ZStim: Data Acquisition and Visual Stimulation Software System
System Requirements: LabVIEW version 8.6 or later, Matlab version 2010 or later, Psychtoolbox version 2.0 or later
Please view the videos below to briefly learn what ZStim system is: Introduction Video* User Interface and stimuli*
(you need to have QuickTime player to view the Videos)

Data Acquisition. The software acquires data through analog input channels. Data acquisition rate, input range, and number of AI channels used are controlled but not limited by the program. A photo detector that is connected directly to the data acquisition board is used to signal the start of the stimulus presentation. Output of a photo detector is recorded using one of the analog input channels (usually AI0). All data acquired is saved in text files.

Visual Stimulation. For generating visual stimuli, the software uses two alternative methods combining background and stimulus images. The stimulus image can directly overlay the background image (left image below), or an image mask can be used for a 1-bit alpha compositing method (right image below).

Images of background, stimulus, and mask are provided to the program. The mask file is a 1-bit monochrome BMP image is used as a 1-bit alpha channel or a 2D matrix of transparency values of the background (value 0 for 100% transparent pixels, and 1 – 100% opaque). The background and the stimulus images are overlapped using the mask to produce each frame of a presentation to display.

Execution:
All parameters of visual stimuli are specified in an input text file. One file can (and usually does) have multiple cases of parameters. Before the presentations start, the file is analyzed by the software and number of cases is automatically counted. All cases or selected subset of cases are executed in pseudo-random or direct order.

The number of trials determines the number of times all cases are repeated. A number of trials are considered to be an experiment. The entire experiment can be repeated multiple times with intermissions that can be used to play movies for cell adaptation.