[Radioautographic study of the connections between field 17 of the cat visual cortex and the hypothalamus]

At different time after administration of tritium-labelled amino acids, in field 17 of the optic cortex, the label was detected in all hypohalamic areas except the ventromedial nucleus. This phenomenon, while supporting and verifying our previous investigations, demonstrates that there exist some direct spatial organizaional bilateral cortico-hypothalamic connections. Normal ultrastructure of the synaptic contacts was studied by means of electron radioautography. Advantages and disadvantages of the radioautographic method are discussed and compared to some modern methods of anterograde degeneration applied for investigating connections in the CNS. A suggestion s made on the role of the connections detected in formation of responses to the information obtained via the optic pathways when the hypothalamus participates in regulating some functions.