Our actions depend on the continuous processing of information from different senses (e.g. vision, touch, smell). The mechanisms by which the brain combines information from different sensory modalities is called multisensory processing. Multisensory processing allows us to focus our attention on a particular speaker in a crowded room by combining auditory inputs from the speech and visual inputs from the mouth movements. Multisensory processing is fundamental in object recognition, which is the mechanism that allows our brain to recognize objects in the environment and act upon them appropriately. In the context of object recognition, different sensory inputs are combined to create a unique neural representation of objects. However, we can also recognize the same object with different sensory modalities. For example, we can recognize a pencil in our backpack by looking into it (vision) or by searching with our hands (touch). This ability depends on a multisensory representation of the pen in our brain.
The perirhinal cortex is a high order association area involved in object recognition. It receives information from all sensory modalities. The aim of the RhinalMultiSense project was to unveil the circuits of perirhinal cortex involved in sensory and multisensory processing. To achieve this goal, I combined neuroanatomical tracing to map the sensory inputs of perirhinal cortex along its rostro-caudal axis. These experiments revealed the origin of sensory inputs to perirhinal cortex and their topographic organization. I then used in vitro electrophysiology coupled with optogenetics to test the circuits involved in processing tactile inputs in perirhinal cortex.
The results of RhinalMultiSense will be fundamental to resolve the mechanisms of multisensory object recognition in the cortex.
