The computation of directional selectivity in the Drosophila OFF motion pathway
- Howard Hughes Medical Institute, United States
Figures
Figure 1
Whole-cell recordings of T5 neurons show small-field, directionally selective responses.
(A) Schematic of the Drosophila visual system with an example T4 (ON) and T5 (OFF) neuron. (B) Schematic of experimental setup. Whole-cell recordings were targeted to soma of GFP-labeled T5 neurons. …
Figure 2 with 1 supplement
T5 receptive field is comprised of spatially offset depolarization and hyperpolarization.
(A) Averaged, baseline-subtracted responses (mean ± SEM) to bar flash stimulus at the indicated positions (numbered below, examples schematized above) along the PD–ND axis of each cell (n = 17 …
Figure 2—figure supplement 1
T5 receptive field comparison between cells aligned to cardinal and diagonal preferred directions, corrected for approximate visual angle.
(A) Averaged, baseline-subtracted responses (mean ± SEM) to bar flash stimuli (width 4, 160 ms) at the indicated positions (numbered below) along the PD–ND axis of each cell (n = 12 cells for …
Figure 3 with 2 supplements
T5 neurons generate directional selectivity using ND suppression.
(A) Schematized responses to the elementary motion stimulus of sequential bar pair flashes. Response could be the sum of the responses to the individual flashes (top), could show preferred …
Figure 3—figure supplement 1
Evidence for ND suppression is robust to measurement type.
This figure shows the same analysis and results as in Figure 3, but summarized using response mean rather than peak. (A) Baseline-subtracted responses (mean ± SEM) to bar pair combinations presented …
Figure 3—figure supplement 2
Apparent motion responses show evidence only for ND suppression even for larger stimuli.
(A) Same as Figure 3B for 4-pixel-wide (9°) apparent motion stimuli. Stimulus schematic depicts positional information only and are presented in a staggered manner to illustrate overlapping …
Figure 4 with 1 supplement
A conductance-based model quantitatively predicts directionally selective responses.
(A) T5 EI model schematic with fast spatially symmetric excitation and slow, trailing-side asymmetric inhibition. (B) Mean measured responses to single bar flashes of 3 widths and two flash …
Figure 4—figure supplement 1
Reliability of model predictions across cells.
Each subplot shows peak measured responses compared to the peak model prediction responses for all the stimuli recorded for an individual cell. Plotting conventions are as in Figure 4C. The bolded …
Figure 5
Conductance-based model recapitulates responses to more complex spatial and temporal stimuli.
(A) Mean measured responses to fast (40 ms) and slow (160 ms) flashes of grating stimuli (dark and background brightness level) in different phases compared with model predictions (same example …
Figure 6 with 2 supplements
A conductance model relying on removal of excitatory input cannot recapitulate T5 responses.
(A) Mean measured responses to single bar flashes of two widths flashed for 160 ms at eight different positions from the same example cell as in Figure 4 (in colors) compared to predicted E+E- model …
Figure 6—figure supplement 1
E+E- model relying on removal of excitatory input cannot recapitulate T5 responses, even when optimized with bars of width 2 and 4.
(A) Mean measured responses to single bar flashes of two widths flashed for 160 ms at eight different positions from the same example cell as in Figure 4 (in colors) compared to predicted E+E- model …
Figure 6—figure supplement 2
E+E- model relying on removal of excitatory input cannot recapitulate T5 responses, even when optimized with flashing and moving bars.
Same as Figure 6—figure supplement 1, but these results were generated using model parameters that were optimized using flashing and moving bars responses of width 2 (brown frame).
Figure 7
Inhibition is superior to removal of excitation for generating directional selectivity.
Figure 8
Comparison between current models for T4/T5 computation of directional selectivity.
One recent model class, represented here by the proposal of Wienecke et al. (2018) uses a tilted linear spatio-temporal filter to represent voltage responses, which are then followed by a nonlinear …
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Genetic reagent (D. melanogaster) | UAS-GFP | Janelia Research Campus | pJFRC28-10XUAS-IVS-GFP-p10 (attP2) | Rubin Lab JFRC28 |
| Genetic reagent (D. melanogaster) | Stable split Gal4 (T5) | Janelia Research Campus | w; VT055812-AD(attP40); R47H05-DBD(attP2) | Rubin Lab SS25175 |
| Software, algorithm | MATLAB | Mathworks Inc | 2018b |
Additional files
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Supplementary file 1
Excitation-Inhibition model parameters (related to Figures 4, 5 and 7).
- https://cdn.elifesciences.org/articles/50706/elife-50706-supp1-v2.docx
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Supplementary file 2
Excitation-Removal of excitation model parameters (related to Figures 6 and 7).
- https://cdn.elifesciences.org/articles/50706/elife-50706-supp2-v2.docx
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Transparent reporting form
- https://cdn.elifesciences.org/articles/50706/elife-50706-transrepform-v2.pdf
