Thursday, April 29, 2010

Bird Brain, Pterosaur Brain

Pterosaur brains were "remarkably bird-like".

"From this, the scientists were able to deduce that pterosaur brains were very bird-like, with reduced olfactory lobes and large optic lobes — suggesting that, like modern birds, they were more interested in what they could see than what they could smell

However, a surprising finding was that the pterosaur brains had two very pronounced balance-related regions called 'floccular lobes'. It is thought that these may have gathered information from the wing membranes, which functioned as sense organs, to enable the reptile to build up a detailed map of the forces experienced by its wings."
"The new findings confirm earlier studies4, 5 showing that pterosaurs had a remarkably bird-like brain — for example, it had reduced olfactory lobes and large, laterally displaced optic lobes."

"A study of pterosaur brain cavities using X-rays revealed that the animals (Rhamphorhynchus muensteri and Anhanguera santanae) had massive flocculi. The flocculus is a brain region that integrates signals from joints, muscles, skin and balance organs.[4]

The pterosaurs' flocculi occupied 7.5% of the animals' total brain mass, more than in any other vertebrate. Birds have unusually large flocculi compared with other animals, but these only occupy between 1 and 2% of total brain mass.[4]

The flocculus sends out neural signals that produce small, automatic movements in the eye muscles. These keep the image on an animal's retina steady. Pterosaurs may have had such a large flocculus because of their large wing size, which would mean that there was a great deal more sensory information to process.[4]"

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