'414 



HANDBCKJK OF I'H'iSIOLOGV 



NEUROPHYSIOLOGY II 



with amnesia (79), ictal depressive feelings (251), a 

 feeling of joy (237), sexual excitement (25, 34, 77) or 

 an acute feeling of hunger (76). In patients undergoing 

 surgery for their seizures these ictal symptoms can be 

 reproduced by stimulation of the amygdala (61, 129, 

 198). 



Patients suffering from this type of seizure often 

 present an interictal syndrome which more often 

 invokes abnormal behavior than that seen in patients 

 suffering from other forms of epilepsy (91, 213). 

 Gastaut and his collaborators (79) state that 72 per 

 cent of psychomotor epileptics show personality 

 traits whicli were once regarded to be characteristic 

 for epileptics in general and were therefore described 

 as 'epileptoid constitution' (see also 71, 75, 78, 85, 230, 

 231). These patients show a striking slowness of 

 movements and thinking and a tendency to persevera- 

 tion, a demeanor which has been called "adhesiveness' 

 or 'viscosity' and which contrasts rather strikingly 

 with the propensity of these patients to be provoked 

 into explosive and violent anger, often for causes of 

 the most trifling nature (see also 248). Manv psycho- 

 motor epileptics also suffer from loss of libido, sexual 

 impotence or frigidity (75, 77) and some show disturb- 

 ances of their appetite (76, 84). It seems that this 

 complex syndrome is essentially the opposite of that 

 produced by bilateral amygdaloid lesions in animals.' 

 A continuous state of subictal irritation liy the focus 

 seems to be its cause.'" 



Interictal disturbances can also be demonstrated in 

 monkeys with chronic epileptogenic lesions of the 

 amygdala. Such lesions seriously hamper the estab- 

 lishment of conditioned reactions to anv modalitv of 



sensory stimuli (185) 



The fact that this deficit is 



cured after excision of the epileptogenic focus proves 

 that it is caused by abnormal discharges and not by 

 destruction of ner\ous tissue. 



In animals "amygdaloid epilepsy" can be produced 

 b\ injection of alumina cream into the amygdaloid 

 region (81, 83, 89, 185, 186, igo, 212, 232). The 

 seizure pattern in these animals faithfully duplicates 

 the responses obtained by amygdaloid stimulation in 

 unanesthetized animals (fig. 10). 



' However, symptoms reminiscent of those seen in animals 

 with bilateral amygdaloid lesions are actually seen in a mi- 

 nority of patients indicating loss of function of the temporal 

 rhinencephalic structures either due to bilateral destructive 

 lesions or functional paralysis by excessive firing (79, 161). 



'" Even more suggestive evidence for such continuous irrita- 

 tion is the phenomenon which has been called "continuous" 

 aura, e.g. in the form of a constant feeling of fear or anxiety in a 

 patient having seizures starting with an aura of fear (225, see 

 also 84). 



Sporadic epileptogenic potentials in patients and 

 animals with amygdaloid epileptogenic lesions are 

 recorded o\er the anterior temporal, insular and 

 uncohippocampal regions (61, 71, 74, 75, 78, 81, 83, 

 89. 92, 94. ••7. '27, 128, 171, 176, 186, 197, 212). 

 Animals with unilateral amygdaloid alumina cream 

 lesions develop after some time a mirror focus in the 

 contralateral amygdala, which finally fires quite 

 independently of the primary lesion (212). Such 

 bilateral foci are frequent findings in human temporal 

 lobe epilepsy (74, 83, 198) and some of them may 

 also originate in this same manner. 



Amygdaloid .seizures in man and animals often 

 start with an initial 'suppression' of cortical electrical 

 activity which even affects the previously present 

 interictal spike discharges (60, 61, 74, 75, 81, 83, 89, 

 100, 117, 128, 134, 176, 198, 212). This corticographic 

 response is very similar to the diffuse low-voltage fast 

 pattern which can be produced by am\gdaloid 

 stimulation (see p. 1403). 



Ma 1^9 



FIG. 10. Different stages of a spontaneous seizure in the cat 

 due to an epileptogenic alumina cream lesion in the left 

 amygdaloid area. The seizure starts with an attention response 

 and slight contraversive turning of the head to the right. Then 

 the pupils dilate and the cat looks frightened; the contralateral 

 forepaw is slightly raised and there is tonic extension with 

 stiffening of the contralateral hind leg. The cat thus assumes a 

 posture as if terrified and about to escape. This is followed by 

 ipsilateral clonic face mo\ements [top right) and jaw mo\ements 

 with salivation {bottom right). A similar sequence of e\'ents is 

 also seen in response to electrical stimulation of the amygdala. 

 [From Naquet (190).] 



