Neural Circuits and Systems Neuroscience
Author: Nicolás Martorell | email: martorellnicolas1995@gmail.com
Nicolás Martorell 1°, Violeta Medan 1°
1° Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires / CONICET
The process of synthesizing different sensory signals related to a stimulus is called multisensory integration. This process increases the collective impact of biologically relevant signals, but how it is implemented at the level of the nervous system remains, mostly, an open question. To understand how multisensory integration is represented in specific brain regions we performed in vivo calcium imaging of neural activity of larval zebrafish. Using the genetically encoded pan-neuronal elav3:GCaMP6f calcium sensor we imaged 4-7 dpf larval zebrafish with a confocal microscope. This allowed us to identify single units and compare their responses to multisensory stimuli and its unisensory components in specific brain regions. Analysis of the optic tectum, torus semicircularis and thalamus showed sparse representation of multisensory stimuli in the three areas, with a low proportion (<10%) of neurons responding consistently to repeated stimulation. Importantly, multisensory stimuli recruited more neurons when compared to visual or auditory stimuli alone although the level of activation of each unit was similar. Although preliminary, these findings suggest that multisensory integration is distributed in diverse but specific brain regions and that its impact in information processing can be studied through in vivo calcium imaging with this audiovisual stimulation paradigm.