EEG lab

The EEG lab (room K.13) allows for conducting EEG experiments. The lab provides EEG equipment in the test room, and a stimulus PC and a data acquisition PC in the control room.

Relevant how-tos

Relevant how-tos are linked here.

Technical specs

Test room

• Approx. 10 m² with a window allowing daylight to come in
• A pan-tilt-zoom camera allows capturing the participant’s activity in the room
• Table for debriefing the participant
• Participant desk and adjustable chair (up/down)
• Sink to wash electrodes

Biosemi Analog-To-Digital (AD) boxes

ActiveTwo MkII Analog-to-Digital-box: EEG (details)

• For recording cortical responses or electroencephalography (EEG)
• serial: ADC 16-11-803
• Compatible with pin or flat-type active electrodes
  • ‘Active electrodes’ entails that signal amplification occurs very near the recording site (minimal inference)
• Amplification is via direct current coupling (DC coupling)
• Both type of electrodes have a build-in high-pass filter (this is needed to prevent aliasing)
  • fifth-order filter that is -3 dB at 1/5th of sample-rate (e.g. 3.3kHz at 16kHz sample rate or speedmode 7/9)
• LSB for standard electrodes is 31.25 nV (1/32th microvolt)

Graph shows the signal diminishing. One equals the dynamic sample rate (e.g. 16 kHz). Taken from the Biosemi website.

Graph shows the signal diminishing. One equals the dynamic sample rate (e.g. 16 kHz). Taken from the Biosemi website.

ActiveTwo MkII Analog-to-Digital-box: ABR (details)

• Special for recording auditory-brainstem Responses (ABR) or frequency-following response (FFR)
• serial: ADC 17-14-1114
• Amplification is via alternating-current coupling (AC coupling; still uses the battery)
  • From the Biosemi website: “In the ABR setup, the difference between a pair of electrodes is digitized after (high gain) AC amplification, whereas with the standard electrodes the voltage with respect to CMS is digitized after (low gain) DC amplification (and the difference between channels is calculated in software).“
• Needs to be operated in speedmode 9 (ABR mode)
• Requires the use of special flat-type active electrodes that have less noise but have–in addition the the low pass mentioned earlier–
  • This filter is an high-pass filter in the electrode amp stage (first-order filter which is -3 dB at 100 Hz)
  • AC input range 8 mV peak-to-peak (AC amplification)
  • DC input range ± 250 millivolt
  • noise over the the full bandwidth less than 4 microvolt peak-to-peak
• CMRR > 150 dB
• LSB for ABR electrodes is 488 pV (1/2048th microvolt)

 

ActiveTwo MkII Speedsettings

AD-box switch

Sample-rate

Pin channels + EX channels + Sensor channels

0	Daisy-chain mode:In speedmode 0 to 3, the AD-boxes work as up to 4 optical fiber ‘daisy chained’ boxes, each with a maximum of 128+8 channels+sensors @ 2 kHz, speedmode switch = box number. (0=Box1, 1=Box2, 2=Box3, 3=Box4). Daisy chain mode requires an extra fiber input to be installed on the front of the AD-box. (Not done at the ILS Labs. equipment)
1
2
3
4	2048 (2 kHz)	256+8+7
5	4096 (4 kHz)	128+8+7
6	8192 (8 kHz)	64+8+7
7	16384 (16 kHz)	32+8+7
8 (AIB-mode)	2048 (2 kHz)	256+8+7+32AIB
9 (ABR-mode)	16384 (16 kHz)	5

BioSemi equipment

• Two 64-channel electrode sets: C1+2, and D1+2.
• Three 32-channel electrode sets: E, F and G.
  • Note: bundles are shared with K.13, so they might be located there. Please coordinate this with any other EEG experiment currently running
• Galvanic Skin Response module (GSR)
• Respiration belt. Nihon Kohden TR-753T.
• Headcaps overview
  • Note: headcaps are also shared between K.02 and K.13
• Biosemi manual for handling the electrodes

History/status of EEG bundles

ID           Lab ID         Status
====================================================
FR19-009794  64Set E1       In use (red shielding)
FR19-009638  64Set E2       In use (red shielding)
FR23-012980  64Set L1       In use (red shielding)
FR23-012737  64Set L2       In use (red shielding)
FR23-013226  64Set M1       In use (red shielding)
FR23-013207  64Set M2       In use (red shielding)
FR23-013219  64Set N1       In use (red shielding)
FR22-012796  64Set N2       In use (red shielding)


FR19-009562  Bundle H       In use (red shielding)
FR17-008213  Bundle G       In use (red shielding)
FR23-013000  Bundle I       In use (red shielding)
FR23-013007  Bundle K       In use (red shielding)

Old bundles no longer in use

FR10-001963  Set A1         Beyond repair
FR10-001949  Set A2         Beyond repair
FR10-001964  Set B1         Beyond repair
FR10-001945  Set B2         Beyond repair
FR17-007647  Bundle E       Decommissioned (demo unit)
FR10-001982  Bundle F       Beyond repair

FR14-004527  Set C1         Decommissioned
FR14-004520  Set C2         Decommissioned
FR13-004469  Set D1         Decommissioned
FR14-004530  Set D2         Decommissioned
==============================================

Auxiliary equipment

• Galvanic skin response
• Insert earphones for EM noise reduced audio stimulation
• Respiration belt, manual

Internal equipment (in the test room)

• 21,5″ LCD (TN panel) Iiyama B2283HS (native 1920 x 1080 at 60Hz, response time 2ms),
• (optional) keyboard
• (optional) buttonbox
• 2x Tangent evo e4 Two-way speakers 10-150 W rms
• Logitech c920 Webcam
• AiPhone intercom, wall mounted

External equipment (in the control room)

• Presentation PC GW-LAB-EEG-01 (Dell 3640):
  • Dual monitor setup (vertical): 2 x iiyama Prolite E2273HDS 22″ (1920×1080)
  • Windows 10 64-bit or Ubuntu Mate 20.04
  • 16GB DDR4 (2x8GB) RAM
  • Intel Core i5-10500 CPU
  • Intel HD Graphics 620
  • 2 Parrallel port card
  • Creative Soundblaster Audigy 5/Rx (Sound card)
  • BioSemi I/O Card: optical out, ActiveTwo usb receiver

• Recording PC GW-LAB-EEG-02 (Dell 3640):
  • Single monitor on desk: 1 x iiyama Prolite E2273HDS 22″ (1920×1080)
  • Single (portable) monitor in cabin: 1 x Asus 15″ ZenScreen (1920×1080)
  • Windows 10 64-bit or Ubuntu Mate 20.04
  • 16GB DDR4 (2x8GB) RAM
  • Intel Core i5-10500 CPU
  • Intel HD Graphics 620
  • Connected to webcam inside cabin
• AiPhone LEF-3 intercom
• Sony integrated stereo amplifier, model: TA-FE230, 120W, super legato linear
• Small ‘Faraday cage’ cardboard box
  • Holds all the coiled cables to prevent them acting as antennes for electrectromagnetic noise an project it into the test room