The next section of the PCC program establishes a list of values which will be used to control inter-stimulus intervals. The first line contains the I.S.I.s for the habituation phase, the next two lines contain I.S.I.s for the acquisition phase, and the following two lines contain I.S.I.s for the extinction phase. This is a total of 42 I.S.I. values. There are the only 3 conditions required in this experiment, but clearly other conditions could be accommodated if necessary. The next lines in the PCC program, after the table but before the 'MAIN' loop, are used to pre-set variables.
Variables are words used to represent numbers.
Any such variable contains the number 0 unless a program statement deliberately changes it. StimCount is a variable which the program will be designed to increased every time a stimulus is delivered. We give it the name 'stimCount' to help us remember what it's purpose is. It could just as easily be called variable1 or V1. Any mix of letters and numbers may be used, as long as the first character is not a number, and also it may not be the same as any of the reserved words used for pre-defined functions.