Plotting somatodendritic attenuation for biophysical models

Hello everyone,

I am using a configuration I found for a biophysical neuron model in the mouse V1 area, namely:

"N": 2350,
            "node_type_id": 471129934,
            "model_type": "biophysical",
            "model_template": "ctdb:Biophys1.hoc",
            "dynamics_params": "471129934_fit.json",
            "morphology": "Rbp4-Cre_KL100_Ai14-180747.06.01.01_495335491_m.swc",
            "model_processing": "aibs_perisomatic",
            "rotation_angle_zaxis": -2.527764895

I am trying to plot the somatodendritic attenuation for a current injection at the soma at steady state. For example, if I apply a -10 pA current injection at the soma for 1000ms, I would like to be able to see the membrane potential depending on what distance from the soma I’m looking at, for example at 100 micrometers, 250 micrometers and 600 micrometers from the soma on the dendritic tree. I am new to this and I would appreciate any help or guidance into how this could be done using the Brain Modelling Toolkit (BMTK). Currently my code doesn’t implement this because I tried to find information about distance-dependent recordings, but wasn’t able to. Thank you in advance!

Currently, my code looks like this:

from bmtk.builder.networks import NetworkBuilder
from bmtk.utils.sim_setup import build_env_bionet
from bmtk.simulator import bionet
import h5py

# Build the network
net = NetworkBuilder('mcortex')
    rotation_angle_zaxis= -2.527764895

for node in net.nodes():

# Set up the simulation environment
    base_dir='sim_ch01',       # Where to save the scripts and config files 
    config_file='config.json', # Where main config will be saved.
    network_dir='network',     # Location of directory containing network files
    tstop=2000.0, dt=0.1,      # Run a simulation for 2000 ms at 0.1 ms intervals
    report_vars=['v', 'cai'],  # Tells simulator we want to record membrane potential and calcium traces
    current_clamp={            # Creates a step current from 500.0 ms to 1500.0 ms  
        'amp': 0.520,
        'delay': 300.0,
        'duration': 1000.0
    include_examples=True,    # Copies components files for tutorial examples
    compile_mechanisms=True   # Will try to compile NEURON mechanisms

from bmtk.builder.networks import NetworkBuilder
from bmtk.utils.sim_setup import build_env_bionet
from bmtk.simulator import bionet
import h5py
# Run the simulation
conf = bionet.Config.from_json('sim_ch01/config.json')
net = bionet.BioNetwork.from_config(conf)
sim = bionet.BioSimulator.from_config(conf, network=net)

# Inspect the spike file
spike_file = 'sim_ch01/output/spikes.h5' 

with h5py.File(spike_file, 'r') as f:
    print("Groups in the spike file:", list(f.keys()))
    if 'spikes' in f:
        print("Populations in the spike file:", list(f['spikes'].keys()))

# Check if the spike file is generated and not empty
from bmtk.analyzer.spike_trains import _find_spikes

    pop, spike_trains = _find_spikes(config_file='sim_ch01/config.json')
    print(f"Population: {pop}")
    print(f"Spike Trains: {spike_trains}")
    df = spike_trains.to_dataframe()
except IndexError as e:
    print(f"IndexError: {e} - Check if the spike file contains the expected population.")
except Exception as e:
    print(f"Unexpected error: {e}")

from bmtk.analyzer.compartment import plot_traces
import matplotlib.pyplot as plt

    v_plots = plot_traces(config_file='sim_ch01/config.json', node_ids=[0], report_name='v_report')
except Exception as e:
    print(f"Error plotting traces: {e}")

The simulation_config.json file has the following parameters:

  "manifest": {
    "$BASE_DIR": "${configdir}",
    "$OUTPUT_DIR": "$BASE_DIR/output"
  "target_simulator": "NEURON",
  "run": {
    "tstart": 0.0,
    "tstop": 2000.0,
    "dt": 0.1,
    "dL": 20.0,
    "spike_threshold": -15.0,
    "nsteps_block": 5000
  "conditions": {
    "celsius": 34.0,
    "v_init": -80.0
  "inputs": {
    "current_clamp": {
      "input_type": "current_clamp",
      "module": "IClamp",
      "node_set": "all",
      "gids": "all",
      "amp": -0.1,
      "delay": 500.0,
      "duration": 1000.0
  "output": {
    "log_file": "log.txt",
    "output_dir": "$OUTPUT_DIR",
    "spikes_file": "spikes.h5"
  "reports": {
    "v_report": {
      "variable_name": "v",
      "cells": "all",
      "module": "membrane_report",
      "sections": "all"
    "cai_report": {
      "variable_name": "cai",
      "cells": "all",
      "module": "membrane_report",
      "sections": "soma"
  "node_sets_file": "$BASE_DIR/node_sets.json"

Many thanks.

Best wishes,