6.7.1 Functional Magnetic Resonance Imaging (fMRI)

• What does fMRI measure to detect brain activity?

  Changes in blood flow
• The BOLD signal detects changes in oxygenated and deoxygenated hemoglobin
• MRI uses a strong magnetic field to align protons within brain tissues.
• What does functional mapping combine to map brain activity?

  MRI and BOLD signal
• Match the benefits of fMRI with their corresponding limitations:

  High spatial resolution ↔️ Lower temporal resolution

  Non-invasive ↔️ Can be expensive

  Safe and repeatable ↔️ Sensitive to movement
• Steps in the fMRI scanning process

  1️⃣ Place the patient inside the scanner

  2️⃣ Present tasks or stimuli

  3️⃣ Measure BOLD signal changes

  4️⃣ Create brain activity maps
• What is the magnetic property of oxygenated hemoglobin?

  Diamagnetic
• What is the magnetic property of deoxygenated hemoglobin?

  Paramagnetic
• The intensity of the BOLD signal correlates with the degree of neural activity.
• The BOLD signal measures changes in oxygenated and deoxygenated hemoglobin
• Match the properties of oxygenated and deoxygenated hemoglobin with their effects on MRI signal:

  Oxygenated hemoglobin ↔️ Weak decrease

  Deoxygenated hemoglobin ↔️ Strong decrease
• Deoxygenated hemoglobin is present in high oxygen areas of the brain.

  False
• What happens to blood flow when a brain area becomes active?

  Increases
• Oxygenated hemoglobin is diamagnetic, whereas deoxygenated hemoglobin is paramagnetic.
• The BOLD signal is used to map brain activity during specific tasks.
• Steps in the procedure of fMRI scanning

  1️⃣ Preparation: Consent and safety checks

  2️⃣ MRI scanner usage: Structural and functional scans

  3️⃣ Task/stimulus presentation: Visual or auditory cues

  4️⃣ Data analysis: Preprocessing and statistical mapping
• Why is the participant secured in the MRI scanner with padding and straps?

  To minimize movement
• Tasks or stimuli are presented through visual or auditory cues within the scanner
• What is analyzed during the statistical mapping phase of data analysis?

  BOLD signal changes
• Match the advantages of fMRI with their explanations:

  High spatial resolution ↔️ Detailed brain structure visualization

  Non-invasive ↔️ No surgery or injections required

  Safe and repeatable ↔️ Uses magnetic fields instead of radiation
• fMRI is often compared with EEG, PET, and CT scans.
• What is a key advantage of fMRI compared to EEG in terms of spatial resolution?

  High spatial resolution
• The BOLD signal intensity is directly proportional to neural activity.
• fMRI detects brain activity by measuring changes in blood flow.
• What does the BOLD signal measure in the brain?

  Oxygenated and deoxygenated hemoglobin
• Oxygenated hemoglobin is diamagnetic, while deoxygenated hemoglobin is paramagnetic.
• What does the BOLD signal intensity correlate with in functional mapping?

  Neural activity
• The initial MRI scan in an fMRI procedure maps brain anatomy.
• What type of stimuli are commonly presented during fMRI tasks?

  Visual or auditory
• Statistical mapping in fMRI data analysis identifies active brain areas.
• Order the phases of fMRI scanning based on their objectives:

  1️⃣ Preparation: Ensure safety and comfort

  2️⃣ Scanning: Collect brain activity data
• What is a key advantage of fMRI in terms of visualizing brain structure?

  High spatial resolution
• fMRI has high spatial resolution compared to EEG.
• PET scans use mild radiation, while fMRI uses magnetic fields.
• What is a major limitation of fMRI in terms of capturing rapid neural activity changes?

  Low temporal resolution