Bio Psyc Brain Scans and Heredity Studies Chapt 4

EEG

• Sums the electrical activity of neurons between two electrodes

• Detects fast-changing brain activity but is poor at localizing it

• Time = 1ms

• Spatial = 10-15 mm

CT

• Forms 3-D image of brain by combining X-rays of cross sections of brains

• Images structure and damage

• Time = < 1 ms

• Spatial = 0.2-0.5 mm

EEG

• Sums the electrical activity of neurons between two electrodes

• Detects fast-changing brain activity but is poor at localizing it

• Time = 1ms

• Spatial = 10-15 mm

CT

• Forms 3-D image of brain by combining X-rays of cross sections of brains

• Images structure and damage

• Time = < 1 ms

• Spatial = 0.2-0.5 mm

MRI

• Measures variations in hydrogen concentrations in brain tissue

• Images structure and damage

• Time = 3-5 s

• Spatial - 1-1.5 mm

PET

• Produces image by emissions from injected substances that have been made radioactive

• Tracks changing activity, detects receptors, etc

• Time = 30 s

• Spatial = 2-3 mm

fMRI

• Detects increases in localized blood flow and oxygen usage during neural activity

• Tracks changing activity

• Time = 1 s

• Spatial = 1-2 mm

Family Study

• Indicates how strongly a characteristic is shared among relatives

• Can show that a characteristic follows family lines

• Confounds heredity and environment

Adoption Study

• Compares adopted children with their adoptive parents and their biological parents

• Susceptible to confounding because the adoption variable is not manipulated

Twin Study

• Compares similarity of twins with that of nontwin siblings, or similarity of identical twins with similarity of fraternal twins

• Allows comparison of two levels of genetic similarity