GANGLIONIC NERVOUS SYSTEM 

 OPTIC LOBE 



529 



OG 



Fig. 698. — Diagrammatic Scheme of the Visual Paths and their Central 

 Connections in the Cephaloiod (after Kajjpers). 



Axons from the visual cells in the compound eye, a, decussate to form a chiasma 

 and enter the optic lobe, terminating in the plexiform layer between the inner, IG, 

 and outer granular layers, OG. The pathway is continued by axons of the granular 

 cells, b, sometimes with an intercalated neurone, c, to the central and pedunculate 

 nuclei of the optic ganglion, OGn. Thence a further relay, rf' to (/*, continues the 

 pathway to the cerebral ganglia to terminate in association areas, e, and, by means 

 of commissural fibres, CF, in the contralateral oiDtic lobe. 



continued by the granular cells, sometimes with an intercalated neurone, 

 to a central mass of cells, the optic ganglion, consisting mainly of a central 

 and a peduncular nucleus ; from this a fourth relay enters the cerebral 

 ganglion to terminate in association areas anteriorly and posteriorly and to 

 decussate to the optic lobe on the other side. It is noteworthy that the 

 large and complex optic lobes (in the octopus) serve as the centres for 

 learning to attack objects that provide food, a demonstration of the 

 effective role vision plays in this essential activity ; thence fibres pass to 

 the cerebral ganglion where are situated the cells responsible for initiating 

 attack-behaviour (Young, 1953). 



Adrian. J. Physiol., 91, 66 (1937). 

 Antrum. Z. vergl. Physiol, 32, 176 (1950). 

 Bardeen. Amer. J. Physiol., 5, 175 (1901). 

 Bernhard. J. Neurophysiol., 5, 32 (1942). 

 Bernhards. Z. uiss. ZooL, 116, 649 (1916). 

 Bethe. Pflugers Arch. ges. Physiol., 68, 449 



(1897) ; 224, 793, 821 (1930). 

 Bovard. Univ. Calif. Publ. ZooL, 18, 103 



(1918). 

 V. Buddenbrock. Grundriss d. vergl. Physiol., 



Berlin, 2, 301 (1937). 

 Bullock. J. Neurophysiol., 8, 55 (1945). 



Yale J. Biol. Med., 17, 657 (1945). 

 Burkhardt. Z. vergl. Physiol., 36, 595 (1954). 

 Burtt and Catton. Nature (Lond.), 170, 285 



(1952). 

 J. Physiol., 125, 566 (1954) ; 133, 68 (1956). 



S.O.— VOL. I. 



Buytendijk. Arch, neerl. Physiol., 18, 24 



(1933). 

 Cajal. Trab. Lab. Invest, biol. Univ. Madrid, 



15, 1 (1917) ; 16, 109 (1918). 

 ten Gate. Ergebn. Physiol., 33, 137 (1931). 



Arch, neerl. PhysioL, 21, 562 (1936). 

 Coonfield. J. comp. Neurol., 55, 7 (1932). 

 Copeland. J. comp. Psychol., 10, 339 (1930). 

 Copeland and Brown. Biol. Bull., 67, 356 



(1934). 

 Crescitelli and Jahn. J. cell. comp. Physiol., 



19, 47 (1942). 

 Darwin. The Formation of Vegetable Moulds 



through the Action of Worms, London 



(1881). 

 Day. J. exp. ZooL, 28, 307 (1919). 

 Eccles, Granit and Young. J. Physiol., 77, 



23P (1933). 



34 



