Fig. 1.

Design of the behavioral setup. a Schematic of the behavioral setup enabling the rapid delivery of odors to the arena using a computer-controlled solenoid valve. The arena dimensions were as follows: horizontal axis = 15 cm, vertical axis = 11.5 cm, and width = 3 cm. The schematic of the fish is to scale with the arena. The blue dashed arrows indicate the water flow deflection on the walls of the arena. b Image series showing the rapid and evenly spread of the odor within the arena after valve opening. The odor was replaced by a dye, and its normalized concentration in the arena is plotted over time (0 = no stimulus; 1 = same concentration as in the odor bottle). c Dynamic of stimulus concentration in the arena over the course of 30 min. The valve was open for 1 min