Disorientation combined with bilateral parietal cortex lesions causes pathintegration deficits in the water maze

The navigational abilities of rats were examined using the water maze after disorientation induced by rotation and/or swimming in darkness. Control an d light-disoriented groups performed similarly, whereas the dark group and the dark-disoriented groups were initially much slower but improved to cont rol:levels. After receiving bilateral parietal lesions, multiple start posi tion tests showed that both rotation groups were severely impaired in findi ng the hidden platform. The effects of disorientation induced by darkness a nd by rotation are therefore separable. (C) 1999 Elsevier Science B.V. All rights reserved.