Journal: bioRxiv

Article Title: Steering From the Rear: Coordination of Central Pattern Generators Underlying Navigation by Ascending Interneurons

doi: 10.1101/2024.06.17.598162

Figure Lengend Snippet: Activation of CsChrimson in 19f cells increases spiking frequency and also triggers state dependent changes in motor activity recorded in isolated larval CNS. A) Representative loose cell-attached recording from 19f cell with 6 and 60 second optogenetic stimulations (red lines above trace indicate time of light pulse). B) Enlarged view of periods before, during and after stimulation. C) Summarised spiking frequency data before, during and after the 60 second stimulation. 19f cell spiking frequency significantly increases during the red light stimulation. D) Pooled data for 6 s stimulations. Asterisks indicate significant differences between the before and during optogenetic stimulation (*P < 0.05, **P < 0.005, ***P < 0.0001; one-way repeated measures ANOVA with Bonferroni post-hoc test). n = 4. E) Extracellular suction electrode recordings from three nerve roots, two thoracic segments (green T3R and blue T3L) and one suction electrode recording from abdominal segment 8 (black A8/9). Extracellular nerve signals recorded from each electrode were rectified and smoothed by filtering with a moving average filter with a time constant of 0.9 s (rect). T3R and T3L overlaid to also observe bilateral asymmetries. Representative trace of motor neuron output while optogenetically stimulating 19f cell population for 60 seconds (red line indicates time of light pulse) showing excitatory response (black arrowhead) from the onset of the stimulation in posterior segment with inhibition in anterior segment T3R. F) Representative trace of motor neuron output while stimulating 19f cells showing inhibitory response in posterior segment also indicated by a black arrow, and excitatory response in anterior segment T3R. G) Pie charts representing percentage of different responses on the onset of 60 second stimulation in posterior regions (left chart) and anterior regions (right chart). n = 9, 18 trials.

Article Snippet: Light stimulation and video capture were synchronized and controlled using LabChart software (LabChart 8.0, ADInstruments), which also managed the recording of behavioral responses.

Techniques: Activation Assay, Activity Assay, Isolation, Inhibition

Journal: bioRxiv

Article Title: Steering From the Rear: Coordination of Central Pattern Generators Underlying Navigation by Ascending Interneurons

doi: 10.1101/2024.06.17.598162

Figure Lengend Snippet: Optogenetic stimulation of 19f cells promotes rhythmic activity in isolated posterior segments and while supressing activity in isolated anterior regions A) Extracellular suction electrode recordings from two nerve roots, thoracic segments left and right sides (green T1R and blue T1L) in preparations where the posterior region is ablated and recorded from separately (black A8/9). B) . Extracellular nerve signals recorded from each electrode were rectified and smoothed by filtering with a moving average filter with a time constant of 0.9 s (rect). Rectified T1R and T1L outputs overlaid and bilateral asymmetries indicated by subtracting the signals from the two channels (Asym. grey line). Representative traces ( A,B ) shows motoneuron output while optogenetically stimulating 19f cells for 60 seconds in the two separated parts of the CNS. C) Summarised average frequency of bilateral asymmetries. D) Summarised average frequency of posterior end bursts. Asterisks indicate significant differences amongst frequencies at different time points (*P < 0.05, **P < 0.005, ***P < 0.0001; one-way repeated measures ANOVA with Bonferroni post-hoc test). Sample size, n = 7.

Article Snippet: Light stimulation and video capture were synchronized and controlled using LabChart software (LabChart 8.0, ADInstruments), which also managed the recording of behavioral responses.

Techniques: Activity Assay, Isolation

Journal: bioRxiv

Article Title: Steering From the Rear: Coordination of Central Pattern Generators Underlying Navigation by Ascending Interneurons

doi: 10.1101/2024.06.17.598162

Figure Lengend Snippet: Optogenetic activation of 19f cells in freely crawling larvae leads to transient suppression of forward locomotion and turning behaviors A) Representative ethograms show different behaviours produced by freely crawling animals over time while optogenetically stimulating 19f cells (pink line represents onset and offset of red light). Different types of behaviours colour-coded in the figure legend on the right. The top two ethograms are the control animals (19f/+, CsChr/+) and bottom is experimental animal (19f/CsChr), where animal pauses for 5-6 seconds (indicated with black box) upon the onset of stimulation. B) Average forward wave frequencies of experimental animals (black line) significantly decreases upon the onset of stimulation (pink box represents start and stop of stimulation) compared to two other controls (grey lines). C) Summary of forward wave frequencies before, during and after the stimulation of experimental animals and two genetic controls. D) Summary of forward wave durations of experimental and control animals. E) Summary of turning event frequencies. F) Figure showing percentage of larvae spent turning. Asterisks indicate significant differences amongst groups (*P < 0.05, **P < 0.001, ***P < 0.0001; one-way repeated measures ANOVA with Bonferroni post-hoc test). Sample sizes were: n = 14 (19f/CsChr), n = 15 (CsChr/+), n = 14 (19f/+).

Article Snippet: Light stimulation and video capture were synchronized and controlled using LabChart software (LabChart 8.0, ADInstruments), which also managed the recording of behavioral responses.

Techniques: Activation Assay, Produced, Control

Journal: bioRxiv

Article Title: Steering From the Rear: Coordination of Central Pattern Generators Underlying Navigation by Ascending Interneurons

doi: 10.1101/2024.06.17.598162

Figure Lengend Snippet: Activation of small numbers of 19f cells using FLP-out optogenetics produces phenotypes consistent with activation of the full 19f-GAL4 expression pattern A,B) Examples of expressing FLP-out CsChrimson in smaller numbers of 19f cells. C) Percentage of trials that interrupted forward locomotion, stimulated for 6 seconds. The data was separated into two groups where 1-2 19f cells were expressed and where more than 2 19f cells were expressed. D) Forward wave frequencies before, during and after 6 second stimulation. E) Summary of forward wave durations before, during and after 6 second stimulations. Asterisks indicate significant differences amongst groups (*P < 0.05; one-way repeated measures ANOVA with Bonferroni post-hoc test). Samples sizes: n = 5 (17 trials) where 1-2 19f cells were expressed, n = 6 (15 trials) where more than 2 19f cells were expressed.

Article Snippet: Light stimulation and video capture were synchronized and controlled using LabChart software (LabChart 8.0, ADInstruments), which also managed the recording of behavioral responses.

Techniques: Activation Assay, Optogenetics, Expressing

Journal: bioRxiv

Article Title: Steering From the Rear: Coordination of Central Pattern Generators Underlying Navigation by Ascending Interneurons

doi: 10.1101/2024.06.17.598162

Figure Lengend Snippet: Optogenetic inhibition of 19f cells in freely crawling larvae suppresses forward locomotion but enhances turning A) Representative ethograms show different behaviours produced by freely crawling animals over time while optogenetically inhibiting 19f cells (pink line represents onset and offset of red light). Different types of behaviours colour-coded in the figure legend on the right. The top two ethograms are the control animals (GtAcr1/+, 19f/+) and bottom is experimental (19f/GtAcr1), where animal is doing more headsweeps during the inhibition of 19f cells. B) Average forward wave frequencies of experimental animals (black line) significantly decreases upon the onset of stimulation (pink box represents start and stop of inhibition) compared to two other controls (grey lines). C) Summary of forward wave frequencies before, during and after the red light of experimental animals and two controls. D) Summary of forward wave durations of experimentals against controls. E) Summary of turning event frequencies. F) Figure showing percentage of larvae spent turning. Asterisks indicate significant differences amongst groups (*P < 0.05, **P < 0.001, ***P < 0.0001; one-way repeated measures ANOVA with Bonferroni post-hoc test). Sample sizes were: n = 14 (19f/GtAcr1), n = 13 (GtAcr1/+), n = 14 (19f/+).

Article Snippet: Light stimulation and video capture were synchronized and controlled using LabChart software (LabChart 8.0, ADInstruments), which also managed the recording of behavioral responses.

Techniques: Inhibition, Produced, Control