Effects of caudolateral neostriatal ablations on pain-related behaviour in the chicken

As a measure of pain-related behaviour, beak guarding was investigated by recording the pecking response of adult chickens to a visually attractive stimulus before and after bilateral suction ablation of the caudolateral neostriatum (CLN). Two control groups of birds were used: a sham-operated group and an ablated group, in which the ablation was confined to the rostral dorsolateral telencephalon. Comparing the birds that had undergone ablation with the sham-operated controls showed that the ablation did not affect pecking behaviour. Five days after ablation, all birds were subjected to partial amputation of one third of the beak. A significant reduction in pecking behaviour (beak-guarding) was observed in both control groups, but was not observed in those birds that had previously received CLN ablations. In a second experiment, where beak amputation preceeded CLN ablation by 6 days, ablation did not affect the reduced pecking. The absence of guarding or other pain-related behaviours would indicate that an intact CLN was necessary for these behaviours to develop but, once they had developed, ablation had no effect.