TIN: Week 1 Flashcards
When was the first X-Ray done and by whom?
In 1895, the German Physicist (Wilhem Rontgen) first x-ray’d his wifes hand
Describe the BOLD effect
BOLD = Blood Oxygenation Level Dependent
Based on magnetic properties of oxyhemoglobin vs. deoxyhemoglobin
fMRI detects surplus of oxygen
Oxyhemoglobin (O2Hb) is diamagnetic (not magnetic), does not have paired electrons and not attracted to magnetic field
Doxyhemoglobin is paramagnetic (or magnetic), reacts more strongly with magnetic field
The more magnetic, the darker the image
Who and in what year was the brain described as a seondary organ that served as a cooling agent for the heart and a place for the spirit to circulate freely?
Aristoteles, 394 - 322 BCE
Who viewed the brain as the “siege of the mind” or the “seat of the animals soul”
Galen (Greek Physician), 2nd Century
Who and in what centrury was interest in anatomy revived?
Da Vinci in the 14th - 17th Century- dissected and drew the brain
When was the EEG invented?
1929 by Hans Berger (German phsychiatrist & physiologist)
Who developed the first commercial CT scanner?
Godfrey Housfield (English electrical engineer), 1967
How does Positron Emission Tomography (PET) work?
PET is a nucelar medicine technique
Involves tagging an active molecule with short-lived radioactive tracer then injecting into the human body
Tissue tracer concentration and location can be detected by GAMMA rays emitted as a byproduct of the decay of the radioactive tracer
Describe MRI:
MRI = Magnetic Resonance Imaging
The workhorse of today’s neuroimaging research
Best technology we have to image the brain
High resolution
Low temporal resolution (considered slow, taking minutes to acquire an image)
High spatial resolution (great amounts of detail)
Describe fMRI:
fMRI =functional Magnetic Resonance Imaging
Characteristics =Measures dynamic changes every couple of seconds in the whole brain during experimental tasks (task-based fMRI) or at rest (resting-state fMRI), based on BOLD effect, used to study healthy brain processes as well as psychiatric and neurological disorders
HIGHEST spatial resolution
LOW temporal resolution
Describe EEG:
EEG = Electroencephalography Characteristics = non-invasive, records brain activity, the signal is picked by multiple electrodes Advantages = cheap, somewhat portable, measures within milliseconds (HIGHEST temporal resolution) Disadvantages = signal measured only on the surface of the scalp leading to lack of localization of brain function, especially in deep brain, LOWEST spatial resolution
Describe MEG:
MEG = magnetoencephalography Characteristics = closely related to EEG, but measures in magnetic field, liquid helium used to cool down sensitive magnetic sensors Advantages= HIGHEST temporal resolution Disadvantages = LOWEST spatial resolution (especially to deep brain)
Describe PET:
PET = positron emission tomography
Characteristics = invasive neuroimaging technique, use of radiopharmaceuticals to measure physiological processes, possible to compute tissue tracer concentration, one of the most commonly used tracer is fluorine-18 (F18) fluorodeoxyglucose (FDG)
HIGH spatial resolution
LOWEST temporal resolution
Describe fNRIS:
fNRIS = functional near infrared spectroscopy Characteristics = non-invasive optimcal imaging technique, detects changes in brain activity through neurovascular coupling with use of near-infrared light, based on BOLD effect Limitations = near infrared light does not penetrate deep through the skull or brain, LOW spatial resolution Advantages = particularly suited to infant brain, HIGH temporal resolution
List the techniques used in neuroimaging from most to least expensive:
PET (2000/hr) fMRI (500/hr) MEG (250/hr) fNIRS EEG
