Neuro Exam 3

• What are the spatial functions of the posterior parietal lobe?


  Egocentric space, such as object location for action, guidance of movement and spatial navigation.
• For what type of attention is the parietal lobe very important?


  Visual attention
• What are the other functions of the posterior parietal lobe (listed as "vaguely spatial")


  Vaguely spatial functions including arithmetic, reading language, and tasks requiring sequencing.
• How are dizziness and vertigo different?

  dizziness= generic

  vertigo= spinning sensation

  
• What are the symptoms of Menière's disease? What is thought to be the cause? How common is it? How is it treated?


  symptoms: vertigo attacks, hearing loss attacks, tinnitus, fullness feeling in ears, duration up to 24 hours, unpredictable

  
  

  cause: too much fluid in inner ear

  
  

  common: 15 in 100,000

  
  

  treated: syptomatic during attack (anti-emetics, dramamine), diuretic for maintenance, histamine antagonist

  
• Why is there a division between somatosensory and posterior parietal disorders?


  lesions in the post-central gyrus

  
  

  The Anterior zone of the parietal lobe is for somatosensitization (touch, proprioception, temperature)

  
  

  The Posterior zone is for integration of input from vision and other senses, for the purpose of movement (Orientation)
• What are the symptoms in cases of focal lesions in postcentral gyrus?


  high sensory thresholds- more pressure required to fire

  ---two point sensory- 2 pts affected instead of just one

  ---touch

  
  

  impaired sense of position- don't know properly where limbs are
• How are sensory thresholds measured?


  pressure to fire

  
  

  Absolute threshold: the lowest level at which a stimulus can be detected

  
  

  Recognition threshold: the level at which a stimulus can be detected and recognized

  
  

  Differential threshold: the level at which an increase in a detected stimulus can be perceived

  
  

  Terminal threshold: level beyond which stimulus can no longer be detected
• What are phantom limbs, and phantom limb pain?


  sensation that missing limbs is still moving or (often) causing pain. Thought to be rewiring of somatosensory cortex

  
• What is a mirror box in the context of phantom limbs, and what is it used for?


  A mirror box has two mirrors in the center used as a visual override of wiring problems in the brain

  
  

  It is used to trick the patient's brain into thinking it is moving the phantom limb from an uncomfortable position granting relief.

  
  

  Reflected limb, visual information overrides the pain

  
• What does the mirror box substitute that is missing in people with phantom limbs?


  (Video: Mirror Box) - Seeing the hand you know isn't there, gives a release of the phantom limb pain
• What is astereognosis (also astereognosia) and how is it assessed?


  = inability to recognize objects by touch

  
  

  (Touch signals are coming in, can't figure out what it is)

  
  

  Test for this problem by blindfolding the patient, placing an object in the hand, and asking the person to recognize and name it by touch only.

  
  

  A pattern is placed on a blindfolded subject's palm for 5 seconds then placed in with a mix of others. The task is to identify the original pattern after handling all six patterns.

  
• What are asomatognosias? What are autopagnosia and how is finger agnosia related to autopagnosia? What is anosognosia?


  asomatognosisa= loss of knowledge of sense of knowing own body/ bodily condition

  
  

  Autopagnosia= inability to localize and orient different parts of the body
• What is CIPA? Why is this often fatal at early ages?

  CIPA= congenital insesitivity to pain

  
  

  fatal at early age- could die from heat/ open blood injury
• What type of agnosia did Ian Waterman have (general term). What was unusual about his case? What factor about Ian Waterman's recovery did your instructor emphasize?

  Asomatognosia

  
  

  Ian Waterman - destruction of fibers for certain proprioceptive receptors - no sense of where limbs are

  
  

  VISION and motivation of not wanting to be in a wheelchair
• What are the symptoms in Balint's syndrome? Be able to recognize vignettes


  bilateral parietal lesions (mostly superior parietal)

  
  

  symptoms:

  -problems fixating on object

  attention limited to one object at a time

  -reaching deficit- misreach

  
• Is neglect treatable? What a very large obstacle in rehabilitation of those with neglect?
• Where are the lesions in Balint's syndrome?

  bilateral parietal lesions (mostly superior parietal)

  
• What are the symptoms in Gerstmann syndrome? Where is the lesion in Gerstmann syndrome?


  -finger agnosia

  -right-left confusion

  -agraphia- inability to write

  -aculculia- inability to do arithmetic operations

  
  

  left-posterior parietal lobe

  --inferior posterior parietal lobe BA 39 and 40
• What is apraxia? (see the slide)


  disorder of movement/ motor skills
• What is optic ataxia? What is simultagnosia? **


  optic ataxia= misreaching

  
  

  simultagnosia= perceive ONE thing at a time. limit to ONE without awareness to others

  
• What percentage of the neocortex are constituted by the frontal lobes?

  20-30%

  
• What does it mean that the frontal lobes are late developing from the evolutionary point of view?
• When is the frontal lobe fully developed?


  early 20s

  -last to evolve

  
• What is the general function of the frontal lobes, be able to explain this to a random stranger


  generating appropriate behavior

  --decides behavior

  --makes decisions and carry out actions
• What 4 general types of information (in 2 categories) have to be taken into account when deciding what action in appropriate?


  Internal Info

  -What just happened

  -Contextual info

  -Knowledge of self

  
  

  External Info

  -External cues for action
• Why are motor functions so important?


  enable organism and underlie the execution of all motivational goal

  
• What is the main problem for patients in locked-in syndrome (not the cause)?

  
• What are the anatomical divisions in the frontal lobes, how do these relate to functional distinctions in the frontal lobe?

  motor-primary

  premotor and supplementary motor cortex- secondary motor cortex

  prefrontal cortex
• What areas constitute the primary and secondary motor cortices?


  primary: BA 4 (motor)

  
  

  secondary: BA 6 (premotor)
• What are the four areas of the prefrontal cortex that we are going with in this class (there are other ways of naming)?


  dorsolateral PFC

  orbitofrontal PFC

  medial PFC

  anterior cingulate
• What is the general direction of information flow in the brain?

  everything moves toward the frontal cortex

  
• Which thalamic nuclei are associated with PFC and motor cortices?

  dorsomedial nucleus of thalamus

  
• What is the input to these thalamic nuclei that gets relayed to the cortex? How is this different from the relays to the visual, auditory and somatosensory cortex?
• What is reflexive movement and how is it related to voluntary movement? What are feedback and feedforward in movement?


  Reflexive movement is produced by stereotyped patterns of muscle contraction

  
  

  Voluntary movement is goal-oriented and improve with practice as result of feed forward (anticipatory) and feedback mechanisms
• What is the difference in the cues used in premotor, supplemental and cingulate motor areas in action sequence choice?

  SMA- intentional cues; spontaneous well-learned actions

  
  

  PMA= external cues; readiness for action role

  
  

  CMA: emotional/ motivational
• What are mirror neurons? What type of actions do they react to? Why did mirror neurons occasion such excitement in psychologists when they were discovered?


  -active during preparation of a movement by self and while watching someone else perform a similar movement

  -tuned to goal-directed actions

  -they were found in monkeys

  
• What aspects of movement does the cerebellum moderate?


  Balance/coordination and accuracy

  Important for tasks requiring timing

  Acquiring new movement sequences
• What aspects of movement do the basal ganglia moderate?


  Force of movement

  Critical for learning motor skills, organizing sequences of movement, " automatic" behaviors and new habits
• What are the two major pyramidal output tracts from the primary motor area? What is the difference between their functions?

  Corticobulbar tracts- controls facial movements. goes to medulla and pons

  
  

  Corticospinal tracts- cortex to the spinal cord