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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

Visual stimulation conditions and location of the recorded zebra finch brain area.A: Positions of the stimulus monitor in the frontal and lateral visual field used in the present study. At a distance of 30 cm from the zebra finch eyes, the monitor covered 75° of visual space. In the 0° position of the monitor (0° visual field corresponded to the monitor center), the visual stimuli presented on the monitor extended 37.5° into the left (ipsilateral) and 37.5° into the right (contralateral) visual field. Likewise, in the 30° position, stimuli ranged from -7.5° to +67.5°, from +22.5° to +97.5° (60° position), from +52.5° to +127.5° (90° position) and from +82.5° to 157.5° (120° position) of the right visual field. B: Schematic representation of the zebra finch brain. The location of the imaged posterior map in the left visual wulst is indicated with a color-coded retinotopic map in the red rectangle; the approximate location of the center of the imaged region is given in mm distance laterally and anteriorly from the Y-point (black arrow).
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pone.0124917.g001: Visual stimulation conditions and location of the recorded zebra finch brain area.A: Positions of the stimulus monitor in the frontal and lateral visual field used in the present study. At a distance of 30 cm from the zebra finch eyes, the monitor covered 75° of visual space. In the 0° position of the monitor (0° visual field corresponded to the monitor center), the visual stimuli presented on the monitor extended 37.5° into the left (ipsilateral) and 37.5° into the right (contralateral) visual field. Likewise, in the 30° position, stimuli ranged from -7.5° to +67.5°, from +22.5° to +97.5° (60° position), from +52.5° to +127.5° (90° position) and from +82.5° to 157.5° (120° position) of the right visual field. B: Schematic representation of the zebra finch brain. The location of the imaged posterior map in the left visual wulst is indicated with a color-coded retinotopic map in the red rectangle; the approximate location of the center of the imaged region is given in mm distance laterally and anteriorly from the Y-point (black arrow).

Mentions: Neuronal activity in the left visual wulst of zebra finches was captured using autofluorescent flavoprotein imaging [38,39]. For data acquisition and analysis we used the Fourier imaging method introduced by Kalatsky and Stryker [42]: To image sensory-driven activity, a temporally periodic stimulus was continuously presented to the bird and the brain’s response at the stimulus frequency was extracted by Fourier analysis. Optical images of visual wulst activation were obtained using a CCD camera (Dalsa 1M30) and a 130 x 55 mm lens with an aperture of 1.2 (Nikon, Tokyo, Japan), controlled by custom software. The acquired image covered 4.6x4.6 mm of the brain surface. The camera was focused below the wulst surface at a depth of 500 μm, and neuronal activity was captured using blue light (455 ±10 nm). Frames were acquired at a rate of 30 Hz, binned to 7.5 Hz and stored as 512x512 pixel images after spatial binning of the camera image. The approximate location of the center of the posterior map of the visual wulst is schematically shown in Fig 1A.


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)

Visual stimulation conditions and location of the recorded zebra finch brain area.A: Positions of the stimulus monitor in the frontal and lateral visual field used in the present study. At a distance of 30 cm from the zebra finch eyes, the monitor covered 75° of visual space. In the 0° position of the monitor (0° visual field corresponded to the monitor center), the visual stimuli presented on the monitor extended 37.5° into the left (ipsilateral) and 37.5° into the right (contralateral) visual field. Likewise, in the 30° position, stimuli ranged from -7.5° to +67.5°, from +22.5° to +97.5° (60° position), from +52.5° to +127.5° (90° position) and from +82.5° to 157.5° (120° position) of the right visual field. B: Schematic representation of the zebra finch brain. The location of the imaged posterior map in the left visual wulst is indicated with a color-coded retinotopic map in the red rectangle; the approximate location of the center of the imaged region is given in mm distance laterally and anteriorly from the Y-point (black arrow).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4390349&req=5

pone.0124917.g001: Visual stimulation conditions and location of the recorded zebra finch brain area.A: Positions of the stimulus monitor in the frontal and lateral visual field used in the present study. At a distance of 30 cm from the zebra finch eyes, the monitor covered 75° of visual space. In the 0° position of the monitor (0° visual field corresponded to the monitor center), the visual stimuli presented on the monitor extended 37.5° into the left (ipsilateral) and 37.5° into the right (contralateral) visual field. Likewise, in the 30° position, stimuli ranged from -7.5° to +67.5°, from +22.5° to +97.5° (60° position), from +52.5° to +127.5° (90° position) and from +82.5° to 157.5° (120° position) of the right visual field. B: Schematic representation of the zebra finch brain. The location of the imaged posterior map in the left visual wulst is indicated with a color-coded retinotopic map in the red rectangle; the approximate location of the center of the imaged region is given in mm distance laterally and anteriorly from the Y-point (black arrow).
Mentions: Neuronal activity in the left visual wulst of zebra finches was captured using autofluorescent flavoprotein imaging [38,39]. For data acquisition and analysis we used the Fourier imaging method introduced by Kalatsky and Stryker [42]: To image sensory-driven activity, a temporally periodic stimulus was continuously presented to the bird and the brain’s response at the stimulus frequency was extracted by Fourier analysis. Optical images of visual wulst activation were obtained using a CCD camera (Dalsa 1M30) and a 130 x 55 mm lens with an aperture of 1.2 (Nikon, Tokyo, Japan), controlled by custom software. The acquired image covered 4.6x4.6 mm of the brain surface. The camera was focused below the wulst surface at a depth of 500 μm, and neuronal activity was captured using blue light (455 ±10 nm). Frames were acquired at a rate of 30 Hz, binned to 7.5 Hz and stored as 512x512 pixel images after spatial binning of the camera image. The approximate location of the center of the posterior map of the visual wulst is schematically shown in Fig 1A.

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