1. Neural Control of Muscle

2. Quick Review: Spinal Cord Flexors Extensors

3. Quick Review: Spinal Reflex Pathways

9. Basal Ganglia

11. Basal Ganglia Circuitry Motor Regions project mainly to Putamen

12. Motor Topography is preserved in Basal Ganglia

13. Caudate Putamen Pallidum (thalamus, hippo.)

16. Ventral Striatum (Nucleus Accumbens)

20. Subthalamic Nucleus Substantia Nigra

26. Globus Pallidus Thalamus/Cortex Tonic output from basal ganglia on cortex is inhibitory Basal Ganglia as a Gating Mechanism Inhibition

27. Basal ganglia and response initiation

28. Globus Pallidus Thalamus/Cortex Consequences of Selective BG Activation Striatum Increased Inhibition Striatum Globus Pallidus Thalamus/Cortex Disinhibition (Gating) ExcitationInhibition

29. Globus Pallidus Thalamus/Cortex Parkinson’s Disease involves increased tonic inhibition. A “stuck” gate. Globus Pallidus Thalamus/Cortex Normal Parkinson’s Inhibition

30. Akinesia Due to Elevated Threshold Input pattern is unchanged. But stronger activation is required to trigger the action.

31. Disorders of the Motor System Structure: Defecit: Motor Cortex Lose Power and Precision Secondary Motor Areas Apraxia (loss of precision) CerebellumAtaxia (difficulty walking) Basal GangliaParkinson’s Disease Huntington’s Disease Hemiballism

32. L-dopa therapy: Restores Motor Function in Parkinson’s Disease One of the miracles of 20 th Century Medicine. But problems can develop over time, and some patients don’t respond well to L-dopa drugs.

35. Black: PresurgeryWhite: With stimulation Deep Brain Stimulation (DBS) Subthalamic nucleus Globus pallidus, Internal Segment

36. Basal Ganglia are not entirely a motor structure… Birdsong is largely stored in the basal ganglia (speech, perhaps?) Parkinson Patients have cognitive deficits as well

37. Basal ganglia system essential for shifting from one goal state to another. Motor domain: Akinesia Parkinson patients become stuck on current action; unable to implement a new action. Cognitive domain: Bradyphrenia (slowed thought) Parkinson patients have trouble switching from one mental set to another.