| Popis: |
One of the neuropathological hallmarks of Alzheimer’s disease is the abnormal accumulation of amyloid-β (Aβ) plaques. To better understand the local effect of Aβ plaques on network activity, we characterized spontaneous slow oscillatory activity (interspersed Up or active states with Down or silent states) near Aβ plaques in APP/PS1 mice. To this end, we used arrays of 16 electrodes with 100 μm separation to record from the cerebral cortex, and the electrodes whose tip was adjacent to an Aβ plaque were identified anatomically. Although the frequency of the oscillations was unaffected, we found lower firing rate during Up and Down states close to Aβ plaques than far from them in the APP/PS1 mouse model, alongside lower activity synchronization in the beta-gamma frequency range, suggesting a local reduction in cortical excitability around Aβ plaques. Reduced synaptic connectivity around Aβ plaques could underlie the decreased excitability, altering the local dynamics of the cortical circuits. |
