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Features of the retinotopic representation in the visual wulst of a laterally eyed bird, the zebra finch (Taeniopygia guttata).

Michael N, Löwel S, Bischof HJ - PLoS ONE (2015)

Bottom Line: We found that the visual wulst can be activated by visual stimuli from a large part of the visual field of the contralateral eye.This confirms earlier electrophysiological studies indicating an inhibitory influence of the activation of the ipsilateral eye on wulst activity elicited by stimulating the contralateral eye.Instead, this brain area may be involved in the processing of visual information necessary for spatial orientation.

View Article: PubMed Central - PubMed

Affiliation: Department of Systems Neuroscience, Johann-Friedrich-Blumenbach Institut für Zoologie und Anthropologie, Universität Göttingen, Göttingen, Germany; Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), Göttingen, Germany.

ABSTRACT
The visual wulst of the zebra finch comprises at least two retinotopic maps of the contralateral eye. As yet, it is not known how much of the visual field is represented in the wulst neuronal maps, how the organization of the maps is related to the retinal architecture, and how information from the ipsilateral eye is involved in the activation of the wulst. Here, we have used autofluorescent flavoprotein imaging and classical anatomical methods to investigate such characteristics of the most posterior map of the multiple retinotopic representations. We found that the visual wulst can be activated by visual stimuli from a large part of the visual field of the contralateral eye. Horizontally, the visual field representation extended from -5° beyond the beak tip up to +125° laterally. Vertically, a small strip from -10° below to about +25° above the horizon activated the visual wulst. Although retinal ganglion cells had a much higher density around the fovea and along a strip extending from the fovea towards the beak tip, these areas were not overrepresented in the wulst map. The wulst area activated from the foveal region of the ipsilateral eye, overlapped substantially with the middle of the three contralaterally activated regions in the visual wulst, and partially with the other two. Visual wulst activity evoked by stimulation of the frontal visual field was stronger with contralateral than with binocular stimulation. This confirms earlier electrophysiological studies indicating an inhibitory influence of the activation of the ipsilateral eye on wulst activity elicited by stimulating the contralateral eye. The lack of a foveal overrepresentation suggests that identification of objects may not be the primary task of the zebra finch visual wulst. Instead, this brain area may be involved in the processing of visual information necessary for spatial orientation.

No MeSH data available.


Related in: MedlinePlus

Iso-azimuth and iso-elevation lines demonstrating the extent of the visual field representation in two birds.Red complete lines denotes the iso-azimuth lines- a combined representation of maps obtained by visually stimulating with azimuth stimulus from different monitor positions. Green lines denotes iso-elevation lines- a combined representation of maps obtained by visually stimulating with an elevation stimulus from different monitor positions. A—bird 1, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from -5°-+125° and vertical limit from 0°-+25°. B—bird 2, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from 20°-+110° and vertical limit from 0°- +25°. Scale bar = 500 μm.
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pone.0124917.g005: Iso-azimuth and iso-elevation lines demonstrating the extent of the visual field representation in two birds.Red complete lines denotes the iso-azimuth lines- a combined representation of maps obtained by visually stimulating with azimuth stimulus from different monitor positions. Green lines denotes iso-elevation lines- a combined representation of maps obtained by visually stimulating with an elevation stimulus from different monitor positions. A—bird 1, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from -5°-+125° and vertical limit from 0°-+25°. B—bird 2, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from 20°-+110° and vertical limit from 0°- +25°. Scale bar = 500 μm.

Mentions: Fig 5A and 5B depict the entire representation of the visual field from birds1 and 2 (single maps illustrated in Figs 2 and 3) which were visually stimulated from -30° to 90°). In bird 1, visual stimuli from -5° to +125° medio-laterally and from 0° (horizon) to +25° above the beak induced measurable activity in the visual wulst. The visual field represented in the visual wulst of bird 2 extended from 20° to 110° laterally and from 0° to +25° above the horizon.


Features of the retinotopic representation in the visual wulst of a laterally eyed bird, the zebra finch (Taeniopygia guttata).

Michael N, Löwel S, Bischof HJ - PLoS ONE (2015)

Iso-azimuth and iso-elevation lines demonstrating the extent of the visual field representation in two birds.Red complete lines denotes the iso-azimuth lines- a combined representation of maps obtained by visually stimulating with azimuth stimulus from different monitor positions. Green lines denotes iso-elevation lines- a combined representation of maps obtained by visually stimulating with an elevation stimulus from different monitor positions. A—bird 1, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from -5°-+125° and vertical limit from 0°-+25°. B—bird 2, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from 20°-+110° and vertical limit from 0°- +25°. Scale bar = 500 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390349&req=5

pone.0124917.g005: Iso-azimuth and iso-elevation lines demonstrating the extent of the visual field representation in two birds.Red complete lines denotes the iso-azimuth lines- a combined representation of maps obtained by visually stimulating with azimuth stimulus from different monitor positions. Green lines denotes iso-elevation lines- a combined representation of maps obtained by visually stimulating with an elevation stimulus from different monitor positions. A—bird 1, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from -5°-+125° and vertical limit from 0°-+25°. B—bird 2, visual stimulation (both azimuth and elevation stimuli) from 0°-90°, fronto-lateral limit from 20°-+110° and vertical limit from 0°- +25°. Scale bar = 500 μm.
Mentions: Fig 5A and 5B depict the entire representation of the visual field from birds1 and 2 (single maps illustrated in Figs 2 and 3) which were visually stimulated from -30° to 90°). In bird 1, visual stimuli from -5° to +125° medio-laterally and from 0° (horizon) to +25° above the beak induced measurable activity in the visual wulst. The visual field represented in the visual wulst of bird 2 extended from 20° to 110° laterally and from 0° to +25° above the horizon.

Bottom Line: We found that the visual wulst can be activated by visual stimuli from a large part of the visual field of the contralateral eye.This confirms earlier electrophysiological studies indicating an inhibitory influence of the activation of the ipsilateral eye on wulst activity elicited by stimulating the contralateral eye.Instead, this brain area may be involved in the processing of visual information necessary for spatial orientation.

View Article: PubMed Central - PubMed

Affiliation: Department of Systems Neuroscience, Johann-Friedrich-Blumenbach Institut für Zoologie und Anthropologie, Universität Göttingen, Göttingen, Germany; Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB), Göttingen, Germany.

ABSTRACT
The visual wulst of the zebra finch comprises at least two retinotopic maps of the contralateral eye. As yet, it is not known how much of the visual field is represented in the wulst neuronal maps, how the organization of the maps is related to the retinal architecture, and how information from the ipsilateral eye is involved in the activation of the wulst. Here, we have used autofluorescent flavoprotein imaging and classical anatomical methods to investigate such characteristics of the most posterior map of the multiple retinotopic representations. We found that the visual wulst can be activated by visual stimuli from a large part of the visual field of the contralateral eye. Horizontally, the visual field representation extended from -5° beyond the beak tip up to +125° laterally. Vertically, a small strip from -10° below to about +25° above the horizon activated the visual wulst. Although retinal ganglion cells had a much higher density around the fovea and along a strip extending from the fovea towards the beak tip, these areas were not overrepresented in the wulst map. The wulst area activated from the foveal region of the ipsilateral eye, overlapped substantially with the middle of the three contralaterally activated regions in the visual wulst, and partially with the other two. Visual wulst activity evoked by stimulation of the frontal visual field was stronger with contralateral than with binocular stimulation. This confirms earlier electrophysiological studies indicating an inhibitory influence of the activation of the ipsilateral eye on wulst activity elicited by stimulating the contralateral eye. The lack of a foveal overrepresentation suggests that identification of objects may not be the primary task of the zebra finch visual wulst. Instead, this brain area may be involved in the processing of visual information necessary for spatial orientation.

No MeSH data available.


Related in: MedlinePlus