Disynaptic Subthalamic Input to the Posterior Cerebellum in Rat

Area of Science:

• Neuroscience
• Neuroanatomy

Background:

• The basal ganglia and cerebellum interact in normal and pathological conditions.
• Neuroanatomical evidence for this interplay, especially in rodents, is limited.

Purpose of the Study:

• To investigate a potential disynaptic connection between the subthalamic nucleus (STN) and the cerebellar cortex in rats.
• To compare this connection with findings in primates.

Main Methods:

• Injected a mixture of rabies virus (RABV) and cholera toxin B-subunit (CTb) into the posterior cerebellar cortex of nine rats.
• Examined the STN for RABV-infected neurons after a suitable survival period for transneuronal infection.

Main Results:

• Prominent RABV labeling in the STN was observed when injections targeted the vermis of lobule VII.
• Minimal STN labeling occurred with injections in the paravermis or hemispheres.
• Evidence suggests the pedunculotegmental nucleus may be an intermediary in this pathway.

Conclusions:

• The STN disynaptically connects to the cerebellar vermal lobule VII in rats, bypassing sensorimotor areas.
• This pathway may primarily influence non-motor cerebellar functions, differing from primate findings.
• This suggests a potentially more complex basal ganglia-cerebellum interaction in rats, possibly related to non-motor tasks.