1. Basal Ganglia Loops

Pathway	Effect on Thalamus	Receptors	Steps
Direct	Disinhibition (GO)	D1 (Stimulatory)	Cortex (+) -> Striatum (-) -> GPi/SNr -> Less GABA to Thalamus -> Thalamus Fires.
Indirect	Inhibition (STOP)	D2 (Inhibitory)	Cortex (+) -> Striatum (-) -> GPe (-) -> STN (+) -> GPi (-) -> Thalamus Inhibited.
Dopamine	Promotes Movement	SNc	Stimulates Direct (D1) and Inhibits Indirect (D2).

2. Deep Cerebellar Nuclei ("Don't Eat Greasy Foods")

Nucleus	Location	Input Zone	Output Target
Dentate	Lateral	Lateral Hemisphere	Premotor Cortex (Motor Planning).
Emboliform	Intermediate	Intermediate Zone	Red Nucleus / Spinal Cord.
Globose	Intermediate	Intermediate Zone	Red Nucleus / Spinal Cord.
Fastigial	Medial	Vermis	Vestibular Nuclei (Balance/Trunk).

3. Cerebellar Peduncles

• Middle (MCP): Largest. Input from Contralateral Cortex (via Pons). "Mossy Fibers".
• Inferior (ICP): Input from Spinal Cord (Proprioception) + Inf. Olive ("Climbing Fibers").
• Superior (SCP): Output to Contralateral Thalamus/Red Nucleus. Decussates in Midbrain.