ActiveTwo

On-line support forums

• ActiveTwo forum at Biosemi.nl - BioSemi hosts an on-line forum for discussion of questions related to their ActiveTwo system.  This forum has evolved into a very useful resource for users and developers.


• Operating ActiveTwo - Google Group for discussion of the ActiveTwo Operating Guidelines booklet, slide presentation and other educational materials.
   

Frequently-asked questions

• What resources can a beginner consult to learn about EEG, EP and ERP methodology?


A few informative texts on EEG, EP and ERP do exist.  Here are a few recommendations:
• An introduction to the event-related potential technique.  Steven J. Luck.  August 2005.  MIT Press.  See details on publisher site.

• Event-Related Potentials: A Methods Handbook.  Todd C. Handy.  October 2004.  MIT Press.  See details on publisher site.

• The Cognitive Electrophysiology of Mind and Brain.  Alberto Zani and Alice Proverbio.  2003.  Elsevier Science.  See details on publisher site.

• Fisch and Spehlann’s EEG Primer: Basic Principles of Digital and Analog EEG-3rd Edition.  Bruce J. Fisch.  January 2000.  Elsevier Science.

• Spehlmann’s Evoked Potential Primer-3rd Edition.  Karl E. Misulis and Toufic Fakhoury.  April 2001.  Butterworth-Heinemann.
Recommendations for additions to this section are welcome.


• Which published papers address the technical rational behind recording from more than 64 EEG channels where source analysis is the ultimate goal?


There are many relevant publications supporting the use of more than 64 EEG channels in research applications, but here is one particularly good review article:
• Pflieger ME, Nakada T. The spatial resolving power of high-density EEG. In: T Nakada (Ed), Integrated Human Brain Science: Theory, Method, Application (Music). Elsevier Science B.V., 2000; pp. 147-91.


• What resources can a beginner consult to learn about digital signal processing?


See http://www.dspguide.com/ for links to a freely downloadable textbook on digital signal processing that comes highly recommended by our customers.


• Can ActiveTwo be used for concurrent EEG / fMRI studies?


A special MRI-compatible version of the ActiveOne system (the predecessor to ActiveTwo) did exist.  However, no MRI-compatible version of the ActiveTwo system exists. 

See f-EEG under the Products section to learn about a new purpose-built MRI-compatible EEG system we offer as of June 2009.

• What resources are available for ActiveTwo support?



1. ActiveTwo User Manual by Biosemi.  This booklet is provided on the software CD delivered with a new system.  Contact us if you need an electronic copy of the latest ActiveTwo User Manual.

2. ActiveTwo Operating Guidelines.  This booklet is provided on the software CD delivered with a new system.  Join the Operating ActiveTwo group on Google Groups if you need an electronic copy of the latest ActiveTwo User Manual. 

3. The Biosemi FAQ page.

4. The Biosemi support forum.

5. This web site.



• Can ActiveTwo accept analog inputs from other devices?


Yes.  ActiveTwo can be configured with auxiliary inputs appropriate for a variety of signal sources other than the active electrodes used to measure EEG, EOG, ECG and EMG.  We offer systems with built-in skin conductance, respiration temperature and pulse sensors, and we can offer systems with built-in auxiliary inputs for digitizing analog signals from other isolated signal sources.  An optional Analog Input Box can be added to the system to permit synchronous sampling of signals from unisolated or poorly-isolated AC-powered signal sources along with the signals measured by ActiveTwo.  For details, contact us to inquire about the compatibility of the specific device you would like to interface with ActiveTwo.


• Does ActiveTwo include all the software I will need to perform complete EEG, EP or ERP studies?


Probably not.  ActiveTwo includes free software, called ActiView, for data acquisition.  If you do not already have another program for post-processing (e.g. digital filtering, artifact rejection, averaging, topographic mapping), then you should consider investing in EMSE Suite or BESA.  For EP or ERP studies, you will also need software and/or hardware for presenting stimuli, such as Presentation or SuperLab.


• Can ActiveTwo be used as a portable system with a laptop computer?


A USB 2.0 interface is now provided with all new ActiveTwo systems and it is available as an upgrade for systems with the NI 6533 PCI card.  Note that you will need a fast laptop with at least one USB 2.0 port.  A 32-bit CardBus expansion slot with a USB 2.0 PCMCIA expansion card is a suitable substitute in case your laptop is not equipped with USB 2.0 ports.


• If I prefer to write my own software or use a tool like MatLab for post-processing, is it possible to get information about the ActiveTwo data format?


The ActiveTwo data format is fully described in a page maintained at the BioSemi website.  Code for reading ActiveTwo data into MATLAB is available in our downloads area.  For customers who would consider writing their own data acquisition software, note that each ActiveTwo system is provided with free data acquisition software.  ActiView is a LabVIEW application, and it is provided with full LabVIEW diagrams (source code).  ActiView is "open source" software, with customers adding their own features, and sharing their code and ideas with each other.


• Can the active electrodes and the head cap be disinfected?


Yes.  The active electrodes can be handled in a manner that would be appropriate for any standard electrodes – they can be immersed in soapy water or disinfectant solution.  The same is true for the head cap.  Note that the potential for degradation of the wire insulation and head cap material by caustic disinfectant solutions exists for ActiveTwo components just as it does for standard electrodes and head caps.  Be sure to immerse the electrodes and head cap in disinfectant solution only as long as is required according to the instructions provided with the disinfectant product.


• Is ActiveTwo compliant with safety standards like UL or CSA?


Yes.  ActiveTwo is designed to be well within the electrical safety guidelines prescribed by these standards.
  
 


• How are the various components of the ActiveTwo connected together.


See the downloads area for a diagram outlining the connections between various ActiveTwo components.

 


• What is the recommended arrangement of computers, monitors, keyboards and mice inside and outside the subject chamber for use with your EEG systems?


Visit the downloads area for a PDF document containing a diagram of the recommended locations and connections between computers inside and outside the subject chamber.
 


• What are the 3D coordinates of the electrode positions in the standard ActiveTwo head caps?


Visit the downloads area for an Excel workbook containing spherical coordinates of the ActiveTwo electrode positions.  Contains information on each of the standard ActiveTwo head cap layouts: 16, 32, 64, 128, 160 and 256 channels.  Custom configurations are available, and the coordinates of the electrode positions in custom caps are not reflected in this workbook.  Also provides a cross reference to relate the positions in the 128 and 256 channel ActiveTwo head caps to other standard electrode positioning systems.

• Can I use software such as Presentation, SuperLab or E-Prime to send trigger codes to ActiveTwo?


Yes.  ActiveTwo has a 16 TTL trigger input bits (in addition to 16 TTL trigger outputs) on the D37 connector on the optical receiver/USB interface.  Software programs that send triggers via a standard parallel port can be connected via a cable such as the one depicted in this diagram.  The unused bits 8-15 on the input port are shorted to ground in this design.  However, these additional 8 input bits could be used to record other trigger events from another computer parallel port, a response button box or another type of device.


• Can you tell me more about how the skin conductance sensor in ActiveTwo works, and how it should be used?


Background on the ActiveTwo skin conductance sensor is contained in this PDF document.

 

Downloads

• ActiveTwo system connection diagram, rev C - ActiveTwoSystemConnectionDiagram.pdf


• Excel workbook containing spherical coordinates of the ActiveTwo electrode positions. Contains information on each of the standard ActiveTwo head cap layouts: 16, 32, 64, 128, 160 and 256 channels. Custom configurations are available, and the coordinates of the electrode positions in custom caps are not reflected in this workbook. Also provides a cross reference to relate the positions in the 128 and 256 channel ActiveTwo head caps to other standard electrode positioning systems. - BioSemiHeadCapCoordinates.xls


• MatLab code to read BioSemi BDF format data files. - MatLabBDFOpenAndRead.zip


• Presentation to ActiveTwo Mk2 trigger cable - PresentationToActiveTwoMk2TriggerCable.pdf


• Background on the ActiveTwo skin conductance sensor and its predecessor, the galvanic skin response (GSR) sensor. - SCAndGSRMeasurementWithActiveTwo.PDF