L3: Brain imaging & Electrophysiology Flashcards
a) What does a CT scan do?
b) How do areas appear on the scan
c) What can a CT scan detect?
a) Narrow beans of x-rays are shot through the body
b) Dense areas appear light
c) clots, fractures, bleeding and changes in brain cavaties
Which fluid appears black on a MR scan?
Cerebrospinal fluid (a clear fluid) but comes up dark on scan
What do PET scans do?
Track blood flow with radioactive tracers. The tracer is a radio-isotope of oxygen
What is the temporal and spatial resolution of PET scans?
Temporal resolution = 30 seconds
Spatial resolution = 10 mm
What does BOLD stand for?
Blood Oxygenation Level Dependent
What did Shaywitz et al find?
fMRI scan study, found activation is strongly lateralised in males but bilateral in females
What did Hagoort et al’s study on semantic priming show?
Patients with RH lesions show priming for associative pairs but not for semantic pairs.
Normal PP’s show semantic priming is fine, showing RH is involved with semantic priming
How do we think abstract thoughts?
In perception-action terms
What is:
a) phonology
b) orthography
c) syntax
a) The SOUND of a language
b) The RULES of writing in a language
c) The ORDER of a sentence
What is:
a) Semantics
b) Pragmatics
a) the MEANING of a word
b) HOW words are used, e.g. same words with different meaning
What is:
a) Phoneme
b) Morpheme
c) Grapheme
a) Smallest significant unit of speech
b) smallest meaning-carrying unit
c) basic unit of a written language
What are the level of graphemes for English, Kana and Chinese?
English: Alphabetic system
Kana: levels of symbols
Chinese: logographic
Why are PET and fMRI scans better at answering “where” questions?
Scans have a slower time scale than most human processing, not ideal for studying when Q’s
How do you isolate ERP signals from EEG data?
Replicate each trial many times, record waveform for each trial. Only the components that occur at the same time will sum together. Examine the latency, magnitude and profile of these stimulus-locked wave components.
What is N400 associated with?
Semantic processing. produced during semantic violation and pragmatic violation
