A microcomputer-based visual stimulator

A microcomputer-based instrument is described that provides visual stimuli for a CRT display and collects and processes response data. The system produces a variety of visual patterns to facilitate the study of the properties of visual neurons of several different animals. The visual patterns include drifting sinusoidal or bar gratings, contrast reversal gratings, and diffuse light. By means of a keypad, the experimenter can select the visual pattern and its parameters, such as depth of modulation, spatial frequency, initial spatial phase, temporal frequency, and rotation angle.     

An electronic visual stimulator

A group of circuits is described that produce various patterns on an oscilloscope screen that are useful in studying vision. These patterns are: a flashing bar, a drifting bar, a flashing grating, and a drifting grating. The circuits have controls for: contrast, velocity, width, position, and orientation with respect to the vertical. This article describes the principles of design and use of these circuit modules as a precise electronic visual stimulator.     

A low-cost computer-controlled function generator suitable for generating visual grating displays

This paper reports a simple low-cost computer peripheral for generation of gratings. Its advantages are minimal CPU operations, reliability, and variety of programmable output functions.     

A microprocessor-based real-time BASIC laboratory: A pulse motor-controlled visual stimulator

Using the Commodore PET as a random pulse generator, an inexpensive visual stimulator for psychophysical experiments can easily be made at low cost. The PIA interface that connects the external experimental devices is easily accessed by PEEKing and POKEing its registers with BASIC. Using pulse motors, two independent stimulator wheels, having 24 different color filters and a 2.4 log (.1 log unit steps) unit range light attenuator, are controlled by a randomized string of pulses via a PIA port, and the responses of the observer as well as the stimulus parameters are automatically written onto the cassette memory for further data analysis.     

A computer-controlled cardiotachometer

A versatile display system for presenting heart rate information is described. The display has a table with 10 rows and 50 columns. This 10 by 50 matrix contains all integers from 0 to 499, so that it can display the instantaneous R-R intervals of a rat’s EKG to the nearest millisecond. At each beat 1 of 10 vertically and 1 of 50 horizontally arranged indicator lights are turned on to provide the coordinates for reading the table. Either beat-to-beat or averaged heart rate or period is displayed. Small and large changes can be easily and accurately observed on the same scale. The lights are controlled by a PDP-8/e. A listing of the assembler program is presented.     

A computer-controlled vapor-dilution olfactometer

A computer-controlled olfactometer with several innovations leading to closer control over the stimulus parameters and minimization of nonolfactory cues is presented. A microcomputer is used to control the stimulus duration and interstimulus interval. Electronic mass flow con-trollers are employed to maintain close control over the flow in the pure air line and the stimulus-bearing line. Both humidity and temperature are closely regulated. Using a nasal catheter, this stimulus delivery system coupled with velopharyngeal closure and oral breathing permits accurate specification of the quantity of stimulus material actually entering a subject’s nares. The design is such that the computer programming, patch panel interface, and threaded tubing allow versatility in the type of olfactometric study that can be conducted. This system is amenable for threshold, electrophysiological, and sensory adaptation studies of olfaction.     

A flexible computer-controlled perception laboratory

Research in perception is often guided or limited by the capabilities of the laboratory. A computer-controlled perception laboratory is described that was designed to be extremely flexible at a modest cost. The laboratory permits control of onset time, offset time, and intensity of visual, auditory, and tactile stimuli. The visual stimuli include single points, text, stereoscopic displays, and two-dimensional representations of three-dimensional objects moving in space. The design of the hardware and software and the criteria that guided our choice of this design are discussed. Finally, potential applications of this laboratory are considered.     

The photoneuromime: An artificial visual neuron for dynamic testing of computer-controlled experiments

The photoneuromime is a simple electronic device that produces frequency-modulated pulses resembling neural spike trains in response to light modulation. It simulates the linear behavior of cat retinal ganglion X-cell receptive field centers and was designed for testing computer programs that track sensitivity to patterns generated on a raster-scan CRT. Besides providing a convenient means for testing computer programs and recording apparatus, which previously required the use of a live preparation, the neuromime is also a valuable teaching tool in sensory psychology and neuroscience.     

A simple inexpensive computer-controlled tone generator

A simple circuit for a keyed tone generator is described. The total construction cost is less than $5. Various adaptations and modifications of the circuit are discussed.     

A simple IC pulse-pair stimulator

The present paper describes a simple and relatively inexpensive brain stimulator circuit for generating trains of conditioning (C) and test (T) pulse pairs for refractory period and excitability cycle analyses. G and T outputs are constant-current monophasic cathodal pulses of adjustable frequency, duration, amplitude, and delay. C and T pulses can be controlled manually or through logic programming and can be fed out the same or separate channels. The stimulator can be operated on either ac or dc supplies and, when battery operated, features a high degree of stimulus isolation.     

A computer-controlled system for training and testing primates

The hardware and software for a computer-controlled training and testing system for primates are described. The computer (DDP-116 in the Computer-Controlled Psychology Laboratory at Carnegie-Mellon University) controls all stimulus presentation, reinforcement, and records data in a form ready for analysis on a larger computer.     

FOCLAB: A language for computer-controlled psychology research

The FOCLAB system, a dialect of FOCAL, provides complete real-time experiment control and data acquisition capabilities in the area of experimental psychology. The language provides digital and analog input/output, graphics (including alphanumerics) on a refresh CRT, and a powerful set of time measurement operations. With these facilities FOCAL may be used in cognitive and operant, as well as psychophysiological research. FOCLAB will operate with either PDP-8 or PDP-12 systems, and can control most of the currently existing lab interface options for these computers. The system will operate on 8K core-only machines, as well as under OS/8.     

A computer-controlled laboratory for studying infant event perception

An integrated software package for testing infants in a habituation procedure is described. The software is written for an Apple II computer with a minimum of 64K of memory. Additional interface cards are required for timing responses and displaying dynamic stimuli. The software is divided into four independent modules: (1) Configure Experiment allows the experimenter to design a specific experiment. (2) Run Experiment controls the running of a previously configured habituation experiment. (3) Calculate Reliability allows a second observer to score the subject for the purpose of computing reliability. (4) Data Summary and Formatting provides a summary of the results and allows the user to flexibly format the data for reading by various statistical packages.     

Painless computer-controlled experimentation

More Es might employ computers to control psychological experiments if computer languages suitable for experimental control were easier to learn. In fact, course author languages intended for writing instructional sequences offer many facilities desirable for experimental control. A particular language, CAN-4, is examined for its suitability, and its use in a concept learning experiment is illustrated.     

Perception of two-dimensional Markov constraints within visual displays

A method is described for constructing visual displays in which statistical constraints are encoded within two spatial dimensions without introducing one-dimensional linear constraints. Within each local group of four elements, the state of one element was determined with a given probability by the previously generated states of the other three. Ss rated such displays on a scale from “lumpy” (or crude texture) to “lacy” (or even texture). The consistency of classification obtained for displays with strong aggregated (“lumpy”) properties was substantially higher than that obtained for displays with strong distributed (“lacy”) properties. An incidental feature of the Ss’ behavior was their deliberate degrading of the visual quality of the displays. Comparison is made with one-dimensional displays concatenated in two dimensions.     

A computer-controlled administration of the matching familiar figures test

The Kagan Matching Familiar Figures Test of Impulsivity/Reflectivity was modified to allow computer control of stimulus presentation and data acquisition via IBM-compatible systems. The comparability of computer administration and traditional hand administration was examined in a split-half study with a sample of 58 students (ages, 18–39 years). Analyses of variance revealed no significant differences between the administration techniques for latency and a small but significant difference for accuracy. Correlations between the two administration techniques were .61 for latency and .40 for error scores. Internal consistency coefficients for computer administration exceeded those for hand administration on both latency and accuracy. These data compare favorably with results reported by others and suggest that computer administration offers a viable alternative to traditional hand administration of the MFFT in research applications.     

APCOL: A programming system for computer-controlled psychology laboratories

The development of on-line computer systems can be facilitated by higher-level programming languages that are more powerful and easier to learn than machine-level Assembly languages. In general, it is not possible to speak ofa programming language without also describing the operating system and functional problem domain of the small computer system for which it is intended. This is because of the great variety in the architecture and configuration of small computers. However, it is possible to state more general requirements and design criteria for on-line computer languages in psychology. APCOL is an example of an integrated programming system. One of the important distinguishing features of the system is that it is implemented both on the small-scale laboratory computer and on a large general-purpose computer linked to the smaller machine via a high-speed communications network. This arrangement permits firsthand access to interactive program construction with immediate test of program function by using the on-line implementation as well as access to the text-editing and mass storage facilities of the large-scale machine.     

A computer-controlled electrogustometer for the estimation of evoked taste thresholds

Reliable taste detection thresholds in humans are difficult to obtain for either research or clinical purposes because ordinary taste stimuli cannot be generated and presented by means of a computer. However, in investigations of taste dysfunction, electrical taste stimulation (electrogustometry) is sometimes employed. Minute anodal direct currents are applied manually to the tongue, giving rise to an acid taste experience through the liberation of protons into the saliva. This experience accords with recent findings on the mechanisms underlying sour taste perception. The device described here is a safe and accurate constant-current device, operating under computer control at very low amperages, making it possible to apply modern psychophysical procedures to the measurement of evoked taste thresholds.