Pre 2.00 versions of WinLTP provided automated electrical stimulation and data acquisition capable of running nearly an entire synaptic plasticity experiment, with the primary exception that perfusion solutions had to be changed manually. This automated stimulation and acquisition was done by using Sweeps, Loops and Delay events in Protocol Builder scripts. However, this did not allow automatically changing many solutions while running multiple slice experiments, or when the solutions had to be changed rapidly and with accurate timing during patch-clamp experiments. In version 2.00 we have added automated perfusion control to WinLTP.

First, perfusion change between sweeps is enabled by adding the Perfuse event to Protocol Builder scripting and is used in slice experiments.  The low cost of WinLTP Advanced Version software and National Instruments M- and X-Series boards means it is cost-effective to run many WinLTP's at once.  These many WinLTP's can independently  control stimulation and perfusion of many slice chambers. making multi-slice experiments feasible.

Second, fast perfusion changes during as well as between sweeps is enabled by using the Perfuse in the protocol scripts which controls changes between sweeps, and by changing digital or analog output during a sweep and is used for single cell single-line perfusion patch-clamp experiments. The addition of stepper control of tube placement allows dual- or triple-line perfusion patch-clamp experiments for up to 48 solutions.

The ability to automate perfusion changes and fully integrate them with the already automated stimulation and data acquisition goes a long way towards complete automation of multi-slice extracellularly recorded and single cell patch-clamp experiments.

Other electrophysiological data acquisition programs can perform automated perfusion control, but users do so by directly inputting analog voltages or digital bits into the program that then outputs them to the perfusion controllers.  In contrast, in WinLTP is unique in that automated perfusion control is integrated into the program.  Users primarily input perfusion channel numbers into the program to control perfusion controllers, and WinLTP converts them to the appropriate analog or digital output.  This substantially simplifies control of automated perfusion.

The coupling of automated perfusion control to the automated stimulation/acquisitiion in the Protocol Builder goes a long way towards achieving fully automated experiments.  In the future we plan to implement detection of stable baseline and incrementing stimulus amplitude for generating I/O curves to go even further towards achieving fully automated experiments.