Real-Time Supervisor System Based on Trinary Logic to Control Experiments With Behaving Animals and Humans

Abstract

A new method is presented based on trinary logic able to check the state of different control variables and synchronously record the physiological and behavioral data of behaving animals and humans. The basic information structure of the method is a time interval of defined maximum duration, called time slice, during which the supervisor system periodically checks the status of a specific subset of input channels. An experimental condition is a sequence of time slices subsequently executed according to the final status of the previous time slice. The proposed method implements in its data structure the possibility to branch like an if-else cascade and the possibility to repeat parts of it recursively like the while-loop. Therefore its data structure contains the most basic control structures of programming languages. The method was implemented using a real-time version of LabVIEW programming environment to program and control our experimental setup. Using this supervision system, we synchronously record four analog data channels at 500 Hz (including eye movements) and the time stamps of up to six neurons at 100 kHz. The system reacts with a resolution within 1 ms to changes of state of digital input channels. The system is set to react to changes in eye position with a resolution within 4 ms. The time slices, experimental conditions, and data are handled by relational databases. This facilitates the construction of new experimental conditions and data analysis. The proposed implementation allows continuous recording without an inter-trial gap for data storage or task management. The implementation can be used to drive electrophysiological experiments of behaving animals and psychophysical studies with human subjects.