Cerebellum

1. Cerebellum

2. M P Climbing Fiber G Mossy Fiber W Cerebellar Cortex • Three Layers • Molecular, Purkinje, Granular Cell • Fibers • Climbing (Olive) • Mossy (Not Olive) • Parallel • Output • Purkinje Cells Outside

3. Describe the three main routes through which the cerebellar cortex can control movement

4. Leaving the Cerebellum - Three Origins -- Three Deep Nuclei • Cerebellar Cortex to Deep Nuclei • Fastigial Nucleus • Interposed Nuclei • Dentate Nucleus • Deep Nuclei To ... • Vestibular Nuclei and Reticular Formation • Red Nucleus • “Motor” Thalamus (VA and VL) Cerebellar Cortex Cerebellar Deep Nuclei Brainstem and Thalamus

5. Flocculonodular Lobe - Vestibulocerebellum • Inferior Cerebellar Peduncle • Direct to Brainstem • Vestibular Nuclei • Via Fastigial Nucleus • Vestibular Nuclei • Vestibulospinal Tract • Reticular Formation • Reticulospinal Tract Fastigial Vestibular and Reticular

6. Midline Anterior Lobe and Vermis (Paravermal) - Spinocerebellum • Superior Cerebellar Peduncle • Via Interposed Nuclei • Reticular Formation, Bilateral • Reticulospinal Tract • Red Nucleus, Contralateral • Rubrospinal Tract • “Motor Thalamus” , Contralateral • To Motor Cortex and Corticospinal Tract Interposed Reticular NucleiRed Nucleus and Motor Thalamus Reticular Nuclei

7. Midline Posterior Lobe - Neocerebellum (Cerebrocerebellum) • Superior Cerebellar Peduncle • Via Dentate Nucleus • Red Nucleus, Contralateral • Rubrospinal Tract • “Motor Thalamus” , Contralateral • To Motor Cortex and Corticospinal Tract Dentate Red Nucleus and Motor Thalamus

8. Motor Cortex IC VA/VL Corticospinal Tract dSCP IPNuc DSCT LMN Gracilis ICP Clarke’s Nucleus Cerebellar Cortex Leg From Cerebellum To Leg The Cerebellum Controls the Ipsilateral Side

9. Contrast differences in symptoms produced by damage to the flocculo-nodular lobe, spinocerebellum and neocerebellum

10. What is a positive Romberg sign, dysdiadochokinesia and dysmetria and what do they indicate? Contrast the type of tremor seen with cerebellar lesions with basal ganglia lesions.

11. Cerebellar Disorders - In General • Ipsilateral Effects • Ataxia without paresis • Wide based Gait, Staggering • Intentional Tremor • Oscillations worsen with targeted movements • Dysdiadochokinesia • Slow movements, jerky, cerebral control • Decomposition of Movement • Dysmetria • Finger to Nose, Heel to Shin

12. Cerebellar Disorders - Vestibulocerebellum • Damage to Floculonodular Lobe • Truncal Ataxia • Off the Midline (Direction?) • No limb ataxia • Nystagmus and Vertigo • Extensor Rigidity (Alpha Rigidity) • Decreased Inhibition by Cerebellum • Increased LVN Activation • Increased Tone • Ipsilateral??? Vestibulo Cerebellum LVN LMN

13. Cerebellar Disorders - Spinocerebellum • Damage to Anterior Lobe or Vermal Region • Homunculus Emphasizes Lower Limb • Lower Limb Ataxia • Wide Based Gait • Ipsilateral Instability • Dysmetria and Dysdiadochokinesia Lower Limb Ipsilateral • Positive Romberg Sign ? Not!

14. Cerebellar Disorders - NeoCerebellum (Cerebrocerebellum) • Damage to the Posterior Lobe • Outside Paravermal • Motor Planning Problems • Mainly in Upper Limb • Dysdiadochokinesia and Dysmetria • Intentional Tremor • Oscillations = Loops • Positive and Negative Feedback

15. Contrast the difference in postural control produced by a lesion of the spinocerebellar tracts versus the vestibular nuclei versus the flocculonodular lobe.

16. Lesion Differences • Dorsal and Cuneocerebellar Tract Damage • Positive Romberg Sign • Vestibular Nuclei Damage • Extreme Postural Instability • Strong Vertigo • FlocculoNodular Damage • Postural Instability without Limb Involvement • Other Cerebellar Damage • Ataxia, Dysmetria, Etc