SPICE Compatible Equivalent Circuit Models of Skeletal Muscle Tissue

We present equivalent circuit models of skeletal muscle tissue for the directions parallel and transverse to the fiber. The parallel model is based on a distributed parameter equivalent circuit approach where the tissue between the electrodes is divided into small segments, each of which is represented by an equivalent circuit. Parameters for the equivalent circuits are calculated from the electrical characteristics of the tissue components and their physical arrangement. We compare the conductivity frequency response of the equivalent circuit modelling approach to other models presented in the literature. The advantage to our equivalent circuit approach is that the tissue models can be readily integrated in circuit simulators such as SPICE. An equivalent circuit model of the tissue load that incorporates both spatial and frequency dependence can be simulated in combination with instrumentation circuits and can aid in the design and optimization of these systems. The possibility of using the equivalent circuit models to simulate nonlinear tissue characteristics is currently being investigated.