Review Questions

Question 1

Neuropsychology is not an exact science. Describe some of the challenges imposed by the methods of study used in neuropsychology.

Answer 1

• Neuropsychology relies on the method of converging operations = examining whether all answers obtained from a set of interrelated experiments using a variety of methods with a variety of populations lead to the same conclusions
  
  • Brain imaging, computer models, laboratory studies, electrophysiological methods, clinical findings
• Need to know how to interpret information from all sources to rule out some conclusions and to provide evidence of most plausible conclusions

Question 2

What is meant by a double dissociation? What is the meaning/importance of a double dissociation for our understanding of brain-behavior relationships?

Answer 2

• Double dissociation: when two related mental processes are shown to function independently of each other (e.g., speech and language comprehension)
  
  • HM (problems with primacy, but not recency)
  • KF (problems with recency, but not primacy)
• Importance:
  
  • Allows us to get more specific about specific behavior deficits and brain lesion locations
  • E.g., learning Broca’s area was not broadly responsible for language but just language production

Question 3

Neuroimaging techniques pros and cons

CAT scan

Answer 3

• Pros:
  
  • Can measure density of brain structures
  • First digital atlas of brain, allowed for lesion mapping
• Cons:
  
  • Requires ionizing radiation
  • Not high spatial resolution

Question 4

Neuroimaging techniques pros and cons

MRI

Answer 4

• Pros:
  
  • Can view the sulci, gyri (gray matter)
  • Resolution down to 1-2 mm
• Cons:
  
  • Not everyone can go into an MRI (no pacemakers or anyone with metal in their body)
  • Claustrophobia an issue

Question 5

Neuroimaging techniques pros and cons

diffusion tensor imaging (DTI)

Answer 5

• Provides info about white matter; can detect the direction that water diffuses in nerve fibers
• Pros:
  
  • Gives us a view of anatomical connectivity
  • Shows us areas of less diffusion which can indicate demyelinating disorders like MS
• Cons
  
  • No structural info

Question 6

Neuroimaging techinques pros and cons

PET scan

Answer 6

• Pros:
  
  • Allows us to see how the brain uses specific molecules; gives a picture of neurotransmitter binding
  • Provides info about absolute levels of brain metabolism (can measure blood flow, oxygen consumption and glucose metabolism)
  • Can be used to look at group differences
• Cons:
  
  • Spatial and temporal resolution is limited (depends on the half-life of the isotope)
  • Using a radioactive isotope ⟶ yearly limit to the number of scans a person can undergo (2-5) ⟶ change over time or response to intervention is hard
  • Requires close proximity to a cyclotron, which is expensive

Question 7

Neuroimaging techniques pros and cons

SPECT

Answer 7

• Pros
  
  • Equipment is less expensive than PET or CT scans¹
• Cons
  
  • Poorer spatial resolution than PET scans
  • Half life longer than isotopes in PET
  • Need additional software to produce 3D images (otherwise images are fairly useless)¹
  • Radiation exposure¹

Question 8

Neuroimaging techniques pros and cons

magnetic resonance spectroscopy (MRS)

Answer 8

• = early attempt to identify signatures of compounds (carbon, oxygen, nitrogen) and their concentration
• Cons
  
  • Can only provide gross info on location (i.e. in the frontal lobe)

Question 9

Neuroimaging techniques pros and cons

fMRI

Answer 9

• Pros:
  
  • Good spatial res in short periods of time
  • Can be repeated on the same individual (⟶ good for change over time and tx response)
  • Widely available
• Cons:
  
  • No metal

Question 10

Distinguish between metabolic and electromagnetic recording methods.

Answer 10

• Metabolic techniques: record activity by tracking blood flow, O2, and glucose
• Electromagnetic techniques: track electrical responses of neurons firing