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A simple method of securing connectors to the heads of animals for eeg recordings
ELECTROENCEPHALOGRAPHYAND CLINICALNEUROPHYSIOLOGY
123
A SIMPLE METHOD OF SECURING CONNECTORS TO THE HEADS OF ANIMALS FOR EEG RECORDINGS JOSE [. JIMENEZ, M. D. AND IGNACIO I~SCOBAR, E. E.
Physiology Department, University of Antioquia, School of Medicine, Medellin (Colombia, S.A.) (Received for publication: July 6, 19:i2)
Plastic miniature connectors are widely used for attaching cortical and subcorticai electrodes for biological recordings. Several methods of securing the connector to the head of the animal have been used: leather harnesses, screws, polyethylene tubing and dental acrylic (Pendleton and Beck 1960). Some of these methods are effective, but they are time consuming and are not without problems, and none of them can compare in simplicity and reliability with the method we have developed. MATERIALAND METHODS
The principle involved consists in using the special anatomy of the frontal sinuses which are, inthecat and other animals, very large and overlie the frontal lobes of the brain.
Fig. I The connector without the aluminum shell showing the two holes at the base, A male connector (Blue Ribl~)n amphenol 572014, Allied Radio Corp.) is prepared by removing the aluminum shell and by carving two retention holes about 5 mm in diameter at the ends of the base of the connector, by means of a dental drill (Fig. i). The free end of the copper strips of' the connector must be reinforced with acrilic to make them stronger and able to resist rubbing against the cage. INSTALLATION After the desired number of electro,' ;s have been implanted in the brain or elsewhere, their free ends are
Fig, 2 Transverse section of the skull of the cat showing the connector in place, Note the acrilic compound filling the frontal sinus and the retention holes of the connector.
soldered to the pins of the connector and the pins are bent fiat against the base and are covered with acrylic compound for insulation. Two holes about 5 mm in diameter, are drilled in the bone over the frontal sinus in such a position that they coincide with the holes in the base of the connector. The connector is placed over the skull and dental acrilic (Nu-Weld) is poured into the sinus and into the holes of the connector on both sides, which is supported by hand until the acrilic hardens (5 rain more or less) (Fig. 2). The incision is then closed after removing a rectangle of skin the size of the connector.
Electroencepb. clin. NeurophysioL, 1963,. ": 123-124
124
J. !. JIMENEZ AND I. ESCOBAR RESULTS AND DISCUSSION
By this method the connector will be permanently secured to the skull of the animal, because the acrylic compound is ~ery resistant and the retention holes in the connector give additional strength. The connector can be kept on the head for the life of the animal, there will be no exposed wires to break and the preparation will be useful for a long time without deterioration. Even though the liquid component of the acrilic compound is very caustic to the tissues, the frontal sinus tolerates the compound very well and in our caseswe had no suppuration. The method is simple and quick and only a drill and acrilic are needed. We have used the method for EEG recording with
very good results, but it could be used for any other biological recording or stimulation experiments. SUMMARY A simple and reliable method for permanent implantation of plastic miniature connectors in the skull of animals is described. REFERE~iCES
PENDLETON,R. B. and BECK,E. C. A plastic pedestal for subcortical bipolar recording in chronically implanted animals. Eleclroenceph.din. Neurophysiol., 1960, 20: 519-520.
Referee: JtMEmZ, J. !. and Escoa^R, I. A simple method of securinw connectors to the heads of animals for EEG recordings. Elcctrocm,ep& din. Newophysiol., 1963, 13: 123-124.
123
A SIMPLE METHOD OF SECURING CONNECTORS TO THE HEADS OF ANIMALS FOR EEG RECORDINGS JOSE [. JIMENEZ, M. D. AND IGNACIO I~SCOBAR, E. E.
Physiology Department, University of Antioquia, School of Medicine, Medellin (Colombia, S.A.) (Received for publication: July 6, 19:i2)
Plastic miniature connectors are widely used for attaching cortical and subcorticai electrodes for biological recordings. Several methods of securing the connector to the head of the animal have been used: leather harnesses, screws, polyethylene tubing and dental acrylic (Pendleton and Beck 1960). Some of these methods are effective, but they are time consuming and are not without problems, and none of them can compare in simplicity and reliability with the method we have developed. MATERIALAND METHODS
The principle involved consists in using the special anatomy of the frontal sinuses which are, inthecat and other animals, very large and overlie the frontal lobes of the brain.
Fig. I The connector without the aluminum shell showing the two holes at the base, A male connector (Blue Ribl~)n amphenol 572014, Allied Radio Corp.) is prepared by removing the aluminum shell and by carving two retention holes about 5 mm in diameter at the ends of the base of the connector, by means of a dental drill (Fig. i). The free end of the copper strips of' the connector must be reinforced with acrilic to make them stronger and able to resist rubbing against the cage. INSTALLATION After the desired number of electro,' ;s have been implanted in the brain or elsewhere, their free ends are
Fig, 2 Transverse section of the skull of the cat showing the connector in place, Note the acrilic compound filling the frontal sinus and the retention holes of the connector.
soldered to the pins of the connector and the pins are bent fiat against the base and are covered with acrylic compound for insulation. Two holes about 5 mm in diameter, are drilled in the bone over the frontal sinus in such a position that they coincide with the holes in the base of the connector. The connector is placed over the skull and dental acrilic (Nu-Weld) is poured into the sinus and into the holes of the connector on both sides, which is supported by hand until the acrilic hardens (5 rain more or less) (Fig. 2). The incision is then closed after removing a rectangle of skin the size of the connector.
Electroencepb. clin. NeurophysioL, 1963,. ": 123-124
124
J. !. JIMENEZ AND I. ESCOBAR RESULTS AND DISCUSSION
By this method the connector will be permanently secured to the skull of the animal, because the acrylic compound is ~ery resistant and the retention holes in the connector give additional strength. The connector can be kept on the head for the life of the animal, there will be no exposed wires to break and the preparation will be useful for a long time without deterioration. Even though the liquid component of the acrilic compound is very caustic to the tissues, the frontal sinus tolerates the compound very well and in our caseswe had no suppuration. The method is simple and quick and only a drill and acrilic are needed. We have used the method for EEG recording with
very good results, but it could be used for any other biological recording or stimulation experiments. SUMMARY A simple and reliable method for permanent implantation of plastic miniature connectors in the skull of animals is described. REFERE~iCES
PENDLETON,R. B. and BECK,E. C. A plastic pedestal for subcortical bipolar recording in chronically implanted animals. Eleclroenceph.din. Neurophysiol., 1960, 20: 519-520.
Referee: JtMEmZ, J. !. and Escoa^R, I. A simple method of securinw connectors to the heads of animals for EEG recordings. Elcctrocm,ep& din. Newophysiol., 1963, 13: 123-124.