Ways of Studying the Brain

• Scanning and Other Techniques:

  • Techniques for investigating the brain are often used for medical purposes in the diagnoses of illness.
  • The purpose of scanning in psychological research is often to investigate localisation - determine what parts of the brain do what.
• Functional Magnetic Resonance Imaging (fMRI):

  • A method used to measure brain activity while a person is performing a task.
  • Detects radio waves from changing magnetic fields.
  • This enables researchers to detect which regions of the brain are rich in oxygen and active.
• Functional Magnetic Resonance Imaging (fMRI):

  • Detects changes in blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain.
  • When a brain areas is more active it consumes more oxygen and to meet this increased demand, blood flow is directed to the active area (haemodynamic response).
• Functional Magnetic Resonance Imaging (fMRI):

  Strengths

  • Unlike other scanning techniques, it doesn’t rely on radiation.
  • If use correctly, it is risk free, non-invasive and straightforward to use.
  • Produces images of very high spatial resolution, depicting detail by the millimetre, providing a clear picture of how brain activity is localised.
  • Can safely provide a clear picture of brain activity.
• Functional Magnetic Resonance Imaging (fMRI):

  Limitations:

  • Expensive to use.
  • Has poor temporal resolution because there is around a 5-second time-lag behind the image on screen and the initial firing of neuronal activity.
  • May not truly represent moment-to-moment brain activity.
• Electroencephalogram (EEG):

  • A record of the tiny electrical impulses produced by the brains activity.
  • Measuring the characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.
• Electroencephalogram (EEG):

  • Measures electrical activity within the brain via electrodes that are fixed to an individuals scalp using a skull cap.
  • The scan recording represents the brainwave patterns that are generated from the action of thousands of neurons, providing an overall account of brain activity.
• Electroencephalogram (EEG):

  • EEG is often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities such as epilepsy, tumours and some sleep disorders.
• Electroencephalogram (EEG):

  Strengths

  • Useful for studying the stages of sleep and in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can easily be detected on screen.
  • Has high temporal resolution.
  • Can accurately detect brain activity at a resolution of a single millisecond. Shows real-world usefulness of the technique.
• Functional Magnetic Resonance Imaging (fMRI):

  • Produces three-dimensional images (activation maps) showing which parts of the brain are involved in a particular mental process and this has important implications for our understanding of localisation of function.
• Electroencephalogram (EEG):

  Limitations

  • Generalised nature of the information received.
  • The EEG signal is also not useful for pinpointing the exact source of neural activity.
  • Does not allow researchers to distinguish between activities originating in different but adjacent locations.
• Event-Related Potentials (ERPs):

  • The electrophysiological response of the brain to a specific sensory, cognitive or motor event can be isolated through statistical analysis of EEG data.
• Event-Related Potentials (ERPs):

  • Has many scientific and clinical applications but in its raw form it is a crude and overall general measure of brain activity.
  • Within data, are all the neural responses associated with specific sensory and cognitive and motor events that may be of interest to cognitive neuroscientists.
• Event-Related Potentials (ERPs):

  • Researchers have developed a way of teasing out and isolating these responses using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out leaving only those responses that relate to a specific stimulus or performance of a specific task.
  • What remains are event-related potentials - types of brainwave that are triggered by particular events e.g attention and perception.
• Event-Related Potentials (ERPs):

  Strengths

  • More specific for the measurement of neural processes that could ever be achieved by raw EEG data.
  • Excellent temporal resolution.
  • Frequently used to measure cognitive functions and deficits such as the allocation of attentional resources and the maintenance of working memory.
• Event-Related Potentials (ERPs):

  Limitations

  • Lack of standardisation in ERP methodology between different research studies which makes it difficult to confirm findings.
  • In order to get pure data, background noise and extraneous material must be eliminated completely which is hard to control and cannot always happen.
• Post-Mortem Examinations:

  • The brain is analysed after death to determine whether certain observed behaviours during the person’s lifetime can be linked to structural abnormalities in the brain.
• Post-Mortem Examinations:

  • The person being analysed would have usually had a rare disorder and have experienced unusual deficits in cognitive processes or behaviour during their lifetime.
  • Areas of damage within the brain are examined after death as a means of establishing the likely cause of the affliction the person experienced.
  • Can also include a comparison with a neurotypical brain in order to ascertain the extent of the difference.
• Post-Mortem Examinations:

  Strengths

  • Broca and Wernicke relied on them to establish links between language, brain and behaviour before neuroimaging was available.
  • Vital for providing a foundations for early understanding of key aspects of the brain.
  • Provides useful information - studied HM’s case - identified areas of damage.
• Post-Mortem Examinations:

  Limitations

  • Correlation v causation.
  • Damage may be due to other unrelated trauma or decay.
  • Ethical issues - need consent from the person before death or a family member.
  • May not be able to provide consent (case of HM).