Biopotentials

Broadband Neural Siganl
= Spikes(High frequency) + Local field potential(LFP, Low frequency)

Electrogram

1. Electrocardiogram (ECG)

Lead I, II, III

Standard line lead: bipolar measurement
두 개의 전극을 가지고 +/- input terminal에 연결
나머지 전극은 ground input에 연결

aVR, aVL, aVF

Augmented lead: unipolar measurement
한 lead를 (+), 나머지 두 개의 전극을 묶어서 (-) input terminal에 연결

2. Electromyogram

Intramuscular EMG

• inserting a needle through the skin
  Surface EMG
• placing the lectrodes on the skin

3. EEG

EEG Source

Excitatory input signal
Low frequency, Long period
Conduction signal(Action potential)
High frequency, Short period
All or None

1. dura mater, skin, hair 등 여러 장벽이 존재하기 때문에 약한 신호는 측정할 수 없다.
2. 측정하는 것은 그나마 강한 low frequency의 post-synaptic potential이다.

Scalp EEG measures summated activty of post-synaptic potential(sum of synchronous activty). It is impossible to determine the activity wihtin a single dendtrite or neruon from scalp EEG.

4. Biopotentials related with Vision

EOG Eye battery measurement(눈이 어디 방향으로 향해있는가)

• single dipole
• well established (0.4~1.0mV)
• moving dipole source

ERG electrical response of retina to optical stimulation

• a mass electrial response of retina to photonic stimulation

  

Visually Evoked Potential(VEP), EEP(retinal prosthesis)