II. Definitions
- Basal Ganglia
- Collection of Neurons and their nucleii near the Thalamus that function to coordinate movement
- Counters the excitatory signals from the Cerebellum to result in smooth movement
- Interconnections to the Cerebral Hemispheres, Cerebellum, Thalamus and Brainstem
III. Anatomy: Components
- Globus Pallidus
- Dorsal Striatum (Putamen, Caudate Nucleus)
- Medial Dorsal Striatum (Caudate Nucleus)
- Internal Capsule (courses between the Caudate Nucleus and Putamen)
- Lateral Dorsal Striatum (Putamen)
- Nucleus Accumbens
- Substantia Nigra (Midbrain)
- Divided into the pars compacta and pars reticulata
- Melanin containing cells in pars compacta produce Dopamine which is transmitted to the Dorsal Striatum
- Parkinsonism results when Dopamine production is deficient
- Functions
- Movement including eye movement (see Pars compacta as above
- Reward-seeking and addiction
- Divided into the pars compacta and pars reticulata
- Subthalamic Nucleus
IV. Anatomy: Images
-
Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
-
Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
V. Pathophysiology
- See Movement Disorder
-
Parkinsonism
- Associated with rigid slow movements, resting Tremor, shuffling gait, mask-like facies
- Basal Ganglia degeneration
- Substantia Nigra degeneration
-
Athetosis
- Slow, writhing movements (esp. hand, wrist)
-
Chorea (e.g. Huntington's Chorea, Sydenham's Chorea)
- Sudden, jerky movements
- Hemiballismus
- Sudden, incoordinated flailing of an extremity
VI. References
- Goldberg (2021) Clinical Physiology, Medmaster, Miami, p. 106
- Goldberg (2014) Clinical Neuroanatomy, Medmaster, p. 61-4
- Netter (1997) Atlas Human Anatomy, ICON Learning, p. 104