Motor performance and motor learning in Lurcher mice

Area of Science:

• Neuroscience
• Ophthalmology
• Genetics

Background:

• Cerebellar Purkinje cells are crucial for motor control.
• Lurcher mice exhibit Purkinje cell degeneration, serving as a model for cerebellar lesions.
• Compensatory eye movements, including the optokinetic (OKR) and vestibulo-ocular reflex (VOR), are vital for visual stability.

Purpose of the Study:

• To investigate the role of the cerebellum in adaptive modifications of the OKR and VOR.
• To determine if compensatory mechanisms exist in brainstem oculomotor pathways following cerebellar damage.
• To analyze the impact of Purkinje cell loss on the gain and phase of compensatory eye movements.

Main Methods:

• Utilized adult Lurcher mice with near-complete Purkinje cell degeneration.
• Recorded OKR and VOR in Lurcher mice and compared them to control animals.
• Assessed adaptive plasticity by subjecting both groups to eight days of visuovestibular training.

Main Results:

• Lurcher mice displayed significantly reduced OKR gain and increased phase lag.
• Minor alterations in VOR gain and phase lead were observed in Lurcher mice.
• Lurcher mice failed to modify either OKR or VOR during visuovestibular training, unlike control animals.

Conclusions:

• An intact cerebellum is indispensable for adaptive modifications in the oculomotor system.
• Compensatory eye movement reflexes are significantly impaired by cerebellar degeneration.
• The brainstem oculomotor pathways in Lurcher mice lack the capacity for adaptive VOR or OKR modification.