Cns basal ganglia


Published on

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide
  • 2 main jobs: 1) helping motor cortex execute PATTERNS of complex movements 2) Helping cortex plan (‘think’) complex motor movements
  • Note the internal capsule tucked in between basal ganglia, cortex and thalamus
  • the putamen circuit has its inputs mainly from those parts of the brain adjacent to the primary motor cortex but not much from the primary motor cortex itself. Then its outputs do go mainly back to the primary motor cortex or closely associated premotor and supplementary cortex. Functioning in close association with this primary putamen circuit are ancillary circuits that pass from the putamen through the external globus pallidus, the subthalamus, and the substantia nigra—finally returning to the motor cortex by way of the thalamus.
  • concerned with putting together sequential patterns of movement lasting 5 or more seconds instead of exciting individual muscle movements.
  • Ref: berne p190-191…xcellent circuit diagrams of basal ganglia in parkinson and huntington’s
  • *Parkinsonism is also seen as a complication of treatment with the phenothiazine group of tranquilizer drugs and other drugs that block D2 receptors. It can be produced in rapid and dramatic form by injection of 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP). This effect was discovered by chance when a drug dealer in northern California supplied some of his clients with a homemade preparation of synthetic heroin that contained MPTP. MPTP is a prodrug that is metabolized in astrocytes by the enzyme MOA-B to produce a potent oxidant, 1-methyl-4-phenylpyridinium (MPP+). In rodents, MPP+ is rapidly removed from the brain, but in primates it is removed more slowly and is taken up by the dopamine transporter into dopaminergic neurons in the substantia nigra, which it destroys without affecting other dopaminergic neurons to any appreciable degree. Consequently, MPTP can be used to produce parkinsonism in monkeys, and its availability has accelerated research on the function of the basal ganglia.
  • Cns basal ganglia

    1. 1. <ul><li>BASAL GANGLIA </li></ul>
    2. 2. Basal Ganglia (Nuclei) <ul><li>Group of deep, interrelated subcortical N </li></ul><ul><li>Accessory motor system that </li></ul><ul><ul><ul><li>Functions usually not by itself but in close association with cerebral cortex & corticospinal motor control system </li></ul></ul></ul><ul><ul><ul><li>Most input signals from: cerebral cortex </li></ul></ul></ul><ul><ul><ul><li>Most output signals back to: cerebral cortex </li></ul></ul></ul>
    3. 3. Anatomy <ul><ul><li>Caudate </li></ul></ul><ul><ul><li>Putamen </li></ul></ul><ul><ul><li>Globus pallidus </li></ul></ul><ul><ul><li>Substantia nigra </li></ul></ul><ul><ul><li>Subthalamic nucleus </li></ul></ul>
    4. 4. Anatomy Overview
    5. 5. Anatomy
    6. 6. The Putamen Circuit – Executing Patterns of Motor Activity
    7. 7. The Putamen Circuit - Functions <ul><li>Putamen circuit + cerebral cortex </li></ul><ul><ul><ul><li>Controls complex patterns of motor activity </li></ul></ul></ul><ul><ul><ul><ul><li>Writing, Cutting paper with scissors, Hammering nails </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Shooting a basketball through a hoop, passing a football, Throwing a baseball </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Most aspects of vocalization </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Controlled movements of the eyes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>And virtually any other skilled movements </li></ul></ul></ul></ul>
    8. 8. The Putamen Circuit - Lesions <ul><li>Globus Pallidus: </li></ul><ul><ul><ul><li>Spontaneous, continuous writhing movements of a hand, an arm, the neck, or the face – Athetosis </li></ul></ul></ul><ul><li>Subthalamus: </li></ul><ul><ul><ul><li>Sudden flailing movements of an entire limb – Hemiballismus </li></ul></ul></ul><ul><li>Putamen: </li></ul><ul><ul><ul><li>Flicking movements in hands, face, & other parts of body – Chorea </li></ul></ul></ul><ul><li>Substantia Nigra: </li></ul><ul><ul><ul><li>Common and extremely severe disease of rigidity , akinesia , and tremors - Parkinson ’ s disease </li></ul></ul></ul>
    9. 9. The Caudate Circuit – Cognitive Control of Sequences of Motor Patterns <ul><ul><li>Cognition </li></ul></ul><ul><ul><ul><li>Most motor actions occur as a consequence of cognition </li></ul></ul></ul><ul><ul><ul><li>Caudate nucleus is pivotol </li></ul></ul></ul>
    10. 10. The Caudate Circuit <ul><li>Timing and Scaling of movements </li></ul>
    11. 12. BG Circuit - Neurotransmitters
    12. 13. ? <ul><li>What was common between Yasir Arafat , Muhammad Ali & Adolph Hitler ? </li></ul>
    13. 14. Parkinson’s Disease <ul><li>Degenerative disorder of basal ganglia </li></ul><ul><li>Dopamine depletion results from: </li></ul><ul><ul><ul><li>Degeneration dopamine nigrostriatal system </li></ul></ul></ul><ul><ul><ul><li>Antipsychotic drugs that block dopamine receptors </li></ul></ul></ul><ul><ul><ul><li>Toxic reaction to a chemical agent </li></ul></ul></ul><ul><ul><ul><ul><ul><li>The Northern California drug dealer!* </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Severe carbon monoxide poisoning </li></ul></ul></ul>
    14. 15. Parkinson’s Disease – Clinical <ul><li>Tremor (involuntary tremor) </li></ul><ul><ul><ul><ul><li>Affects distal segments of limbs (hands and feet; head, neck, face, lips, tongue; or jaw) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Characterized by rhythmic, alternating flexion & contraction movements (4-6 beats/minute) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Disappears during voluntary movement </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Start unilateral- spread bilateral </li></ul></ul></ul></ul><ul><li>Rigidity </li></ul><ul><ul><ul><ul><li>Resistance to movement of both flexors & extensors throughout the full range of motion </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Most evident during passive joint movement </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>involves jerky, cogwheel-type movements requiring considerable energy </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Start unilateral- spread bilateral </li></ul></ul></ul></ul>
    15. 16. Parkinson’s Disease – Clinical <ul><li>Bradykinesia (slowness of movement) </li></ul><ul><ul><ul><li>Movements: </li></ul></ul></ul><ul><ul><ul><ul><li>Are slow to initiate & perform </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Difficult to stop </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Are stiff & staccato in character instead of smooth </li></ul></ul></ul></ul><ul><ul><ul><li>While walking: </li></ul></ul></ul><ul><ul><ul><ul><li>Walking and turning en bloc is difficult </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Freezing spells </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>take small, shuffling steps without swinging arms </li></ul></ul></ul></ul><ul><ul><ul><li>Posture: </li></ul></ul></ul><ul><ul><ul><ul><li>Lean forward to maintain center of gravity </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Loss of postural reflexes – fall (often backward) </li></ul></ul></ul></ul><ul><ul><ul><li>Masked face: </li></ul></ul></ul><ul><ul><ul><ul><li>Emotional & voluntary facial movements become limited </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Loss of blinking reflex </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Failure to express emotion </li></ul></ul></ul></ul><ul><ul><ul><li>Throat: </li></ul></ul></ul><ul><ul><ul><ul><li>Tongue, palate, and throat muscles – rigid </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Drooling common </li></ul></ul></ul></ul></ul><ul><ul><ul><li>Speech: </li></ul></ul></ul><ul><ul><ul><ul><li>slow and monotonous, without modulation and poorly articulated </li></ul></ul></ul></ul>
    16. 17. Parkinson’s Disease – Clinical <ul><li>Advanced Parkinsonian features: </li></ul><ul><ul><ul><li>Dementia (similar to Alzheimer’s disease) </li></ul></ul></ul><ul><ul><ul><li>Falls </li></ul></ul></ul><ul><ul><ul><li>Fluctuations in motor function </li></ul></ul></ul><ul><ul><ul><li>Neuropsychiatric disorders </li></ul></ul></ul><ul><ul><ul><li>Sleep disorders </li></ul></ul></ul>
    17. 20. Parkinson’s Disease – Treatment <ul><li>Nonpharmacologic </li></ul><ul><ul><ul><li>Group support </li></ul></ul></ul><ul><ul><ul><li>Education </li></ul></ul></ul><ul><ul><ul><li>Daily exercise, adequate nutrition </li></ul></ul></ul><ul><ul><ul><li>Botulism toxin injections </li></ul></ul></ul><ul><li>Pharmacologic </li></ul><ul><ul><ul><li>Antiparkinson drugs act by: </li></ul></ul></ul><ul><ul><ul><ul><li>Increasing functional ability of underactive dopaminergic system </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Increase dopamine levels (levodopa) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Augment release of dopamine (amantadine) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Function as dopamine agonists (bromocriptine) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Inhibit metabolic breakdown of dopamine (selegiline) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><li>Reducing excessive influence of excitatory cholinergic neurons </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Anticholinergic drugs </li></ul></ul></ul></ul></ul>
    18. 21. Parkinson’s Disease – Treatment <ul><li>Surgical </li></ul><ul><ul><ul><li>Thalamotomy or pallidectomy performed using stereotactic surgery </li></ul></ul></ul>
    19. 22. Overall Motor Control