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Local motion detectors are required for the computation of expansion flow-fields.

Schilling T, Borst A - Biol Open (2015)

Bottom Line: Tethered flying fruit flies, when confronted with an expansion flow-field, reliably turn away from the pole of expansion when presented laterally, or perform a landing response when presented frontally.Here, we show that the response to an expansion flow-field is independent of the overall luminance change and edge acceleration.As we demonstrate by blocking local motion-sensing neurons T4 and T5, the response depends crucially on the neural computation of appropriately aligned local motion vectors, using the same hardware that also controls the optomotor response to rotational flow-fields.

View Article: PubMed Central - PubMed

Affiliation: Department of Circuits-Computation-Models, Max-Planck-Institute of Neurobiology, Martinsried D-82152, Germany.

No MeSH data available.


Related in: MedlinePlus

T4 and T5 block abolished both landing and avoidance responses. Flight behavior and landing responses of flies with TNT-E expression in T4 and T5 cells. (A) Turning responses of TNT and T4/T5 control flies to an expanding bar with an expansion velocity of 180 deg/s, n=12. (B) Turning responses of T4/T5 blocked flies to an expanding bar, n=12. (C) Maximal turning responses are significantly reduced in T4/T5 block flies (***P<0.001, two-sided t-test compared with both control groups). (D) Flight turning behavior of TNT and T4/T5 control flies in response to a looming circle, n=12. (E) Turning responses of T4/T5 blocked flies to a looming circle, n=14. (F) Maximal turning responses are significantly reduced in T4/T5 blocked flies (***P<0.001, two-sided t-test compared with both control groups). (G) GFP expression in T4 and T5 cells. (H) Example of a landing response. (I) Percentage of flies showing extension of their front legs in response to a looming square presented in front of them. TNT and T4/T5 controls showed a positive response in 97% and 100% of all trials, respectively, whereas T4/T5 blocked flies performed only 6.3% positive leg extension. This reduction was significant (***P<0.001, two-sided t-test compared with both control groups), n=11. All data represent mean±s.e.m.
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BIO012690F2: T4 and T5 block abolished both landing and avoidance responses. Flight behavior and landing responses of flies with TNT-E expression in T4 and T5 cells. (A) Turning responses of TNT and T4/T5 control flies to an expanding bar with an expansion velocity of 180 deg/s, n=12. (B) Turning responses of T4/T5 blocked flies to an expanding bar, n=12. (C) Maximal turning responses are significantly reduced in T4/T5 block flies (***P<0.001, two-sided t-test compared with both control groups). (D) Flight turning behavior of TNT and T4/T5 control flies in response to a looming circle, n=12. (E) Turning responses of T4/T5 blocked flies to a looming circle, n=14. (F) Maximal turning responses are significantly reduced in T4/T5 blocked flies (***P<0.001, two-sided t-test compared with both control groups). (G) GFP expression in T4 and T5 cells. (H) Example of a landing response. (I) Percentage of flies showing extension of their front legs in response to a looming square presented in front of them. TNT and T4/T5 controls showed a positive response in 97% and 100% of all trials, respectively, whereas T4/T5 blocked flies performed only 6.3% positive leg extension. This reduction was significant (***P<0.001, two-sided t-test compared with both control groups), n=11. All data represent mean±s.e.m.

Mentions: Our data so far indicate that the avoidance behavior is distinct from the optomotor response, but depends on the evaluation of local motion signals rather than on overall luminance changes. Since T4 and T5 neurons are known to represent the elementary motion detectors in the fly brain (Maisak et al., 2013), we measured the avoidance behavior of flies with blocked T4/T5 cells. We silenced T4 and T5 cells by expressing the tetanus-toxin light chain (Sweeney et al., 1995) and measured the response of T4/T5 blocked flies to different looming stimuli. The response to an expanding bar was completely abolished in T4/T5 blocked flies (Fig. 2B) compared to both groups of parental control flies (Fig. 2A). To confirm this with another stimulus, we presented a looming circle, a stimulus eliciting very strong avoidance reactions in control flies (Fig. 2D). T4/T5 blocked flies did not react at all to this stimulus (Fig. 2E).Fig. 2.


Local motion detectors are required for the computation of expansion flow-fields.

Schilling T, Borst A - Biol Open (2015)

T4 and T5 block abolished both landing and avoidance responses. Flight behavior and landing responses of flies with TNT-E expression in T4 and T5 cells. (A) Turning responses of TNT and T4/T5 control flies to an expanding bar with an expansion velocity of 180 deg/s, n=12. (B) Turning responses of T4/T5 blocked flies to an expanding bar, n=12. (C) Maximal turning responses are significantly reduced in T4/T5 block flies (***P<0.001, two-sided t-test compared with both control groups). (D) Flight turning behavior of TNT and T4/T5 control flies in response to a looming circle, n=12. (E) Turning responses of T4/T5 blocked flies to a looming circle, n=14. (F) Maximal turning responses are significantly reduced in T4/T5 blocked flies (***P<0.001, two-sided t-test compared with both control groups). (G) GFP expression in T4 and T5 cells. (H) Example of a landing response. (I) Percentage of flies showing extension of their front legs in response to a looming square presented in front of them. TNT and T4/T5 controls showed a positive response in 97% and 100% of all trials, respectively, whereas T4/T5 blocked flies performed only 6.3% positive leg extension. This reduction was significant (***P<0.001, two-sided t-test compared with both control groups), n=11. All data represent mean±s.e.m.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4582123&req=5

BIO012690F2: T4 and T5 block abolished both landing and avoidance responses. Flight behavior and landing responses of flies with TNT-E expression in T4 and T5 cells. (A) Turning responses of TNT and T4/T5 control flies to an expanding bar with an expansion velocity of 180 deg/s, n=12. (B) Turning responses of T4/T5 blocked flies to an expanding bar, n=12. (C) Maximal turning responses are significantly reduced in T4/T5 block flies (***P<0.001, two-sided t-test compared with both control groups). (D) Flight turning behavior of TNT and T4/T5 control flies in response to a looming circle, n=12. (E) Turning responses of T4/T5 blocked flies to a looming circle, n=14. (F) Maximal turning responses are significantly reduced in T4/T5 blocked flies (***P<0.001, two-sided t-test compared with both control groups). (G) GFP expression in T4 and T5 cells. (H) Example of a landing response. (I) Percentage of flies showing extension of their front legs in response to a looming square presented in front of them. TNT and T4/T5 controls showed a positive response in 97% and 100% of all trials, respectively, whereas T4/T5 blocked flies performed only 6.3% positive leg extension. This reduction was significant (***P<0.001, two-sided t-test compared with both control groups), n=11. All data represent mean±s.e.m.
Mentions: Our data so far indicate that the avoidance behavior is distinct from the optomotor response, but depends on the evaluation of local motion signals rather than on overall luminance changes. Since T4 and T5 neurons are known to represent the elementary motion detectors in the fly brain (Maisak et al., 2013), we measured the avoidance behavior of flies with blocked T4/T5 cells. We silenced T4 and T5 cells by expressing the tetanus-toxin light chain (Sweeney et al., 1995) and measured the response of T4/T5 blocked flies to different looming stimuli. The response to an expanding bar was completely abolished in T4/T5 blocked flies (Fig. 2B) compared to both groups of parental control flies (Fig. 2A). To confirm this with another stimulus, we presented a looming circle, a stimulus eliciting very strong avoidance reactions in control flies (Fig. 2D). T4/T5 blocked flies did not react at all to this stimulus (Fig. 2E).Fig. 2.

Bottom Line: Tethered flying fruit flies, when confronted with an expansion flow-field, reliably turn away from the pole of expansion when presented laterally, or perform a landing response when presented frontally.Here, we show that the response to an expansion flow-field is independent of the overall luminance change and edge acceleration.As we demonstrate by blocking local motion-sensing neurons T4 and T5, the response depends crucially on the neural computation of appropriately aligned local motion vectors, using the same hardware that also controls the optomotor response to rotational flow-fields.

View Article: PubMed Central - PubMed

Affiliation: Department of Circuits-Computation-Models, Max-Planck-Institute of Neurobiology, Martinsried D-82152, Germany.

No MeSH data available.


Related in: MedlinePlus