Cerebellar associative sensory learning defects in five mouse autism models

Area of Science:

• Neuroscience
• Autism Spectrum Disorder Research
• Cerebellar Function

Background:

• Sensory integration difficulties are common in autism spectrum disorder (ASD).
• Underlying brain-circuit mechanisms for these sensory issues in ASD remain poorly understood.
• Associative learning, particularly delay eyeblink conditioning, relies on cerebellar plasticity and offers a model for studying sensory learning deficits.

Purpose of the Study:

• To investigate the brain-circuit mechanisms of sensory integration difficulties in autism.
• To examine associative learning deficits in five distinct autism-related mouse models.
• To identify specific perturbations in delay eyeblink conditioning related to cerebellar function in ASD.

Main Methods:

• Utilized five genetically distinct autism mouse models: Shank3+/ΔC, Mecp2(R308/Y), Cntnap2-/-, L7-Tsc1, and patDp(15q11-13)/+.
• Assessed performance in delay eyeblink conditioning to evaluate associative sensory learning.
• Analyzed response probability, amplitude, and timing to characterize learning deficits.
• Examined Purkinje-cell dendritic spine density in select models.

Main Results:

• Reduced learning probability observed in Cntnap2-/-, patDp(15q11-13)/+, L7-Tsc1, and Shank3+/ΔC models, linked to Purkinje-cell/deep-nuclear gene expression.
• Smaller response amplitudes found in L7-Tsc1, Shank3+/ΔC, and Mecp2(R308/Y) models, associated with granule cell pathway expression.
• Aberrant response timing and reduced Purkinje-cell dendritic spine density noted in Shank3+/ΔC and Mecp2(R308/Y) models.
• Defects in instructed learning within the olivocerebellar loop and response representation in the granule cell pathway are suggested.

Conclusions:

• Defects in associative temporal binding of sensory events are prevalent across various autism mouse models.
• Cerebellar circuit dysfunction, affecting both Purkinje cells and the granule cell pathway, contributes to sensory learning impairments in ASD.
• These findings highlight the role of cerebellar plasticity in sensory processing abnormalities observed in autism.