A self-contained,regulated, burst-firing constant-current ac shock generator

A line- and load-regulated constant-current ac shock generator has been designed for animal behavior experiments. The self-contained unit has four operating modes, amplitude adjustment, and a leakage current detection circuit. A unique feature of this generator is that the good load regulation achieved by using a high-voltage source is preserved without such problems as arcing and high current density effects. Circuit schematics, along with a discussion of selected circuits, are included. Experimental data are presented to demonstrate the utility of the device.     

Biphasic constant-current stimulator for whole-animal shocking of marine animals

A constant-current stimulator delivering biphasic pulses was designed and constructed for whole-animal shocking during aversive conditioning of Pleurobrartchaea, a marine gastropod mollusk used for behavioral and neurophysiological research. The advantages of whole-animal stimulation are discussed and results are briefly described with regard to the factors involved in evaluating the procedure. The circuit design and electrode considerations are presented in detail. The basic stimulator design has potential for use as a general instrument for behavioral and physiological research.     

A constant-current shock source for providing direct or alternating current output

A vacuum-tube constant-current shock source. providing ac, smooth dc, and pulsating dc output is described. In addition to output flexibility. the shock source is compact, inexpensive to construct. and has undergone 4 years of testing and laboratory use. Operating instructions, theory of operation, and suggested modifications are included along with performance specifications.     

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.     

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 two-dimensional computer-controlled visual stimulator

A computer-controlled instrument that creates complex two-dimensional patterns on a CRT monitor is described. These patterns are used to elicit visual evoked responses. Patterns are produced on a raster that is rotatable about its center. It is possible to assign to arbitrary regions in the raster any of four independent one-dimensional spatial-temporal functions. For each spatial-temporal function, the experimenter can select an arbitrary spatial profile, the spatial frequency of the profile, the starting phase of the profile, the temporal function, and the depth of modulation.     

An inherent problem in certain constant-current stimulators

A basic and potentially dangerous problem that may occur in the use of triggered constant-current generators for stimulation is discussed in the general case. A solution with schematic illustration is presented for one specific constant-current generator, the CCS-1A manufactured by Electronics of Life Sciences, Inc.     

Amplitude of constant-current pulses can be preset

The required magnitude of stimulation current can be adjusted with a voltage divider, consisting of a 10-turn potentiometer and a digital dial. This method of adjustment offers greater convenience than depending solely on a monitoring oscilloscope for current readings, especially when frequent changes in stimulation current must be made. Tissue polarization is prevented by a shunt gate, which is in operation during the pulse interval.     

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.     

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.     

An ultrasonic auditory stimulator

An auditory stimulator with a frequency range to 40 kHz is described. The onset and cessation of the stimulation tone are carefully shaped in order to eliminate unwanted clicks. Rats have shown marked responses in electrical brain activity to ultrasonic stimulation.     

A photoelectric shock scrambler

A shock scrambler using photoelectric conductors which operate relays is described. The scrambler has advantages of low cost and reliable operation.     

The Nencki Affective Picture System (NAPS): Introduction to a novel,standardized, wide-range,high-quality,realistic picture database

Selecting appropriate stimuli to induce emotional states is essential in affective research. Only a few standardized affective stimulus databases have been created for auditory, language, and visual materials. Numerous studies have extensively employed these databases using both behavioral and neuroimaging methods. However, some limitations of the existing databases have recently been reported, including limited numbers of stimuli in specific categories or poor picture quality of the visual stimuli. In the present article, we introduce the Nencki Affective Picture System (NAPS), which consists of 1,356 realistic, high-quality photographs that are divided into five categories (people, faces, animals, objects, and landscapes). Affective ratings were collected from 204 mostly European participants. The pictures were rated according to the valence, arousal, and approach–avoidance dimensions using computerized bipolar semantic slider scales. Normative ratings for the categories are presented for each dimension. Validation of the ratings was obtained by comparing them to ratings generated using the Self-Assessment Manikin and the International Affective Picture System. In addition, the physical properties of the photographs are reported, including luminance, contrast, and entropy. The new database, with accompanying ratings and image parameters, allows researchers to select a variety of visual stimulus materials specific to their experimental questions of interest. The NAPS system is freely accessible to the scientific community for noncommercial use by request at http://naps.nencki.gov.pl.     

An inexpensive integrated circuit intracranial stimulator

An intracranial stimulation unit which offers precise control of stimulus duration, frequency, and current is described. The unit generates a square wave stimulus output utilizing very inexpensive, easily constructed integrated circuitry.     

The effects of active choice,shock duration,shock experience,and probability on the choice between immediate and delayed shock

The choice between immediate and delayed shock was investigated in three experiments with college students. Some Ss were required to choose between a longer-duration shock immediately and a shorter-duration shock later. Immediate, as opposed to delayed, choices were more frequent when: (a) Ss were required to choose the immediate or the delayed shock in contrast to other procedures in which Ss were required to choose immediate shock or passively wait for automatic shock to occur, (b) the duration of the immediate shock was reduced, (c) the S was given prior experience with shock, and (d) the probability of the immediate shock was reduced. Under some circumstances, shock delay and anxiety increased the frequency of immediate choices.     

A Constant-current AC shock generator

A device has been developed for the effective delivery of a preset constant current AC electric shock. The shock intensity is adjustable from zero to a maximum of 10 ma as the voltage varies between 0 to 5 kv. The 5-kv, 60-HZ, AC voltage insures a constant-current output regardless of skin contact resistance changes. Shock duration is internally controlled and a “fail safe” lockout circuit to render the apparatus inoperative is provided in case of accidental sticking or failure of control relay signals from either internal circuitry or from behavioral programming equipment.