Gap junction networks in mushroom bodies participate in visual learning and memory in Drosophila
Figures
Figure 1 with 3 supplements
Visual learning and memory is abolished upon hyperpolarization of KCs.
(A) Setup of the optogenetic flight simulator system. A 593 nm laser was used to activate halorhodopsin. To avoid influencing the visual perception of the flies, a focuser was used to focus the …
Figure 1—figure supplement 1
Establishing the optogenetic flight simulator system.
Two difficulties have restricted the application of optogenetics to the study of Drosophila visual cognition. First, the excitation light can disturb visual perception; second, Drosophila need to …
Figure 1—figure supplement 2
Blocking the chemical synaptic output of KCs did not impair visual learning and memory.
Visual learning and memory remained intact when chemical synaptic output of KCs labeled with 17d-GAL4 or VT61721-GAL4 was blocked all the lifetime (A) or only post-development (B) by tetanus-toxin …
Figure 1—figure supplement 3
HU-ablation of MBs did not impair visual learning and memory.
(A) Flies of which MBs were ablated by HU demonstrated regular performance. (B, C) HU treatment ablated the MBs. The anti-Fasciclin II labelled brain without (B) or with (C) HU treatment. N = 12 for …
Figure 2 with 1 supplement
Gap junctions in MBs are necessary for visual learning and memory.
(A) Knockdown of inx6 in KCs labeled with 17d-GAL4 impaired visual learning and memory. Knockdown of inx4 or inx5 eliminate the significance of the difference between the performance indices and …
Figure 2—figure supplement 1
Effectiveness of inx RNAi lines.
Relative amount of innexin mRNA in the manipulated flies (elav-GAL4 > UAS-inx RNAi) comparing to the control flies (elav-GAL4/+ and UAS-inx RNAi/+) is shown. The results were normalized to the …
Figure 3 with 3 supplements
Dye coupling reveals presence of gap junctions in KCs.
(A) Schematic representation of MB and summary of dye coupling results. (B–D) One example in which biocytin was loaded into one KC, labeling more than one KC. Magenta, fluorescence of UAS-mCD8::EGFP …
Figure 3—figure supplement 1
Dye coupling between two γ neurons and one α’/β’ neuron.
(A) Z stack of the soma layer of the MB. One dye-filled fiber is visible (arrowhead). (B) Z stack of the soma, calyx and peduncle (PED) of the MB. Two biocytin-filled long fibers (arrowhead) in …
Figure 3—figure supplement 2
Dye coupling between α/β, α’/β’ and γ neurons.
(A) Z stack of the soma and calyx layers of the MB. Two fluorescence-labeled somas were filled with dye (arrow). The one on the left was bright and was presumed to be the one that was loaded. This …
Figure 3—figure supplement 3
Dye coupling between α/β, α’/β’ and non-KC fibers.
(A) Z stack of the soma layer of the MB. Two biocytin-filled somas were observed (arrow). The soma on the right was bright and abnormal in shape and was presumed to be the one that was loaded. (B) Z …
Figure 4 with 2 supplements
Electrical coupling reveals presence of gap junctions between KCs andβ’2mp neurons.
(A) Strategy used to detect electrical coupling between MBONs and KCs. Membrane potentials of MBON somata were recorded during hyperpolarization of KCs using optogenetics. The recorded soma was …
Figure 4—figure supplement 1
No difference observed between NpHR- and Arch-mediated hyperpolarization of KCs.
(A) Scheme for detecting KC hyperpolarization. (B) Current-clamp traces showing hyperpolarization evoked in KCs using laser light with emission at 593 nm. The KCs expressed eArch3.0 (upper, n = 5) …
Figure 4—figure supplement 2
Membrane-potential traces of MBON-β’2mp neurons in the OCT experiments.
The same data shown in Figure 4C, without baseline calibration. Yellow bar, 593 nm laser. Black traces, average of the membrane-potential traces for each recorded β’2mp neurons. Red traces, average …
Figure 5
Dye coupling between KCs and β’2mp neurons.
(A) Z stack of MB lobes and half of the peduncle. Biocytin-filled neurites (arrowhead) are observed within the boundary of the α’/β’ lobe (dotted line) and peduncle (PED). (B–D) The lobe layers were …
Figure 6
Gap junctions between KCs and β’2mp neurons are necessary for visual learning and memory.
Knockdown of inx5 or inx6 in β’2mp neurons results in impaired visual learning and memory. The following RNAi lines were used: inx1: v103816; inx2: v102194; inx3: v39094; inx4: v33277; inx5: v102814;…
Videos
Video 1
Raw stack of the brain in Figure 3.
https://doi.org/10.7554/eLife.13238.012
Video 2
Rotated stack of the brain in Figure 3—figure supplement 1.
https://doi.org/10.7554/eLife.13238.013
Video 3
Raw stack of the brain in Figure 3—figure supplement 2.
https://doi.org/10.7554/eLife.13238.014
Video 4
Raw stack of the brain in Figure 3—figure supplement 3.
https://doi.org/10.7554/eLife.13238.015
Video 5
Raw stack of the anterior half of the brain in Figure 5.
https://doi.org/10.7554/eLife.13238.020
Video 6
Raw stack of the brain in Figure 5.
https://doi.org/10.7554/eLife.13238.021Tables
Table 1
Dye coupling in wild type and inx5/6 knockdown flies.
| WT | INX 5&6 KD | ||
|---|---|---|---|
| Loaded neurons | αβ | 21 | 27 |
| α’β’ | 9 | 10 | |
| γ | 8 | 15 | |
| Dye coupling | 5 | 0 | |
Additional files
-
Supplementary file 1
The specificity and target sequences of RNAi for innexin 1~8.
THU, Tsinghua University.
- https://doi.org/10.7554/eLife.13238.024
