Upregulation of Calbindin in Adult Inhibitory Neurons Reactivates Critical Period Plasticity in Mouse Visual Cortex

Area of Science:

• Neuroscience
• Developmental Biology
• Molecular Biology

Background:

• Critical periods represent windows of heightened synaptic plasticity in the juvenile brain, enabling rapid circuit reorganization.
• Adult brain plasticity typically requires persistent sensory changes, unlike the enduring effects seen during critical periods.
• Transplantation of inhibitory neurons can restore critical period plasticity by altering host inhibitory neuron signaling.

Purpose of the Study:

• To investigate gene expression changes in host inhibitory neurons during transplant-induced plasticity.
• To identify molecular mechanisms underlying the restoration of critical period plasticity in adult visual cortex.
• To assess the functional role of specific gene expression changes in visual cortical plasticity.

Main Methods:

• Transcriptional profiling of host inhibitory neurons in mouse primary visual cortex (V1).
• Gene ontology enrichment analysis to identify differentially expressed genes.
• Protein expression analysis of Calbindin (Calb1).
• Adeno-associated virus (AAV) mediated manipulation of Calb1 expression in inhibitory neurons.
• Intrinsic signal imaging to measure ocular dominance plasticity.

Main Results:

• Gene ontology analysis revealed synaptic plasticity and inhibitory neuron development profiles among differentially expressed genes.
• Calbindin (Calb1) showed high expression during the V1 critical period and in transplant-induced plasticity.
• Calbindin levels in V1 inhibitory neurons were found to regulate the extent of visual cortical plasticity.
• Manipulation of Calb1 expression in inhibitory neurons determined the degree of restored plasticity.

Conclusions:

• Directly inducing critical period-stage gene expression patterns in adult inhibitory neurons can restore juvenile plasticity.
• Calbindin is a key molecular player in mediating transplant-induced restoration of visual cortical plasticity.
• This study provides a molecular framework for understanding and potentially manipulating critical period plasticity in the adult brain.