Presentation on theme: "Cerebellar system and diseases"— Presentation transcript:
1Cerebellar system and diseases Balance & Equilibrium
2Cerebellum Coordination of movement Control of gait, posture (Balance )Control of muscle tone (Motor control )Cognitive functionsAttentionEmotionsLanguage
3Motor coordination Cerebellum does not initiate movement It contributes to coordination, precision, and accurate timing.It receives input from sensory systems and from other parts of the brain and spinal cord,It integrates these inputs to tune fine motor activity.Because of this fine-tuning function,Cerebellar lesions produce disorders in fine movement, equilibrium, posture, and motor learning.
5Intrinsic Fibers Mossy fibers These fibers carry impulses from the inferior peduncle from spinocerebellar pathways, olivocerebellar pathways.Climbing fibersThey carry impulses from the middle cerebellary peduncle. They carry impulses from the cortex and projects to the cortex.
6Phylogenetically..Flocculo-nodulus ARCHICEREBELLUM – related with vestibular nucleiAnterior lobes-PALEOCEREBELLUM- spinocerebellar pathwaysPosterior lobes- NEOCEREBELLUM – cerebello-pontin pathways
7Vestibulo-cerebellum Flocculo-nodulus receives special proprioceptive impulses from the vestibular nuclei (located in pons and the bulb)Equilibrium and balance , spatial orientation.Any lesion will cause ataxia , gait disturbance,Walking difficulty
8Spinocerebellum Vermis, The medial zone of the anterior lobes It receives proprioceptive input from the spinocerebellar tract and from visual and auditory systems.It sends fibres to deep cerebellar nuclei that, in turn, project to both the cerebral cortex and the brain stem, thus providing modulation of descending motor systems; POSTURE, MUSCLE TONE.
9NeocerebellumPosterior lobes receive afferents from cortex through corticopontine pathways.It projects to the cortex via the dentate nucleus. Its projections are to the cerebral cortex through nucleus ruber, thalamus.In association with the differentiation of skeletal muscle this part is the largest in humans.It coordinates skilled movements.
10Many projections (mainly the purkinje cell) relay on deep cerebellary nuclei (mainly dentate nuclei) and then projects.Contrary, Floculo-nodulus directly projects to vestibular nuclei.
11Clinical manifestations of cerebellar dysfunction Muscular coordinationEquilibriumLocomotionNo weaknessInitiation of movement delays.Relaxing delays.Contractions are irregular, intermittent.Speech disturbances
12Features with regard to lobes Posterior lobe(neocortex)Anterior lobe(paleocortex)Flocculo-nodulus(archicortex)Ataxia+++Nystagmus-+/_Intentional tremor_HyptoniaReboundDysmetria..
13Dysmetria Loss of ability to gauge the distance Speed Power of movementThe act may be carried out with too little or too much power.The act may stop before the goal is reachedor overshoot.
14dysdiadokokinesiaDisturbance of reciprocal innervation-coordination of agonist-antagonist muscles.İmpairment of rapid alternating muscles.
15HypotoniaThe body parts may be extended or flexed to extreme positions as the muscle tonus is decreased (flask).
16Intentional tremorTremor is not observed at rest, but during reaching a target tremor becomes established.Diferential diagnosisResting tremor (parkinsonian)Postural tremor (essential , drugs)
17Speech in cerebellar diseases ExplosiveSlurredAs if drunken