874 



HANDBOOK OF PHYSIOLOGY 



NEUROPHYSIOLOGY II 



During this inactivation, the animals show awkward 

 paw and ankle mo\ements and other disorders indi- 

 cating disturbed proprioceptive mechanisms. 



The effects of destruction of the striatum have been 

 extensively studied. Pourfour du Petit early considered 

 the caudate nucleus to be a ganglion essential for the 

 control of voluntary movements. Bilateral destruction 

 of the striatum and part of the surrounding white 

 matter in rabbits produces an irresistible drive to run 

 straight forward [Magendie (172), SchifT (226), 

 Lussana & Lemoigne (171)]. The injection of cor- 

 rosive liquids in the caudate nucleus also produced 

 locomotor movements directed straight ahead re- 

 gardless of obstacles (Beaumis, Fournier, Nothnagel). 

 Nothnagel (202) realized correctly that they were 

 complex movements and not uncoordinated con- 

 tractions of single muscles. He therefore assumed that 

 there must be a center for locomotor movements in the 

 caudate which he called the nodus cursorius. After the 

 negative results of the destruction experiments of 

 Wilson and of von Bechterew in the putamen and 

 caudate nucleus, these early observations were com- 

 pletely forgotten. 



In monkeys and in chimpanzees tiie fact that even 

 bilateral lesions of the anterior edge of the caudate 

 iiucleus do not cause any important disorders seems 

 to be confirmed. Mettler & Mettler (185) were unable 

 to find any significant impairment of motor activity 

 in monkeys and cats with lesions in the caudate nucleus 

 of less than 3 mm in diameter. Howe\er, when most 

 of the caudate nucleus is destroyed, circling move- 

 ments occur to the side of the lesion. After destruction 

 of both caudate nuclei the animals show an incessant 

 drive to walk straight ahead regardless of obstacles 

 and in spite of a slight hypertonia of the hind legs 

 noted by Liddell & Phillips (161). The locomotor 

 movements of the legs are enhanced by the simul- 

 taneous absence of the frontal cortex. According to 

 Delmas-Marsalet et al. (39) unilateral destruction of 

 the caudate nucleus leads to the same disorders as does 

 unilateral labyrinth destruction. Injection of cocaine 

 in the ipsilateral labyrinth after unilateral extirpation 

 of either the caudate nucleus or the prefrontal cortex 

 enhances these circling movements, as does also pas- 

 sive turning in the direction of these movements. 

 Cats with bilateral caudate destruction also .seem to be 

 disorientated and during the first postoperative days 

 could not be influenced either by somatosensory, 

 visual, auditory or vestibular stimulation. 



The theory that these lesions exert an excitatory 

 effect on subcortical centers must be abandoned ijc- 

 cause the locomotor movements last too long, can be 



triggered again by tactile or proprioceptive stimula- 

 tion and can be enhanced by suppression of the visual 

 stimuli after having cea.sed spontaneously 2 weeks 

 after the operation. Akert & Andersson (4), however, 

 describe two cats with extensive bilateral extirpation 

 of the caudate nucleus which showed an obvious 

 tendency to tonic spreading of the forepaws, a re- 

 sponse which has been elicited by Hunter & Jasper 

 (123) through stimulation of the centrum medianum. 

 The .symptoms disappeared after 3 weeks. The ani- 

 mals with bilateral lesions in the caudate nucleus afso 

 showed extensive changes of spontaneous motor drive 

 and reacted like automatons following sensory stimu- 

 lation. 



In the macaque, Edwards cS: Bagg (54) observed 

 tremor, decrease in spontaneous motor activity and 

 occasionally postural disorders after extensive i)ilateral 

 lesions of the caudate nucleus or the lenticular nuclei. 

 As Kennard (145) was able to show in monkeys, no 

 extrapyramidal symptoms and no tremor follow a 

 clean bilateral lesion of the caudate nucleus, re- 

 gardless of whether the operation has been performed 

 through the corpus callosum and the ventricle or 

 through area 8. Only if area 6 is also remo\'ed on both 

 sides simultaneously or later does a bilateral tremor 

 appear in addition to the typical signs of 'area 6 

 lesion' (namely spasticity and grasping reflex). The 

 intensity of the tremor in these cases depended upon 

 the size of the caudate lesion. It was not a typical 

 resting tremor but had a frequency of 8 to 12 per sec. 

 It appeared before and at the beginning of voluntary 

 movements and during the assumption of certain 

 postures of the limijs. Therefore, it is not to be re- 

 garded as a parkinsonian tremor as many investiga- 

 tors have done. 



Bilateral stereotaxic lesions of the putamen alone 

 or of the putamen and globus pallidus of monkeys 

 produce tremor and spasticity only in the presence 

 of simultaneous removal of area 6. The intensity of 

 the tremor depends on the size of the lesion in the 

 putamen. Simultaneous removal of area 4 abolishes 

 the tremor as long as the paresis persists. 



In monkeys a genuine chorea was ne\er observed 

 following lesions in the putamen or caudate. Occasion- 

 ally, irregular in\okmtary jerks of the head and the 

 contralateral limbs could be seen in the resting ani- 

 mal a few days after the operation. Only the chim- 

 panzee with the largest bilateral lesions in both the 

 caudate nucleus and putamen showed, contralateral 

 to the lesion, a definite chorea which lasted one 

 month [Kennard (145)]. 



There is very definite electrophysiological ex'idence 



