PSYC 170  - Summer 2013 - Professor Claffey

Notes: Research Methods


Research Goals

_______________ a single patient
    identify damage in the brain, if detectible
    differentiate a hearing problem versus a language problem versus a memory problem
    identify a specific disease

characterize the ______________ of a population
    planning abilities continue to improve until ~20 years old, then plateau
    do people with ADHD have better or worse working memory compared to non-ADHD controls

identify ________________________ relationships
    the frontal cortex is activated by working memory tasks
    London taxi drivers have enlarged hippocampus
    schizophrenics have enlarged ventricles


creating a ______________________________ of the brain

________________________ - visualizing the stable shape/size of the brain
    acute differences: detecting tumors, hemorrhaging, congenital abnormalities
    subtle differences: contrast size of structures between different populations
        differences tend to be nominal and unclear if cause/correlation

        identify a group of patients that all have damage in a similar area (e.g. right frontal lobe)
        damage might be due to different causes, lesion might be different sizes
        compare differences in behavior between lesion group and non-lesion group

________________________ - visualizing changes in the brain related to activity
    an active area doesn't mean a necessary area
        an alien might observe that a car radio is typically active, but it isn't necessary for motion
    techniques differ in their spatial/temporal resolution

method resolutions

Structural: CT

ct setup ct image

stacks of ________________ images to create a 3D image of the brain
more common for clinical setting than research lab
    cannot distinguish gray and white matter
brightness of imagine is determined by __________________________________
developed in 1960s

Structural: MRI

mr setup mr pathologies
uses powerful magnets to manipulate the atomic spin of hydrogen atoms
used in both clinical and research settings
brightness of image is determined by ________________________________
    differences across tissue: bone, white matter (myelin), gray matter, ventricles
used for analyzing tissue since 1970s

Functional: fMRI

fmri examples
uses MRI to detect rate of deoxygenation of blood
    __________ contrast - blood-oxygen-level dependent
    assumes that areas of high blood deoxygenation are areas of high neuronal activity
    ________________ response - how low it takes for blood flow to change in an area
        takes about 2 seconds to reach peak response, can return to baseline in ~7 seconds or stay sustained
        orders of magnitude slower than the time scale of action potentials
a typical experiment contrasts blood flow for two different conditions
    e.g. viewing pictures and laying still in the dark

Functional: PET

pet setup pet imagepet drug dopamine
subject has a radioactive agent administered through IV
lays in an array of radioactive detectors
    when the radioactive agent interacts in the brain, it releases a radioactive particle
    the array of detectors can triangulate where in the brain the particle came from
able to localize molecular events in the brain
    which molecular event depends on what radioactive agent was used
    examples: using glucose, dopamine binding

Functional: EEG

eeg cap
eeg channels
covers the scalp in electrodes that amplify electrical fields
    produced by action potentials
typically between 10 and 256 different electrodes or channels
sampling >1000 Hz, so at the timescale of action potentials
    depending on states of consciousness,
        there is synchronized activity at different frequencies
    examples: beta (awake), alpha (meditative), delta (deep sleep)
    excellent for detecting epilepsy
the scalp "smears" the signal, so not exact about location
    can't pick up on signals below the cortex
eeg localization

eeg erp erp auditory
    the response to an single event (such as presenting stimuli in an experiment) is noisy
    the response to many, similar events can be averaged together to detect common features
    typically look at:
        latency - timing of respond (e.g. 100 ms after stimulus presentation)
        amplitude - strength of electrical response (e.g. stronger signal for salient stimuli)
        origin - location on scalp (e.g. occipital lobe for visual stimuli)

Animal Techniques

these would not typically fall under neuropsychology,
    but are included because they are driving the field of neuroscience

    a specific area of the brain is damaged by removal, drugs, or electrical stimulation
    allows for the conclusion that an area is necessary for a function

    inserting electrodes directly into the brain to isolate action potentials for single neurons in highly specific brain areas
    useful for understanding how individual neurons in an area respond to stimuli
    neurons can also be stimulated to affect behavior

    introducing new DNA to alter the physiology of an organism
    examples: increase or decrease a specific receptor, transmitter, or metabolic protein

    measure or alter the molecular make-up of neurons
    example: measuring neurotransmitters in synapses, adding genetic material to inhibit RNA
    historically, measuring a molecule required removing the tissue and potentially destroying it
        new techniques allow for the live imaging of molecules in tissue in awake, behaving animal

Behavioral Tasks

tasks that are intended to measure a concept of brain functionality
    could diagnose a deficit in a patient or quantify an ability in a population

    taking an abstract concept (e.g. working memory) and assigning an objective measure (e.g. numbers recalled)
    even when an experiment is technically well-executed (e.g. randomized subjects, valid stimuli, good analysis),
        there can be much debate about whether the task is a good operationalization of a concept

wisconsin card sorting

Wisconsin Card Sorting

 measures _____________________________________________
 subject sorts cards with different colors, shapes and number of items
    the rule for sorting is not revealed and must be guessed
    the rule occasionally changes and subject has
       to detect and adapt to change

Go/No Go

    measures: ______________________
    on most trials subject is shown a green circle ("go") and responds as quickly as possible by pressing a button
    on a minority of trials, a red circle ("stop") is shown instead and subject must not react with the usual button press

tower of hanoi

Tower of Hanoi

 measures: ________________________________________
 subject must re-stack wooden rings onto 3 different pegs
    in order to match a target pattern
only one ring can be moved at a time
subject doesn't physically manipulate them, but instead
    has to solve mentally and describe the moves

Facial Emotions

     measures: __________________________________
    subject is shown a series of faces expressing different emotions and has to identify the emotion
facial emotions

Clinical Scales

    used in both clinical and research settings
    typically measure lifestyle or chronic conditions
    self-reported scales are easily influenced by survey environment and subject's intentions
    there are often multiple, "equally valid" scales for a particular topic, though one may dominate by tradition

Glasgow Coma
    ratings for verbal response, eye tracking and muscle response
    score of 3 indicates full coma, 18 indicates normal consciousness
    predictive of outcome month later

Barratt Impulsiveness Scale (BIS, link)
    self-report (answered by subject about themselves)
        I say things without thinking, I concentrate easily, I like puzzles
    factors: attention, motor, self-control, cognitive complexity, perseverance, and cognitive instability impulsiveness
    adults with ADHD score higher on BIS and perform worse in a continuous monitoring task (Malloy-Diniz et al, 2007)

Beck Depression Inventory
    self-report (answered by subject about themselves)
        I am sad all the time and I can't snap out of it, I don't cry any more than usual
    factors: hopelessness, irritability, guilt, fatigue, weight loss, libido
    facilitated a shift away from a psychodynamic approach towards a cognitive approach
    Related: Hopelessness Scale (BHS), the Scale for Suicide Ideation (SSI)
    correlation between Beck and serotonin sensitivity (Peirson & Heuchert, 2000)


left/right split visual displays
    deliver information to a specific hemisphere of the brain
    test for lateralization of a function

    identify physiological changes in the brain after death
    started with Broca & Wernicke in 1860s
    some modern diseases can only be diagnosed post mortem
        e.g. plaques that indicate Alzheimer's disease versus non-AD dementia

    measure the electrical resistance of the palms
    an emotional response typically cause the palms to sweat, which reduces the resistance
    can indicate an emotional reaction to a stimulus without requiring a verbal/conscious report


Copyright 2013 - Michael Claffey