LGMD Variability and logarithmic compression in dendrites (Jones and Gabbiani, 2012, 2012B)

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A compartmental model of the LGMD with a simplified, rake shaped, excitatory dendrite. It receives spontaneous input and excitatory and inhibitory synaptic inputs triggered by visual stimuli. It generates realistic responses to looming through the velocity dependent scaling and delay of individual excitatory synaptic inputs, with variability. We use the model to show that the key determinants of output variability are spontaneous input and temporal jitter of the excitatory inputs, rather than variability in magnitude of individual inputs (2012B, J Neurophysiol). We also use the model to analyze the transformation of the excitatory signals through the visual pathway; concluding that the representation of stimulus velocity is transformed from an expansive relationship at the level of the LGMD inputs to a logarithmic one at the level of its membrane potential (2012, J Neurosci).
1 . Jones PW, Gabbiani F (2012) Impact of neural noise on a sensory-motor pathway signaling impending collision. J Neurophysiol 107:1067-79 [PubMed]
2 . Jones PW, Gabbiani F (2012) Logarithmic compression of sensory signals within the dendritic tree of a collision-sensitive neuron. J Neurosci 32:4923-34 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Locust Lobula Giant Movement Detector (LGMD) neuron;
Channel(s): I K; I K,Ca; I Calcium;
Gap Junctions:
Receptor(s): Nicotinic; GabaA;
Transmitter(s): Acetylcholine; Gaba;
Simulation Environment: NEURON; MATLAB;
Model Concept(s): Sensory processing; Vision;
Implementer(s): Jones, Peter W [pwjones at cnbc.cmu.edu];
Search NeuronDB for information about:  Nicotinic; GabaA; I K; I K,Ca; I Calcium; Acetylcholine; Gaba;
There are two collections of computer code in this archive: the
jneurosci2012 folder and jnphysiol2012 folder.  The jneurosci2012
folder is for

Jones PW, Gabbiani F. (2012) Logarithmic Compression of Sensory
    Signals within the Dendritic Tree of a Collision-Sensitive
    Neuron. J Neurosci, In press.

This jneurosci2012 version includes code to reproduce figures and
analysis in press right now, and we've added it to the same model
entry alongside the previous version jnphysiol2012, for the 2012B

Jones PW, Gabbiani F. (2012B) Impact of neural noise on a
    sensory-motor pathway signaling impending collision. J
    Neurophysiol 107:1067–1079.

just in a separate version folder, since it is conceptually
the same (just slight changes in the underlying parameters prevent
merging the two versions).

Please refer to the README files in these subdirectories for more
information.  This code was contributed by Dr Pete Jones.

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