Restoring transient connectivity during development improves dysfunctions in fragile X mice.

Area of Science:

• Neuroscience
• Developmental Biology
• Neurodevelopmental Disorders

Background:

• Early cortical circuit maturation and excitation/inhibition (E/I) balance depend on inhibitory neuron development.
• Somatostatin-expressing (SST) neurons regulate parvalbumin (PV) neuron maturation and neural dynamics.
• The role of transient thalamocortical connectivity to SST neurons in neurodevelopmental disorders is unclear.

Purpose of the Study:

• To investigate the nature of thalamocortical connectivity to SST neurons in a mouse model of Fragile X syndrome (FXS).
• To determine if altered connectivity dynamics contribute to FXS-associated circuit and behavioral deficits.
• To explore therapeutic potential of restoring transient dynamics.

Main Methods:

• Utilized a mouse model of Fragile X syndrome.
• Investigated thalamocortical connectivity patterns to SST neurons.
• Employed chemogenetics to manipulate neural dynamics and restore transient connectivity.

Main Results:

• Thalamocortical connectivity to SST neurons was found to be persistently altered in the FXS mouse model.
• Restoration of transient dynamics using chemogenetics ameliorated FXS-associated dysfunctions in circuit maturation.
• Restored transient dynamics also led to recovery of sensory-dependent behaviors in the FXS model.

Conclusions:

• Early transient thalamocortical dynamics are crucial for downstream maturation of sensory functions.
• Persistent thalamocortical connectivity to SST neurons is a key mechanism underlying FXS-related neurodevelopmental deficits.
• Targeting and restoring these early dynamics presents a potential therapeutic strategy for FXS.