Dendritic changes in visual pathways in glaucoma and other neurodegenerative conditions

Visual information is sent from the retina to central visual targets through the optic nerve formed of retinal ganglion cells’ (RGCs) axons. In rodents, the superior colliculus (SC) is the major site of termination of retinal axons, whilst in primates and felines, it is the lateral geniculate nucleus (LGN). Glaucoma is a progressive optic neuropathy characterized by RGC death. There is increasing evidence that neuronal changes occur both in retina and central visual targets in glaucoma and other neurodegenerative diseases such as Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS). Dendrites are fine neuronal processes which support postsynaptic contact elements and are responsible for receiving synaptic signals. The morphology of dendrites has a profound impact on integrating neuronal input to the central nervous system from peripheral targets. This review summarizes different dendritic changes that have been recorded in neurodegenerative processes including those occurring in development, ageing and diseases. The findings suggest dendritic pathology is an early sign in disease and underline the importance of synapto-dendritic structure, providing new insights into therapeutic strategies.