ch 7 - brain imaging (more) Flashcards
Electroencephalography (EEG)
non-invasive way to record electrical activity by using electrodes
also, (ERP and MEG)
Single-cell recording
electrodes are inserted into an individual neuron - they are recorded to see corelation between activity and behaviours
*context of the activity seems important in neuronal firing patterns
States of conciousness: Beta
high-freq + low-amplitude = alert
States of conciousness: alpha
low-freq + high-amplitude = relaxed
States of conciousness: delta
lowest-freq + highest-amplitude = sleep
(in a coma freq is even lower)
EEG of partial sezures
coordinated activity is limited to a few regions of the brain
EEG of generalized seizures
the activity can be see spreas over the ENTIRE brain
Coherence theory
suggests that there is a relation between the EEG activity and behaviour
Lie Detectors
Coherence theory: high coherence
- low-freq + high-amplitude = coordinated activity of neurons, but low cognitive load
Coherence theory: Low coherence
high-freq + low-amplitude = firing at different times, activley processing information
Event-related Portentials (ERP)
Deeper information based on the recordings of an EEG
ERPs are used to study perception, attention, memory, and decision-making, as they provide precise temporal information
Deep-brain stimulation
implanting electrodes in brain
- stimulating the region at freq to treat parkinsons, epilepsy, OCD, depression
-research is underway trying to perform DBS without invasive implants
Transcranial Magnetic stimulation (TMS)
TMS uses magnetic field to stimulate or inhibit neurons
can be used to treat pain, movment disorders, and depression
Computed Tomography scan (CT)
X-rays pass at angles for a 3-D recording
resolution: 1-mm cube called a Voxel (volumetric pixel)
Magnetic Resonance Imaging (MRI)
Radiofrequency energy pulls protons in H atom to 90° and they give off energy as this happens which can be recorded
T1: measure time for proton to re-orient
T2: measures time it desynchronizes when turned off
T1 + T2: maps the tissue
Diffuser Tensor Imaging (DTI)
Maps the movement of water molecules
Functional MRI (fMRI)
shows more active regions of the brain by detecting oxygen-carrying hemoglobin
there is a contrast between oxygenated hemoglobin and deoxygenated hemoglobin
Resting-State fMRI (rs-fMRI)
looks at activity of brain when not engaged in activity
same as fMRI but for recording base stats
Positron emission tomography (PET)
uses radioactive tracers (can be invasive)
