Voronoi-based spatial analysis reveals selective interneuron changes in the cortex of FALS mice

Area of Science:

• Neuroscience
• Neurobiology
• Motor Neuron Disease Research

Background:

• Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease impacting motor neurons.
• Mice with human mutant superoxide dismutase (SOD1) are models for familial ALS.
• Cortical changes in these mouse models are not fully understood.

Purpose of the Study:

• To investigate spatial organization of parvalbumin-immunoreactive interneurons in the motor, somatosensory, and visual cortex of SOD1(G93A) mice.
• To assess changes in interneuron number and spatial distribution during ALS progression.

Main Methods:

• Digital charting of cell locations in cortical samples.
• Cell counting and analysis of spatial distribution using 2D Voronoi diagrams.
• Comparison between end-stage and presymptomatic SOD1(G93A) mice and wild-type littermates.

Main Results:

• Increased numbers of parvalbumin interneurons in motor (35%) and somatosensory (20%) cortical areas of end-stage SOD1(G93A) mice.
• Evidence of increased parvalbumin cell clustering in affected cortical areas.
• Similar alterations observed in presymptomatic mice, indicating early disease onset.
• Visual cortex showed no significant changes.

Conclusions:

• The SOD1-mutant mouse cortex exhibits an altered interneuron architecture, particularly in motor control areas.
• These changes may represent pathogenic factors or early adaptations in ALS.
• Findings suggest disrupted cortical regulation and modulation of motor circuits in motoneuron disease.