Odor-identity dependent motor programs underlie behavioral responses to odors
- Duke University, United States
Figures
Figure 1 with 3 supplements
A novel behavioral paradigm for measuring odor-evoked change in fly’s locomotion.
(A) Schematic of the behavioral arena. (B) Top view of the chamber. (C) Electroantennogram (EAG) recording at different locations (indicated by a dot) shows a large EAG response when the measurement …
Figure 1—figure supplement 1
A detailed schematic showing the parts of the behavioral chamber.
The final chamber consisted of top and bottom assemblies. The bottom assembly was always fixed in place. The top assembly was replaced after a fly was introduced in the arena. During the experiment, …
Figure 1—figure supplement 2
Flow visualization shows a precise interface between odor zone and no odor zone.
(A) The left image shows a side view of the behavioral arena. The field of view is enlarged to visualize the region where the inlet air tube attached to the arena. On the right, a background …
Figure 1—figure supplement 3
Control experiments.
(A) We assessed the effect of air and vacuum on the distribution of the flies in our arena. Each data point represents the fractional time spent inside the odor-zone by a single fly in a 3 min …
Figure 2
Different attractive odors modulate different motor parameters.
(A) Flies decrease their speed when they enter the odor-zone in the presence of ACV0 but not BUN3. Left: Mean changes in speed between before and during periods. (n = 29 for apple cider vinegar …
Figure 3
Two similarly attractive odors modulate different sets of motor parameters.
(A) Attraction index showing that the fly is similarly attracted to two odors—apple cider vinegar (10-2, ACV2, n = 34) and BUN3 (n = 31). Dotted line marks expected value when there is no odor modula…
Figure 4 with 1 supplement
Odors independently modulate multiple behavioral parameters in an odor dependent manner.
(A) 17 parameters which are all significantly modulated by ACV0 at p <0.05 (each parameter is described in detail in Materials and methods). Bars on top indicate the variables that are significantly …
Figure 4—figure supplement 1
Evidence for independence of different motor parameters.
If attraction is a singular motor program, then we would expect other motor programs to scale with the level of attraction. We examine the linear correlations between these parameters for a fly’s …
Figure 5 with 2 supplements
Two similarly attractive odors modulate different sets of motor parameters.
(A) 17 motor parameters show that the parameters modulated by two similarly attractive odor—ACV2 and BUN3 are different. Bars on top indicate the variables that are significantly different from the …
Figure 5—figure supplement 1
Differences in behavior due to BUN3 and ACV2 is not due to a few flies which are very attractive to ACV or due to different temporal evolution of behavior in the two odors.
(A,B). Subsampling of ACV2 flies does not affect behavioral differences. (A) Shows the subsampling. We removed the flies which contributed to the long tail in the distribution of attraction index. …
Figure 5—figure supplement 2
Differences in the motor parameters modulated are not simply due to differences between simple and complex odors.
(A) Behavioral responses due to two complex food odors - ACV and banana are distinct along the first canonical variate. Two monomolecular odors, 2-butanone (BUN3) and ethyl acetate (at a …
Figure 6 with 2 supplements
Activation of single ORN class leads to a change in a subset of motor parameters.
(A) Schematic representation of ORNs activated by ACV0. (B) Ethyl acetate at low concentrations activate only Or42b-ORNs. (C) Behavioral modulation by activation of Or42b-ORNs alone using low …
Figure 6—figure supplement 1
Ethyl acetate at low concentrations nearly saturates Or42b-ORNs without activating any other receptor.
To establish that low concentration of ethyl acetate activates Or42b-ORNs and no other ORNs, we first show that Or42b-ORNs are activated by low ethyl acetate concentration. Next we show that there …
Figure 6—figure supplement 2
Behavioral response to ETA8 is abolished in Or42b mutants.
In figure 6, we show that activating Or42b-ORNs alone using ETA8 results in a change in run duration and angular speed inside. If Or42b-ORNs are indeed responsible for the behavioral effects of …
Figure 7
Higher concentration of ACV activates more ORNs and recruits more motor parameters.
(A) PSTHs showing the response of the Or42b-ORN to ACV and ethyl acetate (mean ± SEM, n = 5-7). (B) At all spike rates, ACV is more attractive than ETA implying that attraction due to ACV is not due …
Figure 8 with 1 supplement
Mutating a single ORN class does not affect attraction to ACV0 but changes certain motor parameters.
(A) In the Or42b mutant, a single ORN class is non-functional. (B) Sample tracks showing that both wild type and Or42b-/- flies are attracted to ACV. Tracks also show that the mutant fly is closer …
Figure 8—figure supplement 1
Responses of wild-type and Or42b mutant flies to the solvent control are not significantly different for any parameter even if not corrected for multiple comparisons.
https://doi.org/10.7554/eLife.11092.022
Figure 9 with 1 supplement
Modulation of motor programs by ACV inside the odor-zone is strongly affected in the Ir8a-mutant.
(A) Three ORN classes activated by ACV are non-functional in Ir8a mutant. (B) The reduction in speed when the wild type flies enter the odor-zone in the presence of ACV is abolished in the Ir8a …
Figure 9—figure supplement 1
Ir8a-ORNs directly modulate speed.
(A) Change in speed as a function of field potential response at the ORN layer in flies in which Ir8a-ORNs are the only ones active. Each data point represents a different odor. Δspeedis the …
Figure 10
Ir8a mutants approach ACV at the same rate as wild-type but spend less time in proximity to it.
(A) Ir8a mutant find the odor as well as the wild-type flies but because they spend less time inside the odor-zone on each visit their attraction to odor decreases with time at a faster rate than …
Figure 11
A new framework for olfactory behaviors.
(A) Current framework. Based on the pattern of ORNs activated by a given odor, a stereotypical motor program is activated with different efficacies leading to different levels of attractiveness. (B) …
Figure 12
Determination of curved walk and sharp turns.
(A) A part of a fly’s walking trajectory. The curved walk is indicated with orange line and sharp turns are marked with black circles. The right panel shows the magnified walking trajectory from the …
Videos
Video 1
This video shows the behavior of the fly to apple cider vinegar (Video 1).
The tracks over the preceding 2 s are marked with dotted white line. The centroid is marked with green. The video also marks stops, sharp turns (S-turns) and curved walk. It shows that the fly slows …
Video 2
This video shows the behavior of the fly to 2-butanone.
The tracks over the preceding 2 s are marked with dotted white line. The centroid is marked with green. The video also marks stops, sharp turns (S-turns) and curved walk. Unlike in apple cider …
Tables
Table 1
17 behavioral parameter.
Parameters are defined in more details in the methods.
| Motor parameter | What it represents | How it is calculated (see Materials and methods for details) |
|---|---|---|
| Attraction index | Overall time spent inside the odor zone | |
| Time spent/transit | Median time spent inside the odor zone per visit | |
| Time to return | Median time spent outside the odor zone between successive entries into the odor-zone | |
| Radial density | Mean distance from the center of the arena | Fly’s location as the distance from the center of the arena. Data were binned to 12 bins and normalized by area of each bin. |
| Speed inside | Mean speed inside the odor zone over the entire period | |
| Speed outside | Mean speed outside the odor zone over the entire period | |
| Speed crossing inside | Acute change in speed in the first 3 s after entering the odor-zone | |
| Speed crossing outside | Acute change in speed in the first 3 s after leaving the odor-zone | |
| Run duration | Average duration of runs | |
| Stop duration | Average duration of stops | |
| Run probability in | Fraction of time a fly spends running while inside the odor zone | |
| Run probability out | Fraction of time a fly spends running when outside the odor zone | |
| Angular speed inside | Angular speed change inside the odor zone | |
| Angular speed outside | Angular speed change outside the odor zone | |
| Smooth turns in | Fraction of time a fly is performing a smooth turn inside the odor zone | |
| Smooth turns out | Fraction of time a fly is performing smooth turns outside the odor zone | |
| Sharp turns at boundary | Fraction of sharp turns near the odor boundary | The fraction of sharp turns which took place at the odor border, i.e. in a ring 2 mm around the border |
