What is Neuropsychology

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What is Neuropsychology
Study of brainbehavior relations
(sometimes referred to as functional
localization) Functional Lateralization refers
to notion that a function may depend on one
side (hemisphere) of the brain
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Definition of Clinical Neuropsychologist

• A clinical neuropsychologist is a professional
  psychologist who applies principles of assessment
  and intervention based upon the scientific study
  of human behavior as it relates to normal and
  abnormal functioning of the central nervous
  system. The clinical neuropsychologist is a
  doctoral-level psychology provider of diagnostic
  and intervention services who has demonstrated
  competence in the application of such principles
  for human welfare following

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• A doctoral degree in psychology from an
  accredited university training program.
• An internship, or its equivalent, in a clinically
  relevant area of professional psychology.
• The equivalent of two (fulltime) years of
  experience and specialized training, at least one
  of which is at the post-doctoral level, in the
  study and practice of clinical neuropsychology
  and related neurosciences. These two years
  include supervision by a clinical
  neuropsychologist .
• A license in his or her state or province to
  practice psychology and/or clinical
  neuropsychology independently, or is employed as
  a neuropsychologist by an exempt agency.

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Different types of Neuropsychologists/ Subareas
?? Experimental neuropsychologists work to
understand the neural bases of cognition by doing
studies Experimental neuropsychology
cognitive neuropsychology or cognitive
neuroscience ?? Clinical neuropsychologists
work in health-related settings (e.g., hospitals,
clinics) with patients Involved in diagnosis
Involved in rehabilitation (e.g., designing
programs) May be involved in research
Clinical neuropsychology
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How do we study brain-behavior relations?
(Techniques)
Invasive Lesion Inject radioactive
tracer Non-invasive Brain-imaging to see what
regions are active during specific mental task
Record activity of cells to determine what
activity makes them respond Present information
to different hemispheres and see which side does
task better or faster
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Why study brain-behavior relations?
?? Diagnostic purposes ?? Rehabilitation
purposes ?? Intellectual curiosity
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Methods in Neuropsychology
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Method of converging operations
Use a number of different methods
and populations ?? Evidence obtained from a set
of experiments converge on the same conclusion
e.g., fMRI and lesion studies
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Research considerations ?? What type of
participants? ?? How will we gather information
about their brains? ?? How will be measure
behavior?
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Research Participants ?? (1) Patients with
lesions ?? (2) Healthy Individuals ?? (3) Animals
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• Patients with lesions
• ?? Question What functions supported by this
• neural site?
• ?? Studies need to include patients with lesions
• to a specific site and patients with lesions to
  a
• different site
• ?? Double dissociation - lesions have converse
• effects on two distinct cognitive functions
• ?? Allow one to conclude that structures/
• functions are independent

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?? Question What neural sites are associated
with a particular deficit? e.g., Memory
impairment associated with damage to Brenda
Milners work with temporal lobe epilepsy and
memory where hippocampus was found to be
important for learning
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Problems with lesion method ?? Brain damage
messy in humans (1) People vary in their genetic
and environmental characteristics e.g.,
differ in education, onset of dementia Lesions
vary in their extent and origin Stroke vs
tumor vs bullet (2) Lesion does not allow us to
observe directly the function served by the
lesioned site
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?? Only know how brain performs without that
particular area ?? We can infer the site may be
critical but we can not identify all the areas
that may be involved ?? Site may not be critical
in performing a particular function rather,
may contain axons that connect regions that must
interact for correct performance
Disconnection syndrome Split brain
Conduction aphasia
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Associated problem single cases or groups ??
Groups of patients may be so hetergeneous in
their behavior that group average is
meaningless Argues for single case
approach ?? Problem with single case approach
Is pattern observed representative of people
in general? Does not allow one to rule out
random error
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?? Use multiple case approach, validating
research findings on a series of patients,
or ?? Follow-up findings from single-case
with group studies
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(2) Neurologically intact Individuals ?? These
persons provide the control group that allows us
to determine thedegree to which performance of
brain damaged people is compromised ??
Well-designed studies must include appropriate
control group
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(3) Animal Populations

• ?? Allows for control over
• Environmental conditions/experience
• Size and nature of lesions
• Genetic differences, etc.

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Gathering Information aboutthe BrainTechniques

• ?? CT Scans
• Uses series of X-ray beams through head.
• Images developed
• on sensitive film. Shows anatomical image
• of brain density.
• CSF lt brain tissue lt blood lt bone
• Darker lt .gt Lighter

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• ?? Advantage
• Can be used with most people
• ?? Disadvantage
• Uses radiation
• Dye may cause allergic reaction
• Results do not have a high spatial resolution
• Structure of brain only

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MRI

• ?? Anatomical image of substances such as water
  or fat - give picture of tissue density
• ?? Relies on passing an external radio frequency
• pulse to disrupt the magnetic fields of nuclei
• and distort the behaviors of atoms
• ?? When atoms fall back in line, they re-emit the
• radio-frequency signal which is detected by a
• receiver coil
• ?? The frequency of this signal reflects the
• number of elements in the nucleus and the
• effect of the surrounding material

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Advantages

• ?? Does not require X-rays or radioactive
• material
• ?? Safe, painless, non-invasive
• ?? Result is high resolution

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Disadvantages

• ?? Expensive
• ?? Cannot be used in patients with metallic
• devices, like clips, pacemakers, or
• possibly orthopedic pins
• ?? Cannot be used with claustraphobic
• patients
• ?? Assesses structure only

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Functional MRI

• ?? In fMRI, MR signal measures functional
• characteristics of brain
• ?? Detects changes in blood flow to
• particular areas of the brain
• ?? Provides both an anatomical and
• functional view of the brain

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Advantages

• ?? Noninvasive - radiation needed
• ?? Multiple scans can be done on an
• individual so can examine changes over time
  (e.g., learning)
• Provides a good measure of brain activity
  over seconds
• ?? Provides a good spatial resolution

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Disadvantages

• Cannot localize processes in time better
• than 1 second
• fMRI does not image neural activity but
  rather response of vascular system to oxygen
  demand and this can lag functional activation as
  well as extend beyond period when activation
  occurred

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PET

• Also provides a functional image of brain
  activity
• ?? Radioactive substance (e.g., glucose)
• introduced into blood
• ?? Radioactive molecule becomes stable by
  releasing positron, collides with electron,
  annihilate each other -producing energy - PET
  detects this energy

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• ?? PET detects how much of the brain fuel
• (oxygen, glucose) is being used by different
  regions
• ?? Areas that are metabolically active emit
• lots of energy those that are less active
• emit less energy

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• ?? Advantages
• Good at examining functioning of a variety of
• neurotransmitters
• ?? Disadvantages
• Involves radiation
• Provides image of brain activity averaged over
  very long time periods (e.g., minutes whereas
  cognitive decisions occur in msec)
• Typically, data on task is averaged across many
  people
• Not very good at determining location of function
  in a given person (does not provide high spatial
• resolution)

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EEG

• ?? Electrical activity of the brain
• ?? Provides information about general
• state of person (e.g., awake)
• ?? Good at detecting various clinical
• disorders
• e.g., sleep, seizures

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• ?? Provides accurate measures of activity
• on a millisecond basis
• ?? But poor at localizing activity
• ?? Does not provide information about
• subcortical structures

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Event Related Potentials(ERP)

• ?? Recording of brains activity that are linked
  to
• the occurrence of an event (stimulus)
• ?? Provides information linked to processes
• such as memory and attention
• ?? Examine components of the waveform
• recorded on the scalp such as
• P300 - S must respond to target stimulus
  (b not d, blank sound) - appears to measure
  attention, updating of memory

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NeuropsychologicalAssessment

• ?? Allows one to separate cognitive functions
• (e.g., STM vs LTM)
• ?? Profile patient strengths and weaknesses
• diagnosis
• ?? Provide a baseline to evaluate change
• e.g., remediation, improvement, decline
• ?? Make statements about prognosis

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• ?? Fixed batteries
• (e.g., Haltead-Reitan, Luria-Nebraska)
• ?? Flexible battery
• ?? Generally measure IQ (Wechsler tests)
• ?? Also measure executive function,
• attention, memory, language, spatial
• ability, motor, sensory function, emotional
  function

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• ?? Need good normative data
• ?? Pre-morbid Estimation
• e.g., NART, WTAR