Model-Based Analysis of Electrode Placement and Pulse Amplitutde for Hippocampal Stimulation

Model-Based Analysis of Electrode Placement and Pulse Amplitutde for Hippocampal Stimulation 170 177 IEEE Transactions on Biomedical Engineering (TBME)

A brain implant performs best when it is properly adapted to the anatomy of the region with which it is meant to interface. Multiple-electrode arrays provide a system which can be adapted to various tissue geometries. Computational models of stimulating systems are useful for evaluating electrode placement and stimulation protocols but have yet to be adequately adapted to the unique features of the hippocampus. As an approach to understanding potential memory restorative devices, we have constructed an Admittance Method-NEURON model to predict the direct and synaptic response of a region of the rat dentate gyrus to electrical stimulation of the perforant path. Following construction of the model, we performed a validation of estimated local field potentials against experimental recordings and used predictions to optimize electrode placement and stimulation amplitudes. Our results suggest that stimulating electrodes placed between the lateral and medial perforant path, near the crest of the dentate gyrus, yield a larger relative population response to given stimuli. Beyond deepening understanding of the hippocampal tissue system, establishment of this model provides a method to evaluate candidate stimulating devices and protocols.