Topic 3

Question 1

-proliferation

Answer 1

-rate of growth of neurons-begins at 5 weeks GA

Question 2

• migration

- integration

Answer 2

• neurons moving to final location (brain stem, cerebellum, etc)
• neurons reach final destination

Question 3

synaptogenisis

Answer 3

neurons spin out axons that connect to each other via dendrites

• anywhere from 1000-100000 connections/neuron
• at the end of the prenatal period, some connections die (if they are inactive) and some strengthen

Question 4

differentiation

Answer 4

occurs AFTER synaptogenesis-separation of function of neurons

• efferent=motor neurons
• afferent=sensory neurons

Question 5

myelination

Answer 5

insulation of neural pathway-occurs at about 20 weeks and continues to age 30 in some areas
-enhanced by physical activity

Question 6

Post-Natal Brain Growth Spurt

Answer 6

• occurs starting at the third trimester and continues to age 4
• at birth, brain 25% of adult weight, at age 3, brain 90% of adult weight-example of cephalo-caudal principle
• attributed to increase in neuron size, branching, and increase in glia and myelin, but highly susceptible to nutrition and extrinsic factors
• allows mother to carry child more easily and may be due to evolutionary explanation-brain too big for pelvic structure at birth

Question 7

activity-independent

activity-dependent

Answer 7

• hardwired processes determined by genetic processes played out in individual neurons (migration, differentiation) [NATURE]
• influence things after axons reach final location and require neural activity (myelination, syaptogenesis) [NURTURE]

Question 8

pruning

Answer 8

connections not made or not stimulated are eliminated (40-70% of original)-keeps system from becoming too confusing
-epilepsy related to this

Question 9

Critical peroids

Answer 9

period of maximum sensitivity to environmental stimuli-a child who misses an opportunity may not develop brain’s circuitry to full potential for that aspect of development

1. organism must be in state of readiness
2. if stimulation does not occur in this window, optimal development is lost forever
3. stimulation affects things permanently
4. critical periods exist for all aspects of behavior

Question 10

Electroencephalography (EEG)

Answer 10

• measures electrical activity with electrodes

- measures an average of event-related potentials (ERP)

Question 11

Computed Technology (CT)

Answer 11

• uses x-ray beams to collect cross sectional images of the brain and develops them onto film
• shows structure of brain

Question 12

Positron Emission Tomography (PET Scan)

Answer 12

• detects radioactive material that is injected/inhaled

- shows brain function

Question 13

Magnetic Resonance Imaging

Answer 13

• detects frequency signals produced by displaced radio waves in a magnetic field
• shows anatomical view

Question 14

Functional MRI

Answer 14

• detects change in blood flow to brain

- provides anatomical and functional view

Question 15

Magnetoencephalography

Answer 15

• measures magnetic fields produced by brains electrical activity
• shows function (how brain responds to stimuli)