Heterogeneous responses to embryonic critical period perturbations within the Drosophila larval locomotor circuit.

Embryonic heat stress during a Drosophila larval locomotor critical period reduces crawling speed and network stability, indicating lasting circuit disruption.

• Why it matters: Critical periods can tune developing networks, but how different connected elements within a circuit respond to the same perturbation remains unclear.
• What they did: Using the Drosophila larval locomotor network, embryos were heat-stressed and later larvae were assessed for locomotor speed, network stability, synaptic drive, and motoneuron excitability.
• The result: Transient embryonic CP perturbation increases premotor interneuron-to-motoneuron synaptic drive while motoneurons adopt reduced excitability, yet the neuromuscular junction preserves normal synaptic transmission despite structural changes.