Considerations on the thalamostriatal system with some functional implications

The thalamostriatal projections are largely neglected in current reviews de aling with basal ganglia function. In the past few years, however, several studies have re-evaluated these projections and have postulated their impli cation in more complex tasks within the basal ganglia organization. In this review, we try to focus on the morphological and functional importance of this system in the basal ganglia of the rat, cat and monkey. Special attent ion is paid to the thalamus as an important place for interaction between t he input and the output systems of the basal ganglia through the thalamostr iatal projections. Thus, we stress on the overlapping thalamic territories between the thalamic projection of the output nuclei of the basal ganglia a nd the thalamostriatal neurons. Our experimental data support the existence of several thalamic feedback circuits within the basal ganglia functional design. Finally, some considerations are provided upon the functional signi ficance of these thalamic feedback circuits in the overall organization of the basal ganglia in health and disease.