Linear summation of torque produced by selective activation of two motor fascicles.

Linear summation of torque was observed while applying selective activation to two different motor fascicles in the cat sciatic nerve. The excitatory stimulus was applied to two or more contacts housed in a four contact self-sizing spiral cuff electrode. To achieve a linear summation of torque, a delay between the two stimuli that was longer than the length of the facilitatory period but less than the length of the refractory period was used.

Selective and independent activation of four motor fascicles using a four contact nerve-cuff electrode.

Any one of the four motor nerves in the cat sciatic nerve could be activated selectively and independently, from threshold to saturation, using a self-sizing spiral cuff electrode containing four radially placed monopolar contacts. These studies were carried out in nine adult cats with acute implants. Of the 36 possible fascicles, 23 fascicles could be activated selectively with current stimuli applied to a single contact and ten of the remaining fascicles could be activated selectively with current stimuli applied to two contacts, "field steering.

Comparison of joint torque evoked with monopolar and tripolar-cuff electrodes.

Using a self-sizing spiral-cuff electrode placed on the sciatic nerve of the cat, the joint torque evoked with stimulation applied to contacts in a monopolar configuration was judged to be the same as the torque evoked by stimulation applied to contacts in a tripolar configuration. Experiments were carried out in six acute cat preparations. In each experiment, a 12-contact electrode was placed on the sciatic nerve and used to effect both the monopolar and tripolar electrode configurations.