Presented by Shu
Mapping Brain with Diffuse Optics
- Optical methods as alternative to MRI or PET (which are not electronic embedded device compatable, e.g. parkinson’s deep brain stimulator or pacemakers or young children).
- Compare IR specta at 750 and 860, distinguish oxygenated vs. deoxygenated hemoglobin (Onaral lab, Drexel)
- measure backscattered light in these wavelengths
- penetration depth of up to 1 cm into brain regions.
- tradeoff in head coverage vs. spatial resolution
- sensitive to haemodynamics in superficial tissue (e.g. scalp / non-brain activity)
- no structural information (shape of head, where photons came from).
- usse fMRI to generate head model. (get head shape).
- 96 sources and 92 detectors -> 1200 usuable source detector pairs.
comparison to fMRI
- see pretty good correlation with fMRI and known brain region – function correlations.
- e.g. audio processing, visual processing etc.
- can correlate activity from different brain regions to pull out connectivity.
- analyzed in resting state networks — just getting correlated connectivity, not necessarily progressive transforms of thought.
- some subjects show better and worse correlation to fMRI