Synaptic alterations in the medial geniculate bodies and the inferior colliculi in Alzheimer's disease: a Golgi and electron microscope study.
CONCLUSIONS
The neuronal loss and the alteration of the synapses in the medial geniculate bodies and the inferior colliculi may be involved in the impairment of communication and symbolic sound perception, which is noticed even in the early stages of Alzheimer's disease.


OBJECTIVE
Alzheimer's disease (AD) is a neurodegenerative disorder, causing a progressive decline of intellectual faculties, gradual impairment of behavior and social performance, impairment of communication and speech eloquence, and various neurological manifestations. We attempted to figure out the synaptic alterations in the medial geniculate bodies and the inferior colliculi in 12 early cases of Alzheimer's disease, who fulfilled the clinical, and laboratory diagnostic criteria of Alzheimer's disease.


METHODS
For the histological study we applied routine neuropathological techniques as well as Bodian staining and rapid Golgi method. We proceeded to electron microscopy for the ultrastructural study of synapses and dendritic spines.


RESULTS
The morphological and morphometric analysis revealed substantial neuronal loss and synaptic alterations in the medial geniculate bodies as well as in inferior colliculi. Dendritic spines of the polyhedral and elongated cells of the medial geniculate bodies were decreased in number. Mitochondrial alterations and fragmentation of Golgi apparatus were seen in 15% of the neurons of the medial geniculate bodies and in 5% of the neurons of the inferior colliculi. Senile plaques and neurofibrillary tangles were not seen in either the medial geniculate bodies or the inferior colliculi.
Baloyannis
Stavros J
SJ
Department of Neurology, Aristotelian University, Thessaloniki, Greece. sibh844@otenet.gr
Mauroudis
Ioannis
I
Manolides
Spyros L
SL
Manolides
Leonidas S
LS
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D005829:Geniculate Bodies / Q000473:pathology*; D006056:Golgi Apparatus / Q000473:pathology; D006801:Humans; D007245:Inferior Colliculi / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D008928:Mitochondria / Q000473:pathology; D016622:Silver Staining; D013569:Synapses / Q000473:pathology*