Embedded hardware-based dynamic clamp systems offer feedback that is fast and precisely timed, but these systems are often expensive and sometimes inflexible. PC-based systems, on the other hand, allow more complex feedback, but real-time performance can be poor³.
The CED Signal dynamic clamp system gives you the best of both worlds. All real-time aspects of the system are executed by the Power1401’s fast embedded processor using pre-calculated lookup tables and optimised floating-point arithmetic, with the feedback calculations triggered by the ADC sampling for maximum stability. This software-based design is quick yet still provides great flexibility. The non-real-time aspects of the system are handled by the controlling PC to allow simplicity and ease of use. The result: a dynamic clamp system integrated into the standard Signal data acquisition software that outperforms generally available dynamic clamp systems, at a reasonable cost.
It has been shown³ by simulations and experiment that the performance of dynamic clamp systems is strongly affected by the update rate and latency of updates. The very high speed methods used by CED provide extremely high rates of update with low latencies, to allow you to undertake the most demanding experiments. The mechanism incorporates a hardware based overflow detector so that you can be sure that the required update rates have been achieved and that your data is trustworthy.
³ Bettencourt JC, Lillis KP, Stupin LR and White JA. Effects of Imperfect Dynamic Clamp: Computational and Experimental results. J Neurosci Methods. 2008 April 30; 169(2):282-289 †
Experimental difference synapse model with superimposed
noise, triggered internally at randomised intervals
During testing we have found that, with older amplifier designs, current clamp performance is not good enough for effective dynamic clamping.
So far the following amplifiers have been tested at CED and seen to work correctly with Signal dynamic clamping:
Other amplifiers will be tested and added to this list in due course.
However, many other amplifiers, including the BA-01X, BA-01M, ELC-01X, ELC01M, ELC03XS, SEC03M, SEC05X and SEC01X from NPI Electronics, are known to work well with current clamping and are therefore suitable for dynamic clamping, but of course this is not to say that other amplifiers are unsuitable. ×
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CED, through this site, does two things that relate to privacy. We would like to explain them.
We offer free down-loads of many files on our site, from test programs to complete install files for updated versions of major packages like Spike2 and Signal.
When customers wish to take a down-load of a major package, we ask a few questions, including their name, email address, the serial number of the software for which they seek an upgrade and whether they would like an automatic email whenever we update the product. This information is emailed back to CED when they access the final down-load screen. Within this email, your browser transmits the type and version of browser you are using, and the screen resolution you are running.
The reasons why we take and keep this information are that it is useful for our software development team to know who has taken the latest versions, and it is useful for our web site development team to know which browsers people are using to view our site, and what resolution they have their screens set to.
When people down-load a major package, we try to write a cookie, a small file in your computer, that records your name, serial number of the software package, and the version you are down-loading. These files have a lifetime of one year.
The reasons for storing this information are firstly that if you ask for another down-load some other time, your details are read from the cookie and are pre-written into the form, to save you looking them up again. The other reason is that next time you access our site, your browser looks through your CED cookies and compares the versions down-loaded with the latest version numbers read from our site. If there is a later version of a product you have already down-loaded, we tell you on the home page screen, so you know that it is worth going to the down-load page again.
None of this information is ever given to anyone outside CED. ×