Cortical activity emerges in region-specific patterns during early brain development.

Area of Science:

• Neuroscience
• Developmental Biology
• Comparative Neurology

Background:

• Precise neural circuit development relies on spontaneous neural activity before functional maturation.
• Rodent cerebral cortex exhibits patchwork and wave activity patterns at birth.
• The occurrence and developmental timing of these patterns in non-eutherian mammals are largely unknown.

Purpose of the Study:

• To investigate the presence and developmental emergence of spontaneous cortical activity patterns in marsupial dunnarts.
• To understand the timing and mechanisms of early cortical activity pattern formation.
• To explore the evolutionary conservation of neural activity patterns in brain development.

Main Methods:

• Utilized a minimally invasive approach in marsupial dunnarts, which undergo postnatal cortical development.
• Recorded neural activity in somatosensory and visual cortices at various developmental stages (from stage 24 to 27).
• Correlated the emergence of activity patterns with cortical layer formation and thalamic axon innervation.

Main Results:

• Discovered similar patchwork and travelling wave activity patterns in dunnart somatosensory and visual cortices at stage 27.
• Observed region-specific and sequential emergence of these patterns, starting as early as stage 24 (somatosensory) and stage 25 (visual).
• Identified the onset of patterned activity coinciding with cortical layer establishment and thalamic axon ingrowth.

Conclusions:

• Evolutionarily conserved spontaneous neural activity patterns play a role in early cortical development beyond sculpting synaptic connections.
• These patterns may regulate other fundamental early events in brain formation.
• The dunnart model provides a valuable system for studying prenatal-like cortical development non-invasively.