[A comparison of problem solving by extrapolation before and after removal of the archicortex and Wulst in cows].

The change in the capacity for extrapolation was studied in crows after ablation of Wulst and the archicortex. After the ablation of the archicortex, the solution of the extrapolation problem does not change. After the ablation of Wulst, the number of "refusals" to solve increases, the number of correct responses diminishes, although it remains significantly higher than the number of errors. It is assumed that the archicortex and Wulst play no decisive part in the process of solving problems involving extrapolation; yet Wulst apparently controls the achievement of the final reaction, by-passing the screen.