Apical length governs computational diversity of layer 5 pyramidal neurons
- The Francis Crick Institute, United Kingdom
- University College London, United Kingdom
- Birkbeck College, University of London, United Kingdom
Figures
Figure 1 with 1 supplement
Reduced dendritic Ca2+ electrogenesis in V2m ttL5 neurons.
(A) Left: diagram of experimental configuration. Right: example traces during BAC firing protocol, recorded from V1 (red) and V2m (blue) ttL5 neurons. (B) Proportion of BAC firing neurons in V1 and …
Figure 1—figure supplement 1
Identification of ttL5 neurons and recording locations in V1 and V2m.
(A) Coronal slice containing visual cortex and LP, showing the injection site and retrogradely labelled neurons (green), tdTomato-expressing Colgalt2-Cre neurons (magenta), a DAPI stain (blue), and …
Figure 2 with 4 supplements
ADP integral correlates with apical trunk length.
(A) Summary data of maximum ADP integral values for all recorded neurons. The dashed line denotes the division between the two groups of cells classified through k-means clustering; asterisk denotes …
Figure 2—figure supplement 1
Maximum ADP integral for all cells split by recording ACSF containing either 1.5 or 2 mM CaCl2.
p and D values are shown for a two-sample Kolmogorov-Smirnov test. All cells recorded during this study in 1.5 mM CaCl2 are included.
Figure 2—figure supplement 2
Maximum ADP integral for all cells including V1 (grey), retro-labelled cells recorded from V2m (blue), and V2m cells labelled in the Colgalt2-Cre mouse line (cyan).
p and D value are shown for a two-sample Kolmogorov-Smirnov test. All cells recorded during this study from Colgalt2-Cre animals are included.
Figure 2—figure supplement 3
Intrinsic properties of in vitro and in silico recorded neurons.
(A) Representative voltage traces for V1 and V2m neurons in response to 500 ms wide depolarizing current steps. The traces show stimulation at 60 pA (grey) and 180 pA (coloured or black) above …
Figure 2—figure supplement 4
Reconstructions and morphological analysis of V1 and V2m neurons.
(A) Full reconstructions of 6 neurons in V1 (top) and 7 neurons in V2m (bottom), labelled with CTB and filled with biocytin during recordings. Black: dendrites and soma. Green: axons. (B) …
Figure 3 with 2 supplements
Shorter model neurons are less prone to burst.
(A) Left: detailed morphology of a ttL5 neuron from the model favoured by Hay et al., 2011 for reproducing BAC firing. Right: reconstructed morphology of the ttL5 neuron from V2m. Injected current …
Figure 3—figure supplement 1
Exploration of Ca2+ electrogenesis under diverse stimulus timings and intensities.
(A) Calcium current densities at the apical bifurcation during coincident stimulation for different relative levels of tuft gCa (as in Figure 3B). N.B. there is a factor of 104 difference in scale …
Figure 3—figure supplement 2
Hot zone size or Ca2+ channel ratio does not account for differences in Ca2+ electrogenesis.
(A) Voltage traces recorded from different parts of the long neuronal morphology containing either a 200 μm (as in the original), or 100 μm long Ca2+ hot zone in the distal apical trunk. (B) Same as …
Figure 4 with 4 supplements
Tuft voltage increases with trunk length due to the widening of bAPs.
(A) Schematic of the simulation: stimulation site in the somatic compartment and recording sites at the distal end of the apical trunk (blue) and in the centre of the tuft (red). Stimulus shown in …
Figure 4—figure supplement 1
Backpropagation of APs in active and passive trunks of different length.
(A) Backpropagation of a somatic spike elicited through a single 3 ms wide 2 nA square current step at the soma in a model neuron with 600 μm apical trunk length. Voltage recordings at different …
Figure 4—figure supplement 2
Tuft voltage increases with trunk length independently of conductance gradients.
Same experiments as in Figure 3A but with uniform distribution of all active conductances in the apical trunk. Total conductance was maintained for each channel.
Figure 4—figure supplement 3
Ih is not critical to the length dependence of Ca2+ electrogenesis.
(A) Plots of peak voltage, width and integral of bAPs under different relative gHCN (shades) in the tuft, both in the presence (dashed) or absence (solid) of Ca2+ channels. (B) Same as A, but …
Figure 4—figure supplement 4
Effect of axial resistance on voltage propagation.
Plots of peak voltage, width, and voltage integral reached in the tuft and the last segment of the trunk for varying values of trunk length and axial resistance (Ra). Default Ra ≅ 382.22 Ω∙cm. The …
Figure 5
Interplay of width and amplitude underlie length dependence of Ca2+ electrogenesis.
(A) Different width voltage steps (i) or same width under differing tuft membrane capacitance conditions (ii) injected into the trunk (blue). Recorded tuft voltage in red, Vrest = −65 mV. (B) Peak …
Author response image 1
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Strain, strain background (Mus musculus, C57BL/6, male) | Colgalt2-Cre | The Jackson Laboratory | RRID:MMRRC_036504-UCD | |
| Strain, strain background (Mus musculus, C57BL/6) | Rbp4-Cre | The Jackson Laboratory | RRID:MMRRC_031125-UCD | |
| Strain, strain background (Mus musculus, C57BL/6) | Ai14 | The Jackson Laboratory | RRID:IMSR_JAX:007908 | |
| Peptide, recombinant protein | Alexa Fluor 488-conjugated Cholera toxin subunit B (CTB) | Thermo Fisher Scientific | Cat.# C34775 | 0.8% w/v |
| Chemical compound, drug | CGP-52432 | Tocris | Cat.# 1246 | 1 μM in ACSF |
| Peptide, recombinant protein | DyLight 594-conjugated streptavidin | Thermo Fisher Scientific | Cat.# 21842 | 2 μg/ml |
| Peptide, recombinant protein | Biocytin hydrochloride | Sigma-Aldrich | Cat.# B1758 | 0.5% w/v |
| Other | DAPI stain | Sigma-Aldrich | Cat.# D9542 | 5 μg/ml |
| Software, algorithm | MATLAB R2018a | MathWorks | RRID:SCR_001622 | |
| Software, algorithm | Python 3.6 | RRID:SCR_008394 | ||
| Software, algorithm | SciPy | RRID:SCR_008058 | ||
| Software, algorithm | NEURON simulation environment 7.7.1 | Carnevale and Hines, 2006 | RRID:SCR_005393 | |
| Software, algorithm | Neurolucida 360 | MBF Bioscience | RRID:SCR_001775 | |
| Software, algorithm | Igor Pro 6.37 | WaveMetrics | RRID:SCR_000325 | |
| Software, algorithm | NeuroMatic 2.5 | Rothman and Silver, 2018 | RRID:SCR_004186 | |
| Software, algorithm | FIJI | https://imagej.net/Fiji | RRID:SCR_002285 |
