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Ocellar structure and neural innervation in the honeybee.

Hung YS, Ibbotson MR - Front Neuroanat (2014)

Bottom Line: In addition, we established which ocellar retinas provide the input to five pairs of large ocellar descending neurons.We found that four of the neuron pairs have their dendritic fields in the dorsal retinas of the lateral ocelli, while the fifth has fine dendrites in the ventral retina.One of the neuron pairs also sends very fine dendrites into the border region between the dorsal and ventral retinas of the median ocellus.

View Article: PubMed Central - PubMed

Affiliation: National Vision Research Institute, Australian College of Optometry Carlton, VIC, Australia ; Department of Optometry and Vision Sciences, Centre of Excellence for Integrative Brain Function, University of Melbourne Parkville, VIC, Australia.

ABSTRACT
Honeybees have a visual system composed of three ocelli (simple eyes) located on the top of the head, in addition to two large compound eyes. Although experiments have been conducted to investigate the role of the ocelli within the visual system, their optical characteristics, and function remain controversial. In this study, we created three-dimensional (3-D) reconstructions of the honeybee ocelli, conducted optical measurements and filled ocellar descending neurons to assist in determining the role of ocelli in honeybees. In both the median and lateral ocelli, the ocellar retinas can be divided into dorsal and ventral parts. Using the 3-D model we were able to assess the viewing angles of the retinas. The dorsal retinas view the horizon while the ventral retinas view the sky, suggesting quite different roles in attitude control. We used the hanging drop technique to assess the spatial resolution of the retinas. The lateral ocelli have significantly higher spatial resolution compared to the median ocellus. In addition, we established which ocellar retinas provide the input to five pairs of large ocellar descending neurons. We found that four of the neuron pairs have their dendritic fields in the dorsal retinas of the lateral ocelli, while the fifth has fine dendrites in the ventral retina. One of the neuron pairs also sends very fine dendrites into the border region between the dorsal and ventral retinas of the median ocellus.

No MeSH data available.


Related in: MedlinePlus

Images of gratings through the honeybee lateral ocellus at the dorsal retinal level (A–F; 140 μm away from the back of the lens) and ventral retinal level (G–L; 80 μm away from the back of the lens). Spatial wavelength: ADGJ: 2°; BEHK: 4°; CFIL: 8°.
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Figure 6: Images of gratings through the honeybee lateral ocellus at the dorsal retinal level (A–F; 140 μm away from the back of the lens) and ventral retinal level (G–L; 80 μm away from the back of the lens). Spatial wavelength: ADGJ: 2°; BEHK: 4°; CFIL: 8°.

Mentions: Both the median and lateral ocellar lenses were able to resolve spatial information at the dorsal and ventral retinal levels (Figures 5–7). This is evident from the fact that oriented gratings can be seen in most of the images shown in Figures 5, 6. However, based on qualitative visual inspection, there is a gradation of image quality. Gratings can be seen quite clearly when viewed through the dorsal retina of the median ocellus, at spatial wavelengths from 4 to 12° (Figures 5A–F). When images were viewed through the ventral retina of the median ocellus, gratings can be just discerned but they are of very poor quality (wavy and patchy) (Figures 5G–L). Images formed through the lateral ocelli are qualitatively better for both the ventral and dorsal retinas (Figures 6A–L). The orientation of the gratings can be clearly observed even with 2° patterns and the imaged gratings are quite sharp. By comparing the images at the ventral and dorsal levels of the lateral ocelli it is qualitatively evident that the images are sharper for the dorsal retina.


Ocellar structure and neural innervation in the honeybee.

Hung YS, Ibbotson MR - Front Neuroanat (2014)

Images of gratings through the honeybee lateral ocellus at the dorsal retinal level (A–F; 140 μm away from the back of the lens) and ventral retinal level (G–L; 80 μm away from the back of the lens). Spatial wavelength: ADGJ: 2°; BEHK: 4°; CFIL: 8°.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928595&req=5

Figure 6: Images of gratings through the honeybee lateral ocellus at the dorsal retinal level (A–F; 140 μm away from the back of the lens) and ventral retinal level (G–L; 80 μm away from the back of the lens). Spatial wavelength: ADGJ: 2°; BEHK: 4°; CFIL: 8°.
Mentions: Both the median and lateral ocellar lenses were able to resolve spatial information at the dorsal and ventral retinal levels (Figures 5–7). This is evident from the fact that oriented gratings can be seen in most of the images shown in Figures 5, 6. However, based on qualitative visual inspection, there is a gradation of image quality. Gratings can be seen quite clearly when viewed through the dorsal retina of the median ocellus, at spatial wavelengths from 4 to 12° (Figures 5A–F). When images were viewed through the ventral retina of the median ocellus, gratings can be just discerned but they are of very poor quality (wavy and patchy) (Figures 5G–L). Images formed through the lateral ocelli are qualitatively better for both the ventral and dorsal retinas (Figures 6A–L). The orientation of the gratings can be clearly observed even with 2° patterns and the imaged gratings are quite sharp. By comparing the images at the ventral and dorsal levels of the lateral ocelli it is qualitatively evident that the images are sharper for the dorsal retina.

Bottom Line: In addition, we established which ocellar retinas provide the input to five pairs of large ocellar descending neurons.We found that four of the neuron pairs have their dendritic fields in the dorsal retinas of the lateral ocelli, while the fifth has fine dendrites in the ventral retina.One of the neuron pairs also sends very fine dendrites into the border region between the dorsal and ventral retinas of the median ocellus.

View Article: PubMed Central - PubMed

Affiliation: National Vision Research Institute, Australian College of Optometry Carlton, VIC, Australia ; Department of Optometry and Vision Sciences, Centre of Excellence for Integrative Brain Function, University of Melbourne Parkville, VIC, Australia.

ABSTRACT
Honeybees have a visual system composed of three ocelli (simple eyes) located on the top of the head, in addition to two large compound eyes. Although experiments have been conducted to investigate the role of the ocelli within the visual system, their optical characteristics, and function remain controversial. In this study, we created three-dimensional (3-D) reconstructions of the honeybee ocelli, conducted optical measurements and filled ocellar descending neurons to assist in determining the role of ocelli in honeybees. In both the median and lateral ocelli, the ocellar retinas can be divided into dorsal and ventral parts. Using the 3-D model we were able to assess the viewing angles of the retinas. The dorsal retinas view the horizon while the ventral retinas view the sky, suggesting quite different roles in attitude control. We used the hanging drop technique to assess the spatial resolution of the retinas. The lateral ocelli have significantly higher spatial resolution compared to the median ocellus. In addition, we established which ocellar retinas provide the input to five pairs of large ocellar descending neurons. We found that four of the neuron pairs have their dendritic fields in the dorsal retinas of the lateral ocelli, while the fifth has fine dendrites in the ventral retina. One of the neuron pairs also sends very fine dendrites into the border region between the dorsal and ventral retinas of the median ocellus.

No MeSH data available.


Related in: MedlinePlus