Brain Development: Neuroplasticity (DP IB Psychology): Revision Note

Brain development: neuroplasticity

• Neuroplasticity refers to the brain’s ability to adapt to change, be that from injury, damage done due to illness or changes brought about due to learning and experience

Types of neuroplasticity

• Structural plasticity refers to changes within brain structures

  • E.g., increased grey matter build-up in the posterior hippocampus due to learning experienced over time

• Functional plasticity (also known as functional recovery) refers to the brain’s ability to replace lost or damaged functions by using existing brain regions in their place

  • E.g., after a stroke, other areas of the brain may compensate for speech or movement deficits

• These changes are gradual, occurring over time as the brain responds to either the extent of damage or the degree of learning/experience

• The build-up of grey matter is due to the increased synaptic connectedness in the brain regions that are repeatedly used

• Neuroplasticity shows the brain is not static or fixed but a dynamic, flexible organ that adapts continuously to environmental stressors and stimuli

Research support for brain development: neuroplasticity

Luby et al. (1998)

Aim:

• To investigate whether childhood poverty is associated with delayed brain development (reduced neuroplasticity) and the extent to which mediating factors may influence early deprivation

Participants:

• 145 children from the USA who were enrolled on a 10-year longitudinal study of Preschool Depression

• The children were categorised as living in poverty

Procedure:

• Annual assessments over 3–6 years measured cognitive, emotional, and social skills.

  Researchers also collected data on caregiver–child relationships and exposure to negative/stressful life events.

  Each child underwent two MRI scans:

  • Session 1: whole-brain scan.

  • Session 2: focused scan of the hippocampus and amygdala

Results:

• MRI scans showed reduced white and grey matter in the hippocampus and amygdala compared to expected developmental levels

• This reduction is evidence of impaired/delayed neuroplasticity

• Children who received positive, nurturing care had less impairment, especially in the hippocampus (more white/grey matter present)

Conclusion:

• Childhood poverty negatively affects brain development and neuroplasticity, but the quality of caregiving can act as a protective factor

 Evaluation of brain development: neuroplasticity

 Strengths

• Luby et al. compared behavioural, cognitive, and social data with MRI results, strengthening the internal validity of the study

• The study’s longitudinal design allowed for tracking real developmental changes over time rather than relying on snapshots

Limitations

• Variables like 'quality of caregiving' or 'social skills' are complex and may have been measured subjectively, reducing validity

• MRI scans can measure brain volume (white/grey matter) but cannot directly explain why these changes occur, so the findings have limited explanatory power

Link to concepts

Causality

• Some children in Luby’s study had pre-existing depression, which may have independently influenced brain development

• This introduces a confounding variable, making it unclear whether impaired neuroplasticity was caused by poverty or by mental health factors

• As a result, the study cannot establish a direct causal relationship between poverty and reduced plasticity

• Further research with control groups (children without depression) would strengthen claims that poverty itself is responsible for developmental delays

Bias

• The study suffers from sample bias as it only included US preschool children living in poverty, limiting the generalisability of the findings

• Since participants also showed depressive symptoms, the results may not apply to:

  • children in poverty without depression

  • children in other cultural or national contexts

  • or children outside the preschool age range

• This reduces the population validity of the study