Synaptogenesis in the mouse olfactory bulb during glomerulus development

Area of Science:

• Neuroscience
• Developmental Biology

Background:

• Synaptogenesis is crucial for forming neuronal networks.
• Olfactory bulb (OB) glomeruli require extensive synapse formation between olfactory neurons and target cells.

Purpose of the Study:

• To track the spatio-temporal pattern of synaptogenesis during mouse OB development.
• To correlate synaptogenesis with glomeruli formation.

Main Methods:

• Electron microscopy (EM) was used to visualize synaptic structures.
• Immunolabelling for SV-2 (transmembrane synaptic vesicle glycoprotein) identified developing synapses.
• Developmental stages E13 to E16 in mice were analyzed.

Main Results:

• No SV-2 labeling or synapses were observed at E13, only electrodense junctions.
• Sparse SV-2 labeling appeared at E14 in the ventral/medial OB.
• A ventro-dorsal gradient of SV-2 labeling was evident by E15, covering the entire OB by E16.

Conclusions:

• Synaptogenesis in the OB exhibits a distinct spatio-temporal pattern.
• The observed pattern of synaptogenesis aligns perfectly with the developmental timeline of OB glomeruli formation.