Limits...
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

Schematic representation of the visual field extent represented in the zebra finch visual wulst.A: Azimuth and the elevation extent of the visual field (shaded area in pink), projected into a 3D space with lines of longitude (azimuth) and latitude (elevation). Small blue circles- points measured at the rim of the pecten, F-fovea, small red circles-measured positions of the fovea, yellow shaded oval region- area of higher density extending from the fovea into the direction of the beak. Visual field in zebra finches which is represented in the visual wulst, thus extend from around -5° frontally to +125° laterally. The visual field below the horizon up to 10° and above the horizon up to 25° is represented in the visual wulst. B—Demonstrates a view of the azimuthal plane along 0° latitude, which shows a binocular overlap of 10°, a lateral monocular visual field of about 125° and a caudal blind area of about 100°, which is not represented in the visual wulst.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4390349&req=5

pone.0124917.g008: Schematic representation of the visual field extent represented in the zebra finch visual wulst.A: Azimuth and the elevation extent of the visual field (shaded area in pink), projected into a 3D space with lines of longitude (azimuth) and latitude (elevation). Small blue circles- points measured at the rim of the pecten, F-fovea, small red circles-measured positions of the fovea, yellow shaded oval region- area of higher density extending from the fovea into the direction of the beak. Visual field in zebra finches which is represented in the visual wulst, thus extend from around -5° frontally to +125° laterally. The visual field below the horizon up to 10° and above the horizon up to 25° is represented in the visual wulst. B—Demonstrates a view of the azimuthal plane along 0° latitude, which shows a binocular overlap of 10°, a lateral monocular visual field of about 125° and a caudal blind area of about 100°, which is not represented in the visual wulst.

Mentions: Fig 8A summarizes our results concerning visual field extent and retinal landmarks in a schematic representation of the visual field. The pink shaded area illustrates the extent of zebra finch visual field from where visual stimuli elicited measurable activation in the visual wulst in our imaging experiments. The visual field measured about 130° in the horizontal plane, extending from around -5° in the ipsilateral visual field to about +125° in the contralateral periphery (azimuth), and about 35° in the vertical direction, extending from -10° to about +25° (elevation) between 30°-60° azimuth. It was reduced to about 15°-20° in vertical extent both frontally and more laterally. Fig 8B shows a schematic and planar bird eye’s view of the fronto-lateral visual field represented in the visual wulst. Frontally, the binocular visual field measures about 10°, the monocular left and right visual field about 130°, while a caudal region of about 100° is most likely not represented in the visual wulst.


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)

Schematic representation of the visual field extent represented in the zebra finch visual wulst.A: Azimuth and the elevation extent of the visual field (shaded area in pink), projected into a 3D space with lines of longitude (azimuth) and latitude (elevation). Small blue circles- points measured at the rim of the pecten, F-fovea, small red circles-measured positions of the fovea, yellow shaded oval region- area of higher density extending from the fovea into the direction of the beak. Visual field in zebra finches which is represented in the visual wulst, thus extend from around -5° frontally to +125° laterally. The visual field below the horizon up to 10° and above the horizon up to 25° is represented in the visual wulst. B—Demonstrates a view of the azimuthal plane along 0° latitude, which shows a binocular overlap of 10°, a lateral monocular visual field of about 125° and a caudal blind area of about 100°, which is not represented in the visual wulst.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0124917.g008: Schematic representation of the visual field extent represented in the zebra finch visual wulst.A: Azimuth and the elevation extent of the visual field (shaded area in pink), projected into a 3D space with lines of longitude (azimuth) and latitude (elevation). Small blue circles- points measured at the rim of the pecten, F-fovea, small red circles-measured positions of the fovea, yellow shaded oval region- area of higher density extending from the fovea into the direction of the beak. Visual field in zebra finches which is represented in the visual wulst, thus extend from around -5° frontally to +125° laterally. The visual field below the horizon up to 10° and above the horizon up to 25° is represented in the visual wulst. B—Demonstrates a view of the azimuthal plane along 0° latitude, which shows a binocular overlap of 10°, a lateral monocular visual field of about 125° and a caudal blind area of about 100°, which is not represented in the visual wulst.
Mentions: Fig 8A summarizes our results concerning visual field extent and retinal landmarks in a schematic representation of the visual field. The pink shaded area illustrates the extent of zebra finch visual field from where visual stimuli elicited measurable activation in the visual wulst in our imaging experiments. The visual field measured about 130° in the horizontal plane, extending from around -5° in the ipsilateral visual field to about +125° in the contralateral periphery (azimuth), and about 35° in the vertical direction, extending from -10° to about +25° (elevation) between 30°-60° azimuth. It was reduced to about 15°-20° in vertical extent both frontally and more laterally. Fig 8B shows a schematic and planar bird eye’s view of the fronto-lateral visual field represented in the visual wulst. Frontally, the binocular visual field measures about 10°, the monocular left and right visual field about 130°, while a caudal region of about 100° is most likely not represented in the visual wulst.

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