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Representation of thermal information in the antennal lobe of leaf-cutting ants.

Ruchty M, Helmchen F, Wehner R, Kleineidam CJ - Front Behav Neurosci (2010)

Bottom Line: Here we selectively stained the three neurons found in single Sc and tracked their axons into the brain of Atta vollenweideri workers.Based on the general representation of thermal information in the antennal lobe and functional data on the Sc-glomeruli we conclude that temperature stimuli received by Sc are processed in the medial of the three target glomeruli.The present study reveals an important role of the antennal lobe in temperature processing and links a specific thermosensitive neuron to its central target glomerulus.

View Article: PubMed Central - PubMed

Affiliation: Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, Germany.

ABSTRACT
Insects are equipped with various types of antennal sensilla, which house thermosensitive neurons adapted to receive different parameters of the thermal environment for a variety of temperature-guided behaviors. In the leaf-cutting ant Atta vollenweideri, the physiology and the morphology of the thermosensitive sensillum coeloconicum (Sc) has been thoroughly investigated. However, the central projections of its receptor neurons are unknown. Here we selectively stained the three neurons found in single Sc and tracked their axons into the brain of Atta vollenweideri workers. Each of the three axons terminates in a single glomerulus of the antennal lobe (Sc-glomeruli). Two of the innervated glomeruli are adjacent to each other and are located laterally, while the third one is clearly separated and located medially in the antennal lobe. Using two-photon Ca(2+) imaging of antennal lobe projection neurons, we studied where in the antennal lobe thermal information is represented. In the 11 investigated antennal lobes, we found up to 10 different glomeruli in a single specimen responding to temperature stimulation. Both, warm- and cold-sensitive glomeruli could be identified. The thermosensitive glomeruli were mainly located in the medial part of the antennal lobe. Based on the general representation of thermal information in the antennal lobe and functional data on the Sc-glomeruli we conclude that temperature stimuli received by Sc are processed in the medial of the three target glomeruli. The present study reveals an important role of the antennal lobe in temperature processing and links a specific thermosensitive neuron to its central target glomerulus.

No MeSH data available.


Processing of thermal information provided by the sensilla coeloconica. The morphologically identified Sc-L glomeruli were insensitive to temperature stimulation (gray and green ROIs), irrespective of whether cold- (A,B) or warm stimuli were applied (D,E). In the medial part of this optical section we found in two examples (specimens) one or two thermosensitive glomeruli (in A and B, blue ROI: ΔF/F ≈ 10%; in D and E, blue ROI: ΔF/F ≈ 6% and black ROI, ΔF/F ≈ 12%, raw data shown). In (C,F) the average change in relative fluorescence is shown (four trials). D, dorsal; L, lateral; M, medial; V, ventral; Sc-L, lateral target glomeruli; Sc-M, medial target glomerulus.
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Figure 5: Processing of thermal information provided by the sensilla coeloconica. The morphologically identified Sc-L glomeruli were insensitive to temperature stimulation (gray and green ROIs), irrespective of whether cold- (A,B) or warm stimuli were applied (D,E). In the medial part of this optical section we found in two examples (specimens) one or two thermosensitive glomeruli (in A and B, blue ROI: ΔF/F ≈ 10%; in D and E, blue ROI: ΔF/F ≈ 6% and black ROI, ΔF/F ≈ 12%, raw data shown). In (C,F) the average change in relative fluorescence is shown (four trials). D, dorsal; L, lateral; M, medial; V, ventral; Sc-L, lateral target glomeruli; Sc-M, medial target glomerulus.

Mentions: In a number of specimens (n = 8) we could identify the Sc-L glomeruli by focusing through the lower (posterior) part of the antennal lobe. We specifically investigated their potential temperature sensitivity in two examples. Our investigations revealed that the Sc-L glomeruli were insensitive to temperature stimuli irrespective of whether warm (30°C) or cold (15°C) temperature changes are presented (Figures 5A–F). In Figure 5A the two Sc-L glomeruli can clearly be distinguished. They do not respond to stimulation with cold-stimuli (15°C, green and gray ROIs, depth = 95 μm; raw data shown in Figure 5B, average signal in Figure 5C). In the medial part, where the third target glomerulus of the Sc is located (Sc-M glomerulus), we identified two glomeruli as candidates based on their relative position to the Sc-L glomeruli (black and blue ROIs, Figures 5B,C). The dorsal glomerulus (black ROI) is stained only weakly. It does not exhibit any substantial activity changes upon temperature stimulation (15°C). However, the second candidate glomerulus (30 μm ventrally, blue ROI) responds with strong oscillations in fluorescence to the applied stimuli (cold-sensitive glomerulus; blue ROI, ΔF/F ≈ 10%).


Representation of thermal information in the antennal lobe of leaf-cutting ants.

Ruchty M, Helmchen F, Wehner R, Kleineidam CJ - Front Behav Neurosci (2010)

Processing of thermal information provided by the sensilla coeloconica. The morphologically identified Sc-L glomeruli were insensitive to temperature stimulation (gray and green ROIs), irrespective of whether cold- (A,B) or warm stimuli were applied (D,E). In the medial part of this optical section we found in two examples (specimens) one or two thermosensitive glomeruli (in A and B, blue ROI: ΔF/F ≈ 10%; in D and E, blue ROI: ΔF/F ≈ 6% and black ROI, ΔF/F ≈ 12%, raw data shown). In (C,F) the average change in relative fluorescence is shown (four trials). D, dorsal; L, lateral; M, medial; V, ventral; Sc-L, lateral target glomeruli; Sc-M, medial target glomerulus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2991144&req=5

Figure 5: Processing of thermal information provided by the sensilla coeloconica. The morphologically identified Sc-L glomeruli were insensitive to temperature stimulation (gray and green ROIs), irrespective of whether cold- (A,B) or warm stimuli were applied (D,E). In the medial part of this optical section we found in two examples (specimens) one or two thermosensitive glomeruli (in A and B, blue ROI: ΔF/F ≈ 10%; in D and E, blue ROI: ΔF/F ≈ 6% and black ROI, ΔF/F ≈ 12%, raw data shown). In (C,F) the average change in relative fluorescence is shown (four trials). D, dorsal; L, lateral; M, medial; V, ventral; Sc-L, lateral target glomeruli; Sc-M, medial target glomerulus.
Mentions: In a number of specimens (n = 8) we could identify the Sc-L glomeruli by focusing through the lower (posterior) part of the antennal lobe. We specifically investigated their potential temperature sensitivity in two examples. Our investigations revealed that the Sc-L glomeruli were insensitive to temperature stimuli irrespective of whether warm (30°C) or cold (15°C) temperature changes are presented (Figures 5A–F). In Figure 5A the two Sc-L glomeruli can clearly be distinguished. They do not respond to stimulation with cold-stimuli (15°C, green and gray ROIs, depth = 95 μm; raw data shown in Figure 5B, average signal in Figure 5C). In the medial part, where the third target glomerulus of the Sc is located (Sc-M glomerulus), we identified two glomeruli as candidates based on their relative position to the Sc-L glomeruli (black and blue ROIs, Figures 5B,C). The dorsal glomerulus (black ROI) is stained only weakly. It does not exhibit any substantial activity changes upon temperature stimulation (15°C). However, the second candidate glomerulus (30 μm ventrally, blue ROI) responds with strong oscillations in fluorescence to the applied stimuli (cold-sensitive glomerulus; blue ROI, ΔF/F ≈ 10%).

Bottom Line: Here we selectively stained the three neurons found in single Sc and tracked their axons into the brain of Atta vollenweideri workers.Based on the general representation of thermal information in the antennal lobe and functional data on the Sc-glomeruli we conclude that temperature stimuli received by Sc are processed in the medial of the three target glomeruli.The present study reveals an important role of the antennal lobe in temperature processing and links a specific thermosensitive neuron to its central target glomerulus.

View Article: PubMed Central - PubMed

Affiliation: Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, Germany.

ABSTRACT
Insects are equipped with various types of antennal sensilla, which house thermosensitive neurons adapted to receive different parameters of the thermal environment for a variety of temperature-guided behaviors. In the leaf-cutting ant Atta vollenweideri, the physiology and the morphology of the thermosensitive sensillum coeloconicum (Sc) has been thoroughly investigated. However, the central projections of its receptor neurons are unknown. Here we selectively stained the three neurons found in single Sc and tracked their axons into the brain of Atta vollenweideri workers. Each of the three axons terminates in a single glomerulus of the antennal lobe (Sc-glomeruli). Two of the innervated glomeruli are adjacent to each other and are located laterally, while the third one is clearly separated and located medially in the antennal lobe. Using two-photon Ca(2+) imaging of antennal lobe projection neurons, we studied where in the antennal lobe thermal information is represented. In the 11 investigated antennal lobes, we found up to 10 different glomeruli in a single specimen responding to temperature stimulation. Both, warm- and cold-sensitive glomeruli could be identified. The thermosensitive glomeruli were mainly located in the medial part of the antennal lobe. Based on the general representation of thermal information in the antennal lobe and functional data on the Sc-glomeruli we conclude that temperature stimuli received by Sc are processed in the medial of the three target glomeruli. The present study reveals an important role of the antennal lobe in temperature processing and links a specific thermosensitive neuron to its central target glomerulus.

No MeSH data available.