neuroimaging

• Case studies which used single cell recording 


  Phineas Gage & Tan Man
• What happened to Phineas Gage ? 


  Severe brain injury which obliterated left frontal lobe of his brain. Caused severe personality change ( aggression ) lesion studies
• What happened to Tan Man? 


  Left frontal lobe caused inability to speak could only say “ tan “ lesion studies
• When is a Single cell recording used ? 


  Only in special cases in humans, for example before surgery in people with epilepsy
• What did a Single cell recording find? 


  grandmother, Jennifer Anniston , Luke skywalker neuron flashed when mentioned.
• scientists in single cell recording 


  Hubel and Wiesel (1962) nobel prize for single neuron activities recording
• Lesion studies 


  Naturally occurring in humans
• What is lesion studies usually used for? 


  Animal models of disease, schischizophrenia, Alzheimer’s, models of memory
• what is a CT/Cat scan good for ? 


  Monitoring strokes, tumours, giloma , infractions
• How is a CT/CAT scan done? 


  Done with radiographers, Xray tube rotates around the body, rays analysed. Structural / anatomical information
• what is used in A pet scan ? 


  Radiation is used to create a 3D image of the brain
• What is pet scan used in? 


  Medical health and brain research BUT it’s not used as often
• Why is a pet scan not used as often ? 


  Poor spatial and temporal resolutions

  4-5mm which means a lot of neurons - want it to be more specific

  limited temporal window for obtaining data

  can’t use if pregnant or breastfeeding

  can’t be tested more than once within guideline timeframes

  expensive as you need cyclotron to make the radioactive compound
• what are the advantages of a PET scan?


  It Is quiet and tells a lot
• How is a PET scan done ? 


  by injecting slightly radioactive tracer in the blood (FDG) can see where it is based on the cognitive function we are performing . It emits posotrun - energy is picked up by computer. tracer means we can measure it. Breaking down emits an electrical charge energy to create an image.
• What does pet look at?

  glucose metabolism
• What is FDG like? 


  Glucose - body treats it in the same way.
• If you’re wanting to test memory through a pet scan, where would the FDG go? 


  To the hippocampus
• Where is the highest activity for learning a new language ?

  Temporal lobe- hearing perception
• where is the highest activity for understanding a language ?

  prefrontal cortex
• What is the cognitive process for language development ? 


  When you’re first learning a language it is activated, then when understanding the language it turns into motor areas
• what Is a pet scan good for? 


  For cognitive psychology it’s good for understanding language, medical - Alzheimer’s progression and brain damage research.
• What does a single cell recording do? 


  Records action potentials from neurones
• What does a lesion study do ? 


  Animal models/ large brain areas
• What do CT images do? 


  Brain structure, involves absorption of X-rays
• What do PET images do?


  brain function, emission of radiation by an injected radioactive tracer
• How do you do an MRI scan?

  • centre of hydrogen atom- small proton
  • protons are like tiny magnets
  • very sensitive to magnetic fields
  • in scanner all of the protons line up
  • somebody sitting there applies short bursts of radio waves
  • Protons spin around in different directions
  • person turns off radio waves, protons realign
  • as they line up again- they realign at different speeds and that’s the measurable signal
  • rate direction and speed they line up is different dependent on The part of the brain. Neurone being used for grey matter, white matter thats what is visable on picture.
• What does fMRI measure?/ what is the BOLD response


  Oxygen level in local blood circulation also known as the BOLD response
• What does the BOLD response stand for? 


  Blood Oxygen Levels dependant activity
• Where does fMRI neural activity come from?

  Oxygen
• How will the proton realign if there’s more blood flow in a fMRI? 


  Differently
• If you’re doing a memory test in fMRI where will there be more blood flow? 


  Hippocampus
• Where is the blood pumped into in a fMRI? 


  Active region
• What changes the field in an fMRI?


  Magnetic field and provides a measurable signal
• What are the advantages of an fMRI? 


  Good resolution

  can see 2-3mm of the brain

  200ms

  Probably the most useful image technique presently
• what are the disadvantages of an fMRI?

  noisy

  can’t do auditory/language function test

  magnetic field can cause problems for people with metal plates / screws or shrapnel inhuries

  need to stay extremely awake

  expensive

  claustrophobic
• What can an fMRI be used in? 


  Lie detections
• What does an fMRI measure in lie detection? 


  Bodily response, sweating, heart rate
• What is active when asked to generate false answers?

  Anterior cingulate cortex
• What is a problem when using fMRI in lie detection? 


  The anterior cingulate cortex is not active if you memorise the lie in advance