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Q: nervous system ( Answered,   0 Comments )
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Subject: nervous system
Category: Science > Biology
Asked by: shackles-ga
List Price: $10.00
Posted: 28 Jul 2004 22:31 PDT
Expires: 27 Aug 2004 22:31 PDT
Question ID: 380621
damage to the cerebellum would impair which function and why
Answer  
Subject: Re: nervous system
Answered By: sublime1-ga on 29 Jul 2004 00:25 PDT
 
shackles...

From the online Multiple Sclerosis Encyclopaedia:

"The cerebellum is responsible for coordinating movement,
 planning, motor activities, learning and remembering of
 physical skills and for some cognitive abilities.
 Interestingly, the size of this brain region within any
 mammal species is a good indicator of its the physical
 capability."

"The cerebellum controls movement by collecting sensory
 nerve inputs, such as limb position, balance information
 and vision, and synthesising them together to control
 movement by sending nerve transmissions down motor nerve
 outputs. The learning of physical tasks is done by trial
 and error and then stored into cerebellar memory. This is
 the reason that we never forget certain skills such as
 riding a bike. There is some evidence that mental
 activities are also co-ordinated in the cerebellum which
 could explain why cognitive dysfunction is sometimes
 associated with damage to the cerebellum."

"Damage to the cerebellum or the cerebellar peduncles is
 very common in multiple sclerosis. This is not surprising
 given the large amount of white matter in these structures."

"Some of symptoms associated with damage to the cerebellum
 or the nervous tracts leading to it are:

- Dysdiadokokinesia (difficulty in performing rapid alternating
  movements)
- ataxia (difficulty in coordinating movements)
- tremors
- loss of balance and vertigo
- muscle weakness
- dysarthria (loss of coordination of the muscles controlling speech)
- loss of postural tone."
http://www.mult-sclerosis.org/cerebellum.html


From Wikipedia:

"...the cerebellum is a complex system mostly dedicated to
 the intricacies of voluntary movement, including managing
 walking and balance. Damage to the cerebellum leaves the
 sufferer with a gait that appears drunken and is difficult
 to control. Some modern fMRI studies show that the
 cerebellum is important for attention, reading, perception
 of time, and may be impaired in dyslexia, Alzheimer's
 disease, and other neurological disorders."
http://en.wikipedia.org/wiki/Cerebellum


From the Springfield Technical Community College's Distance
Education Program page on the cerebellum:

"Movements become much less coordinated after any cerebellar
 damage. The best example of this is seen in precision
 movements, like end-point-contact movements.  If you are
 asked to touch your finger to your nose, as your finger is
 being brought toward your nose your cerebellum normally
 makes corrections to the movement command so that you
 contact your nose (the end point) with no problem. When
 someone has a cerebellar lesion, the corrections are not
 made properly, and the person ends up shaking so much that
 they cannot ever touch their nose."

"All movements are perturbed with cerebellar lesion. This
 shows just how important the cerebellum is."
Much more on the page:
http://distance.stcc.edu/AandP/AP/AP1pages/nervssys/unit13/cerebell1.htm


From the WhyFiles:

"Damage to the cerebellum makes walking difficult, speech
 slurred, most movements unsteady."

[...]

"...the cerebellum is required for timing stop-and-start
 movements, but not for continuous motion."

[...]

"In a study published May 30, Spencer, Zelaznik and
 colleagues reported that cerebellum patients had
 trouble only with discontinuous movements. 'Even
 though most people say cerebellum patients are
 impaired in timing, that's far too broad. The
 impairment is only there when the movement is
 discontinuous,' says Spencer."

"Why could this be? Perhaps, she says, in continuous
 tasks, 'We get our arms cycling, and once you get it
 going, it can go on its own. I can do the task, and
 read or talk, and my arm won't stop. It's kind of
 swinging like a pendulum, going on its own momentum.'"

"Discontinuous movements -- think tap, pause, tap -- are
 different, she says. Once each cycle, you apparently
 need to refer to an internal clock to restart the process.
 And if that clock -- apparently located in the cerebellum
 -- is defective, the result will be impaired movement.
 Poor coordination. That drunken appearance."

"'That's why the cerebellum patients are impaired,' Spencer
 says. 'When they have to turn the movement on and off,
 there are lots of points where the 'clock' can be
 interrupted.'"
http://whyfiles.org/shorties/132cerebellum/


Please do not rate this answer until you are satisfied that  
the answer cannot be improved upon by way of a dialog  
established through the "Request for Clarification" process. 
 
A user's guide on this topic is on skermit-ga's site, here: 
http://www.christopherwu.net/google_answers/answer_guide.html#how_clarify 
 
sublime1-ga


Additional information may be found from an exploration of
the links resulting from the Google searches outlined below.

Searches done, via Google:

"damage to the cerebellum"
://www.google.com/search?q=%22damage+to+the+cerebellum%22
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