 Three Layers ◦ Molecular, Purkinje, Granular Cell  Fibers ◦ Climbing (Olive) ◦ Mossy (Not Olive) ◦ Parallel  Output ◦ Purkinje Cells M P G W Climbing Fiber Mossy Fiber Outside

 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

 Inferior Cerebellar Peduncle  Direct to Brainstem ◦ Vestibular Nuclei  Via Fastigial Nucleus ◦ Vestibular Nuclei  Vestibulospinal Tract ◦ Reticular Formation  Reticulospinal Tract Vestibular and Reticular Fastigial

 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 Reticular Nuclei Red Nucleus and Motor Thalamus Interposed Reticular Nuclei Midline

 Superior Cerebellar Peduncle  Via Dentate Nucleus ◦ Red Nucleus, Contralateral  Rubrospinal Tract ◦ “Motor Thalamus”, Contralateral  To Motor Cortex and Corticospinal Tract Red Nucleus and Motor Thalamus Dentate Midline

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

 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

 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??? LVN LMN Vestibulo Cerebellum

 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!

 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

 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