Chapter 1 - INTRODUCTION

1.1 LTP Program Capabilities

The LTP program is a stimulation, data acquisition and on-line analysis program for studying Long-Term Potentiation (LTP), Long-term Depression (LTD), and related phenomena. It was primarily developed to get accurate on-line measurements of amplitude and slope in order to determine when a stable baseline had been achieved, and to be able to manually reset the amplitude and slope back to baseline.

It is a 32-bit Extended DOS program written in Watcom C that runs on computers using DOS 6.x / Windows 3.x or Windows 95/98. Data acquisition boards that can be used include Axon Instrument' Digidata 1200/1200A, Scientific Solutions' Labmaster, and the inexpensive Pico Technology's Pico 42-ADC, which can be used on PC99 specification computers (which do not have an ISA bus, APPENDIX D.4), or on laptop computers.

The user interface is Windows-like in that it includes Menus and Dialog Boxes that can be activated by keyboard (although not mouse) input. Choosing protocols is done by using Menus and Dialog Boxes. Running protocols is done by pressing Function Keys or using Menus. Most parameters (including detection criteria and graph axes settings) can be altered during the protocol run.

The program functionality includes:

1. The program records synaptic activity in extracellular, intracellular, or patch clamp modes.
2. Repetitive sweeps with simultaneous data acquisition (up to 20,000-150,000 samples on an 8 MB machine and 1,900,000 samples on a 32 MB machine at 100 usec intervals) and stimulation (using two extracellular pathway stimulation, S0 and/or S1, and epoch-like intracellular analog stimulation and digital outputs).
3. The basic protocols are either slow single pathway S0 stimulation, or slow alternating dual pathway (S0 then S1) stimulation.
4. The sweep data can be signal averaged on-line and digitally filtered off-line.
5. On- and off-line calculation and plotting of several waveform parameters includes:
   1. DC Baseline
   2. Peak Amplitude
   3. Peak Latency
   4. Slope
   5. Area
   6. Duration
   7. 10-90% Rise Time
   8. 10-90% Decay Time
   9. Coastline
   10. PopSpike Amplitude
   11. PopSpikeLatency
   12. Average Amplitude
   13. Cell resistance (Rm)
   14. Patch electrode series resistance (Rs) using peak, single and double exponential curve fitting (still being worked on)
6. LTP induction can be produced by
   1. Single train
   2. Repetitive train (theta stimulation)
   3. Primed burst stimulation
7. LTD stimulation and analysis can be performed using fast repetitive sweeps (at up to 2 Hz), or a single sweep lasting several minutes for faster repetitive stimulation.
8. S0 and S1 extracellular stimulation in the same sweep can be used to test for pathway independence.
9. Plotting of ADsweep and Amplitude/Slope graphs on HP LaserJet compatible printers (Some HP DeskJet printers can also be used to a limited extent).
10. Output of AD waveforms and Amplitude/Slope calculations to ASCII files that can be used with spreadsheets (Excel, QuatroPro and Lotus 1-2-3), plotting programs (SigmaPlot and Origin) and waveform reanalysis programs (Origin and IGOR).
11. If networked, the LPT program can send ASCII ADsweep files to another computer which can do different on-line analysis if a custom analysis program is available.

What part of this manual is the most important to read? As a user, I strongly think that if a program is any good, you shouldn't have to read the manual, just start using the program. On the other hand, as a programmer/manual writer, I know that when a user doesn't read the manual they are unaware of a lot of the program functionality. Because I can see both sides of the argument, I strongly recommend that you, at minimum, read the installation section Getting Started (Chapter 2) and Limitations To LTP113E (APPENDIX A) because without reading these sections you could be using the program incorrectly and giving you results that aren't what you think they are. Then scan the rest of the manual and look at the figures to see the other capabilities of the program. Then look at the Known Bugs in LTP113E (APPENDIX B). Hopefully after this you'll carefully read the rest of the manual (ha!).

The program is largely bug free and has been used by the Bristol group for over three years. I've tried to stamp out all the bugs, but I know there are several that are still there. However, all bugs can either be 'worked around' (we do), or else the LTP program simply cannot be used on a particlular computer / AD board combination. I hope this program performs well for you. Let me know how it goes.

The user should understand that one of my primary reasons for making this program freely available is due to its ability to use very inexpensive data acquisition boards. This makes the total cost of LTP data acquisition software and hardware affordable to almost all LTP researchers.

1.2 Computer, Software and Data Acquisition Hardware Requirements

The LTP program is a 32-bit Extended DOS Graphics program that runs on an IBM compatible computer having an Intel 386SX, 386, 486SX, 486, Pentium, Pentium Pro, or Pentium II microprocessor. A math coprocessor for 386SX, 386 and 486SX chips is not required, but will be used if available. The LTP program has not been tested on a AMD K6 or Cyrix x86 chip, but it should work. The program also requires a VGA graphics card and color monitor.

The LTP program requires either MS-DOS 6.0 or 6.2 (with or without Windows 3.0, 3.1 or 3.11), or Windows 95 or 98. The LTP program is not designed to run in the OS/2 or Windows NT operating systems, even in reanalysis mode.

The LTP uses from 4.4 to 32 MB of Extended XMS memory and 8 MB of memory is the practical minimum required.

The LTP program requires a data acquisition board - either the Axon Instruments Digidata 1200/1200A board, the Scientific Solutions Labmaster board, or the Pico ADC-42 board.

To organize and save data files at the end of an experiment, a file compression program such as ZIPMAGIC, PKZIP or WINZIP is suggested. PKZIP and WINZIP are Shareware programs. This type of program not only compresses data files, but also groups many data files into one convenient compressed file. The programs can be obtained from the Internet at the following sites:

1.3 Technical Support

Technical support can be obtained by directly contacting the author:

1.4 Acknowledgements

I would first and formost like to thank my friends and colleagues for help with the testing of the LTP program, for both putting up with crashes, and rewriting your protocol files for yet another ("The Last" ha!) version. In our research group I would like to thank Zaf (my first user!) Bashir, Steve Brathwaite, Zuner (I only want it when it works) Bortolotto, Trevor Bushell, Val Collett, Andy Hargreaves, Andy Irving, Nicola (another new version, no problem!) Kemp, Andreas Luthi, Brian McCaffery, Mary Palmer, Jaques Noel, Gerhard (LTP files can be analyzed with Mac's IGOR) Rammes, Michel (le artiste) Vignes and Zoe Ziakopoulos. In particular, I would like to thank Steve Fitzjohn for detecting most of the bugs you haven't seen, John Isaac for practical help on patch electrode series resistance measurement, and Vern (pClamp) Clark for showing me how to use the LTP program over the network without additional coding!

I would also like to thank all my 'beta testers' in outside labs that have helped me immensely with feedback about the program, in particular Nicola Berretta in Trieste Italy, Bruno Frenguelli in Dundee, and Zygmunt (yes I will do a polynomial curve fit of the synaptic peak) Galdzicki at NIH.

I would especially like to thank Tim Benke for the use of his exponential curve fitting C code, and Graham Collingridge, not only for supporting this work, but also as a former programmer who wrote an earlier LTP program on a 64KB BBC computer and who knows how difficult software development can be.

Finally, I thank the Wellcome Trust and the UK Medical Research Council for support in developing this program.

Go to LTP Manual - Chapter 2

Return to the LTP Manual (Table of Contents)

Return to the LTP Home Page