Self-organization of modular network architecture by activity-dependent neuronal migration and outgrowth

  1. Samora Okujeni  Is a corresponding author
  2. Ulrich Egert
  1. University of Freiburg, Germany
7 figures, 3 tables and 1 additional file

Figures

Model of activity-dependent network development.

Neuronal wiring strategies may involve expansion of neurite fields and migration towards other neurons to increase connectivity modeled as neurite field overlap. (A) Transfer function of membrane …

https://doi.org/10.7554/eLife.47996.002
Figure 2 with 6 supplements
Model of activity-dependent growth and migration.

(A) Activity-dependent growth produced a characteristic overshoot and subsequent pruning of neurite fields. The overall size of developing neurites decreased with increasing migration rates and …

https://doi.org/10.7554/eLife.47996.003
Figure 2—figure supplement 1
Influence of neuronal clustering on neurite field development.

Increasing migration rates in the simulation promoted neuronal clustering leading to lower final CI and smaller neurite field sizes. At the onset of high network activity, neurite fields were pruned …

https://doi.org/10.7554/eLife.47996.004
Figure 2—figure supplement 2
Simulation of saturating network growth.

(A) Decreasing the slope of the sigmoidal transfer function mapping membrane potential to firing rate resulted in saturating growth (inset: blue: a = 0.2) instead of an overshoot (inset: black, a

https://doi.org/10.7554/eLife.47996.005
Figure 2—video 1
Simulated network development with migration rate 0 µm/day.
https://doi.org/10.7554/eLife.47996.006
Figure 2—video 2
Simulated network development with migration rate 10 µm/day.
https://doi.org/10.7554/eLife.47996.007
Figure 2—video 3
Simulated network development with migration rate 50 µm/day.
https://doi.org/10.7554/eLife.47996.008
Figure 2—video 4
Simulated network development with migration rate 300 µm/day.
https://doi.org/10.7554/eLife.47996.009
Figure 3 with 2 supplements
Morphometric analyses of network development.

(A) Dense networks established characteristic mesoscale architectures for the different PKC conditions. PKC networks had a more homogeneous distribution of axons (red), dendrites (green) and cell …

https://doi.org/10.7554/eLife.47996.010
Figure 3—figure supplement 1
Clustering and dendrite development in sparse networks.

Exemplary images with neuronal nuclei (NeuN, red) and dendrites (MAP2, green) stained at 8 and 22 DIV. PKC inhibition diminished and PKC stimulation promoted neuronal migration and clustering of …

https://doi.org/10.7554/eLife.47996.011
Figure 3—figure supplement 2
Development of synapses in sparse networks.

Immunohistochemical staining of dendrites (MAP2, red), presynaptic compartments (synapsin, green) and cellular nuclei (DAPI, blue). Synapse densities on dendrites increased in all PKC conditions up …

https://doi.org/10.7554/eLife.47996.012
Figure 4 with 1 supplement
Development of spontaneous network activity.

(A) SBE rates gradually increased during development until 28 DIV, which was accelerated in clustered PKC+ networks and decelerated in homogeneous PKC networks. In result, SBE rates differed …

https://doi.org/10.7554/eLife.47996.017
Figure 4—figure supplement 1
Sample MEA recordings from dense networks.

(A) SBE spike activity on a MEA electrode. Spike times (blue) were detected with a voltage threshold on high-pass filtered raw data. (B) Global spike histogram (10 ms bins) and spike activity of a …

https://doi.org/10.7554/eLife.47996.018
PFR-dependent Ca2+ gain.

(A) Spiking raster and firing rate averaged across all electrodes within 40 ms bins (synchronized to the frame times of the Ca2+ measurement) and Ca2+ signal for one neuronal soma at 19 DIV in a PKCN

https://doi.org/10.7554/eLife.47996.021
Functional aspects of network maturation.

(A) Network synchrony (average spike train correlation for all electrode pairs determined with 30 ms time bins, mean ± SEM) stabilized early in development in all PKC conditions but was …

https://doi.org/10.7554/eLife.47996.023
Figure 6—source data 1

Source data and Matlab script for Figure 6A,B.

https://doi.org/10.7554/eLife.47996.024

Tables

Table 1
Morphometric analysis of network development under different PKC conditions.

Results are presented as mean ± standard error of mean (SEM). Significance was determined against PKCN, or between specified developmental time windows, using independent Student’s t-test. N

https://doi.org/10.7554/eLife.47996.014
DIVPKC-PKCNPKC+unit
clustering index
80.92 ± 0.01 (1.8*10−10)0.84 ± 0.010.82 ± 0.02 (6.1*10−1)CI
150.9 ± 0.01 (1.5*10−6)0.73 ± 0.010.69 ± 0.02 (1.1*10−1)CI
220.88 ± 0.01 (4.4*10−4)0.75 ± 0.030.67 ± 0.02 (3.3*10−2)CI
290.89 ± 0.01 (8.0*10−9)0.79 ± 0.010.67 ± 0.02 (2.1*10−5)CI
8 vs. 22−4.49 (3.5*10−4)−9.65 (3.1*10−2)−18.6 (1.2*10−5)% change
22 vs. 291.04 (4.9*10−1)4.5 (2.7*10−1)0.01 (1.0)% change
Dendrite size
8476 ± 9 (1.3*10−3)421 ± 12408 ± 8 (3.4*10−1)µm
15797 ± 22 (1.2*10−2)676 ± 37610 ± 30 (2.1*10−1)µm
221413 ± 64 (7.9*10−5)1021 ± 41816 ± 24 (3.6*10−4)µm
291380 ± 74 (1.9*10−4)962 ± 65760 ± 37 (1.3*10−2)µm
8 vs. 22196.59 (4.0*10−20)142.46 (9.1*10−12)100.08 (1.4*10−15)% change
22 vs. 29−2.38 (7.4*10−1)−5.81 (5.0*10−1)−6.86 (2.5*10−1)% change
Synapse density
8281 ± 11 (2.2*10−1)255 ± 18254 ± 14 (9.4*10−1)#
151142 ± 44 (2.3*10−4)754 ± 39510 ± 9 (2.4*10−5)#
222188 ± 100 (2.1*10−5)1427 ± 99885 ± 27 (3.4*10−5)#
292019 ± 110 (4.5*10−8)1114 ± 56669 ± 21 (5.7*10−8)#
8 vs. 22678.77 (4.7*10−24)458.69 (2.1*10−10)248.68 (1.2*10−17)% change
22 vs. 29−7.75 (2.7*10−1)−21.93 (6.7*10−3)−24.35 (1.2*10−6)% change
Dendritic occupancy
80.59 ± 0.02 (6.4*10−1)0.6 ± 0.040.62 ± 0.03 (7.5*10−1)#/µm
151.44 ± 0.05 (1.7*10−2)1.13 ± 0.110.85 ± 0.04 (1.7*10−2)#/µm
221.55 ± 0.03 (9.6*10−2)1.4 ± 0.091.09 ± 0.04 (5.7*10−3)#/µm
291.47 ± 0.04 (3.0*10−5)1.19 ± 0.040.9 ± 0.04 (2.3*10−5)#/µm
8 vs. 22163.83 (7.2*10−28)132.26 (9.0*10−8)76.65 (3.7*10−10)% change
22 vs. 29−5.06 (1.5*10−1)−15.41 (2.3*10−2)−17.45 (3.8*10−3)% change
Neuron density
8255 ± 6 (9.6*10−7)185 ± 11168 ± 7 (2.0*10−1)#/mm2
15214 ± 9 (5.9*10−4)131 ± 17158 ± 12 (2.0*10−1)#/mm2
22107 ± 8 (1.9*10−1)123 ± 685 ± 6 (5.7*10−4)#/mm2
2987 ± 5 (3.0*10−1)96 ± 777 ± 4 (2.6*10−2)#/mm2
8 vs. 22−58.03 (7.3*10−17)−33.66 (1.1*10−4)−49.42 (1.0*10−8)% change
22 vs. 29−18.93 (4.5*10−2)−21.71 (1.3*10−2)−9.79 (2.6*10−1)% change
Maximum connectivity
80.01 ± 0.001 (3.5*10−2)0.013 ± 0.0010.014 ± 0.001 (6.3*10−1)fraction
150.048 ± 0.003 (4.6*10−1)0.053 ± 0.0060.029 ± 0.002 (9.2*10−4)fraction
220.209 ± 0.031 (8.2*10−3)0.104 ± 0.0070.098 ± 0.009 (5.9*10−1)fraction
290.229 ± 0.026 (9.2*10−4)0.116 ± 0.0140.081 ± 0.006 (3.8*10−2)fraction
8 vs. 221987.43 (5.9*10−10)701.18 (2.6*10−11)604.32 (1.4*10−10)% change
22 vs. 299.31 (6.3*10−1)11.48 (5.2*10−1)−17.23 (1.3*10−1)% change
N
8241115
15947
22151111
29171615
Table 1—source data 1

Source data and Matlab script.

https://doi.org/10.7554/eLife.47996.015
Table 1—source data 2

Source data and Matlab script.

https://doi.org/10.7554/eLife.47996.016
Table 2
Electrophysiological characterization of network activity during development.

Data were pooled within defined developmental time windows. Significance was determined against PKCN using independent Student’s t-test. N specifies the number of recorded networks per PKC condition …

https://doi.org/10.7554/eLife.47996.020
DIVPKCPKCNPKC+
AFR
3–50.03 ± 0.01 (1.0*10−1)0.05 ± 0.010.09 (1.4*10−1)
6–90.08 ± 0.01 (2.6*10−3)0.18 ± 0.030.1 ± 0.02 (4.0*10−2)
10–140.36 ± 0.04 (1.8*10−2)0.49 ± 0.030.42 ± 0.04 (2.0*10−1)
15–200.53 ± 0.06 (3.6*10−1)0.61 ± 0.060.76 ± 0.19 (3.6*10−1)
21–270.69 ± 0.08 (2.5*10-1)0.8 ± 0.061.21 ± 0.12 (7.3*10−4)
28–350.6 ± 0.07 (2.9*10−3)0.96 ± 0.091.41 ± 0.15 (6.9*10−3)
36–440.42 ± 0.08 (2.4*10−7)1.18 ± 0.12.04 ± 0.83 (4.3*10−2)
45+0.24 ± 0.02 (9.9*10−8)1.06 ± 0.141.2 ± 0.63 (8.3*10−1)
SBE rate (SBE/min)
3–50.17 ± 0.04 (2.9*10−1)0.11 ± 0.030.54 (1.5*10−2)
6–90.18 ± 0.03 (5.4*10−6)1.02 ± 0.151.46 ± 0.19 (7.4*10−2)
10–141.21 ± 0.13 (2.0*10−8)4.26 ± 0.4411.69 ± 1.27 (3.4*10−10)
15–202.83 ± 0.35 (1.4*10−8)6.36 ± 0.4314.31 ± 2.03 (4.7*10−7)
21–274.58 ± 0.44 (2.4*10−10)10.3 ± 0.6226.82 ± 3 (5.5*10−12)
28–354.98 ± 0.81 (2.2*10−13)16.97 ± 1.0741.1 ± 5.07 (7.9*10-9)
36–444.08 ± 0.75 (9.0*10−12)17.25 ± 1.2826.21 ± 7.05 (8.7*10−2)
45+3.74 ± 0.56 (2.2*10−13)18.85 ± 1.6245.76 ± 23.86 (2.0*10−3)
SBE strength (APs per burst)
3–56.2 ± 3 (1.0*100)6.2 ± 3.83.5 (7.6*10−1)
6–921.6 ± 2.1 (9.4*10−7)9.5 ± 14.6 ± 0.6 (1.2*10−3)
10–1421.2 ± 2.1 (5.7*10−9)9 ± 0.82.7 ± 0.5 (1.5*10−7)
15–2015.2 ± 1.9 (2.1*10−3)8 ± 1.32.7 ± 0.3 (1.2*10−2)
21–2710.1 ± 1 (6.1*10−8)4.9 ± 0.44.4 ± 0.9 (5.4*10−1)
28–358.9 ± 0.9 (2.9*10−6)4 ± 0.52.3 ± 0.3 (1.7*10−2)
36–446.2 ± 0.6 (2.2*10−1)5.1 ± 0.65.1 ± 1.6 (9.8*10−1)
45+5.6 ± 0.8 (4.2*10−2)3.8 ± 0.51.1 ± 0.4 (2.2*10−1)
 PFR (Hz)
3–512.3 ± 3.8 (9.0*10−1)13.2 ± 7.311.5 (9.2*10−1)
6–950.8 ± 4.8 (6.4*10−5)28.3 ± 2.717.4 ± 1.7 (4.9*10−3)
10–1476.6 ± 5.4 (6.7*10−14)32.1 ± 2.310.3 ± 1.4 (2.1*10−9)
15–2059.1 ± 6.5 (5.3*10−5)29.8 ± 3.410.9 ± 1.3 (6.4*10−4)
21–2743.3 ± 4.1 (7.4*10−10)18.9 ± 1.513.7 ± 2 (4.4*10−2)
28–3542.3 ± 4.4 (2.4*10−8)15.5 ± 28.1 ± 1.2 (1.8*10−2)
36–4430.5 ± 3.1 (2.7*10−2)21.4 ± 2.66.1 ± 0.4 (1.3*10−1)
45+27.5 ± 3.8 (1.5*10−2)16.4 ± 2.35.6 ± 1.7 (2.8*10−1)
Network synchrony
3–50.1 ± 0.03 (2.6*10−1)0.04 ± 0.020.08 (3.4*10−1)
6–90.39 ± 0.02 (3.3*10−3)0.29 ± 0.020.15 ± 0.02 (3.1*10−4)
10–140.52 ± 0.03 (2.5*10−10)0.31 ± 0.020.12 ± 0.02 (1.4*10−10)
15–200.53 ± 0.04 (4.6*10−5)0.35 ± 0.020.16 ± 0.03 (1.7*10−5)
21–270.51 ± 0.03 (5.8*10−13)0.26 ± 0.020.2 ± 0.02 (4.8*10−2)
28–350.57 ± 0.04 (2.0*10−10)0.24 ± 0.030.15 ± 0.03 (7.6*10−2)
36–440.53 ± 0.04 (1.3*10−5)0.3 ± 0.030.11 ± 0.03 (1.3*10−1)
45+0.45 ± 0.05 (2.5*10−3)0.26 ± 0.030.14 ± 0.11 (3.8*10−1)
N
3–5731
6–9334024
10–14709247
15–20536527
21–277712156
28–35476229
36–4438574
45+38362
Key resources table
Reagent type (species)
or resource
DesignationSource or
reference
IdentifiersAdditional information
Strain, strain background (Rattus norvegicus domestica)wildtype wistar rat pupsCEMT, University, Freiburg
Genetic reagentAAV9.CAG.GCaMP6s.WPRE.SV40Penn Vector Core, University of PennsylvaniaV3296TI-Rtiter 1e11
Antibodyanti-MAP2 (chicken polyclonal)Abcam, Cambridge, UKab92434 RRID:AB_21381471:500
Antibodyanti-NeuN (rabbit polyclonal)Abcam, Cambridge, UKab128886
RRID:AB_2744676
1:500
Antibodyanti-Neurofilament (mouse monoclonal)Abcam, Cambridge, UKab24571
RRID:AB_448148
1:10
Antibodyanti-Synapsin (mouse monoclonal)Synaptic Systems GmbH, Germany106001
RRID:AB_887805
1:200
Antibodyanti-chicken-Cy2 (goat polyclonal)Abcam, Cambridge, UKab6960
RRID:AB_955003
1:200
Antibodyanti-rabbit-Cy3 (goat polyclonal)Abcam, Cambridge, UKab6939
RRID:AB_955021
1:200
Antibodyanti-mouse-Cy5 (goat polyclonal)Abcam, Cambridge, UKab6563
RRID:AB_955068
1:200
Chemical compound, drug4,6-diamidino-2-phenyindole, diclactate (DAPI)Sigma-Aldrich, GermanyD95621:5000
Chemical compound, drugGödecke6976Tocris Bioscience, Bristol, UK22531 µM
Chemical compound, drugPhorbol-12-Myristate-13-Acetate (PMA)Sigma-Aldrich, Munich, GermanyP15851 µM
Chemical compound, drugPicrotoxinTocris Bioscience, Bristol, UK112810 µM
Chemical compound, drugDMSOSigma-Aldrich, Munich, GermanyD84180.1%
Chemical compound, drugDNase (type IV)Sigma-Aldrich, Munich, GermanyD502550 g/ml
Chemical compound, drugminimal essential mediumInvitrogen, Karlsruhe, Germany21090055
Chemical compound, drughorse serum (heat-inactivated)Invitrogen, Karlsruhe, Germany2605008820%
Chemical compound, drugphosphate buffered saline (PBS)Invitrogen, Karlsruhe, Germany21600010
Chemical compound, drugglucoseSigma-Aldrich, Munich, GermanyG752820 mM
Chemical compound, drugL-glutamineInvitrogen, Karlsruhe, Germany250300240.5 mM
Chemical compound, druggentamycinInvitrogen, Karlsruhe, Germany1575006020 µg/ml
Chemical compound, drugpotassiumD-gluconateSigma-Aldrich, Munich, GermanyG4500125 mM
Chemical compound, drugEGTACarl Roth, Karlsruhe, Germany30545 mM
Chemical compound, drugKClSigma-Aldrich, Munich, GermanyP450420 mM
Chemical compound, drugNa2-ATPCarl Roth, Karlsruhe, GermanyK0542 mM
Chemical compound, drugHepesCarl Roth, Karlsruhe, Germany910510 mM
Chemical compound, drugCaCl2Sigma-Aldrich, Munich, GermanyC38810.5 mM
Chemical compound, drugKOHSigma-Aldrich, Munich, GermanyP4504
Chemical compound, drugMgCl2Sigma-Aldrich, Munich, GermanyMO2502 mM
SoftwareMC Rack softwareMulti Channel Systems, Germanyversions 3.3–4.5
RRID:SCR_014955
SoftwareSpike2 softwareCambridge Electronics Design Ltd., Cambridge, UK.RRID:SCR_000903
SoftwareZenCarl Zeiss, Jena, GermanyRRID:SCR_013672
SoftwareMEA-ToolsEgert et al., 2002 (PMID 12084562)version 2.8
SoftwareFIND toolboxMeier et al., 2008 (PMID 18692360)
SoftwareImageJSchneider et al., 2012 (PMID 22930834)RRID:SCR_003070
SoftwareMatlabMathworks, Natick, MA, USAversions
2014a – 2017a

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