This study has demonstrated that type A botulinum toxin has a depressant effect on the cortical electrical activity of anesthetized and unanesthetized monkeys. Simultaneous recordings of vital signs indicated a relative lack of change in the electrocardiogram, respiration, blood pressure, and heart rate during this time. The change in the electroencephalogram appeared cyclic in nature and independent of dose or time. All animals exhibited signs of respiratory failure characterized by a gradual interference with neuromuscular transmission at the diaphragm, and subsequently died an anoxic death.

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A technique has been developed for recording cerebral cortical activity in semi-restrained monkeys using permanently implanted, extradural, Nu-Way snap studs as the recording electrodes. Implantation is quite easy and requires no special tools. The snap lead is used to connect the animal to the electroencephalograph, thus eliminating bulky animal mounted connectors.The animal is anesthetized, placed in a stereotaxic instrument, and prepared for electrode implantation in the usual manner. Holes are then drilled at the selected points (3/32-in. drill), tapped (No. 6-32), and the studs screwed into the skull to the level of the dura. The studs are then fixed to the skull with dental acrylic. The scalp is joined and a small incision made over each stud. The scalp is then pushed down around the studs allowing them to protrude above the scalp. The incision is sutured and antibiotic administered. The entire operation takes about 60 min. (see