Discrimination of binary patterns by perceptrons with binary weights

Mathematical Biology and Ecology Seminar
Wednesday, November 9, 2011 - 11:00
1 hour (actually 50 minutes)
Skiles 005
Georgia Gwinnett College
  Information processing in neurons and their networks is understood incompletely, especially when neuronal inputs have indirect correlates with external stimuli as for example in the hippocampus. We study a case when all neurons in one network receive inputs from another network within a short time window.  We consider it as a mapping of binary vectors of spiking activity ("spike" or "no spike") in an input network to binary vectors of spiking activity in the output network.  Intuitively, if an input pattern makes a neuron spike then the neuron should also spike in response to similar patterns - otherwise, neurons would be too sensitive to noise.  On the other hand, neurons should discriminate between sufficiently different input patterns and spike selectively.  Our main goal was to quantify how well neurons discriminate input patterns depending on connectivity between networks, spiking threshold of neurons and other parameters. We modeled neurons with perceptrons that have binary weights. Most recent results on perceptron neuronal models are asymptotic with respect to some parameters. Here, using combinatorial analysis, we complement them by exact formulas. Those formulas in particular predict that the number of the inputs per neuron maximizes the difference between the neuronal and network responses to similar and distinct inputs.  A joint work with Jean Vaillant (UAG).