An extrasynaptic GABAergic signal modulates a pattern of forward movement in Caenorhabditis elegans
- Harvard University, United States
- University of Science and Technology of China, China
- University of Toronto, Canada
Figures
Figure 1 with 1 supplement
The GABAergic motor neurons RME restrict head bending amplitude and exhibit intracellular calcium signals that are correlated with head bending.
(A) Schematics showing the innervation of anterior muscles by RME and SMD motor neurons. Note that the cell bodies (denoted by circles) of RMEV (V) and SMDD (D) are located on the ventral side and …
Figure 1—figure supplement 1
Sample cross-correlation between the GCaMP3 signal in the cell body and the GCaMP3 signal in the neurite of a RMEV or a RMED neuron.
https://doi.org/10.7554/eLife.14197.003
Figure 2 with 2 supplements
The head bending-correlated calcium activity of RME depends on cholinergic neurotransmission.
(A, B) The unc-13(e51) and cha-1(p1152) mutant animals are significantly defective in cross-correlation (A) and peak correlation (B) between RME calcium activity and head bending; but the unc-31(e928…
Figure 2—figure supplement 1
Representative traces for GCaMP3 signal in RME in animals immobilized with microbeads (Materials and methods).
Fmin indicates the minimal fluorescence intensity during the recording.
Figure 2—figure supplement 2
Representative traces for calcium signal in RME in unc-54(e1092) mutant animals.
The calcium signal is presented as the ratio between the GCaMP3 signal and the RFP signal expressed in RME.
Figure 3
The head bending-correlated calcium activity of RME is regulated by the cholinergic signal from SMD.
(A) Volumetric view of a 3-D image stack from an animal expressing Pglr-1::GCaMP3 and Punc-25::GCaMP3. A, anterior; D, dorsal; circles highlight cell bodies; a.u., arbitrary unit. (B) Sample traces …
Figure 4 with 1 supplement
SMD regulate the activity of RME via the metabotropic acetylcholine receptor GAR-2.
(A, B) The gar-2(ok520) mutants are defective in cross-correlation (A) and peak correlation (B) between RME calcium activity and head bending, and the expression of Pgar-2::gar-2 rescues the …
Figure 4—figure supplement 1
Blocking neurotransmission from IL2 neurons (Pklp-6::TeTx) or SMB neurons (Podr-2(18)::TeTx) or both does not significantly alter the cross-correlation or peak correlation between RME calcium activity and head movement.
One-way ANOVA with Dunnett’s post-test; transgenic animals are compared with the non-transgenic controls, Mean ± SEM. Peak correlation is the highest correlation within the 1 s time window centered …
Figure 5 with 1 supplement
The GABAB receptor subunit GBB-1 acts in the SMD neurons to limit head bending amplitude.
(A) The gbb-1(tm1406) mutants show an increased head bending amplitude similar to unc-25(e156) mutants. One-way ANOVA with Dunnett’s post-test, n ≥ 8 animals each. Figure 5—figure supplement 1. …
Figure 5—figure supplement 1
The gbb-1(tm1406);gbb-2(tm1165) double mutant animals show increased head bending amplitude, similarly as the gbb-1(tm1406) single mutants.
Student’s t-test, **p<0.01, n ≥ 9 animals, Mean ± SEM.
Figure 6
The activity of the RME GABAergic neurons is causally linked with head bending amplitude.
(A) Video images of locomotory behavior before and during green light illumination in a worm that expresses Arch in RME neurons. The illuminated head region is highlighted in green. (B) Video images …
Figure 7 with 1 supplement
Head bending amplitude correlates with speed and efficiency of forward locomotion.
(A) The angle of attack, measured as the average angle of a body segment with respect to the direction of forward movement, is plotted with the propulsion efficiency, defined as the ratio of the …
Figure 7—figure supplement 1
Optogenetically inhibiting RME neurons that express Arch (n = 11 trials, 5 animals) or optogenetically activating RME neurons that express channelrhodopsin ChR2 (n = 34 trials, 5 animals) significantly reduces propulsion efficiency of forward locomotion.
Here we measured the fractional change of the propulsion efficiency during bouts of forward locomotion before optogenetic stimulation and during optogenetic stimulation. Wilcoxon signed rank test …
Videos
Video 1
Undulatory movement of a wild-type animal on an agar plate.
The animal moves forward towards right at the beginning of the movie.
Video 2
Undulatory movement of a wild-type animal with RMED and RMEV ablated.
The animal in the movie moves towards lower-left corner on an agar plate at the beginning of the movie. Note the increased head bending amplitude in the animal.
Video 3
Undulatory movement of an unc-25(e156) mutant animal on an agar plate.
The animal moves towards upper-right corner at the beginning of the movie and then turns to move towards lower-right corner. Note the increased head bending amplitude in the unc-25 mutant animal.
Video 4
A representative movie for GCaMP3 signals in RMED and RMEV neurons and the head bending in a transgenic animal that expresses GCaMP3 in GABAergic neurons.
Both REMD and RMEV extend processes to the contralateral side to innervate the contralateral muscles and these processes run side-by-side. Because the calcium signals in the cell body and process of …
Video 5
A representative movie for GCaMP3 signals in RMED/V and SMDD/V neurons and the head bending in a transgenic animal that expresses GCaMP3 in a few neurons, including RMED/V and SMDD/V.
RMED and SMDD neurons are labeled with circles on the movie frames. Dorsal to the right and anterior to the low-right corner.
Video 6
Undulatory movement of a gar-2(ok520) mutant animal on an agar plate.
The animal moves down at the beginning of the movie and then turns to move towards left and then up. Note the increased head bending amplitude in the gar-2 mutant animal.
Video 7
Undulatory movement of a wild-type animal with SMDD and SMDV neurons ablated.
The animal moves towards lower-right corner on an agar plate at the beginning of the movie. Note the reduced head bending amplitude in the animal.
Video 8
Inhibiting RME activity with a green laser in a transgenic animal that expresses Arch in RME increases head bending amplitude.
Laser illumination starts when a 'DLP ON' signal appears in upper-left corner and stops when the 'DLP ON' signal disappears. The worm is stimulated for one cycle of illumination, 5 s–34 s. The …
Video 9
Activating RME activity with a blue laser in a transgenic animal that expresses ChR2 in RME decreases head bending amplitude.
The RIS neuron is ablated in the animal. Laser illumination starts when a 'DLP ON' signal appears in the upper-left corner and stops when the 'DLP ON' signal disappears. The worm is stimulated for 2 …
Additional files
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Source code 1
auto tack 23.vi.
The LabVIEW program used to record movement of C. elegans.
- https://doi.org/10.7554/eLife.14197.024
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Source code 2
YS_test_analyze_agarose_free_moving.m.
The Matlab code used to quantify head bending amplitude in moving animals.
- https://doi.org/10.7554/eLife.14197.025
