Term
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Definition
-requires lateralized presentation of stimuli to one hemisphere
-response accuracy/latency is used to determine dominant hemisphere
-duration of presentation of stimuli is short to prevent perception in the central visual areas. |
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Term
| Lateralized Techniques suggest... |
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Definition
this kind of technique suggests that:
-verbal stimuli are better processed in the left hemisphere.
-music and envioronmental sounds are better processed in the right hemisphere
-not all tasks involving verbal stimuli are processed in a verbal manner.
-may reflect laterality of receptive processing oflanguage. |
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Term
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Definition
-severed corpus collasum
-no collasal transfer, each hemisphere works independently. |
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Term
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Definition
-rarely lasts for more than a few weeks
-hemispheres experience contradictory impulses |
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Term
| Do split brain patients suffer learning problems? |
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Definition
| subjects have great difficulty associating names with faces. implying the left hemisphere housed the verbal lable but could not access the right hemispheres image of the whole face. |
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Term
| potential pitfalls with split brain patients: |
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Definition
- using external cues to alert the other hemisphere regarding the nature of the lateralized stimulus.
-becoming test wise
-reorganization due to earlier brain damage.
-relying on other commissures as a learned adaptation. |
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Term
| what can the right hemisphere of a split brain patient do? |
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Definition
-can read
-big vocabulary
-speak a few words
-not a good speller
-limited syntactic competence |
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Term
| list structural neuroimaging techniques: |
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Definition
Cerebral angigraphy
CT scan
MRI |
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Term
| Cerebral Angiography involves: |
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Definition
-injecting dye into the internal carotid artery
-dye-filled arteries are visible when an x-ray is taken.
-determine whether regions surrounding visible artery are damaged. |
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Term
| Computerized Tomography (CT scan) |
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Definition
-xray beam revolves in a plane around the head and monitor intensity of the xray that passes through the other side.
-intensity will vary with density
-computer analyzes info and reconstructs 3D cross section image of brain
-used to pinpoint location oflesions |
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Term
| Magnetic REsonance Imaging (MRI) |
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Definition
-finer detailed cross section than CT scan
-records nuclear magnetic resonance of hydrogen atoms in water with a strong magnetic field
-clear distinction between white and grey matter |
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Term
| List functional Neuroimaging techniques: |
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Definition
PET
SPECT
fMRI
EEG
Probe evoked potential
MEG |
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Term
| 5 parameters functional neuroimaging vary by: |
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Definition
1) temporal resolution
2) spatial resolution
3) how much of the brain is viewed
4) point in time scan is performed in relation to behaviour under study
5) how soon and how many times can the scan be repeated |
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Term
| list electropysiological techniques: |
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Definition
EEG
probe evoked potentials
MEG |
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Term
| Electroencephalogram (EEG) |
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Definition
-measures electrical activity
-alpha waves have highest amp. when subject is in a resting state and reduce in amp. when engaged in mental tasks.
-reduction in alpha waves in one hemisphere indicates that hemispheres greater involvement |
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Term
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Definition
- widely available
- can be performed on infants and comatose subjects.
- canbe used for a long period of time with goood temporal accuracy |
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Term
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Definition
- does not pinpoint locus of brain activity
- not easy to spot changes that occur in response to a stimulus |
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Term
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Definition
evoked-related potential
-an averaging of the waveform that eliminates any aritifacts of noise and permits identification of any electrical activity that occurs specificaly in response to a particular stimulus |
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Term
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Definition
repeated presentation of irrelevant stimulus while subject is performing a specific mental task.
if an area that normally reacts to this irrelevent stimulus is too busy with the mentaltask it is thought that this will show a diminished ERP |
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Term
| Magnetoencephalography (MEG) |
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Definition
-magnetic equivalent of EEG
-a sensitive instrument called a SQUID at the surface of the scalp records the magnetic field genereated by a number of active neurons. |
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Term
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Definition
-allows caluculation of the exact location of the neurons producing the magnetic field
-used to pinpoint the exact area where epileptic activity begins |
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Term
| list metabolic techniques: |
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Definition
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Term
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Definition
-biochemical compounds tagged with gamma ray-emmiting radioactive substances are tracked in the brain through blood circulation
-computers analyze the data picked up by detectors surrounding the head and produce a 3D cross section |
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Term
| name the 2 types of SPECT |
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Definition
-HMPAO SPECT
-HMPAO injected
-trapped in brain tissue at rate proportional to cerebral flow rate
-HMPAO rsolves slowly, activity state of brain at time of injection locked in for many hrs.
-Xenon SPECT
-inhalation of xenon-133
-xenon clears brain tissue quicky, multiple scans can be conducted in one test session
-also more sensitive than HMPAO SPECT to bloodflow changes. |
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Term
| post emission tomography (PET) |
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Definition
-measurement of radiation from positron emitting substances which generate pairs of photons that travle in opposite directions.
-water, glucose and a number of neurotransmitters can be labeled and traced. |
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Term
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Definition
-uses MRI machine to detect magnetic properties of oxygenated blood in the brain
-active areas of the brain become slightly engorged with oxygenated blood |
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Term
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Definition
-patient must lay perfectly still
-indicates only relative degree of activation through increase or decrease in blood flow from resting to active state |
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