8- Bioelectrical signals from the central nervous system Flashcards
(37 cards)
Cite the four main part of the brain.
1- Brain stem-medula oblongata and pons
2- Thalamus
3- Cerebellum
4-Cerebrum
Describe the Brain stem-medula oblongata and pons
Connections from higher areas to the spinal cord and vice versa
Describe the thalamus
Essential link and integration center in transfer of sensory information from periphery to cerebral hemispheres
Describe the Cerebellum
Fine tuning of mvts, learning motor skils, balance and coordination, eye movements.
Describe the Cerebrum
Cerebral cortex, 2-3mm thick
Where are located motor areas ?
Parietal and frontal lobes
where are located visual areas ?
Ocipital lobe
where are located auditory areas ?
Temporal lobe
Where are located sensory areas?
Central/parietal lobe
When was discovered the EEG ?
In 1919 by Hans berger, published in 1929.
What is the idea behing “relative placement” in EEG ?
The distribution of electrodes depends on the surface area of the skull. Electrodes are placed 10-20% steps (% of total longitudinal distance front to back) guided by anatomical landmark.
Describe the electrodes used for EEG
Ag/AgCl (silver chloride) discs with long cables, 1 to 3mm of diameter, electrode-skin impedance <10K(omega)
Describe the amplification sys used for EEG.
Amplification >10power6.
Signal amplitude resolution approx. 1µV, requires low input noise.
High input impedance
preamplification close to the electrode is preferable but expensive
Filtering to selectively record specific F ranges
Bandwidth ca. 1-100 Hz.
What are the two technique for recording EEG ??
Unipolar recording or bipolar recording
What is the principle of unipolar recording EEG ? then what is bipolar ?
Unipolar : One recording spot and a ground electrode. You take the opposite hear as reference.
Bipolar : Two contacts close to eachother and we record in between them. We sitll have a ground siting. You always record one electrode versus the other.
What is the advantage of bipolar recording for ECG ? what are the cons ?
You really get the difference of potential in the small field.
Cons : the diff of potential at a short distance is smaller.
Which caracteristics of the EEF signals can be defined ?
Waveforms
Frequency bands
What depends on the spatial resolution of the recording ?
It depends on the electrode location.
What can EEG signals (waves) can inform on ?
Different phase of wakefulness (relaxed, wakeful, sleepy, asleep, deep sleep or coma)
What changes between different brain waves ?
Amplitude or frequency
Can you define EEG along the development of the brain ?
It changes during childhood an generally slow down during adulhood.
What are the most prominant EEG features that helps to detect anomalies ?
Excessive amplitude
Spikes
Waves
What EEG features can define seizures in epilepsy ?
Waves and spikes
What EEG features can define encephalitis ?
Slow waves and abnormal potentials