Synaptic alterations in the medial geniculate bodies and the inferior colliculi in Alzheimer's disease: a Golgi and electron microscope study

Abstract

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.

Computer-assisted 3-D reconstructions of Golgi-impregnated neurons in the cortical regions of the inferior colliculus of rat

“…Even in the 21st century, quantitative analysis of Golgiimpregnated neurons can provide information on the dendritic organization of auditory and other central nervous system nuclei (e.g., Winer and Prieto, 2001;Cetas et al, 2002;Lorke et al, 2003;Kulesza, 2007;Baloyannis, 2005;Baloyannis et al, 2009;Bose et al, 2010). However, when used as a basis for quantitative analysis, the classical Golgi method (Golgi, 1873) is hampered by several technical problems.…”

Hearing Loss and Cognitive Decline in Older Adults

“…Pure tone audiometry is typically considered a measure of the auditory periphery because detection of pure tones relies on cochlear transduction and neuronal afferents to brainstem nuclei without requiring significant higher auditory cortical processing 31 . Neuropathology associated with Alzheimer’s disease has not been found in the peripheral auditory pathways 32, 33 .…”

At the interface of sensory and motor dysfunctions and Alzheimer's disease

“…These findings have profound implications for the relationship between hearing loss and cognitive impairments in Alzheimer’s disease and dementia. A shared neuropathologic etiology is a possibility (246). Alternatively, hearing loss may be associated with dementia through a causal pathway mediated by social isolation and/or cognitive load.…”