Ling 390 6

3 Pages
100 Views
Unlock Document

Department
Linguistics
Course
LING 390
Professor
Andrea Nicole Santi Isabelle Deschamps
Semester
Fall

Description
Sept 21 - Anatomical MRI vs fMRI - regular mris just give you structure. functional looks for modules. you need anatomy for functional too. - fMRI: what is it? - in order to answer this question, we will look at: - the equipment - giant magnet coil thing - the basis of the signal - it's too difficult to understand how the signal is generated for this class - fMri - Magnetization: magnetic fields and spins (protons in the body become aligned to the field) - fmRi -Excitation: radio frequency pulses knock protons over - Relaxation times: then they go back to their state of alignment with the field, they emit energy that the coil receives - fmrI - Tissue Contrasts: make it possible to encode the spatial information of signal - Fmri - Bold and T2* : concentration of hydrogen in an area (anatomical MRI); amount of oxy- vs. deoxyhemoglobin in an area (functional MRI) - normally, our protons all spin at their own orientation. when you put them in the magnetic field, they all align with it. once they're all ligned up, we disturb them with a radio frequency pulse, causing the protons to go from low to high energy states. depending on the frequency applied, you can disturb different protons and change them differently - T1 is the time is takes the protons to realign with the magnetic field - T2 is the time it takes for the protons to get back to spinning in unison - T2* measures the overall decay of the observable RF signal over a macroscopic region (fMRI signal) - every tissue has its own T1 and T2 value: this is how we differentiate between things - T1- weighted MRi have good grey/white matter contrast - T2-weighted MRI are sensitive to water content - usually, we use T1-weighed in psychology, because the water content isn't as useful - The variations in BOLD signals come from three things: a) increase in neural activity (which causes an increase in oxygen and glucose)
More Less

Related notes for LING 390

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit