Question

which of the following neuroimaging techniques is used to identify functional neural circuits and abnormalities in the white matter tracts of the brain?
positron emission tomography (pet)
functional magnetic resonance imaging (fmri)
magnetic resonance imaging (mri)
diffusion tensor imaging (dti)
question 20 (1 point)
when comparing a trait between sets of twins, what result would indicate that genetics does not strongly influence variation in the trait?
dizygotic twins being just as similar along the trait as monozygotic twins
monozygotic twins being more similar than dizygotic twins
a heritability score close to 1.0
both a. and c.

Explanation:

• For the first question:
• PET: Measures metabolic activity using radioactive tracers, not specifically for white - matter tracts or functional neural circuits in the way described.
• fMRI: Detects brain activity by measuring blood flow changes, not focused on white - matter tracts.
• MRI: Provides structural images of the brain (like anatomy), not focused on functional neural circuits in white - matter tracts.
• DTI: Specifically used to map white - matter tracts and can identify abnormalities in them, which is related to functional neural circuits as white - matter tracts are part of neural circuits.
• For the second question:
• Dizygotic twins (fraternal) share about 50% of their genes, monozygotic twins (identical) share 100% of their genes. If dizygotic twins are just as similar along a trait as monozygotic twins, it suggests that the genetic difference (which is large between the two types of twins) does not strongly influence the trait variation.
• If monozygotic twins are more similar than dizygotic twins, it indicates a genetic influence (since the genetic similarity is higher in monozygotic twins).
• A heritability score close to 1.0 indicates a strong genetic influence.

Answer:

• First question: Diffusion tensor imaging (DTI)
• Second question: Dizygotic twins being just as similar along the trait as monozygotic twins