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Streamed live on Jan 31, 2014
We will hear a presentation from OpenWorm community member Tom Portegys on the following topic. Anyone is welcome to attend this on air hangout and ask questions.
Training sensory-motor behavior sequences in the connectome of an artificial C. elegans
The C. elegans nematode is a small well-known creature, intensely studied for decades. Its entire morphology has been mapped cell-by-cell, including its 302 neuron connectome. The connectome is a synaptic wiring diagram that also specifies neurotransmitters and junction types. It does not however specify the synaptic connection strengths. It is believed that measuring these must be done in live specimens, requiring yet to be developed techniques. Without the connection strengths, it is not fully known how the nematode's nervous system produces sensory-motor behaviors.
From a computing point of view, "programming" the unknown connection weights is a challenging and important problem in its own right. An artificial worm embodying the connectome and programmed to perform a set of sensory-motor sequences taken from measurements of the actual C. elegans would behave realistically in an artificial environment. This is a crucial step toward creating a fully functional artificial creature. Indeed, knowing the artificial weights might cast light on the actual ones.
A hybrid genetic algorithm is presented that trains a large space of thousands synapse weights to perform given sensory-motor sequences accurately. In addition, the training of the C. elegans body muscles to respond with an undulatory movement to a "light touch" sensory stimulus is also presented. These results suggests that the training of authentic sensory-motor locomotion behavior might be possible with the use of a fitness function crafted from high fidelity locomotion measurements.