---

 

The basal ganglia classically include:

1. Caudate nucleus

2. Putamen

3. Globus pallidus

The caudate nucleus + putamen together are called the striatum.

Functionally related structures often included in the basal ganglia circuitry:

• Substantia nigra (midbrain)

• Subthalamic nucleus

---

🧩 Main Functions

1️⃣ Motor Control (Primary Role)

They help:

• Initiate voluntary movement

• Suppress unwanted movements

• Regulate muscle tone

• Coordinate smooth execution of movement

They do not directly send motor signals to the spinal cord, but instead modulate motor output through loops involving:

• Cerebral cortex

• Thalamus

• Motor cortex

---

2️⃣ Cognitive and Emotional Functions

Basal ganglia circuits are also involved in:

• Habit formation

• Reward processing

• Procedural learning

• Motivation

---

⚙️ Simplified Functional Pathways

Two major motor pathways:

• Direct pathway → facilitates movement

• Indirect pathway → inhibits movement

Balance between these pathways allows controlled motion.

Dopamine (from the substantia nigra) modulates this balance.

---

🏥 Clinical Correlation

Disorders of the basal ganglia include:

• Parkinson's disease

  • ↓ Dopamine

  • Bradykinesia, rigidity, resting tremor

• Huntington's disease

  • Degeneration of striatum

  • Chorea

• Hemiballismus

  • Often lesion of subthalamic nucleus

---