Abnormal grooming activity in Dab1(scm) (scrambler) mutant mice

Area of Science:

• Neuroscience
• Behavioral Genetics
• Developmental Neurobiology

Background:

• The Dab1 gene plays a crucial role in neuronal migration during brain development.
• Mutations in Dab1 can lead to structural abnormalities in the cerebellum, hippocampus, and neocortex.
• Altered brain structure can impact complex motor behaviors like grooming.

Purpose of the Study:

• To investigate the effects of the Dab1(scm) mutation on grooming behavior in mice.
• To compare the grooming patterns of Dab1(scm) mutants with non-ataxic controls.
• To elucidate the role of the cerebellum in the execution and organization of grooming sequences.

Main Methods:

• Behavioral analysis of grooming in Dab1(scm) mutant mice and non-ataxic littermate controls.
• Quantitative assessment of grooming parameters such as latency, bout duration, and frequency.
• Observation of grooming component sequencing and regional distribution following water immersion.

Main Results:

• Dab1(scm) mutants exhibited longer grooming latencies, fewer grooming bouts, and shorter bout durations.
• Mutant mice predominantly groomed the rostral part of their body (head washing, forelimb licking).
• While the cephalocaudal grooming sequence was relatively preserved, mutant bouts were incomplete.

Conclusions:

• The cerebellar cortex is involved in the execution of grooming components but not in their sequential organization.
• Cerebral cortices or basal ganglia may be critical for the sequential organization of grooming.
• Dab1(scm) mice display compensatory behaviors, such as increased ambulation and scratching, possibly due to grooming deficits.