Midline thalamic lesion and feline amygdaloid kindling. I. Effect of lesion placement prior to kindling.
Nine cats with electrolytic lesion in the massa intermedia (MI, N = 8) and ipsilateral nucleus centrum medianum (CM, N = 1) underwent primary and secondary site amygdaloid (AM) kindling and primary site retest. During primary site kindling, MI- but not CM-lesioned animals showed a pattern of seizure development strikingly similar to that of forebrain-bisected cats and the development of contralateral hemiconvulsive seizure was coincident with the onset of afterdischarge (AD) in the ipsilateral motor cortex. Unlike the forebrain-bisected ones, the MI-lesioned animals eventually developed bisymmetrical clonic convulsion with initial contralateral and then ipsilateral clonic involvement. At the secondary site, no positive transfer effect was noted in 1 CM-lesioned and 6/7 MI-lesioned cats. When the primary site was retested, a marked interference effect was observed. The lesion site responsible for these unique kindling features was in the rostral half of the MI with varying involvement of the nucleus centralis medialis (NCM). It is concluded that the MI plays an important role both for transhemispheric ictal propagation and for positive transfer effect in feline AM kindling. However, the mechanisms underlying these two phenomenon are unlikely to be the same since these effects can be totally divorced.
Hiyoshi
T
T
Division of Neuroscience, University of British Columbia, Vancouver, Canada.
Wada
J A
JA
D000679:Amygdala; D000818:Animals; D002415:Cats; D004569:Electroencephalography; D007839:Functional Laterality; D007696:Kindling, Neurologic; D008297:Male; D012640:Seizures / Q000503:physiopathology*; D013786:Thalamic Diseases / Q000503:physiopathology*; D013787:Thalamic Nuclei / Q000503:physiopathology*