Cortical Folding

Question 1

Theories of Cortical Folding

Answer 1

• Limited volume of the skull
• Axonal Tension Hypothesis
• Radial Expansion Hypothesis
• Differential Tangential Expansion Hypothesis (not rejected, has more evidence)

Question 2

Study Brain’s Anatomy in vivo

Answer 2

• MRI (Magnetic Resonance Imaging)
• fMRI (Functional Magnetic Reasonance Imaging)

Question 3

MRI

Answer 3

• Magnetic Resonance Imaging
• Use magnetic field to image the brain
• Different types of images depending on research
• Darker = cortex
• Strength of magnet determines the spatial resolution

Question 4

fMRI

Answer 4

• Functional Magnetic Resonance Imaging
• More active areas require more blood for glucose and oxygen consumption
  
  • Measure changes in blood flow
    
    • BOLD: Blood Oxygen Level Dependent
• IS NOT DIRECT MEASURE OF NEURAL ACTIVITY
• Task-based fMRI:
  
  • measure changes during behavioural task compared to control task
• Resting-state:
  
  • Brain activity at rest
• Functional activations are overload onto structural MRI images for anatomical context.
  
  • activations = heat maps

Question 5

Standard Atlas of Talairach and Tournoux

Answer 5

• Created by fitting a single brain into a stereotaxic space
  
  • Brodmann’s Areas were overlaid
• Created for neurosurgeons
• Picked up for neuroimaging researchers to make sense of the location of activation peaks.

Question 6

MNI Stereotaxic Space

Answer 6

• Standard imaging space created by Montreal neurological Institute
  
  • used around the world
• Generated by averaging dozens of MRI scans
  
  • template or average brain
• Standard coordinate system
• Registering subject’s MRI scan into MNI space
  
  • spatial normalization
• Allows to make comparaisons

Question 7

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