CEREBELLUM Functions: Maintenance of balance and posture Coordination of voluntary movements Motor learning Cognitive functions CEREBELLUM Anatomical division CEREBELLUM Developmental division  archicerebellum  vestibulocerebellum  paleoocerebellum  spinocerebellum  neocerebellum  cerebro- (ponto-) cerebellum CEREBELLUM Functional division  VC  flocculonodular lobe  vestibular ncll.  SC - median zone  vermis  ncl. fastigii  SC - paramedian zone  intermediate cortex  ncll. emboliformis et globosus  CC - lateral zone  cortex cerebellar hemispheres  ncl. dentatus Rubro – olivary tract CEREBELLAR CORTEX Connections of the vestibulocerebellum LGB + Sup.Col. Vestibular apparatus Pontine ncll. Flocculonodular lobe (vestibulocerebellum) Vestibular ncll. Spinal motor neurons Vestibulospinaltracts  vestibular reflexes  postural maintenance Vestibulocerebellartract Connections of the spinocerebellum – median zone GN + CN Ncl. thor. (S-C) Vermis (spinocerebellum) Vestibular ncll. Spinal motor neurons Bulbocerebellartract Cuneocerebellartract Spinocerebellartracts Vestibulospinaltracts Ncl. fast. FR Reticulosp.tracts Th. VL MC Ant.corticoospinaltract  control of medial descending (motor) system Connections of the spinocerebellum – paramedian zone GN + CN Ncl. thor. (S-C) Intermediate zone (spinocerebellum) Spinal motor neurons Bulbocerebellartract Cuneocerebellartract Spinocerebellartracts Ncll. emb.+ glob. RN Rubrosp.tract Th. VL MC Lat.corticoospinaltract  control of lateral descending (motor) system Connections of the cerebro(ponto)cerebellum – lateral zone Lateral zone (pontocerebellum) Spinal motor neurons Pontocerebellar tract Ncl. dentatus Pontine ncll. Th. VL Motor cortex Lat.corticoospinaltract  planning and timing of movements  cognitive functions Corticopontinetract Somatotopic organization Projection of both spinocerebellar pathways and motor cortex  ipsilateral anterior lobe  bilateral paramedian (intermediate) zone BASAL GANGLIA BASAL GANGLIA Striatum (neostriatum) – ncl. caudatus (D) - putamen (D) - ncl. accumbens (V) Pallidum (paleostriatum) – globus pallidus ext.s. int.s. Substantia nigra – pars reticularis - pars compacta Ncl. subthalamicus VP VS C Pu GP Ncl caudatus + putamen = dorsal striatum Globus pallidus = dorsal pallidum Substantia innominata: VS = ventr. striatum Ncl. accumbens septi VP = ventral pallidum Ncl. basalis Meynerti Basal ganglia afferents:  cortex  substantia nigra – pars compacta  intralaminar ncll. of thalamus (CM) Basal ganglia efferents:  GPi  SN – pars reticularis  Th. VA/VL  Th. CM (ansa lenticularis + fasciculus lenticularis → fasciculus thalamicus) Basal ganglia intrinsic connections:  Striatopallidal p.  Striatonigral p.  GPe → STN  STN → GP, SNr.  Nigrostriatal p. Motor loop SPINAL REFLEXES  type of afferents  somatic spinal reflexes  visceral spinal reflexes  type of somatosensor  proprioceptive reflexes  exteroceptive reflexes  number of involved spinal segments  monosegmental spinal reflexes  polysegmental spinal reflexes  number of synapses  monosynaptic reflexes  disynaptic reflexes  polysynaptic reflexes Myotatic reflex Withdrawal reflex Myotatic (stretch) reflex Myotatic (stretch) reflex Myotatic (stretch) reflex Reflex loop of Golgi tendon organ (inverse myotatic reflex) Ib Flexor (withdrawal) reflex Renshaw cells Gamma loop EYE MOVEMENTS  Fovea centralis – area of most acute vision  Coordination of 12 oculomotor muscles  Eye movements  conjugated – both eyes in same direction  vergent - during motion of object to and from us  convergent  divergent Four basic types of eye movements  Saccades  Smooth pursuit movements  Vergence movements  Vestibulo-ocular movements Saccadic eye movements  horizontal gaze center - PPRF  vertical gaze center – RF of the midbrain  superior colliculi – information from FEF, retina, auditory, and tactile i. Smooth pursuit movements  elicited by a moving visual target that the eyes follow voluntarily or under direction  the moving visual target is required to initiate this eye movement Vestibulo-ocular movements  stabilize the eyes relative to the external world, thus compensating for head movements Vergence movements Illustrations were copied from: Neuroscience Online, the Open-Access Neuroscience Electronic Textbook Department of Neurobiology and Anatomy University of Texas Medical School at Houston