Sunday, June 24, 2018
Not so special
Pointed from UD.
Dr. Tom Baden ... said: "By measuring the activity of thousands of neurons in the live animal while presenting visual stimuli, we established that different parts of their retinas, looking at different parts of the visual world, do different things. This multi-faceted view makes perfect sense for zebrafish as that's how colour is distributed in their natural habitat. In their natural visual world, most colour information is on the ground and the horizon but above them the objects of most interest are dark silhouettes, so colour vision here is rather pointless." The study found that zebrafish, who during larval and juvenile life stages live mostly in shallow, low current pockets on the sides of streams and rice paddies, only seem to use their colour vision repertoire for looking down and along the horizon, use colour-blind circuits for looking straight up and extremely sensitive ultraviolet vision for looking forward and upwards.Not as special as it might seem. Humans don't have different circuits for different frequencies in vision, but we DO have such a separation by frequency in hearing. Low-frequency rumbles, mid-frequency speech sounds, and high-frequency screeches, have distinct mechanical resonators and distinct hair cells in the cochlea, and use distinct processing centers in the brain. ¶ 12:32 AM
