Ways of investigating the Brain

Question 1

Overview of Brain Investigation Techniques

Answer 1

• Key Techniques:
  1. Functional Magnetic Resonance Imaging (fMRI)
  2. Electroencephalogram (EEG)
  3. Event-Related Potentials (ERPs)
  4. Post-Mortem Examinations
• Purpose: These techniques allow researchers to study brain structure and function, and understand which areas are active during specific tasks or linked to disorders.

Question 2

Functional Magnetic Resonance Imaging (fMRI)

Answer 2

• How it works:
  o Measures brain activity by detecting changes in blood oxygenation and flow (when an area of the brain is more active, it consumes more oxygen, leading to increased blood flow to that area).
  o Produces 3D images (activation maps) showing which parts of the brain are involved in different processes.
• Uses: Identifies active brain regions during tasks (e.g., language processing, motor tasks).
• Strengths:
  1. High spatial resolution (detailed images of brain activity, down to millimeters).
  2. Non-invasive, no need for radiation.
  3. Provides functional and anatomical information.
• Limitations:
  1. Poor temporal resolution (lags slightly in detecting activity).
  2. Expensive and requires a specialist to operate.
  3. Indirect measure of neural activity (measures blood flow, not actual neuron firing).

Question 3

Electroencephalogram (EEG)

Answer 3

• How it works:
  o Measures electrical activity in the brain using electrodes placed on the scalp.
  o Detects brainwave patterns, with different waveforms associated with different states (e.g., alpha waves = relaxation, beta waves = alertness).
• Uses:
  o Commonly used to diagnose conditions like epilepsy, sleep disorders, and coma.
  o Also used to study general brain activity (e.g., in sleep cycles).
• Strengths:
  1. High temporal resolution (records brain activity in real time).
  2. Non-invasive and relatively inexpensive compared to fMRI.
  3. Effective for detecting rapid changes in brain activity.
• Limitations:
  1. Poor spatial resolution (cannot pinpoint the exact location of activity).
  2. Measures surface activity only, missing deeper brain regions.
  3. Can be affected by noise or external electrical interference.

Question 4

Event-Related Potentials (ERPs)

Answer 4

• How it works:
  o A type of EEG that isolates brainwave responses to specific sensory, cognitive, or motor events.
  o By filtering out unrelated brain activity, ERPs reveal brain activity related to a particular stimulus or event.
• Uses:
  o Useful in cognitive neuroscience, studying attention, perception, and memory.
  o Can show how the brain processes stimuli (e.g., in decision-making tasks).
• Strengths:
  1. Excellent temporal resolution (measures activity millisecond by millisecond).
  2. Allows the study of specific cognitive processes (e.g., decision-making).
  3. Non-invasive and cost-effective.
• Limitations:
  1. Poor spatial resolution (like EEG, it does not localise brain activity well).
  2. Requires many trials to isolate the signal from noise.

Question 5

Post-Mortem Examinations

Answer 5

• How it works:
  o Involves examining the brains of deceased individuals, often to study the effects of neurological disorders (e.g., Broca’s area in patients with speech deficits).
  o Can reveal abnormalities in brain structure that might be linked to specific conditions.
• Uses:
  o Crucial for understanding disorders like Alzheimer’s, schizophrenia, and aphasia.
  o Historically important in linking brain regions to functions (e.g., Broca’s and Wernicke’s areas).
• Strengths:
  1. Allows detailed examination of the brain’s physical structure.
  2. Provides insights into underlying anatomical causes of disorders.
  3. Can study deeper brain regions not accessible via non-invasive methods.
• Limitations:
  1. Causality issues: Changes observed post-mortem may not be directly linked to the condition.
  2. Ethical issues related to consent.
  3. Limited to studying individuals who have died, so cannot observe brain function in action.

Question 6

Evaluation of Brain Investigation Techniques

Answer 6

• fMRI: Best for understanding brain function in a specific region but expensive and slow.
• EEG: Excellent for real-time monitoring of brain activity but lacks precision in localising activity.
• ERPs: Good for studying specific cognitive processes with great time accuracy, though still limited in localisation.
• Post-Mortem: Provides anatomical detail and insights into brain abnormalities but cannot show brain function or live processes.

Question 7

Application to Psychological Research

Answer 7

• fMRI: Used in memory research (e.g., brain regions activated during recall), emotion, and decision-making studies.
• EEG: Used in sleep studies, epilepsy diagnosis, and research into brainwave patterns associated with cognitive processes.
• ERPs: Applied to study specific cognitive processes, such as attention (e.g., P300 wave in decision-making).
• Post-Mortem: Vital in understanding disorders like Alzheimer’s disease by examining physical brain changes (e.g., neurofibrillary tangles).

Question 8

Key Exam Points

Answer 8

• Definitions: Be clear on the definitions and processes of fMRI, EEG, ERPs, and post-mortem examinations.
• Strengths and Limitations: Be prepared to evaluate each technique’s pros and cons, particularly regarding temporal and spatial resolution.
• Applications: Be able to explain how each method is used in real-world psychological research, especially in areas like memory, cognition, and neurological disorders.