Brain structures important for solving a sawdust-digging problem in the rat.

Young rats subjected to bilateral lesions to one of 37 different brain sites were initially trained to traverse a narrow runway to reach a goal box containing water. The test involved blocking a portion of the runway with sawdust and determining whether the animals would burrow through the sawdust to gain access to the goal box. Lesions to 30 brain sites produced deficient performance on the sawdust-digging problem. This study, combined with earlier investigation of 11 additional brain sites, shows that 41 of 48 total brain sites are involved in this task. These findings suggest that underlying brain mechanisms include a nonspecific mechanism and several specific mechanisms, such as visuospatial-attentional, visual discrimination, vestibular-proprioceptive-kinesthetic discrimination, response flexibility, but much less place learning mechanisms.