How to move like a vertebrate

Neurophilosophy has really come to life in the last few weeks. A post earlier this week described the neural circuitry that controls swimming in zebrafish, from work published in Nature. Today's post takes the evolution of motion up to tetrapods, with a description of a robotic salamander and what it tells scientists about motor control systems.

And this post about rat metacognition covers the Current Biology paper by Foote and Crystal so I don't have to:

Jonathan Crystal and Allison Foote, of the University of Georgias Department of Psychology, taught rats to associate two different auditory stimuli with different levers. A short burst of static, lasting around 2 seconds, was associated with one lever, and a longer burst, lasting up to 8 seconds, with another. In the second phase of the trials, the sounds were played back to the rats. When the lever associated with each sound was correctly pressed, the rats were given a large reward - 6 food pellets. But if the wrong lever was pressed, they received no reward. The rats were also given the option to decline taking the test - they learnt that they could retrieve a smaller reward - 3 food pellets - without making a decision about which lever to press, by poking their snout through an aperture in a food trough.
During the test phase, the rats were presented with the short and long bursts of static, as well as with bursts of intermediate length, and their responses were recorded. When the length of the sound burst was unambiguous (i.e. either short or long) they ignored the food trough and pressed the lever associated with the sound, so that they received the large reward. But when sounds of an intermediate length (approximately 3 seconds) were played, the rats frequently declined to take the test, and chose instead to retrieve food pellets from the food trough, suggesting that the rats knew that they did not know how to respond in the duration discrimination test.

The paper concludes that the rats have a concept of what they know they know -- that is, a metacognitive concept. My students this week told me that rats are smart; I suppose it's true enough.


Foote, AL, Crystal, JD. 2007. Metacognition in the rat. Curr. Biol. doi:10.1016/j.cub.2007.01.061