Another quick update – I fixed some synapse timing issues in the Temporal Frame engine and finished up the axoaxonic code this weekend. I had a succesful test of sensitization as well, demonstrating the non-Hebbian learning capabilities of a neural matrix. Due to axoaxonic connections, a presynaptic neuron can now cause a direct increase in the synaptic weight of the postsynaptic neuron’s axon terminal (This postsynaptic neuron itself being a presynaptic neuron in another relationship).

The test was performed by generating a 3 neuron matrix. Milo’s left touch sensor was sent as input into neuron 1, while Milo’s right touch sensor was sent as input into neuron 2. Neuron 1 was connected via an axoaxonic connection to neuron 2’s axon terminal – the axon terminal creating the synapse between neuron 2 and neuron 3 in a standard axodendritic configuration. Neuron 3’s output was sent to Milo’s speaker.

The treshold rate of Neuron 3 was set higher than the synaptic weight between neuron 2 and 3, hence if Milo’s right antenna was pressed he would not beep. However, upon touching Milo’s left antenna a few times, via the phenomenon of sensization the synaptic weight between Neuron 2 and 3 was increased, and subsequent pressings of Milo’s right antenna was enough alone to cause Milo to beep, now the synaptic weight had grown strong enough to pass Neuron 3’s threshold.

Cool stuff!