Neuroplasticity
Neuroplasticity refers to the brain's ability to change its neural networks and function in response to environmental demands, learning experiences, or injury. These changes may lead to changes in behaviour. It occurs most rapidly in young children and is incredibly important for growth.
Neuroplasticity operates on multiple levels, including:
Synaptic Plasticity
Changes occurring at the level of individual neurons through the formation or elimination of synaptic connections. This process is central to learning and memory.
Cortical Remapping
Larger-scale reorganization of the brain’s cortical areas, often observed following damage or injury.
Processes Supporting Neuroplasticity
- Neural Pruning: This process involves the elimination of weaker synaptic connections while strengthening frequently used ones, optimizing brain efficiency.
- Neurogenesis: The generation of new neurons in the brain.
- Chronic Stress: Prolonged exposure to stress and elevated cortisol levels can damage neurons in areas like the hippocampus, leading to reduced neuroplasticity.
- Technological Advances: Innovations such as voxel-based morphometry (VBM) and functional MRI (fMRI) enable researchers to map and measure neuroplastic changes, providing deeper insights into how environmental factors shape brain development over time.
Studies have shown that individuals experiencing long-term stress tend to have smaller hippocampal volumes, impairing learning and memory functions.
Key Research Studies
Case studyMerzenich et al. (1984)
Aim: To explore how the sensory cortex of adult owl monkeys adapts after the amputation of a digit.
Participants: Eight adult owl monkeys.
Method: Experimental, repeated measures design.
Procedure: Sensory inputs from the digits were initially mapped using electrodes. Following amputation of one or more digits, remapping was conducted after 62 days to observe cortical changes.
Results: Cortical areas previously dedicated to the amputated digit were taken over by adjacent fingers, demonstrating cortical remapping.
Conclusion: The sensory cortex exhibits neuroplasticity, adapting to physical changes by reorganizing neural connections.
Case studyDraganski et al. (2004)
Aim: To investigate whether learning a new skill (juggling) induces structural brain changes.
Participants: Self-selected sample of individuals without prior juggling experience.
Method: Experimental, mixed design.
Procedure:
- Participants were divided into jugglers and non-jugglers.
- Jugglers practiced a juggling routine for three months, followed by three months of non-practice.
- MRI scans were performed at baseline, after three months, and after six months.
Results:
- Increased grey matter in the mid-temporal cortex of jugglers after practice.
- Grey matter volume decreased after non-practice but remained higher than baseline.
Conclusion: Learning induces growth in brain areas associated with the skill, while lack of practice leads to partial regression, demonstrating neural pruning.
Case studyMaguire et al. (2000)
Aim: To examine differences in hippocampal structure between taxi drivers and non-drivers.
Participants: 16 male London taxi drivers and 50 healthy male non-drivers as a control group.
Method: Quasi-experimental with correlational analysis.
Procedure:
MRI scans were used to compare hippocampal volume. Years of driving experience were correlated with hippocampal structure.
Results:
- Taxi drivers showed increased grey matter in the posterior hippocampus and decreased grey matter in the anterior hippocampus.
- A positive correlation was found between years of driving experience and posterior hippocampal volume.
Conclusion: Neuroplasticity is evident in the redistribution of grey matter within the hippocampus due to the demands of spatial navigation.
Case studyLuby et al. (2013)
Aim: To investigate the relationship between poverty, stress, parenting, and hippocampal development.
Participants: 145 children studied over ten years.
Method: Longitudinal study using MRI, interviews, and questionnaires.
Procedure:
- MRIs measured hippocampal volume.
- Parent-child interactions were observed in a stress-inducing scenario.
- Correlations were analyzed between socioeconomic status, stress, and brain development.
Results:
- Positive parent-child interactions were associated with larger hippocampal volume.
- Stress and poverty negatively correlated with hippocampal development.
Conclusion: Childhood experiences shape brain structure, highlighting the role of neuroplasticity in responding to environmental stressors.
