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Permanently implanted electrode for electromyography of the diaphragm in the waking cat
ELECTROENCEPHALOGRAPHYAND CLINICAL NEUROPHYSIOLOGY
127
PERMANENTLY IMPLANTED ELECTRODE FOR ELECTRO. MYOGRAPHY OF THE DIAPHRAGM IN THE WAKING CAT t A. SCHOOLMAN, M . D . AND B.R. FINK, M . D .
Departments of Neurological Surgery and Anesthesiology, College of Physicians and Surgeons, Columbia University, New York 32, IV. Y. (U.S.A.) (Received for publication: May l I, 1962) (Resubmitted: August 16, 1962)
Implanted wire electrodes anchored to the skull (Delgado 1952) have been widely used in chronic studies of cerebral activity, This note describes a kindred technique for recording action potentials of the diaphragm in respiratory studies on unrestrained animals. MATERIALS Formvar-coated nichrome wire, 0.007 gauge (Driver Harris Co,, Harrison, New Jersey). Polyethylene tubing, I mm and 2 mm bore. Miniature socket, 7-pin cinch type (Acme Electronics Inc,, Broo~tlyn, New York). Stainless steel wire 0.020 gauge. Ple^iglass solution. Semi.liquid plastic INSL-X-E33 (INSL-X Co., inc., Ossining. N. ¥.). CONSTRUCTION OF I'LECTRODE (Fig.
8astrium. The abdomen is then opened in the midline and the liver retracted with a moist sponge, exposing the dome of the diaphragm. The flat multi-electrode surface bearing the ball tips is placed against the diaphragm, close to the central tendon and near the midline to ensure a maximum distance from other muscles, and secured with three or four stitches of 000 atraumatic silk. These stitches transfix the diaphragm, but avoid the pleura. The belly is then closed in layers, leaving the entire electrode assembly buried except for the socket emerging through the occipital incision. The occipital periosteum is now
I)
The nichrome wire is cut into lengths of 21 cm, up to six of which can be incorporated into one multielectrode, Using the electrolytic method of Riley (1949) one end of each length is melted to form a ball approximately 0,5 mm in diameter, The wires are then drawn into a I.$.cm length of 2 mm bore polyethylene tubing, through a row of pinholes spaced at 2-mm intervals along one side of the tubing, leaving the balls against the external surface. Next, the wires are cemented together with plexiglass dissolved in ethylene dichloride and are threaded through a 20-cm piece of I mm bore tubing, which is then fitted into the wider tube. The latter is fused flat between glass slides by pressure with a flatiron heated to about 200°C The wires protruding at the other end of the tubing arc soldered in ,~oted oJ~der to six of the pins of a miniature socket. A 20-¢m length of stainless steel wire is folded in half and me fold soldered to the seventh pin. This wire will anchor the socket to the skull and will also serve as the grounding lead. Finally, the solder area~ are liberally painted with semi-liquid plastic; the plastic hardens in air to form a solid insulated junction with the socket.
!4
INSERTION OF ELECTRODE Using pentobarbital anesthesia (30 mg/kg) and aseptit, technique an occipital skin incision is made and the electrode p~ssed subcutaneously down to the epit Supported by U. S. Public Service Grant RG-4717.
~
Fig. I Diaphragm electrode.
Electroeneegh, olin. NeuroFhysioL, 1963, 13:127-128
128
A. S C H O O L M A N A N D R. R, FINK
Fig. 2 Typical record obtained 25 days after implantation of the electrode. The upper trace is from a peak detector, reflected and two burr holes are drilled through the skull. care being taken to leave the dura intact, The anchoring stainless steel wires are looped under the bone between the holes and firmly tied. Finally the skin is sutured snuBly around the base of the protruding socket. The animals appear comfortable within a few days of the operation; salisfactory electromyosrams can be recorded for about four weeks, (FIB, 2), Thereafter the action potentials become excessively att©nu~ted, presumably as a result of tissue reaction to the electrode.
SUMMARY Brief description of a technique to record action potentials of the diaphragm in respiratory stud;as on unrestrained animals,
REFERENCES DI~LOADO,J. M. R. Permanent implantation of multilcad electrodes in the brain. Yale J. Biol. Mad., 1952, 24: 351=358, Ru~v, J, A. A simple method for weldins thermocouples. Science, i949, 109: 281.
~fere~'e: ,~HOOLMAN,A. AND FINK, B. R. Permanently implanted electrode for electromyolpraphy of the diaphraMm in the waking cat. Elcctroe~ecepk. din. Neuropkysiol., HM3, 15: 127-128.
127
PERMANENTLY IMPLANTED ELECTRODE FOR ELECTRO. MYOGRAPHY OF THE DIAPHRAGM IN THE WAKING CAT t A. SCHOOLMAN, M . D . AND B.R. FINK, M . D .
Departments of Neurological Surgery and Anesthesiology, College of Physicians and Surgeons, Columbia University, New York 32, IV. Y. (U.S.A.) (Received for publication: May l I, 1962) (Resubmitted: August 16, 1962)
Implanted wire electrodes anchored to the skull (Delgado 1952) have been widely used in chronic studies of cerebral activity, This note describes a kindred technique for recording action potentials of the diaphragm in respiratory studies on unrestrained animals. MATERIALS Formvar-coated nichrome wire, 0.007 gauge (Driver Harris Co,, Harrison, New Jersey). Polyethylene tubing, I mm and 2 mm bore. Miniature socket, 7-pin cinch type (Acme Electronics Inc,, Broo~tlyn, New York). Stainless steel wire 0.020 gauge. Ple^iglass solution. Semi.liquid plastic INSL-X-E33 (INSL-X Co., inc., Ossining. N. ¥.). CONSTRUCTION OF I'LECTRODE (Fig.
8astrium. The abdomen is then opened in the midline and the liver retracted with a moist sponge, exposing the dome of the diaphragm. The flat multi-electrode surface bearing the ball tips is placed against the diaphragm, close to the central tendon and near the midline to ensure a maximum distance from other muscles, and secured with three or four stitches of 000 atraumatic silk. These stitches transfix the diaphragm, but avoid the pleura. The belly is then closed in layers, leaving the entire electrode assembly buried except for the socket emerging through the occipital incision. The occipital periosteum is now
I)
The nichrome wire is cut into lengths of 21 cm, up to six of which can be incorporated into one multielectrode, Using the electrolytic method of Riley (1949) one end of each length is melted to form a ball approximately 0,5 mm in diameter, The wires are then drawn into a I.$.cm length of 2 mm bore polyethylene tubing, through a row of pinholes spaced at 2-mm intervals along one side of the tubing, leaving the balls against the external surface. Next, the wires are cemented together with plexiglass dissolved in ethylene dichloride and are threaded through a 20-cm piece of I mm bore tubing, which is then fitted into the wider tube. The latter is fused flat between glass slides by pressure with a flatiron heated to about 200°C The wires protruding at the other end of the tubing arc soldered in ,~oted oJ~der to six of the pins of a miniature socket. A 20-¢m length of stainless steel wire is folded in half and me fold soldered to the seventh pin. This wire will anchor the socket to the skull and will also serve as the grounding lead. Finally, the solder area~ are liberally painted with semi-liquid plastic; the plastic hardens in air to form a solid insulated junction with the socket.
!4
INSERTION OF ELECTRODE Using pentobarbital anesthesia (30 mg/kg) and aseptit, technique an occipital skin incision is made and the electrode p~ssed subcutaneously down to the epit Supported by U. S. Public Service Grant RG-4717.
~
Fig. I Diaphragm electrode.
Electroeneegh, olin. NeuroFhysioL, 1963, 13:127-128
128
A. S C H O O L M A N A N D R. R, FINK
Fig. 2 Typical record obtained 25 days after implantation of the electrode. The upper trace is from a peak detector, reflected and two burr holes are drilled through the skull. care being taken to leave the dura intact, The anchoring stainless steel wires are looped under the bone between the holes and firmly tied. Finally the skin is sutured snuBly around the base of the protruding socket. The animals appear comfortable within a few days of the operation; salisfactory electromyosrams can be recorded for about four weeks, (FIB, 2), Thereafter the action potentials become excessively att©nu~ted, presumably as a result of tissue reaction to the electrode.
SUMMARY Brief description of a technique to record action potentials of the diaphragm in respiratory stud;as on unrestrained animals,
REFERENCES DI~LOADO,J. M. R. Permanent implantation of multilcad electrodes in the brain. Yale J. Biol. Mad., 1952, 24: 351=358, Ru~v, J, A. A simple method for weldins thermocouples. Science, i949, 109: 281.
~fere~'e: ,~HOOLMAN,A. AND FINK, B. R. Permanently implanted electrode for electromyolpraphy of the diaphraMm in the waking cat. Elcctroe~ecepk. din. Neuropkysiol., HM3, 15: 127-128.