A gated electronic switch for stimulation and recording with a single electrode
A circuit design is described for an electronic device which is gate controlled to rapidly switch electrode connections between a stimulator and an amplifier. An integrated switch in the circuit is operated by transistor-transistor logic pulses and will conduct analog signals of up to 15 V amplitude. Electrographic records made using the switch show multi-unit spike discharge after repetitive stimulation of the amygdala in the kindled rat.
Cyclic nucleotides in the amygdala of the kindled rat
The basolateral amygdala of rats was stimulated once daily until three successive fully kindled seizures were elicited. Twenty-four hours after the last seizure the rats were sacrificed by focused microwave irradiation to the head. Tissues from homolateral and contralateral amygdala and cerebral cortex were assayed for cAMP and cGMP content. No significant changes in cyclic nucleotides were measured in the kindled animals. These studies indicate that long term changes in the steady-state level of total tissue cyclic nucleotides do not occur concomitant with the persistently altered excitability associated with kindling of the amygdala.
Digital nerve action potentials in healthy subjects, and in carpal tunnel and diabetic patients
A technique is described for stimulating and recording from nerves in the finger using surface electrodes. A decrease in amplitude and velocity was found with increasing age. In control subjects the digital potential was approximately one and a half times larger than the potential recorded at the wrist. In patients with carpal tunnel syndrome there was some reduction in amplitude and velocity of the digital potential, but the changes were more marked at the wrist. In diabetic patients more uniform changes were found in the two segments. The technique was particularly useful in enabling conduction velocity to be calculated in the digital nerves when no potential could be recorded at the wrist.