Larvae of the zebrafish can recognize unicellular prey individual receptors to UV light. Such a high sensitivity characteristic of cones the area of the greatest density of receptors, similar to the Central fovea (the fovea) other animals. Differences in sensitivity of cells in different areas of the retina are determined by the morphology of receptors and genetic settings phototransduction. The authors of an article published in the journal Neuron, believe that the study of the perception of light zebrafish will help to better understand the structure of sensory systems of other animals, including humans.
In General, the sensitivity of different types of photoreceptors in the world works on the same principle: photons (light particles) act on the protein channels of cells, alter the flow of ions through the membrane and trigger the release of neurotransmitter at the opposite end of the receptor. However, depending on the type of light-sensitive cells, and even its location on the retina, the ratio of the photon flux and the release of neurotransmitter vesicles varies considerably. For example, the sticks respond even to single photons and the need for vision in low light, and cones transmit the signal faster, but less sensitive. In the Central fovea (the fovea, the point of the greatest density of photoreceptors) of the retina sensitivity of cones is higherthan in other zones. The study of the mechanisms of the settings of individual receptors will help us to understand the structure and evolution of sensory systems.
Scientists from the UK and Germany under the leadership of Tom Baden (Tom Baden) from the University of Sussex investigated the ultraviolet device of view of the larval zebrafish. These fish feed on plankton, which are poorly visible in the water in the spectrum visible to human light. Researchers have verified that for a successful hunt the larvae of zebrafish need to see in the ultraviolet range. For starters, scientists have reproduced a vision of the world fish using two cameras: one recorded the aquarium with ciliates (food for larvae) in the yellow light, the other in the ultraviolet. Then, on the contrary, covered the aquarium with larvae of zebrafish and ciliates yellow and UV light and watched how active fish will react to prey. Finally, the same experiment was conducted with larvae, which is using genetic tools have removed the UV cones of the retina.
On camera recording the yellow light was visible the General background of the aquarium, but ciliates was impossible to consider; in unicellular ultraviolet light in the surface layer of water looked like bright dots.