As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday, 6 January 2017

Hummingbirds see motion in an unexpected way

Date: January 5, 2017
Source: Cell Press


Have you ever imagined what the world must look like to hummingbirds as they zoom about at speeds of up to 60 miles per hour? According to new evidence on the way the hummingbird brain processes visual signals reported in Current Biology on January 5, you can't. That's because a key area of the hummingbird's brain processes motion in a unique and unexpected way.

"In all four-limbed vertebrates studied to date, most of the neurons in this [motion-detecting] brain area are tuned to detect motion coming from behind, such as would occur for an impending collision or when being attacked from behind by a predator," says Douglas Altshuler of the University of British Columbia. "We found that this brain area responds very differently in hummingbirds. Instead of most neurons being tuned to back-to-front motion, almost every neuron we found was tuned to a different direction. We also found that these neurons were most responsive to very fast motion."

The brain area in question is known in birds as the lentiformis mesencephalic, or LM for short. (In mammals, it's called the nucleus of the optic tract.) The LM is responsible for processing visual signals sent to the brain as images move across the retina.

The primary interest of the Altshuler lab is in understanding flight. To understand how birds fly, the researchers needed to understand how they see the world. Hummingbirds were of special interest because of their remarkable ability to zoom quickly and then stop to hover in place while sipping nectar in midair.


Continued

No comments:

Post a comment