Cerebellum Study Resources

CEREBELLUM ● ● ● ● Very small in the posterior part of the brain Made up of half of the neurons of the brain (very dense with cells) Part of the hindbrain but not part of the brain stem ○ Hindbrain = cerebellum + pons + medulla Cerebellum function = coordination of movements, what you are intending to perform ● ● Made up of densely packed grey matter = folia White matter branches = arbor vitae (means tree of life and leaves) Anterior lobe ● Superior part of the cerebellum ● The cerebellum is like a sheet that was scrunched up ● What should have been the anterior front section of the brain is not sitting superior ● In other animals its anterior but because we are bipedal = cerebellum has had to fold ● Controls gross body movements like locomotion ● Whole muscle groups at once Posterior lobe ● Skilled motor tasks ● Individually move fingers ● Speech (control of the throat, movement of the jaw, tongue and lips, playing the piano) Floccular-nodular lobe ● Balance and posture ● Coordinating the vestibular system and the visual system ● Underlies sea sickness (eyes = still but vestibular apparatus is tipping) Cerebellum acts as a comparator and predictor of movements ● ● ● ● ● ● ● ● ● ● ● Cerebellum complicates multi-joint movements Acts as a comparator and predictor of movements When movement happens, a small signal from the pontine nuclei goes to the cerebellum Different inputs (sensory signals) feed back into the cerebellum and tell the cerebellum how much you moved and how much that intended movement was performed Cerebellum compares what was intended with what was performed (can tell the body to make the correction and perform that movement that was intended) Uncoordinated movements if the signal mismatches Body is represented across the surface of the cerebellum Locomotion = requires movement of the limbs Posterior = overrepresentation of hands, face, feet (fine movements) Vermal means worm = middle part which executes and performs movements, gets the feedback and finetunes (fixes) movement back to the motor cortex Lateral = planning of the movement, pre plans how much the joints will have to move to complete the intended movement, does not go back to the motor cortex because it's just the planning SPINAL CORD ● Encased in the vertebral column and meningeal layers ● CSF flows through it ● Only goes up to lumbar 2 and the rest are nerves ● Gives rise to 31 pairs of spinal nerves ● Each pair of spinal nerves comes from the vertebra (no nerves arise from the coccyx) ● Functions of different regions are shown in the image ● The inferior end of the spinal cord is the conus medullaris ● Which them becomes the cauda equina and filum terminale ● Filum terminale = thin structure composed of pia mater which starts at the first or second lumbar vertebrae and goes down until it anchors onto the coccygeal vertebrae Spinal cord functions 1. - Homeostasis Integrates stimulus and produces an immediate response Produces a reflex Integrate spinal reflexes through grey matter Info doesn’t have to go all the way to the brain, spinal cord can produce a reflex itself 2. Relay channel between the body and the brain - Relay conduit for impulses to and from the brain via specific tracts - Different tracts are located in different areas of white matter - White and grey matter Ventral horn contains cell bodies of lower motor neurons (nerves that project out to muscles and mediate reflexes) Dorsal horn is where sensory input comes into the spinal cord (no cell bodies/sensory neurons) → project into the dorsal horn and into the tracts Sensory neurons easier to run up the outside (white) then go to the inside