Movement disorders and lesions of pigeon brain stem analogues of basal ganglia

The nucleus spiriformis lateralis (SpL) and the nucleus tegmenti pedunculo-pontinus, pars compacta (TPc) of the pigeon are thought to be analogous to the mammalian substantia nigra. The analogy is based upon comparative neuroanatomical and histochemical similarities. To test the analogy on a behavioral basis, unilateral electrolytic or kainate lesions were produced in selected nuclei of the diencephalon and mesencephalon. Birds demonstrated behaviioral disturbances similar to those induced in mammals after lesions to the substantia nigra. The most obvious disturbance was a persistent turning in a direction opposite to the side of the lesion. The birds also demonstrated postural problems and arhythmic movements of the head or whole body tremor. The similarities in movement disorders strengthen on a behavioral basis, the suggested analogies between the mammalian substantia nigra and the SpL and TPc. The pigeon may be another useful experimental model to study movement disorders associated with damage to the basal ganglia.