CEREBELLUM

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CEREBELLUM. MEGHAN REDA KENYSE TRIM ELIZABETH BRODERICK DUNYA MAJEED DEANNA COLARUSSO. Cerebellum. The "little brain". Structure. Bottom of the brain, under the cerebral cortex and behind the pons. Divided into two hemispheres contains narrow midline zone: vermis Surface
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CEREBELLUM MEGHAN REDA KENYSE TRIM ELIZABETH BRODERICK DUNYA MAJEED DEANNA COLARUSSO Cerebellum The "little brain" Structure
  • Bottom of the brain, under the cerebral cortex and behind the pons.
  • Divided into two hemispheres
  • contains narrow midline zone: vermis
  • Surface
  • Gray matter
  • White matter
  • Arbor Vitae
  • Lobes
  • Flocculonodular
  • Anterior/Posterior
  • Medial Zone
  • Spinocerebellum
  • Lateral Zone
  • Cerebrocerebellum
  • Dominant Neurons
  • Purkinje Cells
  • Jan Evangelista Purkyně
  • Communicate decisions
  • emit action potentials at a high rate even in the absence of synaptic input
  • Granule Cells
  • Glutamate
  • Mossy fibers
  • form excitatory synapses with the granule cells
  • Determining Function Learn about function by examining the effects of damage to the cerebellum. Basic Functions
  • Involved in voluntary movement
  • Involved in the precision of movement
  • Involved in the coordination and accurate timing of movement
  • Receives input from both the spinal cord and the sensory systems
  • Allows people to balance their body and maintain equilibrium
  • http://www.youtube.com/watch?v=BTH2KvFLcHo&noredirect=1
  • Feedback Loop
  • Involved in a feedback loop for muscle movement using two types of information:
  • Cortex sends a message to both the motor neurons in the brainstem and spinal cord, and to the cerebellum
  • At the same time, the cerebellum receives input from muscle spindles, joints, and tendons
  • Integrates these two types of information
  • Also involved in proprioception and kinesthesia
  • Principles
  • Feetforward Processing
  • Signals move unidirectionally
  • No self-sustaining neural activity
  • Divergence and Convergence
  • A lot of convergence, particularly in input
  • Modularity
  • Divided into independent modules that have different functions
  • Plasticity
  • The synapses in the cerebellum are susceptible to modification
  • Motor Learning The cerebellum is required for certain types of motor learning Marr-Albus Theory
  • When the cerebellum receives input from a climbing fiber, an action potential will cause a single Purkinje cell to fire several action potentials
  • Marr-Albus theory - these climbing fibers act as a teaching signal
  • The fibers induce long lasting change
  • This remains a theory, not a fact
  • Eyeblink Conditioning Paradigm
  • Classical conditioning
  • Conditioned stimulus - tone
  • Unconditioned stimulus - air puff
  • Unconditioned response - eye blink
  • Conditioned response - eye blink
  • Lesions in the cerebellum inhibit this learned blink response, indicating cerebellar learning
  • Possible Cognitive Functions
  • Believed that the cerebellum is involved in more than just movement
  • Attention and language
  • Regulating fear and pleasure responses
  • Little is known
  • Primary function is movement
  • Cerebellum Roles There are 4 main functions 1. Maintenance of balance and posture 2. Coordination of voluntary movements 3. Motor Learning 4. Cognitive Functioning Cerebellum Roles Maintenance of balance and posture
  • Important in making postural adjustments, while keeping balance
  • Has input from vestibular receptors and proprioceptors, which helps adapts commands to motor neurons to compensate for shifts in body position or changes in weight upon muscles.
  • Cerebellum Roles Bad Cerebellum
  • Serious walking issues
  • Balance problems
  • Trouble moving
  • Gait ataxia – wide-based, staggering walk, may shuffle, veer to side, may fall
  • http://www.youtube.com/watch?v=eBvzFkcvScg
  • Good Cerebellum
  • Tightrope walking
  • Running
  • Dancing
  • Cerebellum Roles Coordination of Voluntary movements
  • Most movements are composed of a number of different muscle groups acting together in a coordinated manor.
  • Coordinating timing and force of these muscles help to create fluid body movements
  • Cerebellum Roles
  • Bad
  • People who have damage to their cerebellum have difficulty with hand eye coordination as well.
  • Good
  • Helps us to take a complex task and coordinate our movements to create a thoughtless task. http://www.youtube.com/watch?v=Es489XP8Xtc
  • Cerebellum Roles
  • Motor Learning
  • The cerebellum plays a major role in fine tuning and adapting motor programs to make accurate movements with a trial and error system. Example: Learning to hit a baseball, playing tennis
  • Cerebellum Roles
  • Cognitive Function
  • There is not a clear understanding of exactly how the cerebellum is involved with language but it is know that it does contribute toward it.
  • Damage
  • A disorder that is linked to cerebellum damage is called Dysmetria http://www.youtube.com/watch?v=jnQcKAYNuyk
  • Damage The Cerebellum is known as the "mini-brain" because it contains more neurons than all other areas combined and has several main functions
  • coordinating skilled voluntary movements by influencing muscle activity
  • controlling equilibrium and muscle tone through connections with the vestibular system and the spinal cord through its gamma motor neurons
  • there are three different functional divisions in the cerebellum: vestibulocerebellum, spinal cerebellum, cerebrocerebellum Damage to the cerebellum causes trouble with rapid movements requiring aim/timing
  • clapping hands, speaking, writing, etc.
  • people seem generally clumsy and unsteady
  • Ataxia
  • One type of dysfunction
  • From Greek language, literally meaning "not ordered"
  • An estimated 150,000 people in the US are diagnosed with Ataxia
  • There are many different types of Ataxia
  • Spinocerebellar Ataxia is largest group
  • No known effective treatment/cure
  • But, some symptoms can be made better with medication
  • Can affect anyone of any age
  • Most commonly hereditary caused by either a dominant or recessive gene
  • Can be non-hereditary
  • Many times, people are not aware that they carry the ataxia gene until their children begin to show signs of having the disorder
  • Experiences of Ataxia: Vestibulo Cerebellum Important in Equilibrium and Balance
  • Posture Instability
  • Swaying while standing
  • Nystagmus
  • Involuntary back-and-forth eye movements
  • Experiences of Ataxia: Spinal Cerebellum Contains Vermis & Paravermis Vital in the Execution of Movement
  • Truncal Ataxia
  • Wide-based "drunken sailor" gait
  • Uneven stride, with steps of different lengths and not always straightforward
  • Falling is a big concern of people who suffer from this
  • Experiences of Ataxia: Cerebro-Cerebellum Vital in the Planning of Movements
  • Appendicular Ataxia
  • Disturbances in carrying out voluntary, planned movements
  • Problems with speech - monotone with breathiness and accelerations or pauses between syllables
  • Dysarthria
  • "Explosive" or "scanning" speech, with rapid bursts of words
  • Dysmetria
  • Inability to judge distances or ranges of movement
  • Experience hypometria (undershooting) or hypermetria (overshooting) when reaching for an object
  • Also seen when a patient is asked to reach out and touch someone's finger or touch his/her own nose
  • Impaired alternating movements
  • Turning the hand over and back
  • The Rebound Phenomenon
  • When a patient is flexing his/her elbows isometrically against resistance and the resistance is suddenly removed without warning, they may strike themselves
  • Ataxia A person with Ataxia may have other movement disorders such as:
  • Chorea
  • Jerky, involuntary movements affecting shoulders, hips, and face
  • Dystonia
  • State of abnormal muscle tone resulting in muscle spasms/abnormal posture A person with Ataxia may also experience other neurological symptoms:
  • Dementia
  • Seizures
  • Parkinsonism
  • Tremors and impaired muscular coordination
  • Ataxia as a Symptom of Neurological Disorders Inherited
  • Freidrich Ataxia
  • Autosomal recessive gene
  • Progressive damage to CNS by degeneration of nerve tissue in spinal cord and demyelination
  • Spinocerebellar Ataxia
  • Types 1-28
  • Some caused by autosomal dominant, others recessive
  • Episodic Ataxia
  • Type 1/Type 2
  • Autosomal dominant gene induced by startle/stress
  • Results from misfiring of Purkinje cells in Cerebellum
  • Vitamin E Deficiency
  • Mutation of TTPA gene
  • Inability to retain and use Vitamin E (can't neutralize free radicals)
  • Accumulation of free radicals within cells
  • Causes nerve cells to die off due to deprivation
  • Wilson's Disease
  • Autosomal recessive gene
  • Copper accumulates and manifests in tissues due to mutation in Wilson's Disease protein
  • Non-inherited
  • Brain lesion/tumor
  • Toxins
  • Lead, Sedatives, Alcohol
  • Infections
  • HIV, Syphilis, Prion Disease
  • Paraneoplastic Syndrome
  • Arising from specific forms of cancer in the body
  • Multiple Sclerosis
  • Multiple Sclerosis
  • Inflammatory Disease
  • Body's own immune system attacks and damages Myelin
  • Inability to transmit neural signals
  • Leads to demyelination
  • More common in women
  • Causes are unknown and still being researched
  • Could be due to environmental factors or infections
  • Loss of Sensitivity, Muscle Weakness, Muscle Spasms, Difficulty Moving, Problems with Speech/Swallowing, Bladder/Bowel Difficulties, Blindness, Paralysis
  • http://www.youtube.com/watch?v=h19muxVqiOs
  • THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT An attempt to relate the evolution of cerebro-cerebellar mechanisms to the early foundations of language, including visual-spatial working memory and vocalizations of early hominins.
  • The combination of visual-spatial working memory and vocalizations act as the predecessor to the language spoken today. Vandervert, L. (2011). The evolution of language: The cerebro-cerebellar blending of visual-spatial working memory with vocalizations. Journal Of Mind And Behavior, 32, 317-332.
  • THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT Literature illustrates the increase in size of the cerebellum that occurred in the last million years of evolution. One plausible reason for the cerebellum's dramatic growth: "The cerebellar evolution resulted in the rapid and increased skill in the manipulation of ideas and progressive increases in language dexterity." THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT Working Memory is composed of three basic components:
  • an attention-controlling system which serves as a "central executive"
  • a visual-spatial sketchpad which manipulates visual images within an ongoing flow of visual-spatial experience
  • a phonological loop which both stores and rehearses speech-based information
  • THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT According to Vandervert, there are multiple cerebellar internal models that contribute to motor, sensory and higher cognitive functions of the cerebral cortex. In novel situations, such internal models begin to blend in order to increase connections and compensate for the new experiences. The blending of internal models generates new context for the brain to process. This is believed to be an explanation for the development of language in humans. THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT It is believed that capuchin monkeys are the closest to imitating the early development of language as Homo habilis once exhibited long ago. THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT
  • "Sub-vocal speech enhances the effectiveness of working memory in complex tasks."
  • As capuchin monkeys work in nut-cracking, low-volume vocalizations accompany tool manipulation. It is hypothesized that the sequences of visual-spatial working memory of the capuchin monkeys are associated with the sequences of tools, via the same processes as homo habilis.
  • THE EVOLUTION OF LANGUAGE: THE CEREBRO-CEREBELLAR BLENDING OF VISUAL-SPATIAL WORKING MEMORY WITH VOCALIZATIONS L. VANDERVERT CONCLUSION The last million years of the evolution of cerebro-cerebellar blending of visual-spatial working memory with vocalization in Homo habilis was the driving mechanism behind the evolution of language. Sources
  • http://www.csuchico.edu/~pmccaffrey/syllabi/CMSD%20320/362unit7.html
  • https://en.wikipedia.org/wiki/Cerebellum
  • Vandervert, L. (2011). The evolution of language: The cerebro-cerebellar blending of visual-spatial working memory with vocalizations. Journal Of Mind And Behavior, 32, 317-332
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