Giedd Study (develop, bio)

Question 1

Aim

Answer 1

To investigate how the brain changes over childhood and adolescence.

Question 2

Procedure

Answer 2

• Over 300 brain scans (MRIs) from both male and female participants taken from approx age 5 to 20 (longitudinal)
• Neuropsychological testing also occurred at approx 2 year intervals

Question 3

Findings

Answer 3

• Brain has reached approx 90% of adult size by age 6
• Hormones can influence development (neurons) in the brain
• **White matter (myelinated axons) **
  - Increases throughout childhood and adolescence (corpus callosum most obvious white matter in brain - develops front to back)
• Grey matter (dendrites and axon terminals)
  - Subcortical: inside the cortex
  - Within the basal ganglia, caudate decreases in size in teen years. Females typically have a larger caudate and a small caudate is correlated to ADHD and Tourette’s (more common in males).
• Cortical: outer surface
  - General decrease during childhood (started as early as the study began, at age 5)
  - Different areas of the brain reach their maximum thickness at different times (in an inverted U-pattern on a graph)
  - Grey matter loss first occurs in areas responsible for primary functions
  - Latest development: a specific area of prefrontal cortex that is thought to be linked to inhibition of impulses, weighing consequences, prioritizing and strategizing
• Supports belief that some cognitive abilities are difficult for children/adolescents based on brain development and theories of localization

Question 4

Strengths

Answer 4

• Logitudinal
  - Difference can be seen over time but would be more valuable if a longer time span was used (only 2 scans for each participant)

Question 5

Limitations

Answer 5

• Participant variability
  - Characteristics of sample are unclear
• Research still unclear, only correlations have been found (no causation)

Question 6

Ethical Considerations

Answer 6

• Informed consent
  - confined space of a MRI
• Protection from harm

Question 7

Research method

Answer 7

Correlational research