fORP FAQs

I would like to try out your response pad before buying it. Where can I see it? We'll be exhibiting at several conferences in 2008 including ISMRM in May, Human Brain Mapping in June, and Neuroscience in November. Please stop by and try out our response devices.
With some fMRI equipment, we sometimes have problems with noise on the images. Is this something we have to worry about with your response pads? With an all-plastic, all-fiber system you don't have to worry about problems like intermittant noise that can arise unpredictably in any system with wiring in the magnet room. The electronic interface sits next to the computer, and everything after that is all plastic. All of our response pads and pointing devices are light-based, and contain no metal and nothing electronic.
We would like a matching electrical response pad for our mock scanner setup. Do you have a non-fMRI system like the fiber optic one? Yes. Our Trainers are electrical copies of our fiber optic button boxes. The 2 or 4 button boxes attach directly to the USB port of a computer (no additional power supply). An additional input functions as either a trigger in, or an optical screen refresh detector. Outputs are bootloaded through the USB port can include time stamping.
Our scanner has several different groups using the same fMRI equipment. Some people use EPrime, some people use Presentation, we use both Macs and PCs, and someone wants to use MatLab?. Which of these programs will work with your interface? All of them. Our interface is compatible with every program we know of, and then some. With Serial, Parallel and USB outputs, and 8 program options for each we've tried to cover all the bases.
I have an idea for a different type of response device I would like to use in an fMRI study. Do you make special "one-of-a-kind" systems? Yes. We are usually working on one or two special projects like this at any given time. Using components of our standard system we can usually complete special projects in a quick and economical way.
We would like a joystick and a response pad. Do we have to buy two complete systems? You just need to buy 1 interface and 1 fiber optic bundle, and the handhelds you want. We have 7 standards handhelds, including up to 8 buttons and two pointing devices.
For our study would like to have a handheld with two boxes, one with 2 buttons and the other with 5. Can you make this for us? Yes, we can make any special handheld you specify. Our interface can be used for up to 8 butttons, or 4 buttons and 2 continuous detectors. Depending on the handheld enclosure, special configurations cost about the same as our standard handhelds.
How long have you been making the fORP? We started making the fORP about 11 years ago. At first we just made them for a few people, but then people from other research sites started to call us. It's continued growing by "word of mouth" and the power of the web. By the end of 2006 the fORP was being used at hundreds sites in over 26 countries.
What happens if my response pad breaks? We'll fix it. It's under warranty for 1 year, so any malfunction is fixed for free. If it is caused by misuse then it is repaired at a reduced charge. After one year, we charge parts and labor.
What happens if I buy the fORP and don't like it? Please tell us what is wrong. We will try our hardest to fix the problem. If you still don't like it, send it back. We don't want anyone to be unhappy with our system.
I'm a MEG user and the sound of the button's clicking is a problem. Can you fix this? We have lots of MEG users and we make the button extra quiet for them. Just let us know when you place an order.
I like your response pads, but want the buttons in different places. Can you do this? We have no problem moving the buttons, or placing them in a different enclosure. We've done this for many customers. Our button are actually specially designed optical switches which can be mounted in a variety of ways.
What if there is something I don't like about the fORP? Please tell us. We've spent the past 10 years making the fORP better based on constant feedback from users. We really are interested in what your experience is, and will do what we can to make it better for you in the short and long run.
What are the TTL lines for? These are generally used by people using either the parallel port on their computer, or a special purpose i/o board. We can provide cabling for either case.
How does the program switch on the interface work? The switch is read when the interface unit is powered-up, so all you have to do if you want to run the interface with a different software package is a) select the program number you want, b) unplug the power connection and wait a few seconds, and c) plug the power back in.
How do I connect the trigger in? This depends a little on your scanner. Usually the hardest part is indentifying the appropriate output from your MR scanner. If it is a TTL signal, you can connect it directly to the BNC input on the interface unit. There's a helpful trick for debugging the trigger signal: With nothing connected to the BNC input, you can generate 'fake' triggers by shorting the BNC's center conductor to its cylindrical case, using a paperclip or similar small piece of metal. This will not harm the interface (or you!), but it will result in the interface generating the outputs that would result from a proper trigger signal. This can be helpful because sometimes its not clear if the software is responding correctly to triggers.
Does your interface work with EPrime, Presentation, and Superlab? Yes. Our customers tell us they are using all of these packages.
Our lab developed its own programs. Which output on the interface should we use? The bitwise serial output is probably the best from a performance standpoint as of today. From a timing standpoint, the TTL output is as good, but it is less universal since it requires a parallel port or special i/o card.

We would like to hear from you if you are interested in having special types of interfaces or protocols. In particular, it would make a great deal of sense for us to transmit hardware-based timing information along with the button-press information, and we could do this quite easily, but there does not seem to be software now that would use this.

We're using a real-time system. How fast is your response time? We use a synchronous modulation and detection scheme to optically scan the buttons, mostly for historical reasons where we wanted high immunity from ambient light fluctuations. The present scanning takes 200 us per button. So 4 buttons systems have time resolution of 0.8 ms (8 buttons, 1.6 ms).

But this answer gives a false impression: the hardware interface delay (through serial, TTL, or USB) and the operating system timing overheads, can severely delay the final reception of the signal by the end software.

We have a new interface that is optically interchangeable with our present one which supports sub-millisecond timing.

Why do I need the fiber optic bundle to go out of the magnet room? Wires can carry noise into the room. The radio frequency receiver in MR systems is incredibly sensitive (signals at the thermal noise level are routinely measured) and any increase in noise is generally unacceptable because it leads to longer scan times or degraded image quality.

Wires can of course be filtered, and this can go a long way to solving the noise problems that they bring.

But the worst thing about noise is that it's unpredictable, so testing if a system adds noise or not is never a fully convincing effort: it may be fine one day and noisy the next when, say, an elevator motor is turned on, or an electrocautery unit is in use.

Fiber optics provide the most reassuring solution to this problem, as long as they go all the way from the 'outside world', through the penetration panel, and to the response device, because they are not conductors. In addition to eliminating conducted noise, the non-conduction means that subjects are electrically isolated which is a valuable safety point.

Why do I want "no metal and nothing electronic" in the magnet room? Metals interact with magnetic fields. Ferrous metals are especially dangerous and are often strictly forbidden because they can be drawn into the magnet and harm people or equipment along the way. But even non-ferrous metals like aluminum can create odd problems by interacting with time-varying magnetic fields, as well as by having magnetic susceptibilities that distort the shape of the magnetic field near the imaging region of interest.

Just as wires can carry noise into the magnet room, so too electronics in the room can generate noise. This is generally more of a concern as the electronics in question approach the bore of the magnet, since the proximity to the imaging area is what matters here. Most modern electronics involves switching components, and switching waveforms have broad frequency distributions that can be detected as intermittent radio frequency noise. If there is nothing electronic in the magnet room, this potential noise source is eliminated.

 


Current Designs, Inc. 3950 Haverford Ave. Philadelphia PA 19104 US T: 215 387-5456 F: 215 386-4857