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31 Cards in this Set
- Front
- Back
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What is Phrenology |
Created by Francis Gall (1800s), he believed that bulges on skull corresponded to areas of brainunderneath and that these bumps determined characteristics or traitsof persons |
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Explain the Divided Visual Field (DVF) method of hemispheric laterlization experiments |
Stimulus presented to one visual field (VF) is initiallyreceived and processed by contralateral hemisphere. VF differences in response time or accuracy reflectearly distinctions in hemispheric functioning.
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Issues to be controlled in hemispheric lateralization studies
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Participant handedness
Participants centrally fixate prior to stimulus presentation Constant viewing distance for stimuli Stimuli need to appear at approximately 2 degrees of visualangle from fixation Stimulus exposure time should be 180msecs or less |
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Issues to be controlled in hemispheric lateralization studies
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Mask presented after stimulus to interrupt stimulus processing
Consider the type of response made (verbal vs. button press) Button press: unilateral or bilateral handed responses? Auditory stimuli you use a dichotic listening task |
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Experimental Ablation
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Removal/ destruction ofpart brain lab animal. Functions no longer performed are controlled bythe brain region removed/destroyed
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Sham legion |
Control lesion, duplicates all stepsproduce lesion except the step actually causesbrain damage
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Stereotaxic surgery:
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Brain surgery using stereotaxicapparatus to position electrode in specific position inbrain
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Stereotaxic atlas:
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Collection drawings brain sectionscertain animals, complete with measurementsproviding co-ordinates for stereotaxic surgery
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Stereotaxic apparatus:
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Device enables electrodeinsertion in specific part of brain
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Legion studies in humans
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Study of brain damage in living patients. For example stroke or TBI. Or autopsy studies of brain damage in dead patients. For example damage to Brocas area. |
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Transcranial magnetic stimulation (TMS)
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Stimulation of cerebral cortex by magnetic fieldproduced by passing pulses of electricity through awire coil near the skull. Can be used to impair cognitive function (high levels). Can be used to stimulate the level of activity in acertain region of the brain (low level). Non-invasive. Crude measure of localisation.
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Computerised Tomography (CT scan)
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-Circular x-ray tube and x-ray detector patient's head in tube
-Detector measures amount radioactivity -8-9 horizontal scans/patient,combined 3D representationbrain -Detect tumours and other structural abnormalities |
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Magnetic Resonance Imaging (MRI)
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-High resolution image derived from measurement ofwaves hydrogen atoms emit when activated byradio-frequency waves in a magnetic field
-MRI picks up energy expended by hydrogen atomsas they return to rest -MRI scans all planes and detects structural abnormalities smaller than 1mm indiameter |
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Diffusion Tensor Imaging (DTI)
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-Imaging method that uses modified MRI scanner toreveal bundles of myelinated axons in the living humanbrain
-Allows small bundles of fibres to be examined by tracing the fibre tract and determining determining the movement of water molecules -Application- detection at veryearly stages of the ischemic event |
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Positron Emission Tomography (PET)
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-Measures metabolic activity in specific areas of brain using device that reveals the localization of aradio-active tracer in brain.
-Radio-active 2-DG (2 deoxyglucose) injected and decay is measured -Result is picture brain slice: relative activity regions High operating costs: cyclotron |
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Functional Magnetic Resonance Imaging(fMRI)
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Permits measurement of regional metabolism inbrain using oxygen levels. Very detailed, 3D image
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Micro-electrodes:
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fine electrode, single neuron
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Macro-electrodes:
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Overall neural activity. Macro-electrodes record activity from largenumber neurons. Can be invasive or non-invasive
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Electroencephalography (EEG)
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-Electrical (neural) activity recorded via scalp using macroelectrodes
-EEG - sum electrical activity throughout head, APs,PSPs, electrical signals from muscles, eyes, skin,blood -Cannot give clear view of location of neural activity |
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Event-Related Potential (ERP)
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plot of average EEG signals at each time-point
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Magnetoencephalography (MEG)
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Detects groups of synchronously activatedneurons via magnetic field induced by their electricalactivity
-Superconducting quantum interference devices(SQUIDs) -MEG traces averaged over a series of trials to obtainevent-related fields (ERF) -ERF used in surgery |
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Electrooculography (EOG)
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-Procedure recording eye movementsthrough electrodes places around eye
-Vertical and horizontal EOG -Useful in conjunction with ERPs |
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Electromyography (EMG)
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-Procedure recording electrical activity muscles -Muscle tone (tension): contraction few muscle fibresat rest
-Movement: number muscle fibres contractsimultaneously -EMG: two electrodes skin surface over muscle. Uses integrated EMG signal (smooth curve) foranalysis |
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Skin Conductance (SC)
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-Ability skin conduct electricity (electrodermalactivity)
-Skin Conductance Level (SCL): steady level ofSC associated with situation -Skin Conductance Response (SCR): transientchange in SC associated with brief stimulus -Measure change in SC due to stimulus |
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Cardiovascular Activity
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-Electrical activity heart usingchest electrodes Arterial Blood Pressure (BP)
-Systoles: measure peak pressure duringperiods heart contraction (heart beat). Diastoles: measure minimum pressure duringperiods heart relaxation -BP: ratio SBP to DBP (mmHg) |
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Concordance Rates |
Determines if pairs of twins share a trait of interest. Twins are concordant if they both have the trait. Twins are discordant if only one posses the trait. Monozygotic twinsconcordant diagnosis greater than dizygotic twins |
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Which brain measurement technique usesx-rays?
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CT scan - Computerised Tomography
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The brain measurement technique that uses aradioactive tracer is
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PET - Positron Emission Tomography
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Which of the following techniques allows us toexamine the different functions of thecerebral hemispheres in normalparticipants?
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Divided Visual Field
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Which of the following techniques measuresblood oxygen levels?
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fMRI – functional Magnetic ResonanceImaging
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Which of the following techniques maps axonswithin the brain?
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DTI - Diffusion Tensor Imaging
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