Evidence for anatomical but not functional asymmetry in the hemidecorticate rat.

Studied 51 male Long-Evans rats with unilateral ablation of the left or right cerebral neocortex or left or right hippocampus using a battery of tests of spatial orientation, motor coordination, and social behavior, including Morris water task, radial arm maze, feeding, narrow beam traversing, puzzle latches, hoarding, grooming, nest building, running wheel activity, male–male interaction, and shock-induced aggression. Comparison of the brains of operated and control Ss confirmed previous suggestions that the right hemisphere of the rat is bigger and may have different connections than the left hemisphere. Despite the morphological asymmetries, comparison of the behavior of Ss with right and left hemidecortication and right and left hippocampal lesions failed to show a single instance of functional asymmetry in the rat brain. These behavioral results contrast with previous reports of functional asymmetry in the control of activity, orientation, and rotation. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)