cerebellum,

Purkinje cell
Professor M Häusser, Sarah Rieubland and Arnd Roth, UCL
Winner of the Wellcome Image Awards, 2015.
“Scanning electron micrograph of tree-like branches (dendritic tree) spreading out from a particular type of nerve cell (Purkinje cell, or neurone) found in the brain. The finger-like projections in this elaborate network act like tiny sensors, picking up information and passing on messages to help control and coordinate muscle movement. This particular neurone is from the cerebellar cortex in a rat brain.” 

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Cerebellum and rostral portion of the brainstem: dorsal view

1. Genu of corpus callosum
2. Head of caudate nucleus
3. Lamina of septum pellucidum
4. Columns of fornix
5. Short gyri of insula
6. Tributary of thalamostriate vein
7. Stria terminalis
8. Lamina affixa
9. Interthalamic adhesion
10. Stria medullaris thalami
11. Habenular trigone
12. Habenular commissure
13. Pineal body
14. Superior (cranial) colliculus
15. Inferior colIiculus
16. Brachium of inferior (caudal) colliculus
17. Medial geniculate body
18. Culmen
19. Quadrangular lobule
20. Primay fissure
21. DecIive
22. Lobulus simplex
23. Folium of vermis
24. Superior semilunar lobule
25. Tuber of vermis
26. Horizontal fissure
27. Inferior semilunar lobule

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Cerebellum:

  • The conscious decision to move voluntary muscles is initiated in the cerebral hemisphere
  • The fine control of muscular movements requires a significant level of non-conscious operation

Example:

  • Muscular activities associated with responding to changes in body position to remain balanced and upright
  • Sensory activities such as judging the position of objects and limbs
  • the tensing of muscles in order to manipulate tools effectively
  • feedback information on muscle position, tension and fine movements
  • operation of antagonistic muscles to coordinate contraction and relaxation

Neurones from the cerebellum carry impulses to the motor areas so that motor output to the effectors can be adjusted appropriately in relation to these requirements.

Sensory information has to be processed from: the retina, the balance organs in the gene, spindle fibres give information about muscle tension, the joints

More than half of the neurons of the brain occupy the intricately grooved but comparatively small part of the brain that we call the cerebellum (literally translating to ‘little brain’). We know that the cerebellum plays a vital role in motor control, but links to attention and language have also been suggested. Above, someone with a normally functioning cerebellum has drawn a wave. Below, someone with a disease of the cerebellum has attempted to replicate it: 

External image

Upon dissecting this brain region, it’s possible to see why only a sixth of its surface is visible from the outside: it bears a deep and fern-like grooved structure. The core white matter of this region is sometimes called the arbor vitae, a 'tree of life’. 

External image

youtube

In this Neuromechanics weekly, Dr Waerlop Introduces the cerebellum and talks about its importance clinically, since it contains more than ½ of the neurons in the brain! It’s anatomy and inputs from the periphery are discussed. The take home message is the cerebellum is the key to understanding and directing movement, since it receives feedback from most ascending and descending pathways.

  • BRAIN STEM

Central core of the brainstem regulates internal organs and is responsible for regulation of blood gases and the maintenance of blood pressure. The hypothalamus is in the brainstem, and it  controls hunger, thirst, sex, thoughts emotions and internal organ function.

Reticular activating system - the brainstem regulates the entire cycle of sleep and wakefulness and the ability of the cerebrum to carry out conscious mental activity.

The Limbic system plays a crucial role in emotional status and psychological function. Uses norepinephrine and epinephrine and serotonin and dopamine as the neurotransmitters. 

  • CEREBELLUM

Posteriorly to the brainstem, it’s involved in regulating skeletal muscle coordination and contraction and the maintenance of equilibrium.  It plays a crucial role in movement and BALANCE 

  • CEREBRUM

Development of a much larger cerebrum is what distinguishes human beings from the rest of the animal kingdom. Cerebrum gives us THE ABILITY TO THINK AND SPEAK.

The Cerebrum is responsible for mental activities and a conscious sense of being. Likewise it is responsible for our conscious perception of the external world and our own body, emotional status, memory and control of skeletal muscles that allow willful direction of movement, as well as language and communication.