AMYGDALA 1 405 



etSP. 



AA/JA;\Aju_^A^JillUX 



FIG. 5. Examples of various amygdaloid stimulation responses. A: Inhibition of the knee jerk 

 elicited every 2 sec. (upper tracing) and of respiration [loiver tracing) in the cat. [Prom Kaada (133)-] 

 R: Activation of respiration by amygdaloid stimulation in the cat. [From Koikegami & Fuse (146).] 

 C: Increase in uterine tonus and contractions followed by a short phase of inhibition in response to 

 amygdaloid stimulation in the rabbit. [From Koikegami cl al. (151).] D: Inhibition of activity of 

 small intestine produced by amygdaloid stimulation in the cat. [From Koikegami ct al. (149).] 



and often the animal assumes its habitual posture to 

 perform these acts (ii, 72, 82, 87, 88, 133, 135, 168, 

 172, 175, 190, 245). 



Amygdaloid stimulation also influences uterine 

 tone and contractions (fig. 5C). The response is 

 diphasic, with an initial period of activation followed 

 by inhibition, and is most marked during estrus and 

 feeble during the luteal phase and earlv pregnancy 



(15O. 



Pupillary dilatation is often elicited with retraction 

 of the nictitating membrane and slight exophthalmus 

 (11, 13, 41, 72, 133, 135, 152, 168, 172, 175, 190, 

 209, 239, 245). More rarely pupillary constriction is 

 seen (13, 152, 172) or dilatation interrupted h\ an 

 interim period of constriction (72). 



Other vegetative responses reported are piloerection 

 (72, 135, 168, 172, 175, 190, 245), secretion of a 

 thick sympathetic type of saliva (fig. 6) or, more 

 rarely, of a thin parasympathetic type (11, 13, 22, 72, 

 73. 87. i35> h8, 155. 168, 172, 190, 209, 239, 245), 



and also secretion of the lacrymal and nasal glands 

 (11, 13, 22, 72, 73, 155, 168, 172, 175, 190). 



Finally, it has been claimed that amygdaloid stimu- 

 lation may influence the body temperature so as to 

 produce an initial drop of about 1 °C for 40 to 45 

 min., followed after 3 to 8 hr. by a peak of tempera- 

 ture of about 2°C above the initial value, with gradual 

 return to normal in about 24 hr. (150). Unfortunately, 

 the absence of adequate controls makes e\'aluation of 

 these results diflicult. 



Endocrine Riwponses 



In the female rabbit amygdaloid stimulation seems 

 to elicit release of gonadotrophic hormone from the 

 pituitary, as judged from the occurrence of ovulation 

 (151, 221). This effect is said to occur very frequently 

 during estrus and some response can even be ob- 

 tained in the anestrus phase, as evidenced i)y the 

 presence of enlarged and sometimes hemorrhagic 

 follicles. 



