A dimensão da amígdala cerebral e a agressividade no touro de lide.

Aggressive behaviour control of both animals and humans, seems to be dependent on several brain areas, such as the orbitofrontal and prefrontal cortex, part of the hippocampus and the amygdala. This study evaluated the morphology and size of the brain, as well as fighting bulls' amygdala in comparison to beef cattle, in order to verify a putative association of this brain structure with aggressive behaviour modulation in fighting bulls. The authors assessed the morphology and dimensions of the brain and amygdala in 120 bovines, 60 fighting bulls and 60 crossbred beef cattle, and correlated the size of the amygdala with the behaviour presented by fighting bulls during Portuguese bullfighting. The two groups showed differences concerning cerebral hemispheres conformation, brain weight/carcass weight ratio and amygdala size. The latter was remarkably smaller in fighting bulls than in beef cattle. Moreover, it was demonstrated that fighting bulls with an smaller amygdala size presented a higher bullfighting ability than those showing an inappropriate behaviour for bullfighting. Thus, this anatomical feature may contribute to the different modulation of behavioural patterns displayed. [ABSTRACT FROM AUTHOR]