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Visual‐field‐specific heterogeneity within the tecto‐rotundal projection of the pigeon
Author(s) -
Hellmann Burkhard,
Güntürkün Onur
Publication year - 1999
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.1999.00681.x
Subject(s) - tectum , neuroscience , dorsum , biology , nucleus , visual field , projection (relational algebra) , anatomy , optic tectum , afferent , visual system , superior colliculus , stimulus (psychology) , retinotopy , retrograde tracing , diencephalon , midbrain , central nervous system , visual cortex , computer science , psychology , algorithm , psychotherapist
The organization of the tecto‐rotundal projection of the pigeon was investigated by means of anterograde and retrograde tracing techniques. Besides the known organization in tecto‐rotundal connectivity, this study additionally demonstrates major variations in the ascending projections of different tectal subfields. We show that the ventral tectum opticum (TO) has significantly more projections onto the nucleus rotundus (Rt) than dorsal tectal areas. This difference coincides with differential innervation densities of afferent fibres within rotundal subregions. While ventral tectal efferents project onto the ventral and central Rt, dorsal tectal efferents mainly arborize within limited areas between the central Rt and its dorsal cap, the nucleus triangularis. Thus, the ventral TO, representing the lower and frontal field of view, exhibits a quantitatively and spatially enhanced projection onto the Rt, as compared with the dorsal TO. The data presented here demonstrate a visual field‐dependent projection pattern of ascending tectal outputs onto different rotundal domains. The data are consistent with behavioural studies, demonstrating tectofugal lesions to suppress visual stimulus analysis mainly within the frontal field of view.