Stimulation in the Diencephalon 243 



the upper and anterior part of the wall of the third ventricle was 

 found to provoke peculiar seizures, characterized by sudden sweat- 

 ing, flushing, salivation, lachrymation and respiratory disturb- 

 ances. Strongin and Hinsie (1938) studied the secretory rate in 

 schizophrenia and found it to increase as the deterioration pro- 

 ceeded; it was assumed that as the patient regressed to more in- 

 fantile levels his salivary secretion likewise returned to the infantile 

 level characterized by a high rate of flow (Lourie, Barrera and 

 Strongin, 1942). In depressions of the manic-depressive type the 

 flow, on the other hand, is said to be diminished (Lourie, Barrera 

 and Strongin, 1942; Ekblad, 1944). 



In many of the examples enumerated above there is a more or 

 less clear indication as to the region of the central nervous system 

 engaged in the control of the secretion of saliva. Diencephalic and 

 cortical areas seem to be of particular interest. There is direct ex- 

 perimental evidence to show that electrical stimulation of certain 

 diencephalic and telencephalic regions may affect salivary secretion. 



Stimulation in the diencephalon. In their classical experiments on 

 "Gehirn und Sympathicus" Karplus and Kreidl (1909) mainly 

 studied effects on the pupil of electrical stimulation of the base of 

 the brain in the hypothalamic area; they observed also, however, 

 secretion of saliva, tears and sweat. The secretion they observed 

 could have been of sympathetic origin and even brought about by 

 adrenaline from the suprarenals, since the experiments were on 

 cats. Stavraky (1936) stimulated the posterior hypothalamus from 

 the opened third ventricle in cats under dial anaesthesia and 

 recorded various effects which were ascribed to excitation of the 

 sympathetic nervous system, among them salivation. 



From such experiments on anaesthetized animals it can be con- 

 cluded that the salivary glands belong to those structures, inner- 

 vated by autonomic nerves, that can be activated from the hypo- 

 thalamus. Experiments on unanaesthetized animals have, however, 

 been necessary to throw light on the functional significance of the 

 salivary secretion which can be initiated from this region. In 

 different patterns of physiological reactions which can, in freely- 

 moving cats, be imitated by electrical stimulation of various parts 

 of the hypothalamus from an implanted electrode, secretion of saliva 

 often is one of the symptoms. In ''sham rage" (Bard, 1928) of cats, 

 for instance, spitting is described as a characteristic feature. Ran- 

 son, Rabat and Magoun (1935) implanted a bipolar needle electrode 



