Neural Circuits and Systems Neuroscience
Author: Nicolas Martorell | Email: martorellnicolas1995@gmail.com
Nicolas Martorell1°2°, Emiliano Marachlian3°, German Sumbre3°, Violeta Medan1°2°
1° IFIBYNE (UBA – CONICET), Buenos Aires, Argentina
2° Departamento de Fisiología, Biología Molecular y Celular (FCEN, UBA)
3° Biologie, École Normale Supérieure, Paris, France
The Optic Tectum (OT) in the zebrafish brain (Danio rerio) is known to be a visual processing hub. Neurons in the Tectal Neuropil (TN) are known for feature-based detection of stimuli, while the Periventricular Layer (PVL) relays this information to other regions, such as decision-making neurons in the Hindbrain. We investigate if the OT responds to auditory stimulation, and whether the response to visual stimulation is enhanced by the addition of an auditory stimulus. 4-7 dpf transgenic zebrafish were embedded in agarose and recorded with a confocal microscope (HuC:GCaMP6f, N=73) or with a Single Plane Illumination Microscope (H2B:GCaMP6f, N=10). Five repetitions of visual looming stimuli and short auditory stimuli were presented either separately or combined, varying the salience of the visual stimulus by changing its contrast. Auditory responses were observed in the OT in 64% of fish and were stronger and more common in the TN than in the PVL. During multisensory trials, both TNs and PVL neurons showed an increased activation probability when compared to visual-only stimulation. This enhancement was stronger for lower salience stimuli and correlated with increased pre-motor and motor activity. This study shows a classically visual brain region responding to a different modality, and highlights the effect of multisensory integration on behavior and decision making.