Magnetic Resonance Imaging (MRI)

By Isabelle! and sofia and ronaldo

Introduction – What is it?

• Why it’s a technique used in psychology whereby a participant is placed prone inside a scanning machine while magnetic fields and pulses of radio wave energy are used to create three-dimensional images of structures within the brain.

• This allows researches to see, by detecting changes in oxygen consumption, what brain activity and which brain structures are involved in various cognitive processes.

MRI

• This technology is based on the discovery that when the body is exposed to a strong magnetic field, the protons in the water inside the body change their alignment.

• The signal from the scanner can then be transformed into a visual representation

• MRI scans are relatively safe compared to CT scans where there is an exposure to X-ray radiation

Strengths

• Show evidence of brain activity which other scanning techniques cannot show

• Regarded as the best scanning technique for soft tissues, like brain structures

• Images from MRI scans are digital and can be studied further on the computer

• There are no serious side effects associated with it (harmful ionizing radiation is not used)

Weaknesses

• Strong magnetic current can affect pacemakers, artificial limbs and medical devices containing iron

• Iron pigments in tattoos cause skin irritations, possible risk of allergic reactions

• MRI scans are generally more expensive than other neuro-imaging methods

• Requires a trained radiologist to analyze the images produced

Maguire et al. – Taxi driver study

Aim:• Investigate the function of Hippocampus in spacial memory.

Method:• Participants were 16 mentally and physically healthy right handed male taxi drivers.• Age range from 32 to 62.• Controls were 50 mentally and physically healthy right handed male.• Age range and distribution was similar to the taxi drivers.• Participants and controls were scanned with the same MRI machine.• The amount and density of the grey matter in the hippocampus (which translates into the processors) was

counted.

Findings: • Taxi drivers have a significantly larger hippocampus.• The volume of the hippocampus correlates with the amount of time as a taxi driver.

Conclusion & Evaluation: • MRI can be used to detect the active areas of the brain.• Maguire et al. argue that this study demonstrates the plasticity of the hippocampus in response to

environmental demands.

The End