Technology in Psych Research

Techniques Used to Study the Brain in Relation to Behaviour

Inquiry Questions

  • To what extent can we see inside the brain?

  • Can we observe mental processes using modern technology?

  • What is the structure of the brain, and are there limits to what can be seen?

  • What are the principles of brain imaging techniques?

Neuroimaging Techniques

  • Neuroimaging refers to techniques that allow researchers to visualize the brain's structure and function without invasive methods such as autopsy.

  • Common neuroimaging techniques include:

    • Computerized Axial Tomography (CAT)

    • Magnetic Resonance Imaging (MRI)

    • Functional Magnetic Resonance Imaging (fMRI)

    • Positron Emission Tomography (PET)

    • Electroencephalography (EEG)

Computerized Axial Tomography (CAT)

  • Functionality: Works on differential absorption of X-rays to produce images of brain structure.

  • Process: Subject lies in a cylindrical apparatus where a moving X-ray source scans the head.

  • Strengths:

    • Non-invasive and relatively quick method.

    • Allows for imaging of soft tissues and blood vessels simultaneously.

  • Limitations:

    • Involves radiation exposure.

    • May not be used for patients with certain medical devices due to radiation risk.

Magnetic Resonance Imaging (MRI)

  • Functionality: Does not use X-rays; employs magnetic fields to examine the brain's hydrogen atoms.

  • Abilities: Produces high-resolution 3D images of brain structures.

  • Strengths:

    • Better resolution than CAT, especially for soft tissue abnormalities.

    • No radiation exposure, reducing the risk of cancer.

  • Limitations:

    • Cannot be used with patients who have metal implants.

    • May cause discomfort or anxiety in claustrophobic individuals.

    • Longer scan times (up to 40 minutes).

Functional Magnetic Resonance Imaging (fMRI)

  • Functionality: Similar to MRI but provides dynamic images showing brain process in action based on blood flow.

  • Spatial Resolution: Approximately 1-2 mm, allowing for precise localization of brain activity.

  • Temporal Resolution: About 1 second, which is less suitable for quick neural processes.

  • Applications: Analyzes tasks involving memory, emotional responses, etc.

  • Challenges: Requires participants to stay still, and distinguishing actual signals from noise can be difficult due to head movement.

Positron Emission Tomography (PET)

  • Functionality: Uses a radioactive tracer to visualize active brain areas based on glucose metabolism.

  • Spatial Resolution: Approximately 4 mm, useful for identifying tumors or cognitive disorders.

  • Temporal Resolution: 30-40 seconds, limiting its ability to observe rapid neural processes.

  • Advantages: Can detect brain diseases and also provides a visualization of blood flow in active regions.

  • Limitations: Involves radiation exposure and less spatial precision compared to fMRI.

Electroencephalography (EEG)

  • Functionality: Measures electrical activity produced by the synchronous firing of large groups of neurons.

  • Strengths:

    • Perfect temporal resolution, detecting changes in milliseconds.

    • Non-invasive and relatively low-cost.

  • Limitations:

    • Low spatial resolution, making it difficult to localize brain signals accurately.

    • Requires experience to interpret results accurately due to noise from muscle movements and other artifacts.

Application of Neuroimaging in Research Studies

  • Research studies using neuroimaging techniques provide insights into brain structure and processes. Some notable studies:

    • Draganski et al (2004): Used MRI to study brain changes from learning to juggle.

    • Maguire et al (2000): Compared MRI scans of London taxi drivers with controls to investigate hippocampus role in spatial memory.

    • Freed et al (2001): Employed PET to study dopamine activity in Parkinson's disease patients.

Final Considerations

  • When selecting a neuroimaging technique, researchers must consider factors such as:

    • Available technology

    • Costs

    • Ethical considerations

    • Specific research aims

Exam Tip

  • Understand that neuroimaging itself is not a research method but rather a tool utilized within various research methodologies.