Specific disruption of thalamic inputs to the auditory cortex in schizophrenia models

Area of Science:

• Neuroscience
• Genetics
• Pharmacology

Background:

• Auditory hallucinations in schizophrenia are treated by antipsychotics targeting D2 dopamine receptors (Drd2s).
• The neural mechanisms underlying antipsychotic sensitivity in schizophrenia remain unclear.
• Schizophrenia-associated 22q11 deletion syndrome (22q11DS) provides a model to study these deficits.

Purpose of the Study:

• To investigate the disruption of neural circuits in murine models of 22q11DS.
• To identify the mechanisms of antipsychotic sensitivity in schizophrenia-associated psychosis.
• To elucidate the role of Dgcr8 and microRNAs in thalamocortical pathway dysfunction.

Main Methods:

• Utilized murine models of 22q11DS.
• Examined synaptic transmission in thalamocortical glutamatergic projections.
• Assessed Drd2 levels and microRNA processing in the thalamus and auditory cortex.
• Measured acoustic startle response.

Main Results:

• Identified disrupted synaptic transmission in auditory thalamocortical projections in 22q11DS mice.
• Found elevated Drd2 levels in the thalamus of 22q11DS mice, increasing sensitivity to antipsychotics.
• Demonstrated that Dgcr8 haploinsufficiency causes Drd2 elevation and hypersensitivity.
• Observed deficient acoustic startle response in 22q11DS mice.

Conclusions:

• Dgcr8-microRNA pathway disruption leads to elevated Drd2 and aberrant thalamocortical function.
• This thalamocortical disruption is a key pathogenic mechanism in schizophrenia-associated psychosis.
• Findings suggest novel therapeutic targets for auditory hallucinations in schizophrenia.