A microcomputer based system for spike processing at low cost.

A system is described for the quantification of neuronal activity utilizing a microcomputer as an alternative to a conventional hard-wired ratemeter. The system, which counts the number of action potentials occurring in successive epochs, consists of a microcomputer and a small number of external electronic components (e.g. D leads to A chips, counter chips and latches) housed together with the power supply in a subrack. Output is both digital (a video monitor is used to display the count, cumulative count and elapsed time) and analogue (a chart recorder is used to record a frequency/time histogram) for two channels. Variables such as epoch time and analogue output scaling are read in from switches via latches hung onto a data-bus and can be altered without interference with the running of the program. The program is written in BASIC and stored on a C-MOS memory chip. In comparison to alternative storage systems (i.e. cassette and floppy disk) this has the advantage of immediate access and low cost; furthermore the program is readily modified.