Synapse pathology in dementia

Yuusuke Hatanaka, Keiji Wada, Yoshitaka Nagai

Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry

The function of synapses is essential for regulating synaptic plasticity and many brain functions. Therefore, synapse pathology is likely to be a central cause of brain dysfunctions including dementia. Postsynaptic structures called ‘dendritic spines' receive excitatory inputs from presynaptic neurons. Because there is a clear correlation between synaptic function and dynamic morphology of spines, time-lapse morphometric analysis of spines is a strong tool for evaluating synaptic function. In this review, we illustrate the commonalities of synapse pathology among several diseases with dementia, that is, decreased spine number and size, and enhanced turnover ratio of spines. These abnormal characteristics of spines can be interpreted as decreased synaptic strength and destabilization of neural circuits.

Address correspondence to Dr. Yoshitaka Nagai, Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry (4-1-1 Ogawahigashimachi, Kodaira, Tokyo 187-8502, Japan)