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Nontraumatic headholders for mammals
Physiology and Behavior. Vol. 1, pp, 97-98. Pergamon Press Ltd., 1966 Printed in Great Britain
BRIEF COMMUNICATION Nontraumatic Headholders for Mammals R O B E R T P. E R I C K S O N
Department of Psychology, Duke University, Durham, North Carolina (Received 2 July 1965) ERICKSOn, R. P., Non-traumatic headholdersfor mammals. PHYSIOL.B~HAV. 1 (1): 97-98, 1966--Headholders are described for the cat, rat, squirrel, monkey, opossum and tree shrew which are relatively painless and minimize damage to the head. This type of headholder permits easy access to the head and various orientations of the head. It is stable enough for extracellular recordings of the electrical activity of CNS neurons. The general plan is to hold the head in a clamp bearing up on the upper hard palate or upper teeth, and down on the frontal bones or infra-orbital ridge. These headholders should be particularly useful in sensory experiments since the ear is not damaged by ear pins. They are easy to construct, and should be applicable to all mammals. Headholders
Mammals
Nontraumatic headholders
Rot
MOST devices available to hold the head of an anesthetized animal for experimental manipulation of the brain make use of ear pins to orientate and stabilize the head. This is inconvenient for auditory experiments, and is also hazardous in taste experiments since the chorda tympani nerve which passes over the inner surface of the ear drum may be damaged. This kind of device also makes it very difficult or impossible to alter the position of the animal's head. The head holders described in this report permit easy manipulation and orientation of the animal's head, and do not use ear bars. They are very simple and inexpensive to build, requiring no precise machining; brass is an adequate material. The general plan is to hold the anterior portion of the animal's skull in a clamp which presses up on the upper teeth or roof of the mouth, down and on the forehead or orbital ridge. These headholders are steady enough to permit extracellular recordings from single CNS neurons [1,2], and firm enough to permit removal of bone with rongeurs. All these headholders are variations of the same design. The headholder for a long-nosed animal, the rat, is shown in Fig. 1 in detail as an example. The side view of the skull is shown in one view. The head is supported by a mouthpiece (M) which contains a hole for the upper incisors, and has raised edges alongside the molars to prevent lateral movement. The head is pressed against this mouthpiece by a bar (P). The bar is forced downward by a wing-nut on a bolt (B). A raised fulcrum (RF) is needed for proper orientation of-the pressure bar. The headholder is mounted on a bar by which it is attached to whatever apparatus is being used. Because of this method of manipulation, these headholders may be oriented in any position. Headholders for two other long-nosed animals are shown in Fig. 2. Notice that in both of these a number of holes are drilled in the mouthpiece to accommodate the teeth. For these headholders, strips of brass were soldered along the edges of the mouth-piece to prevent lateral movements of
p
B
~
J M
RF
IM o b
....
• 8
i
2
INCHES
FIG. 1. The rat headholder. See text for description. Skull of rat head shown in lateral view. Pressure bar (P) not shown in top and end views. (B), bolt; (M) mouthpiece; (RF), raised fulcrum. Slot in pressure bar for bolt permits adjustment of bar to individual animal. 97
98
ERICKSON
the head. These strips were ~ in. sq. for the opossum headholder and ~r in. sq. for the tree shrew headholder. The mounting bar, not shown here, may be attached wherever convenient. Head_holders for 2 flat-faced species, the cat and the squirrel monkey, are shown in Fig. 3. Because of the configuration of these heads, the pressure bar cannot be placed
against the forehead; thus these bars are designed to press down on the infraorbital ridge. They also differ from the previous beadholders in that the mouthpiece is designed to press up against the roof of the mouth rather than the teeth. Thus a piece of brass is soldered onto the main body of the headholder to fit up against the roof of the mouth. This piece is ~ in. thick for the cat and 1s in. for the monkey.
Squirrel monkey
Tree shrew
p
,
[~~
•
[
Be ~JI-RF(.,M,)
Opossum p
~
F
~ I
I
I
Be
F
|
INCHES
INCHES
FIG. 2. As Fig. 1, for two other long-nosed species. Height of raised fulcrum indicated. (1=),fulcrum.
FIG. 3. As Fig. 1, for two flat-faced species. Height of raised fulcrum indicated. (F), fulcrum.
REFERENCES
1. Erickson, R. P., R. L. King and C. Pfaffmann. Som¢ characteristics of transmission through spinal trigcminal nucleus of rat. J. Neurophysiol. 24: 621-632, 1961.
2. Erickson, R. P., J. A. Jane, R. Waite and I. T. Diamond. Single neuron investigation of sensory thalamus of the opossum. J. Neurophysioi. 27: 1026-1047, 1964.
BRIEF COMMUNICATION Nontraumatic Headholders for Mammals R O B E R T P. E R I C K S O N
Department of Psychology, Duke University, Durham, North Carolina (Received 2 July 1965) ERICKSOn, R. P., Non-traumatic headholdersfor mammals. PHYSIOL.B~HAV. 1 (1): 97-98, 1966--Headholders are described for the cat, rat, squirrel, monkey, opossum and tree shrew which are relatively painless and minimize damage to the head. This type of headholder permits easy access to the head and various orientations of the head. It is stable enough for extracellular recordings of the electrical activity of CNS neurons. The general plan is to hold the head in a clamp bearing up on the upper hard palate or upper teeth, and down on the frontal bones or infra-orbital ridge. These headholders should be particularly useful in sensory experiments since the ear is not damaged by ear pins. They are easy to construct, and should be applicable to all mammals. Headholders
Mammals
Nontraumatic headholders
Rot
MOST devices available to hold the head of an anesthetized animal for experimental manipulation of the brain make use of ear pins to orientate and stabilize the head. This is inconvenient for auditory experiments, and is also hazardous in taste experiments since the chorda tympani nerve which passes over the inner surface of the ear drum may be damaged. This kind of device also makes it very difficult or impossible to alter the position of the animal's head. The head holders described in this report permit easy manipulation and orientation of the animal's head, and do not use ear bars. They are very simple and inexpensive to build, requiring no precise machining; brass is an adequate material. The general plan is to hold the anterior portion of the animal's skull in a clamp which presses up on the upper teeth or roof of the mouth, down and on the forehead or orbital ridge. These headholders are steady enough to permit extracellular recordings from single CNS neurons [1,2], and firm enough to permit removal of bone with rongeurs. All these headholders are variations of the same design. The headholder for a long-nosed animal, the rat, is shown in Fig. 1 in detail as an example. The side view of the skull is shown in one view. The head is supported by a mouthpiece (M) which contains a hole for the upper incisors, and has raised edges alongside the molars to prevent lateral movement. The head is pressed against this mouthpiece by a bar (P). The bar is forced downward by a wing-nut on a bolt (B). A raised fulcrum (RF) is needed for proper orientation of-the pressure bar. The headholder is mounted on a bar by which it is attached to whatever apparatus is being used. Because of this method of manipulation, these headholders may be oriented in any position. Headholders for two other long-nosed animals are shown in Fig. 2. Notice that in both of these a number of holes are drilled in the mouthpiece to accommodate the teeth. For these headholders, strips of brass were soldered along the edges of the mouth-piece to prevent lateral movements of
p
B
~
J M
RF
IM o b
....
• 8
i
2
INCHES
FIG. 1. The rat headholder. See text for description. Skull of rat head shown in lateral view. Pressure bar (P) not shown in top and end views. (B), bolt; (M) mouthpiece; (RF), raised fulcrum. Slot in pressure bar for bolt permits adjustment of bar to individual animal. 97
98
ERICKSON
the head. These strips were ~ in. sq. for the opossum headholder and ~r in. sq. for the tree shrew headholder. The mounting bar, not shown here, may be attached wherever convenient. Head_holders for 2 flat-faced species, the cat and the squirrel monkey, are shown in Fig. 3. Because of the configuration of these heads, the pressure bar cannot be placed
against the forehead; thus these bars are designed to press down on the infraorbital ridge. They also differ from the previous beadholders in that the mouthpiece is designed to press up against the roof of the mouth rather than the teeth. Thus a piece of brass is soldered onto the main body of the headholder to fit up against the roof of the mouth. This piece is ~ in. thick for the cat and 1s in. for the monkey.
Squirrel monkey
Tree shrew
p
,
[~~
•
[
Be ~JI-RF(.,M,)
Opossum p
~
F
~ I
I
I
Be
F
|
INCHES
INCHES
FIG. 2. As Fig. 1, for two other long-nosed species. Height of raised fulcrum indicated. (1=),fulcrum.
FIG. 3. As Fig. 1, for two flat-faced species. Height of raised fulcrum indicated. (F), fulcrum.
REFERENCES
1. Erickson, R. P., R. L. King and C. Pfaffmann. Som¢ characteristics of transmission through spinal trigcminal nucleus of rat. J. Neurophysiol. 24: 621-632, 1961.
2. Erickson, R. P., J. A. Jane, R. Waite and I. T. Diamond. Single neuron investigation of sensory thalamus of the opossum. J. Neurophysioi. 27: 1026-1047, 1964.