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Self-centering head holder system for small animal stereotaxy
Brain Research Bullerin, Vol. 4, pp. 141-143. Printed in the U.S.A.
Self-Centering Head Holder System For Small Animal Stereotaxy E. R. MARCHAND
AND J. N. RILEY
Department of Neurosciences, M-008, University of California San Diego School of Medicine, La Jolla, CA 92093 (Received
2 September
1978)
MARCHAND, E. R. AND J. N. RILEY. Self-centering head holder system for small animal stereotaxy. BRAIN RES. BULL. 4(l) 141-143, 1979.-Plans are given for the construction of a small animal head holder and associated selfcentering device which may be attached to a stereotaxic instrument. The system offers accuracy with ease of operation. Stereotaxy
Head holder
A CRITICAL feature of stereotaxy in the rat and other small animals, with respect to accuracy, is the centering of the head so that the midsagittal plane of the animal is aligned with the center of the stereotaxic instrument [l]. This is especially important for reproducibly targeting small brain structures in an experimental series of animals. We have developed a system which avoids many of the problems associated with centering of the head in conventional small animal stereotaxy. The system employs two devices: a head holder, and a thumbscrew driven ear-bar advance unit which is attached to a stereotaxic instrument. The head holder, which consists of a stationary ear bar assembly and a sliding ear-bar assembly with a removable ear-bar (Fig. l), facilitates ear-bar placement in the external auditory meatus, as this can be carried out away from the stereotaxic instrument. Also, preliminary surgery (e.g., scalp incision, trephining, etc.) can be performed before placing the animal in the stereotaxic machine. The holder can be used without the ear-bar advance unit and makes head centering a much easier operation. To mount an animal, the head holder is placed with the stationary assembly facing the operator. The sliding ear-bar assembly is moved to the maximum open position by backing off the thumbscrew. With the removavbie ear-bar out of the instrument, the anesthetized animal is positioned so that the stationary ear-bar is aligned with the animal’s external auditory meatus. The head is then moved toward the operator, guiding the ear canal over the ear-bar tip. Once positioned, the head is held in place with one hand while the removable ear-bar is grasped with the other. The removable
ear-bar is then inserted in the opposite auditory meatus. Using the removable ear-bar to hold the head in place, the sliding ear-bar assembly is moved up, the ear-bar guided into the assembly and the thumbscrew is advanced to finger tightness. Care must be taken in all steps-especially in tightening the thumbscrew-to avoid crushing the bulla, and thus miscentering the head in the apparatus. The ear-bar advance attachment, detailed in Fig. 2, is used to automatically center an animal mounted in the head holder. The unit includes a base plate, right and left adjustable ear-bar holders and a thumbscrew drive, which uniformally advances the stereotaxic instrument’s ear-bars toward the center line. The entire head holder system, as used with a Kopf stereotaxic instrument, is illustrated in Fig. 3. To center a mounted animal, the head holder is placed on the base plate, near the mid-line of the instrument. The thumbscrew is turned, driving the instrument’s ear-bars into the guide holes in the head holder. In our laboratory this system has proven to be more accurate and easier to use than the conventional method for mounting small animals for stereotaxic procedures. ACKNOWLEDGEMENTS The authors express their appreciation to Mr. Clifford Gwin of the University of California, San Diego Medical School Machine Shop for his assistance in the design and fabrication of the system, and to Mr. Anthony Sanchez of the Office of Learning Resources for the machine drawings. Joseph N. Riley was supported by USPHS Postdoctoral Fellowship NS-05732.
REFERENCE 1. Hurt, G. A., J. Hanaway and M. G. Netsky: Stereotaxic atlas of the mesencephalon 115, 1971.
Copyright
@ 1979 ANKHO
in the albino rat. Confinia. neurol. 33: 93-
International
Inc.-
0361-9230/79/010141-03$00.80/O
MARCHAND
142
/-lo-24 Thread
Fig. 1. Assembled
AND RILEY
7 I
head holder and machine drawing of head holder components. Dimensions are given in millimeters except for the 10-24 thread, which is National Course.
SELF-CENTERING
HEAD HOLDER
247 mm
‘64
-II
a
II ~~,~~~~~~~~~~~~_~~~~~~~~_ __.,c_----------_---------a -----------_________?I
I~_-------------------_‘_
,&,--~;g< __
_==_
PI I
Fig. 2. Assembled ear-bar drive mechanism and machine drawing of ear-bar drive mechanism. Dimensions are given in millimeters except for screws, which are either National Course (10-24) or National Fine threads.
Fig. 3. Head holder and ear-bar drive mechanism attached to a Kopf small animal stereotaxic instrument.
Self-Centering Head Holder System For Small Animal Stereotaxy E. R. MARCHAND
AND J. N. RILEY
Department of Neurosciences, M-008, University of California San Diego School of Medicine, La Jolla, CA 92093 (Received
2 September
1978)
MARCHAND, E. R. AND J. N. RILEY. Self-centering head holder system for small animal stereotaxy. BRAIN RES. BULL. 4(l) 141-143, 1979.-Plans are given for the construction of a small animal head holder and associated selfcentering device which may be attached to a stereotaxic instrument. The system offers accuracy with ease of operation. Stereotaxy
Head holder
A CRITICAL feature of stereotaxy in the rat and other small animals, with respect to accuracy, is the centering of the head so that the midsagittal plane of the animal is aligned with the center of the stereotaxic instrument [l]. This is especially important for reproducibly targeting small brain structures in an experimental series of animals. We have developed a system which avoids many of the problems associated with centering of the head in conventional small animal stereotaxy. The system employs two devices: a head holder, and a thumbscrew driven ear-bar advance unit which is attached to a stereotaxic instrument. The head holder, which consists of a stationary ear bar assembly and a sliding ear-bar assembly with a removable ear-bar (Fig. l), facilitates ear-bar placement in the external auditory meatus, as this can be carried out away from the stereotaxic instrument. Also, preliminary surgery (e.g., scalp incision, trephining, etc.) can be performed before placing the animal in the stereotaxic machine. The holder can be used without the ear-bar advance unit and makes head centering a much easier operation. To mount an animal, the head holder is placed with the stationary assembly facing the operator. The sliding ear-bar assembly is moved to the maximum open position by backing off the thumbscrew. With the removavbie ear-bar out of the instrument, the anesthetized animal is positioned so that the stationary ear-bar is aligned with the animal’s external auditory meatus. The head is then moved toward the operator, guiding the ear canal over the ear-bar tip. Once positioned, the head is held in place with one hand while the removable ear-bar is grasped with the other. The removable
ear-bar is then inserted in the opposite auditory meatus. Using the removable ear-bar to hold the head in place, the sliding ear-bar assembly is moved up, the ear-bar guided into the assembly and the thumbscrew is advanced to finger tightness. Care must be taken in all steps-especially in tightening the thumbscrew-to avoid crushing the bulla, and thus miscentering the head in the apparatus. The ear-bar advance attachment, detailed in Fig. 2, is used to automatically center an animal mounted in the head holder. The unit includes a base plate, right and left adjustable ear-bar holders and a thumbscrew drive, which uniformally advances the stereotaxic instrument’s ear-bars toward the center line. The entire head holder system, as used with a Kopf stereotaxic instrument, is illustrated in Fig. 3. To center a mounted animal, the head holder is placed on the base plate, near the mid-line of the instrument. The thumbscrew is turned, driving the instrument’s ear-bars into the guide holes in the head holder. In our laboratory this system has proven to be more accurate and easier to use than the conventional method for mounting small animals for stereotaxic procedures. ACKNOWLEDGEMENTS The authors express their appreciation to Mr. Clifford Gwin of the University of California, San Diego Medical School Machine Shop for his assistance in the design and fabrication of the system, and to Mr. Anthony Sanchez of the Office of Learning Resources for the machine drawings. Joseph N. Riley was supported by USPHS Postdoctoral Fellowship NS-05732.
REFERENCE 1. Hurt, G. A., J. Hanaway and M. G. Netsky: Stereotaxic atlas of the mesencephalon 115, 1971.
Copyright
@ 1979 ANKHO
in the albino rat. Confinia. neurol. 33: 93-
International
Inc.-
0361-9230/79/010141-03$00.80/O
MARCHAND
142
/-lo-24 Thread
Fig. 1. Assembled
AND RILEY
7 I
head holder and machine drawing of head holder components. Dimensions are given in millimeters except for the 10-24 thread, which is National Course.
SELF-CENTERING
HEAD HOLDER
247 mm
‘64
-II
a
II ~~,~~~~~~~~~~~~_~~~~~~~~_ __.,c_----------_---------a -----------_________?I
I~_-------------------_‘_
,&,--~;g< __
_==_
PI I
Fig. 2. Assembled ear-bar drive mechanism and machine drawing of ear-bar drive mechanism. Dimensions are given in millimeters except for screws, which are either National Course (10-24) or National Fine threads.
Fig. 3. Head holder and ear-bar drive mechanism attached to a Kopf small animal stereotaxic instrument.