Ways of studying the brain

• Briefly evaluate the use of EEGs as a way of identifying cortical specialisation in the brain. (3)

  • Non-invasive and safe way of measuring brain activity.
  • Helps to identify activity in various regions of brain
  • Can be used as a diagnostic tool e.g. for epilepsy
  • It lacks precision for detecting individual neurons' activity.
• EEG measures general brain activity, while ERPs are responses to specific stimuli.
• Temporal resolution refers to the precision of a brain-scanning technique in measuring activity with respect to time.

  • It indicates how quickly changes in brain activity can be detected.
• Electroencephalogram (EEG) and Event-Related Potentials (ERPs):

  • Have high temporal resolution.
  • Can detect changes in electrical activity in the brain within milliseconds, making them effective for studying fast neural processes.
• Functional Magnetic Resonance Imaging (fMRI):

  • Has low temporal resolution.
  • Measures brain activity indirectly by detecting blood flow changes, which take several seconds to occur. This means fMRI cannot detect rapid changes in neural activity.
• Functional Magnetic Resonance Imaging (fMRI):

  • Has high spatial resolution (typically 1–2 mm).
  • This makes fMRI effective at identifying the precise location of brain activity, which is valuable for studying specific regions and their functions.
• Electroencephalogram (EEG) and Event-Related Potentials (ERPs):

  • Have low spatial resolution.
  • They provide limited information about where activity occurs in the brain because they measure general electrical activity from large groups of neurons, often across broad regions.
• Explain the differences between fMRI and ERPs as ways of studying the brain

  • fMRIs have poor temporal resolution whereas ERPs have good temporal resolution
  • fMRIs have good spatial resolution whereas ERPs have poor spatial resolution
  • fMRIs provide an indirect measure of neural activity whereas ERPs offer a direct measure of neural activity
  • different methodology - fMRIs work by measuring changes in blood oxygenation as a measure of neural activity whereas ERPs measure electrical activity via electrodes to detect brainwaves triggered by certain events
  • fMRIs are more expensive than ERPs.
• Explain the similarities between the fMRI and ERP as ways of studying the brain

  • fMRIs and ERPs are both non-invasive and do not use radiation (risk-free)
  • fMRIs and ERPs both measure brain activity linked to events/tasks.
• Cortical specialisation refers to the idea that different areas of the brain are responsible for specific functions and behaviours. This concept is also referred to as localisation of function.
• fMRIs indirectly measure the electrical activity of neurons by recording changes in blood flow.
• fMRIs use magnetic fields and radio waves to monitor blood flow.

  • it measures the change in the energy released by haemoglobin, reflecting the activity of the brain (oxygen consumption) to give a moving picture of the brain
  • activity in regions of interest that can be compared during a baseline task and during a specific activity
• In ERPs, electrodes are put on the scalp and detect neuronal activity (directly below where they are placed) in response to a stimulus introduced by the researcher.
• In postmortem examinations, the brain is examined after death to try and correlate structural abnormalities/damage to behaviour.
• fMRI research is expensive leading to reduced sample sizes which negatively impact the validity of the research. Whereas EEGs and ERPs are cheaper so can be more widely used in research.
• In EEGs, electrodes are put on the scalp and detect neuronal activity directly below where they are placed.

  • Differing numbers of electrodes can be used depending on the focus of the research.
• fMRI captures dynamic brain activity as opposed to MRI/post-mortem examinations which purely show physiology.
• The interpretation of fMRI is complex and is affected by temporal resolution, biased interpretation and by the baseline task used.
• Spatial resolution refers to the accuracy or precision of a brain-scanning technique in identifying the location of brain activity.

  • It indicates how well a method can pinpoint where activity occurs in the brain.