Neuroanatomy S1 E8: Cerebellum #neuroanatomy #ubcmedicine

0:00 [Music] the cerebellum is connected with the entire central nervous system through millions of connections it influences all of our cortical functioning and output and has a particular influence on motor function that we will focus on here it receives information about our muscle and joint position or proprio receptive information balance or vestibular information as well as vast connections to and from the cerebral cortex this makes the cerebellum the coordinator and predictor of cortical output and it is responsible for a sort

0:47 of quality control and constant error correction we'll start with an anatomical overview and then take a closer look at each one of these systems [Music] here you can see the cerebellum the tentorium cerebelli a dural reflection isolates it in the posterior cranial fossa it is connected to the brain stem through three cerebella peduncle here the Bellum is detached from the brain stem this is the anterior

1:34 surface with the cerebellar pedones that connected to the brain stem a superior middle and inferior cerebella peduncle this little bit of cerebellum here is the fulus it is connected to the nodule here and to together they form the Fulon nodular lobe the Fulon nodular lobe is responsible for balance this is the posterior surface in the midline you can see the vermouth this is the superior

2:21 surface and this is the inferior surface the cerebellum sits on foran Magnum and in cases with increased intracranial pressure this inferior bit of the cerebellum the cerebellar tonsils can herniate into foran Magnum and press onto the brain stem where the breathing Center is located you can see how the different parts of the cerebellum are folded and then folded again this results in a tremendous increase in surface area which allows the accommodation of millions of neurons in in fact more than the entire central nervous system combined so what does the cerebellum do with this exceptional

3:07 computing power from an evolutionary perspective balance is the oldest function taken on by the cerebellum in order to be effective in coordinating balance it must receive input from the labyrinth in our inner ear our balance organ and then influence both our core and limb musculature here on the an interior surface of the cerebellum you can see the lobe of the cerebellum responsible for balance the focular nodular lobe it comprises the fulus and the nodule this Fulon noal lobe has close connections with this midline structure of the cerebellum the

3:55 vermis trunkal musculature is coordinated through the vermis the vestibular nuclei send projections to the focular nodular lobe through the inferior cerebellar peduncle in the focular nodular lobe the information is analyzed and then sent back to the vestibular nuclei and the reticular formation from there projections go to the lower M neuron system in the spinal cord to ensure trunkal stability the next system to develop in the cerebell circuitry is in involved in the coordination of gate and limb movement this system will need precise information about the position of our limbs so that movements can be coordinated and initiated from the

4:41 correct starting point in this system ongoing movement patterns are coordinated and error detection systems allow for the immediate correction of the movement here on the superior and posterior surface of the cerebellum we can see the lobe resp responsible for this coordination the anterior lobe it is separated from the posterior lobe through the primary fissure in order to coordinate movement and detect errors the cerebellum needs to receive information from the proprioceptors in the musculosceletal system this spino cerebella information projects to the anterior lobe through the posterior spinal cerebellar tract which enters to the inferior cerebella

5:28 peduncle this tract contains the information from muscle spindles joint receptors and GGI tendon organs about the position of our limbs in space as well as muscle tone the anterior spino cerebellar tract swings over the superior cerebellar peduncle and also enters the anterior lobe of the cerebellum it originates from the spinal border cells which send a copy of the actual motor command reaching the lower motor neuron system to the cerebellum the cerebellum can now compare the motor command to the actual movement of the limbs any mistake can be rapidly corrected the cerebellum can

6:14 project directly to the lower motor neuron system for trunkal stability for limb movement the information feeds back to the cerebral cortex through the thalamus and from there to the lower motor neuron system in the spinal cord these connections allow for the coordination of limb movement error detection and immediate correction the largest part of the cerebellum has reciprocal connections with the cerebral cortex from a motor perspective it is here that fine coordination of complex movement patterns is coordinated in particular I hand coordination is processed here this part of the

7:01 cerebellum also allows us to have motor interaction with the world around us it receives environmental cues and adjusts our movements accordingly the world around us is of course not static everything and everyone can move the cerebellum can analyze the movement patterns of people and objects around us predict the consequence of these movements and adjust our movement accordingly this is the posterior lobe of the cerebellum it is by far the largest area of the cerebellum these huge middle cerebellar pedones contain the millions of connections that come from the cerebral cortex cortical fibers descend to The Ponds where they synapse in the

7:47 pony nuclei from here fibers cross the midline and enter the opposite or contralateral side of the cerebellum in the posterior lobe this information is is processed and streamlined coordinated output is fed back to the cerebral cortex the output from the posterior lobe is through the dentate nucleus here and here from the dentate nucleus fibers exit through the superior cerebellar peduncle and cross over to the contralateral red nucleus of the midbrain to the thalamus and from there

8:33 to the cortex I felt as though I was on a rocking ship so every time I took a step my feet felt like they were going beneath the floor and then they were floating up off the floor a few feet even so it felt as though my proprioceptive system wasn't quite coordinating properly or something I wasn't receiving the depth of the space around me I could see where the floor was but my senses were telling me something else you get used to tracking where you are in space in the most minute kind of ways you get used to tracking your senses and connection to touch and weight and flow um and you

9:21 rehearse that and I also trained that way and I've been doing it for so long now it's 20 years that um that it feels sort of like second nature the cerebellum automates our cortical output it constantly monitors ongoing firing patterns and corrects any errors that occur it scrutinizes our environment and predicts the movement of the world around us it then adjusts our movement in relation to that [Music] world [Music]