3~

J. P. Rosenfetd and R. Kowatch, Brain Res., 88 (1975) 181"185 / ) : / 5 ̧

~ : ! ~ Y : I ¸

The effect of morphine on per~phera, pain induced by sinusoidal current ~o the: grid floor and on a~(erSiVe ~S ~ub~::: coeruleus of the ponfin: reticular formation; interc~lliduiar a~3d the dorsaMaterat oentral gray substance o f ~-ats. Morphine at dosages of 20 mg/kg produces clear analgesia to pefpher~l pain, but fails to alter the nocicepdve reaction threshold to aversive bra~n stimNa~ien in ~a~o. The simplest ;mer~retafion of the results is :hat opiate involves inhibition:of nocicepfion below the level of the brain stem.

S T O M A T O L O G Y

m

Y. Shigenaga, S. Mata~o, M. Kus~yama and A. Sakai, Brain Res., 67 (1974) 153-156

Tooth pulp afferents are presumed to be an exclusive source of noxious input based on t~,e assumption tha: only pain sensations arise from stimulation of teeth. The pre~ent study examined the 1: rojection of tooth pulp afferents to the cerebral cortex of ~hc rat usi~3g evoked potential and single-~nit analyses. Two regions, corresponding t:> son,uric sensor), areas g and ll[, contained neurons responsive to tooth pulp electric~-I stimulation. Some neurons r{ceived exclusive input from tooth and others also received cortvergent input fi'om cuta~eou.~; s:ructures. Based on response latencies, the latt,:r group, located in somatic sensory area H, appears to receive input from fi~e posterior nuclear region (PO) of the thalamus. First, spike latencies of units receiving exclusive tooth pulp input suggest direct projections fl'om the thalamie ventrobasal complex. These resaRs are consistent with previous reports of tooth pulp input to neurons in somatic sensory areas of cai~ (Andersson, oo A., Keller, O. and Vykhoky, L., Beam Res., 50 (1973) 473-475) an:d primate (Van Hassel, H. J., Biedenbach, M. A. a~3d Brown, A. Co, Arch. oral Bio,'., 17 (t972) 1059-1956). However, this is the first report to demonstrate dearly that some neurons in somatic sensory area i[ receive exclusive inp~t from tooth pulp.

t~3~e~3ce of ~igemi~3N H~o~eus caud~l~s o~3 the ~espo~ses o~ ca~ ~r~ge~i~a~ braH~ s~e~a ~eu~oss wi~h oro~l!aoia~ ~eoha~oreoo#~Ne ~ields

Bo 3. Sessle a~3_d F. Oreenw{~od, B~'ain Re.% 67 (1974)-330-333

TEe influence of trigemina~ nucleus cauda]is on neuronal activity ir~ trigeminal

mecha~of~epfive: fieI6 si~ ef beth trig:minotha]amic relay neurons and inter~eurons. ~;actotomy at

g r~dea d~s~a~ements .of:S:kin' produced by a precisely ;~OnirocNe: m~a~n~ai S~nul~t or: There ~ults are co nsiste nt With the hypot h-

t6ni~: :theiIitatO~y influence on sy"naptic transmissi on

r ! ? :

PHYS1[CAL MEDICINE

Teneion perception, in patients havin9 pNn a~soeiated w~h chronic muf~ele ten~Jon

R. S; Fowler, Jr. and G, H. Kraft, Arch. Pkys. Med. Rehab., 55 (i974)

Chronic muscle tension is thought to play a causal rote in the variety of head, sick neck and jaw pain symptoms. The authors investigated the relationship betweer~ chronic muscle tension and the ability to estimate muscte tension !eveis. They examin.. ed by electromyographic technique 10 patients having pain associated with cnronk: muscle tension and35 normal subjects. The findings were: (1) Subjects with pain gave significant higher average estimate of muscle tension than did norma~ perso~s. {21

ff muscle e average persons.

~ximatety ~ject may does not elaxat{oa

skills learned outside the laboratory setting, h is suggested that with the training of muscle relaxation the patient will be trained in muscle tension perception.

Se~4:~sue i n~e~ of the neck in ~u~o~Qbi~e aceident~, Factors irff~a~eneieg prog~esLe

M. Hob1, & Bone & Surg., 56-A (I974)

The authors reviewed 146 patients who had ~o preexisti~g cervicat degenerative: