Developmental Regulation of Homeostatic Plasticity in Mouse Primary Visual Cortex

Area of Science:

• Neuroscience
• Developmental Biology
• Systems Neuroscience

Background:

• Homeostatic plasticity is crucial for neural network stability.
• Developmental regulation of homeostatic plasticity mechanisms is poorly understood.
• Lack of methods to manipulate neuronal activity across developmental stages hinders research.

Purpose of the Study:

• To investigate developmental differences in homeostatic plasticity using a novel DREADD-based method.
• To compare homeostatic plasticity during the critical period (CP) and adulthood in the mouse visual cortex.

Main Methods:

• Utilized designer receptors exclusively activated by designer drugs (DREADDs) to suppress neuronal activity in L2/3 of the mouse visual cortex.
• Applied DREADDs at two developmental timepoints: the critical period (P24-P29) and adulthood (P45-P55).
• Assessed changes in excitatory synaptic scaling, intrinsic neuronal excitability, and inhibitory synaptic plasticity.

Main Results:

• During the CP, activity suppression induced both excitatory synaptic scaling and intrinsic homeostatic plasticity.
• In adulthood, excitatory synaptic scaling persisted, but intrinsic homeostatic plasticity was absent.
• Quantal inhibitory input changes were absent during the CP but present in adults.

Conclusions:

• The same neuronal populations exhibit distinct homeostatic plasticity mechanisms at different developmental stages.
• Homeostatic plasticity mechanisms are recruited in a modular fashion, adapting to the evolving needs of neural circuits.
• Findings highlight the dynamic and stage-specific nature of homeostatic plasticity in the developing brain.