6B. Infant, Child, and Adolescent Brain

Question 1

Average brain weight of newborn baby

Answer 1

370 grams or 13 ounces (slightly less than a pound)

Question 2

Average weight of adult brain

Answer 2

3 pounds or 1.3-1.4 kg

Question 3

Growth rate of brain immediately after birth

Answer 3

1% per day

Question 4

Growth rate of brain 3 months after birth

Answer 4

0.4% per day

Question 5

Volume of brain 90 days after birth compared to volume at birth

Answer 5

64% larger

Question 6

Fastest growing region of brain

Answer 6

Cerebellum. More than doubles its volume during first 90 days

Question 7

During first three months of life, number of neurons in cortex increases by ____ to ____%

Answer 7

23-30%

Question 8

By __ years of age, brain has reached __% of its adult size

Answer 8

5, 90%

Question 9

2-year old’s brain has ___% more/less? synapses than adult brain

Answer 9

50% more synapses

Question 10

2-year old’s brain is __% the size of an adult brain

Answer 10

80%

Question 11

Compare human brain development to that of other animals

Answer 11

Humans are born with less developed brains, they take longer to mature. Develop extensively after birth, allowing them to be easily shaped by experience

Question 12

Changes in neural connections during critical periods coincide with…

Answer 12

High rates of learning

Question 13

Brains develop until…

Answer 13

30 years of age

Question 14

Gray matter density of most regions ______ with age, but ______ in ____________ until ____

Answer 14

Gray matter density of most regions declines with age, but increases in left temporal lobe until age 30

Question 15

Describe brain development in 20-somethings

Answer 15

Changes in where myelination occurs. Earlier in life, more myelination is found in visual, auditory, and limbic cortices. Closer to 30, frontal and parietal neocortices become more myelinated, which helps working memory and higher cognitive functions

Question 16

Plasticity is crucial for…?

Answer 16

Critical periods

Question 17

Plasticity is unique to humans. True or false?

Answer 17

False.

Question 18

Two types of plasticity

Answer 18

Experience-expectant and experience-dependent

Question 19

Experience-expectant plasticity

Answer 19

Integrating environmental stimuli into normal developmental patterns. Being exposed to common experiences (language, faces, touch) during critical periods is essential for healthy brain function

Question 20

Experience-dependent plasticity

Answer 20

Continuing changes in organization and specialization of brain regions as result of life experiences that are not universal or anticipated. Includes skills developed throughout life, with no critical period for their acquisition. Occurs all the time.