Telencephalic projections to the nucleus of the basal optic root and pretectal nucleus lentiformis mesencephali in pigeons
Date
2005
Authors
Wylie, Douglas R W
Ogilvie, Catherine J
Crowder, Nathan
Barkley, Ryan R
Winship, Ian R
Journal Title
Journal ISSN
Volume Title
Publisher
Cambridge University Press
Abstract
In birds, the nucleus of the basal optic root (nBOR) of the accessory optic system (AOS) and the pretectal nucleus lentiformis mesencephali (LM) are involved in the analysis of optic flow and the generation of the optokinetic response. In several species, it has been shown that the AOS and pretectum receive input from visual areas of the telencephalon. Previous studies in pigeons using anterograde tracers have shown that both nBOR and LM receive input from the visual Wulst, the putative homolog of mammalian primary visual cortex. In the present study, we used retrograde and anterograde tracing techniques to further characterize these projections in pigeons. After injections of the retrograde tracer cholera toxin subunit B (CTB) into either LM or nBOR, retrograde labeling in the telencephalon was restricted to the hyperpallium apicale (HA) of the Wulst. From the LM injections, retrograde labeling appeared as a discrete band of cells restricted to the lateral edge of HA. From the nBOR injections, the retrograde labeling was more distributed in HA, generally dorsal and dorso-medial to the LM-projecting neurons. In the anterograde experiments, biotinylated dextran amine (BDA) was injected into HA and individual axons were reconstructed to terminal fields in the LM and nBOR. Those fibers projecting to the nBOR also innervated the adjacent ventral tegmental area. However, tracing of BDA-labeled axons revealed no evidence that individual neurons project to both LM and nBOR. In summary, our results suggest that the nBOR and LM receive input from different areas of the Wulst. We discuss how these projections may transmit visual and/or somatosensory information to the nBOR and LM.
Description
Keywords
Keywords: cholera toxin B subunit; dextran; animal tissue; article; lens nucleus; mesencephalon; nonhuman; pigeon; pretectum; priority journal; somatosensory system; telencephalon; ventral tegmentum; visual system; Animals; Biotin; Brain Mapping; Cholera Toxin; Col Accessory optic system; Optic flow; Optokinetic; Pretectum; Visual Wulst
Citation
Collections
Source
Visual Neuroscience
Type
Journal article