lgn-simulator is a visual stimulus-driven simulator of spatiotemporal cell responses in the early part of the visual system consisting of the retina, lateral geniculate nucleus (LGN) and primary visual cortex. The model behind is a linear mechanistic, firing rate model that incorporates the influence of thalamocortical loops, in addition to the feedforward responses. The advantage of the simulator lies in its computational and conceptual ease, allowing for fast and comprehensive exploration of various scenarios for the organization of the cortical feedback.

• Source code

Theory

• Receptive fields
• Linear information processing
• Impulse response function
• Convolution theorem
• Spatio-Temporal summation
• Descriptive model
• Mechanistic model
• The dLGN circuit
• Fourier transform

Getting started

The lgn-simulator is written as library. Thus the library can be included in main.cpp files and used in different applications. The namespace is lgnSimulator.

#include <lgnSimulator.h>
using namespace lgnSimulator;

int main(int argc, char *argv[])
{
    ...
}

A minimalistic main.cpp file can be found here.

Development and technical details

lgn-simulator is written in C++ using Qt Creator. The main classes are:

• lgnSimulator::Integrator: computes the forward and backwrad FFT of both 2d and 3d datasets.
• lgnSimulator::Stimulus: virtual class for stimulus types.
• lgnSimulator::Neuron: virtual class for neuron types.
• lgnSimulator::Kernel: virtual class for kernels.

Neurons

Kernels

Non-seperable kernels can be added by creating a subclass of lgnSimulator::Kernel. Alternatively a seperable kernel can be added by creating a subclass of lgnSimulator::SeparableKernel, which is also a subclass of lgnSimulator::Kernel. Seperable kernels consist of a lgnSimulator::SpatialKernel and a lgnSimulator::TemporalKernel.

Spatial kernels:

Temporal kernels:

Stimulus

The stimlus can be both gratings (lgnSimulator::Grating) or natural scenes/movies (lgnSimulator::NaturalScene and lgnSimulator::NaturalSceneVideo).

Grating stimuli:

All classes

List of all classes in the simulator is found here: All classes