Flashcards
Human Neuroimagining
Cards in this deck (19)
- 1What are examples of structural imaging techniques?- Provides a picture of brain anatomy
- CT Scans
- MRI Scans
- DTI - 2What are examples of functional imagining techniques?- Provides a picture of brain activity
- PET Scans
- fMRI
^ These are haemodynamic techniques = rapid delivery of blood to active neural tissues - 3What does structural imagining involve?It provides a picture of brain anatomy.
Based on differential absorption of x-rays by different tissues (e.g. brain and skull), particularly the ventricles. - 4Explain CT Scans- Structural imagining technique
- Passing a narrow x-ray beam through the same object at many angles, creating many images
- Images are manipulated using computing and mathematical techniques to create 3D images - 5Explain MRI Scans- Structural imagining technique
- Large magnet and specific radio-frequency pulse generates a brain signal that produces an image
- Used to study brain anatomy and neural function
- Great spatial resolution - proton density is different in different neural tissues - 6Explain DTI- Structural imagining technique
- "Diffusion tensor imaging"
- based on differential ability of water molecules to diffuse in different direction in white matter
- good for fibre tracks because of the longitudinal and cross-sectional difference in diffusion - 7E- Images show radioactive isotopes in active neural tissue
- Requires injection of radio labelled isotope (e.g. glucose/oxygen) - 8Explain fMRI- Detects changes in regional cerebral blood flow
- blood changes MRI signal
- Brightness in fMRI images = when part of the brain is very active, it releases a messenger to the local arteries, released retroactively by active neurons, and causes the arteries to expand, causing more blood flow to the region - 9Examples of haemodynamic techniques- PET
- fMRI - 10Examples of electrophysiological techniquesBased on measuring electromagnetic fields, generated by ionic current flow in active neurons
- EEG
- MEG - 11Explain EEG- measures the potential differences on the scalp
- they bend because it takes the path of least resistance and when you encounter discontinuity, the tissues will bend so they're discontinuous on the skull - 12Explain MEG- measures the extracranial magnetic fields
- different property - areas like skull and scalp dont matter because they're completely transparent to magnetic fields so there is no distortion
- better spatial resolution than EEG - 13Statistical analyses of functional brain images- individual brains must be normalised to a standardised size and shape
- done by digital warping and rotating images
- Two standard template brains
1. Talairach Atlas: based on single well-characterised brain
2. Montral Neurological Institute Atlas: based on average of several hundred MRI scans - 14Evoked vs intrinsic brain activity- Evoked: Event related responses
- Intrinsic brain oscillations: (particularly electrophysiological) (includes fMRI resting state, EEG/MEG brain rhythms) - 15Theta OscillationsEncode various sequences of episodic memory
- 16Beyond Blobology- "Looking at individual blobs that get activated to define tasks and looking at networks"
- 17Reproducibility Crisis- concerns about the reproducibility of biomedical and scientific results
- These problems are particularly acute in neuroimagining
- Open science movement aims to address these issues via
1. Pre-registration: register hypothesis before experiment
2. Data sharing: with other researchers - 18Imagining in clinical psychiatry- diagnoses in psychiatry are based entirely on behavioural, not biological criteria
- established view in psychiatry: "brain imagining has no role to play in routine clinical care" - 19Why is neuroimaging not very useful in clinical psychiatry?- low specificity, sensitivity, and standardisation of current imaging protocols
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- Neuropsychology Flashcards on Human Neuroimagining, created by Tess San on 07/09/2018.
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- Tess San
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