Dr. Klieber,
I am with Bruxton Corporation, about which Lars Thomsen was so kind to
give a reference in his reply. We are a software company that works with
hardware from a variety of vendors. We also ported the HEKA Pulse
program from the Macintosh to Windows. Both Instrutech and HEKA are
distributors of ours. (That will tell you something about my biases).
I'll try to give my perspective on your questions, which is that of a
vendor in the market. I can tell you more about what hardware and
software combinations are available that I can about actual use in a
laboratory.
Hans-Georg Klieber wrote:
>> I am particularly interested in your experience regarding
> - amplifiers
Lars Thomsen has addressed this in his reply.
If you want an amplifier that is completely computer-controlled, you
might want to look at the HEKA EPC-9 (http://www.heka.com). This
amplifier is most useful in combination with HEKA software, since the
acquisition program is tightly coupled with the control of the
amplifier.
The majority of the development of the EPC-9 was performed in the lab of
Dr. Neher at the Max-Planck-Institut fuer biophysikalische Chemie in
Goettingen.
> - computer controlled measurement (whole cell, single
> channel), hardware & software
The Axon (http://www.axonet.com) Digdata samples at up to 330kHz and
provides 32 A/D channels. The A/D and D/A have 12 bit resolution. There
is no electrical isolation between the computer and the analog inputs
and outputs.
The Instrutech (http://www.instrutech.com) ITC-16 and ITC-18 sample at
up to 200kHz and provide 8 A/D channels. The A/D and D/A have 16 bit
resolution. The analog inputs and outputs are optically isolated from
the computer.
The HEKA EPC-9 contains an Instrutech ITC-16 built in, which complicates
comparing prices with other amplifiers.
As far as software goes, we (Bruxton) offer high-speed continuous
recording (Acquire), similar to the AxoScope and pClamp Fetchex
programs. Both Acquire and AxoScope run under Windows. pClamp runs under
DOS.
For whole-cell recording, consider Axon pClamp or HEKA Pulse. pClamp is
a suite of programs originally constructed in the lab of Dr. Henry
Lester at Caltech. Pulse is based on programs constructed in the lab of
Dr. Erwin Neher at the MPI in Goettingen. Pulse supports both the Axon
Instruments and the Instrutech hardware. It also performs real-time
control of the EPC-9.
Pulse places great emphasis on the user constructing experimental
protocols in advance, then executing them during the experiment. The
protocols can include P/N for leak subtraction and multiple series (that
is, performing one stimulus pattern, then moving to another). If you use
Pulse, get a large (17") monitor, because the electrophysiologists who
designed the program wanted every feature available as a button or an
indicator in front of them during an experiement. The windows are
filled.
> - choice of mass storage
If you use pClamp, AxoScope, or Pulse, you should write to a normal hard
disk.
Acquire supports writing to DAT (using a commercial HP DAT drive). This
is suitable only for high-speed continuous recording. The customers who
are happiest with this feature are those studying channel kinetics or
who are recording from many channels simultaneously.
Instrutech offers devices (VR-10 and VR-100) that digitize analog data
to video tape using a VCR. You can then replay the data into a computer.
This can be useful for off-line recording.
> - software to further evaluate the measurments
The pClamp package contains Fetchan and Clampfit, which perform analysis
on pClamp recordings. If you want to go further, you must read the files
into some other program for analysis.
The Pulse package is available with PulseFit, which performs analysis of
Pulse files.
We offer TAC, a program that performs single-channel analysis of pClamp,
Pulse, and Acquire files. We also offer Data Access, a package that
allows you to read pClamp, Pulse, and Acquire files into many data
analysis programs.
A note about platform:
- The software and hardware from Bruxton, HEKA, and Instrutech is
available for Windows 95, Windows NT, Windows 3.x (with Win32s) and the
Apple Macintosh. No software is available for DOS.
- The software and hardware from Axon is available for the PC. The
pClamp package runs under DOS or under Windows 95. I have been told that
for pClamp to run under Windows 95, the system must be rebooted in DOS
mode. AxoScope runs under Windows 95 and Windows 3.x (it does not
require Win32s).
Axon Instruments also offers some Macintosh software, but I am not
certain of the current status of these packages. Lars Thomsen mentioned
AxoGraph. There is also an acquisition program called AxoData, which
uses the Instrutech ITC-16 for acquisition.
A note about "rolling your own":
If you want to construct your own software, you could use common
hardware, for example, from National Instruments (as Lars Thomsen
suggests).
Axon Instruments advertises LabView drivers for the Digidata 1200A/B, so
you could use that hardware with pClamp, and use LabView to construct
additional acquisition programs.
All the hardware vendors support Visual Basic, so you could use Axon or
Instrutech hardware with appropriate acquisition programs, and use
Visual Basic to construct additional acquisition programs.
I hope this is helpful.
-- Dan
--
Dan Brown
Bruxton Corporation, Seattle
Phone: (206) 782-8862
Web: http://www.bruxton.com
