I4I0 HANDBOOK OF PHYSIOLOGY ^- NEUROPHYSIOLOGY II 



EFFECTS OF AMYGDALOID STIMULATION 



(Koodo.Gosloyf. Mac Lfon a Oelgodo, a othrrs ) 



AUTONOMIC 



Trophotrope- 

 Porosympothetic 



Licking, Chewing 

 Iptilateral Face 

 Tonic Adversion 

 Tonic Stiffening 



Facilitation « 



Mot. Effect!. 



Conditioning of^ 

 Mot Effects 



SOMATIC, 



Alertmg 



Feor 



Rage 



BEHAVIOURAL 



ELECTROCORTICC 

 GRAPHIC 



ELECTROPHYSiOLOeiCALLY 

 DEMONSTRATED CONNECTIONS OF 

 THE AMYGDALA. 



(0»n Results ) 



SEPTUM. 



PREOPTIC AREA, 

 ANTERIOR ; 



HYPOTHALAMUS.' 



POSTERIOR 

 HYPOTHALAMUS. 



\^ ^NUCLEUS CAUDATUSl^ 

 \.GLOBUS PALLIDUS, Jl 



ENTOPEDUNCULAR N.' 



SUBTHALAMUS.o- 



BRAIN STEM > 

 TEGMENTUM. r 



PEDUNGULUS.o- 



EFFECT OF STIMULATION OF 



THE CONNECTED STRUCTURES. 



I Mess, Mogojn & olheri } 



- Licking, Chewing 



Trophotrope - 

 ►Parosympathetic 

 Mof Inhibition 



Ergotrope- 

 — ►Sympothelic 

 Mot Facilitation 



Rogt, 

 Fear. 



*-Mol Inhibition 



-►Mot Facilitation 



Tonic 

 ""Effects 



Alerting. 

 _^ECG Low 

 voltage, fast 



Activity. 



-Mot Effects. 



FIG. 8. Diagram illustrating the clectrophysiologically demonstrated direct and indirect con- 

 nections of the amygdala and their functional significance. On the left hand side are listed the re- 

 sponses to amygdaloid stimulation as described in the literature. The middle column lists the structures 

 which on electrophysiological investigation were shown to be fired in a direct or indirect way from 

 the amygdala. On the right hand side the responses obtained by stimulation of tliese structures as 

 reported by Hess, Magoun and others are listed. Note that the responses obtained upon amygdaloid 

 stimulation are also obtained from one or other of the subcortical structures to which the amygdala 

 projects and that there is a topographical grouping of these effects in the subcortex, and that such 

 a grouping is absent at the amygdaloid level. [From Gloor (96).] 



loid responses. Neuronal recruitment at successive 

 synaptic stations .seems to induce a patterned sequence 

 of responses together with a gradual increase in the 

 intensity of certain responses. Furthermore it seems 

 that clearly noticeable effects, resulting in overt 

 somatomotor, vegetative or behavioral changes, only 

 appear when there is after-discharge, i.e. seizure 

 activity. .'Ml this concurs in sug.gesting that the amyg- 

 dala is not in actual command of the various mecha- 

 nisms which it is capable of influencing when elec- 

 trically stimulated, but rather acts as a modulator of 

 activities integrated at subcortical levels (97, 99). 



« The only exception to this is the report by Koikegami et al. 

 (148) stating that bats were no longer able to fly after amyg- 

 daloid lesions. Their wing-spreading reflex elicited by pinching 

 their neck was also abolished on the side of the lesion. 



LESION E.XPERIMENTS 



Amygdaloid lesions have to be bilateral to produce 

 any detectable changes. The varied somatomotor'^ 

 and autonomic mechanisms, so clearly influenced 

 by amygdaloid stimulation, show only transient 

 minor deficits or none at all after bilateral destruction 

 of the amygdala. Such transient autonomic changes 

 described include some tendency to increase in arterial 

 pressure, decrease in heart and respiratory rates, 

 some instability of blood sugar and blood sodium 

 concentration, hyperemia and ulcerations of the gas- 

 trointestinal mucosa (16), increased salivation (148), 

 piloerection (252) and slight hypothermia with rela- 

 tive poikilothermia (10, 148, 199, 204). 



There is some evidence that endocrine changes 



