Striato-nigro-thalamic mechanisms in the organization of behavior

Studies were carried out on the correlates of neuronal rearrangements in the caudate nucleus and parafascicular nuclei of the thalamus during the development of operant-defensive reflexes. The spatial organization of many subcortical projections of the striopallidum have been determined, these involving interactions of the striato-nigro-thalamic structures during the formation of food and defensive reflexes of different levels of complexity; this is the classical model for the study of behavior in experimental conditions. Despite numerous investigations of the subcortical mechanisms of behavior, particularly those aimed at elucidating the role in these processes of the neostriatum and its associated thalamic nuclei and the substantia nigra, many aspects of the interactions of these structures during the formation and execution of behavioral acts remain unclear. Thus, there has been insufficient study of the role of the neurochemical mechanisms of the neostriatum in the organization of conditioned feeding reflexes during free behavior. Additionally, the topical organization of dopamine-containing connections in the midbrain with the neostriatal nuclei in cats has not received full study. In dogs, these afferents have not been studied at all. The nature of the relationship between the spike activity of the caudate nucleus and the ventral anterior and ventrolateral nuclei of the thalamus during operant-defensive behavior remains unclear. The aim of the present work was to study these questions, which are linked to an understanding of the function of striato-nigro-thalamic mechanisms in the organization of behavioral acts.