Related Experiment Video
Updated: Jun 25, 2026

Stereotaxic Infusion of Oligomeric Amyloid-beta into the Mouse Hippocampus
Published on: June 17, 2015
Oligomeric amyloid beta associates with postsynaptic densities and correlates with excitatory synapse loss near
Robert M Koffie1, Melanie Meyer-Luehmann, Tadafumi Hashimoto
1Neurology Department, Massachusetts General Hospital, Charlestown, MA 02129, USA.
Abstract:
Synapse loss correlates with a cognitive decline in Alzheimer's disease (AD), but whether this is caused by fibrillar deposits known as senile plaques or soluble oligomeric forms of amyloid beta (Abeta) is controversial. By using array tomography, a technique that combines ultrathin sectioning of tissue with immunofluorescence, allowing precise quantification of small structures, such as synapses, we have tested the hypothesis that oligomeric Abeta surrounding plaques contributes to synapse loss in a mouse model of AD. We find that senile plaques are surrounded by a halo of oligomeric Abeta. Analysis of >14,000 synapses (represented by PSD95-stained excitatory synapses) shows that there is a 60% loss of excitatory synapses in the halo of oligomeric Abeta surrounding plaques and that the density increases to reach almost control levels in volumes further than 50 microm from a plaque in an approximately linear fashion (linear regression, r(2) = 0.9; P < 0.0001). Further, in transgenic cortex, microdeposits of oligomeric Abeta associate with a subset of excitatory synapses, which are significantly smaller than those not in contact with oligomeric Abeta. The proportion of excitatory synapses associated with Abeta correlates with decreasing density (correlation, -0.588; P < 0.0001). These data show that senile plaques are a potential reservoir of oligomeric Abeta, which colocalizes with the postsynaptic density and is associated with spine collapse, reconciling the apparently competing schools of thought of "plaque" vs. "oligomeric Abeta" as the synaptotoxic species in the brain of AD patients.
More Related Videos
04:41Preparation of Oligomeric β-amyloid1-42 and Induction of Synaptic Plasticity Impairment on Hippocampal Slices
Published on: July 14, 2010
10:19Neurodegeneration in an Animal Model of Chronic Amyloid-beta Oligomer Infusion Is Counteracted by Antibody Treatment Infused with Osmotic Pumps
Published on: August 14, 2016
Related Concept Videos
Alzheimer Disease ll: Pathophysiology
Amyloid Fibrils
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid Fibrils
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Alzheimer Disease l: Introduction
Dementia l: Introduction
Alzheimer's Disease: Overview
The clinical diagnosis of AD hinges on the presence of memory and other cognitive impairments. Biomarkers, such as changes in Aβ and tau...