[Efferent connections of the centrum medianum of the cat thalamus demonstrated by the autoradiographic technic].

Efferent connections of the centrum medianum and parafascicular nucleus (CM-Pf complex) were investigated by the anterograde autoradiographic method in cat. Projections from CM-Pf complex ascend to the ventral nuclear complex and non-specific thalamic nuclei, preoptic, dorsal, lateral and posterior fields of the hypothalamus and to the subthalamic region. The descending pathways arise only from the caudomedial parts of the CM-Pf complex. They are projected to the pretectum, superior colliculus, pontine reticular formation, locus coeruleus, nucleus parabrachialis and periaqueductal grey of the midbrain and pons, as well as to the raphe nuclei, magnocellular reticular field and the inferior olive of the medulla. Previous studies suggest that the caudomedial CM-Pf part is not projected directly to the cortex and striatum.