This review refers in places to installing resources from the A-V Library, but it applies to installing any sort of additional resources.

1. Channels and Channel Sets: This discussion is for the Nexus-10 but applies, in general, to the other Nexus amplifiers as well. On the outside of the body of the Nexus-10 there are 10 input plugs (and one ground connection) which receive streams of electrical data from sensors applied to the client. The first two plugs (from left to right after the ground) on the Nexus-10, named “A&B” and “C&D” accept a total of 4 inputs (2 each). The remaining plug connectors accept one sensor each. The sensors are attached to the client’s body and measure electrical changes. The Nexus measures the electrical changes and converts them into streams of numbers that can be manipulated and graphed by the software. You have probably seen some of the raw data streams presented on the line graph instruments on Nexus screens.

Monitoring and feeding-back physiologic data means taking those raw data streams and calculating useful information from them For example, from the raw electrical activity of the heart we could calculate heart rate and heart rate variability. From the raw electrical activity of muscle we could calculate the average magnitude. From the raw electrical activity of the scalp we could calculate amplitude of various clinical bands such as alpha. The Nexus-10 comes with 70 of these common calculations built in to what is called its “default channel set”. The raw data from the Nexus comes into the computer as up to 10 streams of data, depending on how many sensors are plugged in. Then the additional 70 channels in the default channel set provide the mathematical formulae for processing and calculating additional data. Thus there are 10 raw and 70 derived (also called virtual) channels, i.e., 80 channels total.

Think of a channel set as a software operation that turns those 10 raw streams of data into 80 manipulated streams. The first ten of those 80 streams are the raw unprocessed data directly from the sensors (after having been sampled and converted to digital values that can be plotted or manipulated.) The remaining 70 data channels are called “Virtual Channels” or “Derived Channels” because they are calculated from some combination of the actual 10 or less sensor inputs.

While Sensor Channel A may have the raw moment-to-moment voltage fluctuations of the heart muscle, a derived channel can tell you the heart rate or even the heart rate variability. Channel B may have the raw moment-to-moment fluctuations of electrical activity of the brain at a point on the scalp. But channels derived from B can calculate the instantaneous amplitudes of different frequency bands in the EEG, such as theta and beta, and feed that data to your software screen.

If you need a special set of calculations that are not provided among the 70 derived channels of the default channel set, you can design a custom channel set. This is an advanced topic but the skill is easily acquired.

All the screens that come with the Nexus are attached to the default channel set. If you attach a different channel set the on screen instruments may calculate their display values differently, or they may not work at all. That will become more understandable after we talk about instruments and screens.

2. Instruments and Screens: When you look at a Nexus screen you see a variety of bar graphs, line graphs, numerical readouts, spectral displays, and perhaps animations. These are called “screen objects.” They are also called “virtual instruments,” or just “instruments.” They are usually connected to one or more channels, and like a real instrument they display some aspect of the actual raw or derived data streams, depending on the attached channel set. When you right-click on these instruments you see a set of menu choices that take you to secondary dialogue windows that enable you to adjust the properties of these instruments. Some of the instruments, mostly the bar graphs and line graphs, allow you to set threshold levels. You can tell the program what to do when an instrument value is either above or below the threshold.

A “screen design” (also called a “screen set”) is a set of screen objects, many of which are connected to individual channels in the attached channel set. Each screen set must be linked to a channel set in order to function. By default new screen designs attach to the “default channel set”. Custom designed screens, like ours, may be attached to customized channel sets. That way if you open a screen which requires something other than the default channel set calculations, the correct channel set will load automatically. Be cautious. During a session you can not change between screens that have different channel sets. The results can be unpredictable.

A screen is usually organized around a particular goal. Goals include 1) signal checking, 2) signal acquisition, 3) physiological assessment, 4) training, and 5) statistical review. The screens we are talking about using here are all associated with training (biofeedback or neurofeedback).

In the bar graphs and line graphs that we use for biofeedback training we can set a threshold and we can choose what action is to take place when a signal, measurement, or calculation goes over or under the set threshold. For example, you can set the software so that as finger temperature goes up, the volume of an audio mp3 file will increase proportionately. Another example – you can set the feedback on a bar graph displaying SMR EEG amplitude so that when the current value falls below your set threshold BioTrace+ will “inhibit all feedback” and a video will stop playing.

“Inhibit all feedback” is an important setting in our case. This is because the actual video and DVD replay instruments only have two settings – 1) Pause video during inhibit, and 2) Shrink video during inhibit. You can toggle either or both of these settings off or on. Regardless of those settings, the video or DVD will play constantly until it receives the signal “Inhibit all feedback”. Thus, for example, if the SMR EEG amplitude falls below threshold, the SMR EEG amplitude instrument sends an “inhibit all feedback” signal to the “video replay instrument”, and the video pauses and/or shrinks. If the client can keep his or her SMR EEG above threshold, then the video will keep playing. With Nexus you can have a DVD or video playing on a second monitor in front of the client, and when your instrument goes below threshold and sends an “Inhibit all feedback” message, the clients monitor will stop playing the DVD or video.

3. File Directory Structure: This next section assumes that you know how to navigate Windows to browse through the folders and files on your hard drive. If you do not, please take some time with a good Windows tutorial or friend and learn. At some point you will be very glad you did. In Windows XP you can double left-click on an icon on your Windows XP screen called “My Computer”. This will open a window where you will see resources including your hard disk drives. If “My Computer” does not open then left click once on a blank part of your screen, then double left click “My Computer” again but faster. Alternatively, you can left click once on “My Computer” and see it “selected”. Then right click on it to display a smaller “context sensitive” window from which you can select “Open”. Most computers have only one disk, called “Local Disk (C:), but some computers have more. Double left-click on “Local Disk (C:)” and you will see a list of folders and files on your “C:” drive. Look for the one called BioTrace and double left-click on it. [ In rare cases your BioTrace+ software may have been installed on Local Disk (D:). ] You should see something like the following.

After the last folder you see the file “BioTrace.exe”. This is the actual software program that is run when you first click on the BioTrace+ icon on your screen. At various times, and depending upon the screens you are using, BioTrace.exe uses files from the other folders, such as Animations, Audio, Channels, Screens, Video, and others which you can see in the above figure.

4. Adding new screens and channel sets to your Biotrace system: This is rarely a problem (and will be described below). However, some video files are very large and may cause a problem with your computer in general. You can not damage BioTrace+ by adding files to these folders, but if your hard drive is small, or already nearly full, you can quickly fill up critical disk space and your system and software performance may deteriorate.

If you don’t know how much disk space you have left on the drive that contains BioTrace+ (usually C), then please double click on My Computer again. You will see a list of your drives and the “Free Space” remaining.

CAUTION: The amount of free hard disk space on drive “C:” should NEVER be allowed to be smaller than twice the amount of RAM memory installed on your computer. Otherwise, your performance is likely to suffer.

If you don’t know how much RAM you have on your computer then assume you have at least 2 GB. So the amount of hard disk free space remaining after copying the new resources (screens, video, audio, etc.) should never be allowed to fall below 4 GB. You can find out how much ram you have by right clicking "My Computer" then left clicking "Properties" and reading the information.

Insert the disk with your new Nexus resources in your computer’s CD/DVD drive. A few moments after insertion you may get a popup window asking you what you want Windows to do. You may be given choice to play videos, play media files, copy files, etc. The only option to choose is one that says something like “Open folder to view files using Windows Explorer”. By double clicking on this option another window will open like the one for BioTrace+ above. If it doesn’t open, or if you are not comfortable with this process then do the following.

If necessary, cancel the dialogue window where your computer asks you what to do with the inserted disk. Keeping your window with BioTrace+ folders on your desktop, double left-click again on My Computer. This time navigate to the drive containing your CD. This will usually be drive (D:) but it may be (E:) or higher if you have multiple drives inside or attached to your computer. Your CD/DVD drive will probably be listed as “Devices with Removable Storage”. It may look like “CD/DVD-RAM Drive (D:) CD Drive”. Double click on it. Now you will also be able to see what is on your new Nexus resources disk.

At this point you should see two “explorer” windows on your screen. In the explorer with the new resource files you will usually see several files and several folders. The files often are ".txt" and ".pdf" files that contain the most current information for installing your resources. If you have not read the documents on your new CD yet, you should read them now. When it is time to install your new Nexus resources you should note folders on your resource disk with names like "Animations", "Audio", "Channels", "Protocols", "Screens", "Videos". These folders all contain files that can be transferred to the similarly named folder in your BioTrace directory in the other explorer window. In all the folders just mentioned you are likely to see single files except in the "Screens" folder where you will often find a subfolder. The entire subfolder needs to be copied to your Biotrace "Screens folder". If you have not yet explored the contents of the various folders in your Biotrace directory, now would be a good time to do so.

Here is how you copy files from your resource CD to your Biotrace folders. If you have a resource folder called "Channels" double click on it and examine the contents. These files need to be dragged "into" the "Channels" folder in your Biotrace directory. Find the first file to transfer and left click on it once and release the mouse button to select the file. Pause a moment. Then while still pointing at the file press and hold down the left mouse button. While holding down the mouse button, drag the file (move the mouse pointer) from the from the resource CD over to the "Channels" folder in BioTrace+. When your mouse cursor is precisely over the folder, the folder should change color to indicate it has been targeted. At that time release the left mouse button. You may see a notification that the file is transferring. If you want to know if it really transferred, double click on the targeted folder in BioTrace+. You will now see all the files contained in that folder. Your new file should be there.

To copy screen designs you will follow a slightly different procedure. On your resource CD you will have a folder titled "Screens". Double click on it and examine its contents. If it does not have its own subfolder within it, in other words, if it only has single files, then you will have to open the Screens folder in your Biotrace window and decide which folder in which to place the files, e.g., "Favorites" or "My screens." Mostly likely your resource CD will have a subfolder within its screens folder. You must drag this entire subfolder into the screens folder of Biotrace. Caution: Do not drag a screens folder from your resource disk into a subfolder of the Screens folder in Biotrace. Your new screens folder must ultimately appear as one of the many folders in your screens folder.

Follow these guidelines to install the remainder of your files. Always be aware of how much disk space you have remaining.

5: For more information: Your Nexus Biotrace software comes with an excellent user manual. If you do not have the hard copy you can read it from within BioTrace+. You will find it under the help menu at the top of your screen. Your mentor is also a good resource. You can also contact the vendor of your new software or your Nexus technical support.

rev. January 14, 2009