MATLAB: Neural Network Clustering: Querying a neuron hit on a Self organising Map

Question

Is there a command within the Neural Networks toolbox to query a neuron on a SOM?

I created a input training matrix of 9 animals with 7 features per animal(eg. size, legs, wings, etc). I tried to use a 2×2 SOM to classify these animals. The SOM suggested that Neuron1=2 hits, Neuron2=1 hit, Neuron3=4 hits, Neuron4=2 hits.

I would like to interrogate each neuron to find out which of the 7 vectors mentioned triggered it (eg. which two animals triggered Neuron1) so the map is more representative of which vectors are associated with various neurons.

Any help will be deeply appreciated.

PS: I've used the nctool command to generate the SOM.

Thanks. John.

Answer 1

Kohonen created his SOM to be used as data a visualization aid; NOT a classifier.

He developed the LVQ algorithms for classification. I'm pretty sure they are initialized with SOM.

Check with Kohonen's books and comp.ai.neural-nets.

How many nodes do you have on your map? If you want to separate the 9 animals on the map, try increasing the dimensions on the map.

Once you have a map can't you introduce just one animal to see where it falls?

Better yet: Use LVQ that's what Kohonen designed it for.

Hope this helps.

Thank you for formally accepting my answer.

Greg