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Updated: Jul 5, 2026
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Experience-Dependent Remodeling of Juvenile Brain Olfactory Sensory Neuron Synaptic Connectivity in an Early-Life Critical Period
Published on: March 1, 2024
Vision triggers an experience-dependent sensitive period at the retinogeniculate synapse
1Department of Neurology, F. M. Kirby Neurobiology Center, Children's Hospital Boston, and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115, USA.
Summary
Visual experience sculpts thalamic circuits later than previously thought. Several days of vision after eye opening are crucial for synaptic plasticity, which is rapidly reversible, challenging earlier developmental timelines.
Area of Science:
- Neuroscience
- Developmental Biology
- Visual System Research
Background:
- The mammalian visual system's cortical circuits are shaped by sensory experience during critical periods.
- Subcortical regions, like the thalamus, were traditionally considered to develop independently of vision at earlier ages.
- Recent research indicates vision influences synaptic circuit formation in the thalamus.
Purpose of the Study:
- To investigate the timing and necessity of visual experience for synaptic plasticity in the visual thalamus.
- To determine the duration of visual input required for experience-dependent synaptic reorganization.
- To explore the reversibility and developmental window of thalamic circuit plasticity.
Main Methods:
- Mice were subjected to varying durations of dark rearing (vision deprivation) at different postnatal days.
- Synaptic strength and connectivity at the retinogeniculate synapse were quantified.
- Changes in synaptic function and neuronal input were analyzed in response to visual experience manipulation.
Main Results:
- Dark rearing from birth did not affect retinogeniculate synapse development.
- Deprivation starting at postnatal day 20 (p20) weakened synaptic strength and increased retinal inputs to thalamic neurons.
- Several days of visual experience post-eye opening were necessary for synaptic reorganization, with shorter periods being insufficient.
- Connectivity changes were reversible upon restoring vision.
- Deprivation starting at p25 still weakened synapses but did not lead to the recruitment of additional retinal inputs.
Conclusions:
- Synaptic circuits in the visual thalamus exhibit unexpected malleability during a late developmental period, beyond typical synapse elimination phases.
- A specific sensitive period for thalamic plasticity exists after eye opening, requiring several days of visual input.
- This thalamic plasticity window overlaps with cortical sensitive periods, suggesting subcortical influences on cortical visual processing.
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