Mad Science 2006 : Deliberate brain damage affects learning
Researchers at Cardiff University brain - damaged 20 male pigmented rats (Dark Agouti strain) and 20 male albino rats (Sprague-Dawley strain).
All the animals were anaesthetised and placed in a custom-built head-holding device. The skin on their heads was peeled back to expose their skulls. Ten animals from each group were injected through the skull and directly into six different parts of the brain with a chemical that destroys brain cells. The remaining rats were used as ‘controls’ and, although they underwent surgery to expose their skulls, did not receive chemical injections into their brains.
After regaining consciousness following the surgery, all of the animals were forced to swim in a water maze for a total of 36 trial sessions during which the lighting was varied. Each trial ended when the rat found the hid- den escape platform, or after 120 seconds had elapsed. For some rats, as little as 15 seconds elapsed between trials. The rats were then killed by lethal injection.
The researchers concluded that the albino rats were better swimmers than the pigmented rats, but the pigmented rats had better vision in the dark.
Ref. Futter JE, Davies M, Aggleton JP, Bilkey DK. Behavioural Neuroscience2006; 120:150-161. ‘The effects of cytotoxic perirhinal cortex lesions on spatial learning by rats: a comparison of the Dark Agouti and Sprague-Dawley strains.’