Introduction to neurotechniques

structural and functional co-evolved

structural = brain anatomy

functional = investigate living dynamic brain

Pre-neuroimaging (structural)

lesion studies

study functional brain damage; relshp bet brain & beh

drawback: precise location of lesion only available after they died

Pre-neuroimaging (functional)

Angelo Mosso (pioneer of functional brain imaging)

link cerebral blood flow and cognition

studied using brain weight (apparatus), brain pulsations in newborns, exposed brains of skull defect patients

X-rays: wilhelm rontgen

doesn't work because of the lack of contrast

ventriculography/pneumoence...walter dandy: adverse side effects including death (drill hole in brain)

EEG: electroencephalography (Hans Berger)

1.measure brain function in real time 2. first measure of epileptic spikes 3. char of several stages of sleep

main use now: detect & char epileptic seizures +fMRI: which brain regions are involved

Commercial CT scan (Computed tomography); Godfrey Hounsfield. Also know as X-ray CT or CAT scan.

combine x-rays from many directions to reconstruct the volume or interest in slices

PET (most expensive) positron emission tomography

nuclear medicine technique > tag active mol of short lived tracer > injected into body

tissue tracer conc & location: computed by detecting gamma rays emitted as byproduct of decay of radioactive tracer.

tracers decay quickly (short half life), need to be produce onsite in cyclotron (expensive)

MRI

study brain structures 1.(high-res anatomical scanning)

  1. look at microstructural changes with diffusion tensor imaging (DTI)
  2. map white matter tracks in brain (distinguish gray matter (neuronal cell bodies) from white matter (myelinated tracts)

little hardware/software mods can be used for research

fMRI*

1.measure dynamc changes every couple of secs in whole bbrain during experimental tasks (task-based fMRI) 2. at rest (resting state fMRI)

modern-day phrenology: find discrete location of specific brain functions

spatial vs temporal resolution

3D structural: takes mins to acquire: Low temporal res.
High amt of details: high spatial res

fMRI: dynamic imaging. few secs to scan: high temporal res
poor amt of details in images: low spatial res

used to track normal/abnormal dev of neural
pathways in childhood