavioral states of the animal. What factors affect multisensory integration? How does the mammalian brain reconstruct a multisensory world at different states? Here, we summarize recent findings on bottom-up and top-down factors that can modulate sensory processing and multisensory integration. We discuss cortical circuits that are responsible for modulation of multisensory processing based on recent rodent studies. We suggest that multisensory information is not a simple, fixed signal in the brain. Multisensory processing is dynamically modulated in the mammalian brain and leads to a unique and subjective experience of perception.