Studies of Neuromodulation of Oscillatory Systems in Aplysia, by Means of Genetic Algorithms

Abstract

Neural modeling methods were used to obtain insights into the role of neuromodulatory cotransmitters. Although the work was guided by specific experimental observations on feeding in Aplysia, it was meant as a more general treatment of behavioral systems. Genetic algorithms were used to evolve the parameters needed to permit a simple two-neuron circuit to oscillate and contract muscles that execute rhythmic feeding responses. The evolved circuits were found to possess a number of "emergent" properties not specifically selected for. The fitness of the circuit decreased under a variety of conditions, particularly when the rate of the rhythmic program increased. The fitness of the system could be restored when an autoregulatory cotransmitter system was added and served to dynamically alter the parameters of the muscles that generated the behavior.

Computational model of the distributed representation of operant reward memory: combinatoric engagement of intrinsic and synaptic plasticity mechanisms

“…Comparison with previous models of the feeding CPG Several previous studies described models of the Aplysia feeding neural network that can simulate aspects of feeding. Some of these previous models were abstract in design (Kupfermann et al 1992;Deodhar and Kupfermann 2000), whereas others adhered to biological constraints (Ziv et al 1994;Susswein et al 2002;Cataldo et al 2006;Hurwitz et al 2008). The present model was an extension of our previous studies of the Aplysia feeding circuit (Kabotyanski et al 1994;Ziv et al 1994;Susswein et al 2002;Cataldo et al 2006Cataldo et al , 2009Baxter et al 2010), and represents the most comprehensive model to date.…”

Computer Evolution of Chemotaxis in Model Nematodes

“…Analysis of such an ensemble of models can then lead to general insights and focus the design of crucial experiments that distinguish between the different possibilities. Indeed, evolutionary approaches are increasingly being employed in behavioral neuroscience and related areas, including studies of locomotion [Beer et al, 1999;Bryden and Cohen, 2008;Ijspeert, 2001], neuromodulation in Aplysia [Deodhar and Kupfermann, 2000], path integration in ants [Vickerstaff and Di Paolo, 2005], and even selective attention in humans [Ward and Ward, 2008].…”