An adaptable head holder for cats

T E C H N I C A L NOTES E d i t e d by H. S H I P T O N , AN

A. M. B R I T , I.R.E. a n d F. B U C H T H A T ~ , M.D.

ADAPTABLE

HEAD

HOLDER

FOR

CATS

V. B. B R o o K s , P h . D . , G. J. Wn~SBURY, A . M . I . E . ( A u s t . ) a n d N . A. J r ~ B r R G The Rockefeller Institute for Medical Research, N e w York, U.S.A., and T h e Department of Physiology, Australian National University, Canberra, A . C . T . , Australia (Received f o r p u b l i c a t i o n : J u l y 5, 1958) A simple h e a d holder f o r cats h a s been developed t h a t can be u s e d in m a n y k i n d s of e x p e r i m e n t s a n d t h a t also f o r m s p a r t of a s t e r e o t a x i c i n s t r u m e n t . T h e basic u n i t consists of t h e f r a m e , in which t h e h e a d is held either by a P a l m e r head-holder, or b y some

by A l l a n screws. T h e l a t e r a l b a r s have d i a m e t e r s of 5/16", t h e a n t e r i o r a n d p o s t e r i o r b a r s of 1". T h e f r a m e is s u p p o r t e d b y a n a r m t h a t is c l a m p e d to a r i g i d p o s t (11~" d i a m e t e r ) , w h i c h is set in a h e a v y base. The f r a m e is held level a c c u r a t e l y a t 90 degrees

Fig. 1

View of skull held in the head frame. Alignment bars for manipulator in place. o t h e r nose clamp, as well as by one set of b a r s f i t t i n g into t h e e x t e r n a l a u d i t o r y m e a t i , a n d a n o t h e r b e a r i n g on t h e s u b o r b i t a l ridges. F i g u r e 1 shows a skull held with t h e l a t t e r a r r a n g e m e n t . T h e h e a d f r a m e consists of f o u r s t a i n l e s s steel b a r s t h a t are held t o g e t h e r

to the post by m e a n s of a l i g n m e n t p i n s t h r o u g h j o i n t s of the s u p p o r t i n g a r m w i t h tile f r a m e a n d w i t h t h e c l a m p on the post. T h e p r o x i m i t y of t h e e a r - b a r s to each other is a d j u s t a b l e by m e a n s of t h e screws holdi n g t h e m in the h e a d f r a m e . T h e holder g r i p p i n g t h e

[ 349 ]

350

V . B . B R O O K S , G. J. W I N S B V R Y

nose as well as the holders for the e y e - b a r s are c l a m p e d to the a n t e r i o r b a r of the f r a m e . The holders f o r the eye-bars consist of alunfinum pieces into which fit the eye-bars p r o p e r (?;/16" d i a m e t e r ) , the lower s u r f a c e s of which are level with the zero plane of the frame. A d j u s t m e n t s in the anterior-posterior direction are made by sliding the b a r s relative to the clamps, rind fixing them with t h u m b screws. L a t e r a l a d j u s t m e n t s can be made by movement of the ,~lamps

qml N. A. J E R N I ~ E R ( I

r a c k - a n d - p i n i o n m o v e m e n t s t h a t are so c l a m p e d tog e t h e r as to give mobility in three dimensions, b u t t h a t can also be moved as one unit anterio posteriorly along the grooved s u p p o r t a r m t h a t is ,'lamped to the post. The unit is shown in figure 1. To place an electrode stereotaxically in the brain, the m a n i p u l a t o r has to be aligned in relation to the head frgme. Horizontal alignment of the m a n i p u l a t o r is assured by the plaeelnel~t; of aligmneJ t pins t h r o u g h

Fig. 2 .~-llgnlnent bars removed. Manipulator, nlic~odrlve, and microelectrodc holder ilt ItbLCO. .loi,~" the anterior bar of the fr:lme. Thei] align mcnt is assured hv their fit int~ a groov~' on the, anterior :~Sl)Cet of that bar to whh.h tlwv :try, fix,.'d with t h m n b screws. The skull thus pixovs ~bout tlw eill'-bars :l]ll[ iN hehl firmly betwt'en l}lc cye }mrs and a noseelamp or a stabilizing b a r p r e s s i n g ag~dnst the roof of the nlouth. The needle or i n s t r u m e n t to be placed in the b r a i n is held by an assembly of three heavy, graduated,

r l a m p s :,,l,l bars, as well a~ by ~roo\'in~ of the manil,ulator s u p p o r t arm. The simph, fixture u s e d t o align the two p a r t s in the a n t e r i o p o s t e r i o r ;,nd lateral directions is :~lso illustr:~ted ilL figaro' 1. A sial) of almnimml with two :digm,d u p r i g h t brass t)ars u p o n it is s{.r{,w{,d It> the post(,rior eml of ~he head frame. A horizontal test bar, inserted into the m a n i p u l a t o r s u p p o r t arm, is tlwn brougltt a g a i n s t tlle u p r i g h t s , nnd th(, p~sitiou of the m~lnilmlatov is a d j u s t e d until the

AN ADAPTABLE

351

HEAD HOLDER FOR CATS

horizontal test b a r touches both test u p r i g h t s . The elamp holding the m a n i p u l a t o r to the s u p p o r t post is then tightened, and the horizontal b a r as well as the slab with the vertical test b a r s are removed (fig. 2). The unit is then ready for stereotaxie work. Coordin'~tes are read on the g r a d u a t i o n s of the m a n -

when the head is held with a nlodified P a l m e r holder. Tbe edges of the scalp have been sutured to -t metal ring t h a t is held on the posterior b a r of the frame, thus f o r m i n g "t pool of mineral oil to cover the exposed brain. Electrodes are held in adjustable, finger-tight, universal joint holders, t h a t can be moved

Fig. 3 ('at held by modified P a l m e r kohler in head f r a m e . M a n i p u l a t o r l'cnl()vcd.

il)ulator , " z e r o " having been established carefully befo reha nd. F o r non-stereotaxie experiments it is often conwmient to remow~ the alignment pins t h a t fix :~11 ;,omponents at right "~ngles, so t h a t individual a d j u s t m e n t s of angles can be nmde. One advantage of the head f r a m e is the ease with which accessory equipment can be m o u n t e d upon it. F i g u r e 3 shows a eat in position

ilt three dhnensions ll/elltS.

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by small r~.:k-am]-plnion ('Hit b e

move-

e;isi]~" a(Ti!olllluo(l:lted

ell

the h e , d frame. S U M M A R "( A simple head hohler for e.ls is ,]eseribe,] t h a t C;llI lie u s e d

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for

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t:lxie exl..rimonts.

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