Related Experiment Video
Updated: May 17, 2026
12:06
Transmission Electron Microscopy as the Visualization Technique for Analysis of Circadian Synaptic Plasticity in the Mouse Barrel Cortex
Published on: August 19, 2025
Developmental switch in spike timing-dependent plasticity at layers 4-2/3 in the rodent barrel cortex
Chiaki Itami1, Fumitaka Kimura
1Department of Physiology, Faculty of Medicine, Saitama Medical University, Moroyama, Saitama 350-0495, Japan. chiaki@saitama-med.ac.jp
Summary
Sensory deprivation alters brain maps by changing spike timing-dependent plasticity (STDP). A developmental switch in STDP rules around postnatal day 13-15 in mice S1 dictates whether synapses strengthen or weaken, impacting cortical map reorganization.
Area of Science:
- Neuroscience
- Developmental Biology
- Synaptic Plasticity
Background:
- Sensory deprivation during critical periods causes lasting changes in cortical maps.
- Spike-timing-dependent plasticity (STDP) at layer 4 (L4)-L2/3 synapses is crucial for this reorganization in the rodent somatosensory cortex (S1).
- Whisker deprivation reverses the normal L4-then-L2/3 firing order, leading to synaptic depression and map changes.
Purpose of the Study:
- To investigate the developmental changes in STDP properties at L4-L2/3 synapses in mouse S1.
- To determine how these changes influence synaptic plasticity and map reorganization following sensory deprivation.
- To elucidate the molecular mechanisms underlying immature STDP.
Main Methods:
- Electrophysiological recordings in mouse S1.
- Induction of synaptic plasticity using specific stimulation protocols.
- Sensory deprivation experiments (whisker removal) at different developmental stages.
- Pharmacological manipulation to probe molecular pathways (Ca2+, protein kinase A).
Main Results:
- STDP rules undergo a significant developmental switch around postnatal days 13-15 (P13-P15).
- Before P13, timing-dependent long-term potentiation (t-LTP) was dominant, irrespective of spike order, requiring postsynaptic Ca2+ and protein kinase A.
- Whisker deprivation before P13 failed to induce synaptic depression, while deprivation after P14 resulted in depression, indicating a critical period for deprivation-induced suppression.
Conclusions:
- A developmental shift in the STDP rule occurs in mouse S1 L4-L2/3 synapses.
- This switch transitions the system from activity-dependent synapse formation (before P13) to circuit reorganization (after P14).
- The findings highlight the dynamic nature of synaptic plasticity during development and its role in shaping sensory cortical maps.
