From brain activities to mathematical models The TempUnit model, a study case for GPU computing in scientific computation.
What part of the brain?
How to study it ?
First attempt: use of a MLP What is a MLP?
First Attempt: MLP (2)
Results (1)
Results (2)
Crack the code !! Frequency code (Number of spikes in a time lap) ? Spatial coding (distributed trough the network) ? Temporal code (Precise binary pattern) ? Spatio-temporal code (Synchronies) ? Something else ?
The model x XtXt
Learn the parameters v i Solving a system of linear equation oversized. Much faster and straightforward than backpropagation for the MLP Example of a learned basis function
Performances compared to MLP
Check Chap. 12
Graph of Neuronal Activity The output activity of a TempUnit neural network can be described by a graph directly related to its connectivity – You determine the topology of your graph easily Allow to determine the input activity for a particular desired output
Can a real biological neuron do that ?
Pattern recognition
learning rules for unsupervised learning
EPSP from the integrate-and-fire model To find the position of the maximum (peak), one has to resolve the following equation: (Gerstner & Kistler, 2002) From the integrate and fire, the α function: time
The new equation of the TempUnit model: With μ, the maximum value: time p=0 p=6 p : position of the synapse
From equations to a simulation software