Active-TwoActiveTwo is a powerful high-resolution biosignal acquisition system that incorporates some revolutionary concepts.  Active electrode technology is just one of the significant innovations in the ActiveTwo system.  By placing active electronics within millimeters of the actual electrode contact, ActiveTwo virtually eliminates the need to prepare the scalp before applying electrodes.  This can cut measurement preparation time by an estimated 15 -30 minutes for most laboratories!

ActiveTwo can also be equipped with additional sensors for respiration, skin conductance, temperature, plethysmograph (pulse) and other parameters.  An optional isolated analog input box makes it possible to acquire almost any type of signal synchronously with the signals sampled by the ActiveTwo A/D box.

As an added benefit, ActiveTwo comes with powerful data acquisition software developed in National Instruments’ LabView.  We provide the compiled software so you do not need to own LabView, and you do not need to be a programmer to operate the system.  For those laboratories with programming resources, the source code is provided so that you can add any special features that you may need.

Each ActiveTwo system is built upon a basic set of items known as the Base System.

Base Components:

  • A/D interface box with no amplifier/converter modules (no channels installed)
  • USB 2.0 interface box with USB 2.0 cable
  • Rechargeable battery unit – 2 each
  • Battery charger with A/C adapter
  • ActiView Data Acquisition Software

Typical Additional Components:

  • Amplifier/Converter modules – up to 32 8-channel modules per A/D interface box
  • Active Electrodes – A/D interface can accommodate up to 256 active electrodes in sets of 32 on high-density connectors and/or up to 8 with individual leads and touch proof connectors
  • Head Caps – with electrode holders and position labels
  • Active Electrodes – with individual leads and touch-proof connectors
  • Trigger Interface Cable
  • Optional Sensors – for galvanic skin response, respiration, temperature, or pulse/plethysmograph

Other Options:

  • Custom-configured auxiliary inputs on the A/D interface box.  These inputs are appropriate for use with battery-powered or self-powered signal sources such as a condenser microphone or a photocell.
  • Analog input box with up to 16 bipolar / 32 monopolar channels and fiber-optic coupling to main A/D interface box

You May Also Need:

  • Consumable supplies
  • Post-processing software
  • Electrode position measurement hardware/software
  • Stimulus delivery software
  • Behavioral response measurement hardware
  • Installation and training

In addition, you will need computers, monitors and interface cables/devices to streamline operation between operator area and subject chamber.  We find that most customers prefer to source these items through their normal channels.  If you prefer to have us provide these items, we can do so if it is more convenient for you.


ActiveTwo EEG (9)

High density surface EMG as described in the recent publications on the Biosemi site is possible with the addition of the sEMG accessories. The original model of the high density sEMG probe was made for ActiveOne, so the connector differed. The current version separates the electrode grid from the preamp as in:

Less dense sEMG can be accomplished with an elastic fabric with electrode holders like the EEG cap stretched over a muscle.  This would need to be custom-made, but would not be expensive.

Fine wire EMG would require either spring contact adapters or safety socket leads with inline active headstage. If your fine wire electrodes will be stripped but unterminated, you need spring contacts, and if your electrodes terminate in safety sockets, you need inline adapters.

We expect the new reinforced ActiveTwo active electrodes to last 350-500 uses, based on our experience with the new product so far, and based on automated repeated-strain testing.

The way ActiveTwo electrode sets are built, they are not repairable by the end-user, but we can replace single electrodes for you. We can so this quickly (24 hours plus transit), efficiently, and at low cost (or free under warranty). Electrodes are warranted against material/manufacturing defects for one year, and we charge by the repair after that. We find that offering extended warranties motivates less careful handling, so we don’t offer extended warranties.

Follow the steps in this other FAQ to identify the problem before contacting us to ask about the procedure and the cost of a repair.

We do offer individual EXG pin-type electrodes that you can insert in the cap as substitutes for faulty ribbon cable leads. This would be a short term stop gap solution only. We strongly recommend having a backup set of electrodes on hand after a year or two so that if the first set needs repair, you can continue to run with the other set while the repair is undertaken. You would not need to buy the spare set right away — just budget to have it once the electrodes have had enough use that they may begin experiencing problems. 250-350 recordings is a good mark for when you should have a spare set of electrodes on hand.

You CAN install current versions of ActiView on Windows 10. But, before you do so, if the system was orignally delivered before January of 2017 you should update the firmware on the optical receiver / USB interface so that you do not have to go through the very long and arduous process of installing an unsigned driver on Windows 10.

You can update the firmware using any Windows 7 or 8 computer with the MSWinUSB2 driver installed, even if it is not the computer you have been using for ActiView. If you are just using a Windows 7 or 8 computer to update firmware on the optical receiver / USB interface, there is no need to install the LabVIEW Runtime Engine or ActiView on this computer. You WILL need the LabVIEW Runtime Engine and ActiView on the new Windows 10 computer, but you WILL NOT need to install a driver after the firmware update has been performed.

See the procedure outlined at faq/install_USB.htm for detailed instructions.  The section at the bottom marked IMPORTANT is the place to begin.

The positions in these caps come from the Oostenveld and Praamstra 5% system.  See for background and for links to electrode coordinates in a variety of formats. Depending on what software you are using for analysis, we might be able to provide another file format. The Biosemi channel assignments (relating electrode labels to electrode sites in the Oostenveld and Praamstra nomenclature) are below:

Chan1 A1 Fp1
Chan2 A2 AFp1
Chan3 A3 AF7
Chan4 A4 AF3
Chan5 A5 AFF5h
Chan6 A6 AFF1h
Chan7 A7 F9
Chan8 A8 F7
Chan9 A9 F5
Chan10 A10 F3
Chan11 A11 F1
Chan12 A12 FFT9h
Chan13 A13 FFT7h
Chan14 A14 FFC5h
Chan15 A15 FFC3h
Chan16 A16 FFC1h
Chan17 A17 FT9
Chan18 A18 FT7
Chan19 A19 FC5
Chan20 A20 FC3
Chan21 A21 FC1
Chan22 A22 FTT9h
Chan23 A23 FTT7h
Chan24 A24 FCC5h
Chan25 A25 FCC3h
Chan26 A26 FCC1h
Chan27 A27 T7
Chan28 A28 C5
Chan29 A29 C3
Chan30 A30 C1
Chan31 A31 TTP7h
Chan32 A32 CCP5h
Chan33 B1 CCP3h
Chan34 B2 CCP1h
Chan35 B3 TP9
Chan36 B4 TP7
Chan37 B5 CP5
Chan38 B6 CP3
Chan39 B7 CP1
Chan40 B8 CPz
Chan41 B9 TPP7h
Chan42 B10 CPP5h
Chan43 B11 CPP3h
Chan44 B12 CPP1h
Chan45 B13 P9
Chan46 B14 P7
Chan47 B15 P5
Chan48 B16 P3
Chan49 B17 P1
Chan50 B18 Pz
Chan51 B19 PPO9h
Chan52 B20 PPO5h
Chan53 B21 PPO1h
Chan54 B22 PO7
Chan55 B23 PO3
Chan56 B24 POz
Chan57 B25 PO9
Chan58 B26 POO9h
Chan59 B27 O1
Chan60 B28 POO1
Chan61 B29 I1
Chan62 B30 Ol1h
Chan63 B31 Oz
Chan64 B32 Iz
Chan65 C1 Fpz
Chan66 C2 Fp2
Chan67 C3 AFp2
Chan68 C4 AFz
Chan69 C5 AF4
Chan70 C6 AF8
Chan71 C7 AFF2h
Chan72 C8 AFF6h
Chan73 C9 Fz
Chan74 C10 F2
Chan75 C11 F4
Chan76 C12 F6
Chan77 C13 F8
Chan78 C14 F10
Chan79 C15 FFC2h
Chan80 C16 FFC4h
Chan81 C17 FFC6h
Chan82 C18 FFT8h
Chan83 C19 FFT10h
Chan84 C20 FCz
Chan85 C21 FC2
Chan86 C22 FC4
Chan87 C23 FC6
Chan88 C24 FT8
Chan89 C25 FT10
Chan90 C26 FCC2h
Chan91 C27 FCC4h
Chan92 C28 FCC6h
Chan93 C29 FTT8h
Chan94 C30 FTT10h
Chan95 C31 Cz
Chan96 C32 C2
Chan97 D1 C4
Chan98 D2 C6
Chan99 D3 T8
Chan100 D4 CCP2h
Chan101 D5 CCP4h
Chan102 D6 CCP6h
Chan103 D7 TPP8h
Chan104 D8 CP2
Chan105 D9 CP4
Chan106 D10 CP6
Chan107 D11 TP8
Chan108 D12 TP10
Chan109 D13 CPP2h
Chan110 D14 CPP4h
Chan111 D15 CPP6h
Chan112 D16 TPP8h
Chan113 D17 P2
Chan114 D18 P4
Chan115 D19 P6
Chan116 D20 P8
Chan117 D21 P10
Chan118 D22 PPO2h
Chan119 D23 PPO6h
Chan120 D24 PPO10h
Chan121 D25 PO4
Chan122 D26 PO8
Chan123 D27 PO10
Chan124 D28 POO2
Chan125 D29 O2
Chan126 D30 POO10h
Chan127 D31 Ol2h
Chan128 D32 I2


ActiveTwo is provided with drivers and host data acquisition software for Windows and Mac computers, and drivers also exist for Linux. Note that certain applications, such as event-related potentials, often require a separate computer to run experimental control / stimulus delivery software.

In brief, the computer requirements for the ActiView data acquisition software are:

  • Operating system: Windows 7, 8, or 10 or Mac OS X
  • RAM: 8 GB or more
  • Hard Drive: recommend 250 GB, but user should anticipate free space needed for data (file size in bytes is approximately = 3 X AD rate in Hz X number of channels X number of seconds recorded)
  • Display: 1440 X 900 or higher resolution display
  • One free USB port

Note: The ActiveTwo computer DOES NOT NEED A PARALLEL PORT.  A parallel port on the experimental control computer can be used to send stimuli to ActiveTwo.

In addition, the following are recommended for the ActiView computer:

  • Network interface and remote storage for data backups
  • Accessories such as KVMA switch box, extra monitor / keyboard / mouse, extension cables, etc to permit access to the EEG display from the separate room for the subject

The ActiveTwo Base System has no channels. The Base System consists of the parts that every ActiveTwo system needs to have, but excludes the parts that are used to custom configure ActiveTwo for various purposes, like amplifier/converter (AC modules).  The AC modules give the system the capacity to record from active electrodes. With four of the eight channel modules, the base system will have the capacity for 32 channels. If you want 32 electrodes on the scalp, then you need four modules, but if you also want to use four individual flat-type electrodes, you need another eight-channel module (four modules for EEG and one module for EXG1-8). The modules have eight channels, so you can only expand the system in increments of eight channels. You don’t have to buy the electrodes to use with EXG5-8, but you need the eight channel module.

Maybe.  There is no way the EEG system can harm the TMS system, but there are some TMS systems that are essentially useless with some EEG systems.  You need a a suitable combination of features in each to be successful at all in using TMS with EEG.

Desirable attributes:

  • Coils designed specifically for use with EEG will have a cable that exits the coil tangential to the head surface so that the coil does not pass close by EEG electrodes and cables.
  • A coil to be used with EEG should be passively cooled, since active cooling by means of a fan will induce electromagnetic interference in the EEG.
  • The TMS recharge mechanism should be designed to avoid inducing electromagnetic artifacts in the EEG.
  • The TMS system should be shielded so that no more than 3 milligauss of electromagnetic interference from the TMS system’s power supply reaches the electrodes and cables.
  • The TMS system should be able to produce a TMS pulse in response to an input trigger with a low and predictable latency.  Long, but especially unpredictable latency in responding to an input trigger will result in TMS artifacts that are difficult to impossible to remove from the EEG.

Aside from attributes of the TMS system, there are also important considerations regarding the EEG system in this relationship. See the other FAQ entry on that topic.

Electrodes and head caps can have positions derived from systems based on the International 1020 System.  When the positions are based on 1020, the labels on the caps and electrodes can either be the actual 1020 position names (such as Fp1, Cz, etc) or they can be what is called ABC, which actually means A1, A2, …A32, B1, B2,…B32, etc  Another way to refer to the ABC labeling is arbitrary alphanumeric.  The 1020 system is not arbitrary because the names are based on anatomical landmarks and the odd=left and even=right numbering is predictable and interpretable.  When you have only one type of cap in your lab, it makes sense to use 1020 labels for caps with positions based on the 1020 system.  However, if you have 32 channel caps AND 64 channel caps, then you might find it useful to be able to use the A1-32 labels for the A cable and the B1-32 labels for the B cable and complementary A1-32 labels on the 32 channel caps and A1-B32 labels on the 64 channel caps.  This way, the A cable can be used for the whole head in 32 channel studies of for just the left side of the head in 64 channel studies.  This does provide a short term savings if you don’t want to have two A cables on-hand, but using 1020 labels on everything is more convenient and at the limit it will not cost any more (because cables that are used less frequently will last longer).

The inside diameter of adhesive ring should be about the same size as, or larger than, the diameter of the electrode contact.  The inside diameter of the adhesive ring should not be larger than the outer diameter of the electrode housing.  The outside diameter minus the center hole determines how much surface area contacts the skin, thus determining how tightly the adhesive will adhere to the skin.  Also, the outside diameter will limit how close you can place electrodes to one another and to other features, such as the eyes.

Using ActiveTwo as an example, the electrode contact on a flat-type electrode has a diameter of about 4.5 mm.  An adhesive ring with 5 mm id (center hole) would be  idea, but the 5×13 adhesives are rather expensive because they are manufactured in Europe.  We recommend using a 4×19 or a 4×12 adhesive ring.  The 4×12 is a good choice when placing the electrodes close to one another or close to the eyes for startle measurements.  The 4×19 is a good choice when you have plenty of room and the primary concern is how well the electrodes stick to the skin.


This is a sample list of some recent publications.  For more, visit Google Scholar.