Neuroscience - Block 2 - Part 2

davidwurbel7's version from 2016-02-24 17:28


Question Answer
Originated in the inferior olivary nucleus (medulla oblongata)Olivocerebellar Tract
Tract that enters the cerebellum through the inferior peduncleOlivocerebellar tract
Always terminal fibers of these olivocerebellar tractsClimbing fibers
Mostly from crossed and uncrossed pontocerebellar fibers and enters the cerebellum through the middle cerebellar peduncleMossy Fibers
Coordination of voluntary muscle activity. Especially skilled motor activity. Regulation of posture and balance. Maintenance of muscle tone. Computes and adjusts eye movements for - Tracking moving targets and binocular alignmentCerebellum
The cerebellum output influences muscles on this sideIpsilateral
Cerebellar cortex is highly folded in parallel planesFolia
This lobe of the cerebellum can only be seen from belowFlocculonodular Lobe
Phylogenetic Archicerebellum and functionally Vestibulocerebellum is the same as the anatomicalFlocculonodular Lobe
Phylogenetic Paleocerebellum and functionally Spinocerebellum is the same as the anatomicalVermis
Phylogenetic Neocerebellum and functionally Pontoocerebellum/Cerebrocerebellum is the same as the anatomicalLateral Hemispheres
Balance and eye movements. Substantial input from the CN VIII (coordinates CN III, IV, VI). Vestibular nuclei inputArchicerebellum
Central axis posture and balancePaleocerebellum
Fine motor control (especially distal). Timing, motor planning, and coordination of limb movementsNeocerebellum
Cerebellar layer is outermost and contains - Outer layer of stellate cells, Inner layer of basket cells, Dendrites of Purkinje cells, Many parallel axons and terminalsMolecular Layer
Cerebellar layer that consists of a single layer of Golgi I Purkinje cell bodies. Sends profuse dendrites into the molecular layer. Sends axons through the next layer to the white matter beneath. Acquires myelin when entering white matterPurkinje Layer
Cerebellar layer that consists of granule and Golgi cells. Granule axons bifurcate and run parallel to the folia surfaceGranular Layer
The principal output cells of cerebellar cortexPurkinje Cells
Receives extensive excitatory input from one climbing fiberPurkinje Cells
Deliver inhibitory signalsPurkinje Cells
Indirectly synapse through granule and Golgi cells and can innervate thousands of Purkinje cellsMossy Fibers
Climbing and mossy/granule fibers (inputs) are alwaysExcitatory
Purkinje fibers (outputs) areInhibitory
Stellate, basket, and Golgi interneurons areInhibitory
Basket and stellate cells inhibit these cellsPurkinje Cells
Golgi interneurons inhibit these cellsGranule Neurons
Golgi cells are excited by granule cells but send back inhibitory signals to the granule cell (i.e., inhibits granule input)Feedback Inhibition
Basket cells inhibit Purkinje cells outputFeedforward Inhibition
The largest of the bilateral deep cerebellar nuclei located most laterally from the midlineDentate Nucleus
All neocerebellum efferents terminate hereDentate Nucleus
Output forms the majority of the superior cerebellar peduncle efferentsDentate Nucleus
Emboliform nucleus lies medially to the dentate nucleus and with the globose nucleus makes up theInterposed Nuclei
Input to this comes from the paleocerebellum (spinocerebellum) cortexInterposed Nuclei
Outputs via the superior cerebellar peduncle to the red nucleus of the midbrain (synapses with the descending rubrospinal neurons)Interposed Nuclei
The most medial nucleus also receives input from the spinocerebellumFastigial Nucleus
Crossed and uncrossed axons exit via the inferior cerebellar peduncle to the vestibular nuclei and reticular formation. The reticular formation then projects to the spinal cord as reticulospinal fibersFastigial Nucleus
Only region to receive direct input from a sensory nerve. Only region to have any direct connections other than to the deep cerebellar nucleus. Outputs directly via the inferior cerebellar pedunclesArchicerebellum
Synapse directly with the vestibular nuclei (CN VIII) in the dorsolateral brain stemArchicerebellum
Archicerebellum synapses directly with this cranial nerveCN VIII
Contains the dorsal spinocerebellar tract, cuneocerebellar tract and olivocerebellar tractMedial Zone
Contains the olivocerebellar tract and pontocerebellar tractLateral Zone
Contains the olivocerebellar tract and vestibulocerebellar tractFlocculonodular Lobe
Axons from motor related areas. Descend the corona radiate. Descend through internal capsule. Synapse in pontine nuclei. Pontocerebellar fibers decussate. Enter cerebellum through the middle cerebellar peduncleCorticopontocerebellar Tract
Part of the Corticopontocerebellar Pathway that contains Axons from motor related areas. Descend the corona radiate. Descend through internal capsule. Synapse in pontine nucleiCorticopontine Tract
Part of the Corticopontocerebellar Pathway that contains Pontocerebellar fibers decussate. Enter cerebellum through the middle cerebellar pedunclePontocerebellar Tract
Lesions of the corticopontine projections or pontine gray nuclei results in these deficitsContralateral Deficits
Lesions after the decussation in the Corticopontocerebellar tract result in these deficitsIpsilaterally Deficits
Fibers in this tract in the inferior olivary nucleus of the medulla decussate and enter the cerebellum via the inferior cerebellar peduncle and terminate as the climbing fibers that synapse with Purkinje cells and intracerebellar nucleiCortico-Olivocerebellar Tract
The sequence of this tract is - Axons from motor related areas, Descend through corona radiata, Descend through internal capsule, Synapse on the inferior olivary nuclei, the fibers decussate, Enter cerebellum through the inferior cerebellar peduncleCortico-Olivocerebellar Tract
The cerebroreticulocerebellar axons also arise from all over the cerebral cortex, but especially sensorimotor areasReticulocerebellar Pathway
Terminate in the reticular formation, decussate in the pons and medulla and enters the cerebellum by the inferior and middle cerebellar pedunclesReticulocerebellar Pathway
Relays information about limb position and movement to the cerebellum. This includes proprioceptive information from muscles, tendons, and joints, and exteroceptive information from skin receptorsSpinocerebellar tracts
Tract carries lower limbs proprioceptive and tactile information from - Muscle spindles, Golgi tendon organs, Joint receptors, Cutaneous exteroceptorDorsal Spinocerebellar Tract
Enters the spinal cord through the dorsal root and synapse in Clarke's nucleus (C8 - L3). Fibers from below L3 travel in the fasciculus gracilis to L3, where they then synapse in Clarke's nucleusDorsal Spinocerebellar Tract
These have widespread connectivity and can thus integrate information about the entire limb - Muscle length, Muscle force and ProprioceptionClarke’s Nucleus
The equivalent of the dorsal spinocerebellar tract but for upper limbsCuneocerebellar Tract
Proprioceptive and exteroceptive information enters the spinal cord through the posterior horn from C1 - C7. Unlike the DSCT these inputs do not synapse in the spinal cord (Clarke's column does not exist at the cervical levels). Instead, they travel with the fasciculus cuneatus to the medulla where they synapse in the accessory cuneate nucleusCuneocerebellar Tract
Analogous to Clarke's column in the lower limbs for the upper limbsAccessory Cuneate Nucleus
Picks up proprioception, touch, and vibration information descussates, then synapse in the anterior gray horn of the spinal cord. Continue to the cerebellumVentral Spinocerebellar Tract
Axons of this tract enter through the superior cerebellar peduncleVentral Spinocerebellar Tract
Inputs come directly from CN VIII signaling 3-D changes in head position but mostly via the vestibular nuclei (which also comes from CN VIII) in the brain stemVestibulocerebellar Pathway
Pathway exits via the superior cerebellar peduncles and decussates at the same time. Axons synapse in the ventrolateral nucleus in the thalamus before continuing to the primary motor cortex. Cerebellar influence is on the descending corticospinal neurons that decussate in the medullary pyramidsDentothalamic Pathway
Neurons in the globose and emboliform nuclei travel through the superior cerebellar peduncle and simultaneously decussate. End up synapsing with cells of the contralateral red nucleus in the rostral midbrain decussate again as the rubrospinal tractRubral Pathway
Pathway exits via the inferior cerebellar peduncles to synapse on both sides of the lateral vestibular nucleus. Processing of positional and movement information for control of visual and postural reflexes largely takes place in the vestibular nuclei. This pathway is also responsible for extensor muscle tone, and dizzinesssFastigial Pathways