CEREBELLUM Functions: Maintenance of balance and posture Coordination of voluntary movements Motor learning Cognitive functions > CEREBELLUM Anatomical division http://users.telenet.be/zeldzame.ziekten/List.z/zkhers6.jpg CEREBELLUM Developmental division qarchicerebellum §vestibulocerebellum qpaleoocerebellum §spinocerebellum qneocerebellum §cerebro- (ponto-) cerebellum CEREBELLUM Functional division qVC §flocculonodular lobe §vestibular ncll. § qSC - median zone §vermis §ncl. fastigii qSC - paramedian zone §intermediate cortex §ncll. emboliformis et globosus qCC - lateral zone §cortex cerebellar hemispheres §ncl. dentatus https://cnx.org/resources/c8b477169645b8977bff02e86d9b38ed2a81ed00/1612_Cerebellar_Peduncles-02.jpg The overall feedback pathway between the red nucleus and cerebellum. The red nucleus projects to the cerebellum via a synapse in the inferior olivary nucleus (rubro-olivary projections shown in green and olivocerebellar fibers shown in blue). The cerebellum, in turn, projects back to the red nucleus from the interposed nucleus (shown in red, which includes a Purkinje cell axonal input to interposed nuclei). The relationship of this circuit with the spinal cord is indicated by the presence of the rubrospinal tract. Rubro – olivary tract CEREBELLAR CORTEX https://s3.amazonaws.com/classconnection/224/flashcards/7262224/png/circuits-15062F93D3A2802C801.pn g Cerebellar connections http://fce-study.netdna-ssl.com/2/images/upload-flashcards/04/72/99/10047299_m.png Connections of the vestibulocerebellum LGB + Sup.Col. Vestibular apparatus Pontine ncll. Flocculonodular lobe (vestibulocerebellum) Vestibular ncll. Spinal motor neurons Øvestibular reflexes Øpostural maintanence Connections of the spinocerebellum – median zone GN + CN Ncl. thor. (S-C) Vermis (spinocerebellum) Vestibular ncll. Spinal motor neurons http://fce-study.netdna-ssl.com/2/images/upload-flashcards/04/73/02/10047302_m.png Ncl. fast. FR Th. VL MC Øcontrol of medial descending (motor) system Connections of the spinocerebellum – paramedian zone GN + CN Ncl. thor. (S-C) Intermediate zone (spinocerebellum) Spinal motor neurons Ncll. emb.+ glob. RN Th. VL MC Øcontrol of lateral descending (motor) system The overall feedback pathway between the red nucleus and cerebellum. The red nucleus projects to the cerebellum via a synapse in the inferior olivary nucleus (rubro-olivary projections shown in green and olivocerebellar fibers shown in blue). The cerebellum, in turn, projects back to the red nucleus from the interposed nucleus (shown in red, which includes a Purkinje cell axonal input to interposed nuclei). The relationship of this circuit with the spinal cord is indicated by the presence of the rubrospinal tract. Connections of the cerebro(ponto)cerebellum – lateral zone Lateral zone (pontocerebellum) Spinal motor neurons Ncl. dentatus Pontine ncll. Th. VL Motor cortex Øplanning and timing of movements Øcognitive functions The overall feedback pathway between the cerebral cortex and cerebellar cortex. The cerebral cortex projects to the cerebellum via a synapse in the basilar pons (shown in blue) second-order neurons pass through the middle cerebellar peduncle as pontocerebellar fibers to the cerebellar cortex (shown in blue). The feedback to the cerebral cortex involves a projection from the dentate nucleus to the ventrolateral nucleus of the thalamus, which, in turn, projects to the motor and premotor cortices (both shown in red). https://classconnection.s3.amazonaws.com/260/flashcards/3634260/png/screen_shot_2014-07-23_at_23352 _pm-14764B70363618B8C94.png http://www.benbest.com/science/anatmind/FigII8.gif Somatotopic organization Projection of both spinocerebellar pathways and motor cortex q ipsilateral anterior lobe q bilateral paramedian (intermediate) zone http://www.eneurosurgery.com/wpimages/wpad1cb303.png http://media.tumblr.com/tumblr_lm2qdayf9s1qipf9c.png BASAL GANGLIA https://o.quizlet.com/HPCV0mjiPuNkCXuxs0Aw0w_m.png 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 https://o.quizlet.com/1oL0anCIZPNp.dV6BYHCcQ.png 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 http://www.people.vcu.edu/~mikuleck/motsysp&l/img032.gif Basal ganglia afferents: q cortex q substantia nigra – pars compacta q intralaminar ncll. of thalamus (CM) http://image.slidesharecdn.com/basalganglia2010-110105020929-phpapp01/95/basal-ganglia-2010-17-728. jpg?cb=1294193400 https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Basal_ganglia_circuits.svg/1010px-Basal_g anglia_circuits.svg.png Basal ganglia efferents: q GPi q SN – pars reticularis ØTh. VA/VL ØTh. CM q (ansa lenticularis + fasciculus lenticularis → fasciculus thalamicus) https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Basal_ganglia_circuits.svg/1010px-Basal_g anglia_circuits.svg.png Basal ganglia intrinsic connections: q Striatopallidal p. q Striatonigral p. q GPe → STN q STN → GP, SNr. q Nigrostriatal p. Motor loop http://biomed.brown.edu/Courses/BI108/BI108_2003_Groups/Deep_Brain_Stimulation/images/normalloop.gi f http://clinicalgate.com/wp-content/uploads/2015/04/B9781437704341000967_f071-001-97814377043412.jpg https://o.quizlet.com/PIllKvY8l4Fd4FRZeBipCw.png https://o.quizlet.com/BrlqfkbhRNno.5LcRvM6SA.png SPINAL REFLEXES q type of afferents §somatic spinal reflexes §visceral spinal reflexes § q type of somatosensor §proprioceptive reflexes §exteroceptive reflexes q number of involved spinal segments §monosegmental spinal reflexes §polysegmental spinal reflexes § q 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 http://images.slideplayer.com/10/2809432/slides/slide_38.jpg Renshaw cells http://www.learnneurosurgery.com/uploads/1/6/6/8/16689668/4608712_orig.png Gamma loop https://www.liverpool.ac.uk/~rbj/RBJ/rbjteaching/spindle.jpg EYE MOVEMENTS qFovea centralis – area of most acute vision qCoordination of 12 oculomotor muscles qEye movements §conjugated – both eyes in same direction §vergent - during motion of object to and from us Øconvergent Ødivergent Four basic types of eye movements q Saccades q Smooth pursuit movements q q Vergence movements q q Vestibulo-ocular movements https://kin450-neurophysiology.wikispaces.com/file/view/BS_review.png/136377209/555x417/BS_review.p ng Saccadic eye movements http://nba.uth.tmc.edu/neuroscience/m/s3/images/copyright_marked_images/8-3_NEW.jpg qhorizontal gaze center - PPRF qvertical gaze center – RF of the midbrain q Øsuperior colliculi – information from FEF, retina, auditory, and tactile i. Smooth pursuit movements qelicited by a moving visual target that the eyes follow voluntarily or under direction qthe moving visual target is required to initiate this eye movement http://images.slideplayer.com/12/3455775/slides/slide_18.jpg Vestibulo-ocular movements https://cnx.org/resources/2bb12f0b0553360ab2a32df14cf182418e94deb5/1419_Vestibulo-Ocular_Reflex.jpg q stabilize the eyes relative to the external world, thus compensating for head movements Vergence movements https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQlokIG-DzLqrSjAFdxazS4tcpxWs3_GRQV5YzFPXfVS9L 7V9ti http://img.youtube.com/vi/RiLX-rbxBKA/0.jpg Illustrations were copied from: Neuroscience Online, the Open-Access Neuroscience Electronic Textbook Department of Neurobiology and Anatomy University of Texas Medical School at Houston