In vivo functional diversity of midbrain dopamine neurons within identified axonal projections
- Goethe University, Germany
Figures
Figure 1 with 1 supplement
1000-fold reduction of conventional FG-concentrations leads to intact FG-labelled DA neurons in vivo.
(A) Confocal images of a dilution series of Fluorogold/ACSF injections. (Top panel, 1st row) merged images of injections sites (4x magnification) in dorsal striatum with TH in green and FG in blue. …
Figure 1—figure supplement 1
FG-labelling detection method.
(A) Detection method of intrinsic FG signals. The left image shows the TH-mask (TH in green), the right image shows the FG-channel (FG in black), the TH-mask is overlaid on both images in magenta, …
Figure 2
Experimental design and electrophysiological data of control neuron and FG-labelled SN DA neuron.
(A) Experimental design for FG-labelled DA dataset. Control DA neurons were recorded in untreated mice (only ‘Day 7’). (B1, C1) spontaneous in vivo extracellular single-unit activities of a …
Figure 3 with 1 supplement
Retrograde tracing with highly-diluted (0.002%) fluorogold prevents perturbation of in vivo electrophysiological properties of identified nigrostriatal dopamine neurons.
(A) Anatomical mapping of all extracellularly recorded and juxtacellularly labelled neurons (projected to bregma −3.16 mm; control in black, FG-labelled in green). Note the anatomical overlap of …
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Figure 3—source data 1
Electrophysiological data.
All included electrophysiological parameters analyzed for recorded control and projection-defined DA neurons.
- https://doi.org/10.7554/eLife.48408.007
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Figure 3—source data 2
Labelling detection.
Labelling detection parameters (labelling intensity of individual cells, backgrounds, Delta, standard deviation of backgrounds and number of positive FG-positive marks after thresholding) for FG-labelled DA neurons.
- https://doi.org/10.7554/eLife.48408.008
Figure 3—figure supplement 1
Comparison of in vivo firing properties of control and FG-labelled neurons.
(A1–P1) Scatter dot-plots (line at median) and bar graphs showing no significant differences in various parameters of firing. (A2–P2) Feature maps of respective parameters.
Figure 4 with 4 supplements
Dorsal and ventral striatal-projecting DA neurons intermix within the mSN.
(A1–D1) Injection sites for fluorescent tracing experiments injecting FG into the DLS (A1; bregma +0.86 mm), DMS (B1; bregma +0.74 mm), lNAcc (C1; bregma +0.86 mm), mNacc (D1; bregma +1.54 mm). (Left…
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Figure 4—source data 1
Anatomical reconstruction.
(A1, B1) Mean (N = 3 animals for each projection) and accumulated numbers of FG-labelled and projection-defined DA neurons in distinct midbrain regions. (A2, B2) Percentages of mean and accumulated projection population. (A3, B3) Percentages of mean and accumulated local cell population.
- https://doi.org/10.7554/eLife.48408.014
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Figure 4—source data 2
Anatomical reconstruction - DLS DLS-projecting cells counted in different regions and at distinct caudo-rostral levels.
- https://doi.org/10.7554/eLife.48408.015
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Figure 4—source data 3
Anatomical reconstruction - DMS DMS-projecting cells counted in different regions and at distinct caudo-rostral levels.
- https://doi.org/10.7554/eLife.48408.016
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Figure 4—source data 4
Anatomical reconstruction - lNAcc DLS-projecting cells counted in different regions and at distinct caudo-rostral levels.
- https://doi.org/10.7554/eLife.48408.017
Figure 4—figure supplement 1
Anatomical segregation of different DA systems in the midbrain.
(A) Serial reconstruction of retrogradely traced DA neurons across the caudorostral extent of the midbrain reveals anatomical position of DA neurons projecting to DLS (green), DMS (cyan), lNAcc …
Figure 4—figure supplement 2
Calbindin expression of midbrain DA neurons does not co-segregate with specific axonal projections.
(A) Confocal 20x images of retrogradely FG-traced midbrain DA neurons (injection site: lNAcc) costained for TH (green), FG (white) and CB (red). Note the intermingling of CB-positive and CB-negative …
Figure 4—figure supplement 3
Striatal fluorogold infusion sites show high reliability across animals.
(A–D) Monochromatic (FG) images of infusion sites for DLS (A), DMS (B), lNAcc (C) and mNAcc (D), given as five examples, each outlining detectable FG with overlay of corresponding stereotactic maps. …
Figure 4—figure supplement 4
In vivo activities of midbrain DA neurons recorded under anesthesia do not correlate with isoflurane concentrations.
(A–C) Frequency (Hz), SFB (%) and CV (%) of individual neurons plotted against isoflurane concentrations during respective recordings. Note the absence of significant correlations between functional …
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Figure 4—figure supplement 4—source data 1
Electrophysiological data – DA neurons, recorded in awake mice, home cage.
All included electrophysiological parameters for recorded DA neurons in awake mice during home cage activity. Data were collected in the context of a previous study (Duvarci et al., 2018).
- https://doi.org/10.7554/eLife.48408.018
Figure 5
Projection-defined midbrain DA systems projecting to dorsal and ventral striatum are predominantly parallel and non-overlapping.
(A) Infusion sites in green nissl counterstained 100 μm sections of double retrograde tracing experiments using fluorogold (blue) for mNAcc (A1), lNAcc (A2) and DMS (A3) and red fluorescently …
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Figure 5—source data 1
Double labelling Single-labelled and double-labelled.
DA neurons counted in caudal, intermediate and rostral sections (N = 3 animals for each comparison).
- https://doi.org/10.7554/eLife.48408.020
Figure 6 with 1 supplement
High in vivo burstiness in lateral compared to medial DLS-projecting SN DA neurons.
(A1, B1) Spontaneous in vivo extracellular single-unit activities of a representative DLS-projecting DA neuron located in the lSN (A1) and a representative DLS-projecting DA neuron located in the …
Figure 6—figure supplement 1
Comparison of in vivo firing properties of lSN and mSN DA neurons projecting to DLS.
(A1–P1) Scatter dot-plots (line at median) and bar graphs showing significant differences selectively in SFB contingency (% of >and < 5%). (A2–P2) Feature maps of respective parameters.
Figure 7 with 3 supplements
Functional segregation of in vivo electrophysiological properties mSN DA neurons with distinct axonal projections.
(A1, B1) Spontaneous in vivo extracellular single-unit activities of a representative DS-projecting DA neuron located in the mSN (A1) and a representative lNAcc-projecting DA neuron located in the …
Figure 7—figure supplement 1
DLS and DMS-projecting DA neurons located in the mSN do not exhibit significantly different in vivo firing properties.
(A) Anatomical mapping of all extracellularly recorded and juxtacellularly labelled neurons (projected to bregma −3.16 mm; DLS in red, DMS in cyan). Inset, FG-injection sites in the DLS and DMS (FG …
Figure 7—figure supplement 2
Comparison of in vivo firing properties of DS and lNAcc-projecting DA mSN neurons.
(A1–P1) Scatter dot-plots (line at median) and bar graphs showing significant differences in kurtosis, skewness, SFB (%), SFB contingency (% of >and < 5%), bursts per minute, pauses per minute. (A2–P…
Figure 7—figure supplement 3
lNAcc-projecting DA neurons located either in mSN or VTA do not exhibit significantly different in vivo firing properties.
(A) Anatomical mapping of all extracellularly recorded and juxtacellularly labelled neurons (projected to bregma −3.16 mm; mSN in magenta, VTA in brown). Inset, FG-injection site in the DLS (FG in …
Figure 8 with 2 supplements
DA neurons projecting to medial or lateral shell of the nucleus accumbens display distinct in vivo firing rates.
(A1, B1) Spontaneous in vivo extracellular single-unit activities of a representative lNAcc-projecting DA neuron located in the mSN (A1) and a representative mNAcc-projecting DA neuron located in …
Figure 8—figure supplement 1
lNAcc and mNAcc-projecting midbrain DA neurons do not exhibit significantly different in vivo firing properties.
(A1–P1) Scatter dot-plots (line at median) and bar graphs showing significant differences in firing frequency (Hz) and pause duration (s) (A2–P2) Feature maps of respective parameters.
Figure 8—figure supplement 2
Low success rate in identifying mPFC-projecting DA neurons.
(A) (Top panel) FG-injection sites (0.002%, 2 × 1 μl, 50 nl/min) in PrL (bregma: 1.98 mm, lateral: 0.3 mm, ventral: 1.5 mm) and IL (bregma: 1.98 mm, lateral: 0.3 mm, ventral:2.1 mm) nucleus. (bottom …
Figure 9
Midbrain dopamine neurons with distinct source-target topographies display functional in vivo firing differences.
(A) Diagram of the organization of distinct midbrain DA subtypes defined by their source-target topography. Single midbrain source areas and striatal target areas are colored individually (midbrain: …
Additional files
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Source code 1
Matlab scripts for generation of feature mapsCustom script used in order to create feature maps as in Figure 3—figure supplement 1, Figure 6—figure supplement 1, Figure 7—figure supplement 2 and Figure 8—figure supplement 1.
- https://doi.org/10.7554/eLife.48408.031
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Transparent reporting form
- https://doi.org/10.7554/eLife.48408.032
