Morphological plasticity of postsynaptic neurones in reactive synaptogenesis

Area of Science:

• Neuroscience
• Cellular Biology
• Neuroanatomy

Background:

• Partial deafferentation leads to degenerating axon terminals and vacant postsynaptic sites.
• These sites can be re-supplied by sprouted axon terminals in some brain regions.
• Synaptic reorganization mechanisms vary depending on the brain area's capacity for axonal sprouting.

Purpose of the Study:

• To investigate synaptic reorganization in brain regions with limited axonal sprouting after deafferentation.
• To demonstrate the active role of postsynaptic elements in synaptic regeneration.
• To explore dendritic responses to deafferentation and their contribution to functional recovery.

Main Methods:

• Morphological analysis of central nervous system tissue from developing and adult animals.
• Observation of synaptic changes following partial deafferentation in specific brain regions (e.g., cerebellar cortex, lateral geniculate nucleus).

Main Results:

• In regions with limited sprouting, surviving dendrites form presynaptic specializations (axonization), creating new dendrodendritic synapses.
• Denervated dendritic arborizations undergo adaptive size reduction (atrophy).
• Both mechanisms contribute to a partial functional recovery after deafferentation.

Conclusions:

• Synaptic reorganization after deafferentation involves active participation of postsynaptic neuronal elements, particularly dendrites.
• Dendrites exhibit plasticity through axonization and atrophy in response to deafferentation.
• These structural adaptations facilitate partial functional recovery in the central nervous system.