CH 5: Research Methods of Biopsychology Flashcards
Describe 2 x-ray based techniques for visualizing the living human brain.
(1) Contrast X-Ray Techniques:
- injecting into 1 compartment of the body a sub that absorbs X-rays less/more than surrounding tissues
(2) Computed Tomography (CT):
- computer-assisted x-ray procedures
- used to visualize brain & other internal organs
Describe the PET technique.
- PET = position emission tomography
- Visualizes brain activity via measuring the accumulation of radioactive flurodeoxyglucose (FDG) in active areas of brain
- Each pet scan = image of levels of radioactivity (indicated by colour coding) in various parts of horizontal level of brain.
–> Used to show correlation b/w brain activity & cognitive activity, but can’t prove that brain activity CAUSED the cognitive activity
List 3 magnetic-field-based techniques for imaging the living human brain.
- MRI = magnetic resonance imaging
- fMRI = functional MRI
- Diffusion Tensor Imaging
Describe how an MRI is used to image the living human brain.
- MRI = structural brain-imaging procedure
- High-res images constructed from measurement of radio-frequency waves that H-atoms emit as they align w/ powerful magnetic field
- Provides clearer images of brain than CT
- Prod 3D images
Describe how an fMRI is used to image the living human brain
- Prod images rep the ^O2 flow in blood to active areas of brain
- Active areas of brain take up ^O2 blood
- -> thus oxygenated blood accumulates in activate areas of brain
- Oxygenated blood has magnetic properties that influence the radio-frequency waves emitted by H-atoms in MRI
–> Used to show correlation b/w brain activity & cognitive activity, but can’t prove that brain activity CAUSED the cognitive activity
Describe how DIFFUSION TENSOR IMAGING is used to image the living human brain
- Identifies pathways along which H2O molecules rapidly diffuse
- Helps understand connections among brain structures
List 2 trans-cranial stimulation techniques.
- Transcranial Magnetic Stimulation (TMS)
2. Transcranial Direct Current Stimulation (tDCS)
Describe TMS
- MAGNETIC stim temp turns off part of brain while effects of disruption on cognition & behaviour are assess
- Turns off an area of human cortex by creating a magnetic field under a coil positioned next to skull
- Can also ‘turn on’ areas of cortex
Describe tDCS
- ELECTRICAL stim temp ^activity in part of brain while effects of stimulation on cognition & behaviour are assessed
- Stimulates (‘turns on’) area of cortex by applying an electrical current through 2 electrodes placed directly on scalp
What are trans-cranial stimulation techniques used to establish?
- The causal effects of human cortical activity on cognition behaviour
List 2 psychophysiological measures of brain activity.
- Electroencephalography (EEG)
2. Magnetoencephalography (MEG)
Describe EEG.
- Measure of gross electrical activity of the brain
- Recorded via large electrodes placed on scalp
- Scalp EEG signal reflects sum of electrical events throughout head – incl. action potentials & postsynaptic potentials etc.
- Its value relies on fact that some EEG wave forms are ass w/ particular states of consciousness (ie. aroused, relaxed, asleep, etc)
Describe MEG.
- Also monitors brain activity from scalp
- Measures changes in magnetic fields on the surface of scalp that are produced by changes in underlying patterns of neural activity
List 2 psychophysiological measures of SOMATIC NS activity.
- Muscle tension
2. Eye movement
How is muscle tension psychophysiologically measured?
- via Electromyography (EMG)
- EMG activity recorded b/w 2 electrodes taped to surface of skin over muscle of interest
How is eye movement psychophysiologically measured?
- via Electrooculography (EOG)
- based on fact that steady potential diff exists b/w the front (positive) & back (negative) of eyeball
- When eye moves, a change in electrical potential b/w electrodes placed around eyes are recorded.
List 2 psychophysiological measures of AUTONOMIC NS activity.
- Skin conductance
2. Cardiovascular activity
How is skin conductance psychophysiologically measured?
Define SCL & SCR.
- Emotional thoughts & experiences ass. w/ ^ability of skin to conduct electricity
- Skin Conductance Level (SCL) = measure of background live of skin conductance ass. w/ particular situation
- Skin Conductance Response (SCR) = measure of transient changes in skin conductance that are ass. w/ discrete experiences
- -> ie) sweat glands become active in emotional situations
- -> rel sweat
- -> ^electrical conductivity of skin
How is cardiovascular activity psychophysiologically measured?
HEART RATE
- Electrical signals ass. w/ each heartbeat recorded via electrodes placed on chest
- Recording = ECG = electrocardiogram
BLOOD PRESSURE
BLOOD VOLUME
- Changes in blood V in p articular parts of body ass w/ psychological events
- ie) boner in men during sexual arousal
Define STEREOTAXIC SURGERY & list the 2 things it requires.
= Experimental devices precisely positioned in depths of brain
Requires:
- atlas to provide directions to target site
- instrument for getting there
List 4 types of lesion methods.
- Aspiration lesions
- Radio-frequency lesions
- Knife cuts
- Reversible lesions
Describe Aspiration Lesions
- Aspiration = tissue drawn off by suction through fine tip of glass pipette
- Used when lesion is made in area of cortical tissue that’s accessible to the eyes & instruments of surgeon
- -> Leaves underlying white matter & major bv’s undamaged