Case studies: Merzenich et al. (1984), Draganski et al. (2004), Draganski et al. (2006), Maguire et al. (2000)

Neuroplasticity is the ability of the brain to change throughout the course of life by making and breaking synaptic connections between neurons. This changing of the brain is also caused by both genetic and env factors. At the largest scale, cortical remapping occurs.

Studying neuroplasticity is crucial for understanding how biological factors influence behavior and mental processes. It provides insights into the brain’s ability to adapt and reorganize, impacting various behaviors and psychological phenomena.

Here are key case studies for neuroplasticity.

Merzenich et al. (1984)

One of the early studies of neuroplasticity on the level of cortical remapping was done by Merzenich et al. (1984). Researchers examined cortical hand representation in 8 owl monkeys, mapping sensory inputs by stimulating fingers with electrodes. Following amputation of a middle finger, cortical remapping was observed 62 days later, with immediate areas near finger 3 (i.e.2 and 4) enlarging.

Strengths	Weaknesses
– Insights gotten from modeling on animals allowed some confirmation of neuroplasticity	– How generalizable can the results of animal research be for humans? – Ethicality of harming animals

Draganski et al.’s (2004)

In Draganski‘s study, 24 participants were randomly assigned to control and experimental groups.

• All participants were assigned to 2 groups (control and experiment). Each had an initial scan, then the experimental group learned a juggling routine for three months
• All participants underwent a second brain scan
• Following this, the experiment group ceased practicing for another three months before a third brain scan was conducted
• Initially, there were no discernible differences between the groups in the first brain scan
• However, the second scan revealed that the juggler group exhibited significantly greater grey matter in the mid-temporal area, associated with movement coordination
• While the discrepancies decreased in the third scan, jugglers still demonstrated higher levels of grey matter compared to the control group.

Strengths	Weaknesses
– Has control group, allowing to see if learning (IV) had effect on DV (grey matter)	– Population validity, not representative, meaning cannot generalize findings – Environmental influences may impact accuracy of results, ie. some participants may have exposure to learning new things at work etc

Draganski et al. (2006)

He then looked at med students in 2006, explored the effects of activities on grey matter among medical students.

• Conducted 3 brain scans—three months before medical exams, shortly after, and three months post exams
• Medical students showed a sustained increase in grey matter, post-practice cessation (unlike in the previous study where jugglers saw a decline)
  -> suggesting the enduring impact of exam preparation compared to juggling
• Additionally, the study found that while learning bolstered grey matter, exam-related stress reduced it, particularly in hippocampal regions.

Strengths	Weaknesses
– Supports idea that these areas were involved in formation of new memories – Quasi experiment studying real-life events, higher eco validity	– Generalizability of findings: participants being med students may have different memory capacity compared to non-med students

Maguire (2000)

Taxi Drivers in London

In a quasi-experiment conducted by Maguire (2002), brain scans compared the posterior (hind) hippocampus of 16 right-handed, male licensed taxi drivers with 50 right-handed males who didn’t drive taxis. Since taxi drivers undergo rigorous navigation training due to the nature of their profession, the aim of the study was to determine if there was a difference in the hippocampus between professional drivers and non-professionals.

Results revealed increase brain matter volume in the posterior hippocampus of taxi drivers compared to the controls (non professional). However, control subjects exhibited greater volume of grey matter in the anterior (front) hippocampus. This suggests no overall difference in grey matter volume in the hippocampus between the two groups.

These findings indicate structural disparities in the hippocampi of London taxi drivers, implying that extensive navigation practice affects this brain region.

Strengths	Weaknesses
– Findings showed hippocampi’s likely functions in navigation	– Quasi-experimental nature: lack control in group assignment, preventing casual inference – Androcentric: Participants were strictly male and of a certain age group, this meant that results may not be easily generalizable to the rest of the population

Read here for more on Hippocampus
Read here for more on Case Studies Checklist in Biological Approach to Behavior