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PowerLab

ML317 EOG Pod

research

Applications

The EOG Pod is used to measure and display eye movement and position.

In the human the EOG Pod can be used in the measurement of saccadic

and pursuit eye movements. It is ideal for use in undergraduate teaching

laboratories.

The ML317 EOG Pod is a signal conditioner designed to record horizontal and

vertical eye position and movement. The device features a manual DC offset

and is supplied with three shielded lead wires with snap-on connectors.

System Compatibility

The EOG Pod connects to any PowerLab hardware units with Pod ports (8-

pin DIN inputs). PowerLab and MacLab (except 4s, 8s and 16s) units

without Pod ports require the ML305 Pod Expander.

The EOG Pod is supported by the following versions of LabChart and Scope

software:

WINDOWS

MACINTOSH

• LabChart v3.4.8 or later

• LabChart v3.6.3 or later

• Scope v3.6.3 or later

• Scope v3.6.3 or later

Note: Earlier software versions do not support Pods.

Theory of Operation

The EOG Pod is a DC coupled biopotential amplifier with a fixed low-pass

filter (500 Hz) to remove high frequencies. On the front of the Pod, an

offset knob is provided to remove DC drift. The offset control provides ±15

mV of offset range (at input) for all range selections.

The EOG Pod utilizes the steady corneal-retinal potential in the detection of

eye movement and position. This steady dipole may be used to measure

eye position by placing surface electrodes to the left and right of the eyes

(Figure 2). When the gaze is straight ahead, the steady dipole is

symmetrically placed between the two electrodes, and the EOG output is

approximately zero. When the gaze is shifted to the left, the positive cornea

comes closer to the left electrode, which becomes more positive. There is

an almost linear relationship between horizontal angle of gaze and EOG

output (approximately ±30º of arc). Electrodes can also be placed above and

below the eye to record vertical eye movements and using two EOG Pods,

simultaneous vertical and horizontal eye movements can be measured.

Specifications

Amplification Range

±2 mV, ±1 mV, ±500 _V, ±200 _V, ±100 _V

Pod Gain

x1000

Gain Error

±5% untrimmed, ±0.1% when calibrated

Frequency Response

DC to 500 Hz

Low Pass Filter

500 (fixed) 2nd order Butterworth

Temperature Drift

±3 mV/°C

CMRR

>80 dB

IMRR

>110 dB

Input Impedance

<100 M

Ω

Front Panel Control

offset knob for initial zeroing of device

Input Bias (Maximum)

±10 nA @ 25 °C

Input Connector

3 shielded lead wire connectors

Cable Length

1.5 m

Weight

200 ga

The ML317 EOG Pod is supplied with three snap-on connector shielded

lead wires which snap connect to conductive (Ag/AgCl) adhesive

electrodes (MLA1010).

Order #

Model

Product

PY2 77-0043 ML317

EOG Pod

PY2 77-0043 ML317 EOG Pod

CAUTION: Read “Statement of Intended Use” on our website

or in “Getting Started with PowerLab” before use.