Directional dependence of intraocular transfer of stimulus detection in pigeons (Columba livia).

Abstract

The eyes of the pigeon (Columba livia) are positioned laterally in the head. Thus, there is only a small area of binocular overlap, which constitutes the frontal visual field and a large area of monocular vision in the lateral visual fields. The conditions were examined under which intraocular transfer occurs in pigeons; that is, the transfer of information between both portions of the visual field of one eye. Different groups of head-fixed birds learned to discriminate the presence of a bright light from its absence in an instrumental conditioning situation with water as reinforcer. After the animals had acquired the task when the stimuli were viewed in either the frontal or lateral visual field, the stimuli were moved into the converse visual field. Transfer was shown to be directionally selective: It occurred when stimulus presentation was changed from the lateral to the frontal visual field but not when this change was in the opposite direction.

Classical conditioning of jaw movements in the pigeon: Acquisition and response topography

“…The apparatus used for head fixation and water delivery has been described in detail elsewhere (Mallin & Delius, 1983;Remy & Emmerton, 1991, Figure 1), as has the system for monitoring jaw movements (Deich, Houben, Allan, & Zeigler, 1985). Briefly, each pigeon was restrained in a cloth bag, and using the headblock, its head was fixed in position just above the opening of a small plexiglass container.…”

Limits of intraocular and interocular transfer in pigeons

“…Nye concluded that pigeons lack the neural capabilities to learn a task in the lateral visual field. Other evidence showed that pigeons are capable of learning a discrimination task in the lateral visual field [38,36,26,10,3], however none of those experiments tested free moving animals while moving the stimuli to the side in consecutive steps. The main differences between Nye's experiments and the present one are the number of steps used to move the screen to the 90…”

“…However, the transfer from lateral to frontal position was slightly better (around 10%) than the reverse performance. Remy and Emmerton [36] described the existence of information transfer from the lateral to frontal visual field and a lack of information transfer from the frontal to the lateral visual field, in a light detection task, also using jaw movement as a measure. Roberts et al [38] confirmed those results in unrestrained pigeons employing a symbolic delayed matching to sample task.…”

“…Very often, the experimental conditions prevented the birds from walking freely while solving the task (examples can be found in Refs. [26,38,36,34]). Therefore, visual mechanisms that may play an important role in ecologically valid conditions like optic flow due to locomotion and head movements have not been considered.…”

“…The thalamofugal pathway can be considered homologeous to the mammalian geniculo-cortical pathway. In pigeons, but not in chickens, this pathway mainly receives visual input from the yellow visual field [36,19], which is transmitted to the contralateral thalamic nucleus geniculatus lateralis, pars dorsalis (GLd). The GLd projects bilaterally to the telencephalic visual wulst [41,21,14].…”