Experimentation

HARDWARE

At present, all of our experimental stimuli are administered from an Apple iMac computer utilizing Psychophysics Toolbox, which operates with MATLAB software (The MathWorks, Inc.; Natick, MA), or from a PC running Presentation (Neurobehavioral Systems, Inc.; Albany, CA) or DMDX software. We also have an Apple Mac Mini running PsyScope X software. For the iMac and PC, stimuli triggering is run through a StimTracker Model ST-100 (Cedrus Corporation; San Pedro, CA). For PsyScope, all timing for experiments, along with all responses made during experiments, is managed by a Response Button Box developed by ioLab Systems. Both of these devices have millisecond resolution accuracy, and are not susceptible to the same drag that Mac and PC system “clocks” are. Responses by the subject are triggered either by voice (See the OptoAcoustics system [link]) or button-press from a Current Designs (Philadelphia, PA) fiber optic system. The actual peripheral response buttons in the MSR are two 2-button response pads (a total of four buttons) utilizing a photodiode system that sends signals directly to the stimulus computer via a USB plug. The interface between the buttons and the computers is a 904 FIU series photodiode box.

SOFTWARE

Stimuli are normally administered via Psychophysics Toolbox, which operates with MATLAB or, if from the PC, via Presentation or DMDX software. We use this for both auditory and visual experiments. PsyScope X is set up on the Mac Mini but is rarely used. The PC can also run Psychophysics Toolbox but currently this software cannot utilize the response pads in the MSR.