A time-division multiplexer-demultiplexer for duplex video recording and playback

A solid state circuit is described that allows two sources of video information to be multiplexed and recorded by one videotape machine. On playback, the same circuit is used to demultiplex the recorded video signal so that each of the original video channels may be independently viewed on separate television monitors.     

An accurate repeat cycle timer.

This timer was designed to provide a compact and quiet unit to control the presentation of visual stimuli by means of a slide projector, but it is not limited to this use. It is a solid state device, ready for use as soon as switched on, and is made largely from commercial logic units. The output is in the form of contact closures: the ON relay and the OFF relay give short pulse closures at the beginning of their respective cycles. With circuit values as shown in Fig. 1, times, from 0.5 to 10 sec in increments of 0.5 sec with an accuracy of ±1%, are selected by separate switches on the ON and the OFF cycles. Single interval solid state timers have been described by Saslow and Markowitz (1964) and by Tapp and Clark (1964).     

Another inexpensive,efficient, solid state shock scrambler

This paper describes an inexpensive, solid state shock scrambler. The circuit employs TTL logic and mercury-wetted relays for quiet, reliable operation. The unit can control shock presentation to 16 grids and operates with an efficiency of 50%; for example, on any given clock pulse, 50% of the grids are positive and the other 50%, negative.     

Conditioning circuits

A circuit of mutually exciting neurones capable of approaching and maintaining a state of permanent excitation has been described by Rashevsky as a possible mechanism for the production of conditioned reflexes. The mode of approach of such a circuit to the steady state is examined in some detail under slightly more general assumptions, and an estimate is made of the order of magnitude of the time required to reach this state.     

Limbic hypertension induced by stress and septal stimulation

For this study, it was postulated that hypertension of emotional origin is generated within the limbic system. To validate this thesis, septal induced blood pressure elevations were combined with a stressful experience in adult rats (spontaneously hypertensive and Wistar Kyoto rats). Stress consisted of intermittent confinement in a plexiglass tube. The results revealed that hypertension induced by electric stimulation of the septum during the stressful state could subsequently be elicited by the stressful state alone, without electric stimulation of the septum. It was postulated that the cortically modulated stress circuit converged with the electrically activated limbic pressor circuit at the level of the septum. This convergence resulted in the formation of one cortico-limbic circuitry which could be activated by stress alone. This underlying mechanism may be considered as a model of neural sensitization in the production of stress-induced limbic hypertension.     

A simple,inexpensive stimulus waveform generator

A simple circuit for a sine wave generator is described. The total cost for construction is approximately $30.00. At present, the unit is used to generate a sinusoidally modulated light stimulus for steady state visual evoked response experiments. Modifications of the circuit for other applications are discussed.     

A microprocessor control system and solid state interface for controlling electrophysiological studies of conditioning

This paper describes a microprocessor control system and solid state interface for controlling the apparatus in combined behavioral-electrophysiological studies of conditioning. The computer program, which is designed to control classical conditioning of the rabbit’s nictitating membrane response, provides the flexibility to control all conditioning parameters (e.g., interstimulus and intertrial intervals, trial type, and sequence of trial types) with only minor modifications. The system is free from artifacts that can distort electrophysiological recordings and can easily be modified to accommodate other behavioral paradigms in which electrophysiological responses are recorded.     

A machine-level software program for the generation of aversive conditioning schedules using the KIM-1 microprocessor

A microprocessor system can be used both to control aversive conditioning (classical, signaled and Sidman avoidance, and conflict) experiments and to acquire behavioral data in multiple subjects at a fraction of the cost of solid state systems. The software described in this paper can be used to program tones and shocks and count responses, independently, in up to 12 animals simultaneously.     

Kinetic Models of (M-R)-Systems

Kinetic models using enzyme kinetics are developed for the three ways that Louie proved that Rosen’s minimal (M-R)-System can be closed to efficient cause; i.e., how the “replication” component can itself be entailed from within the system. The kinetic models are developed using the techniques of network thermodynamics. As a demonstration, each model is simulated using a SPICE circuit simulator using arbitrarily chosen rate constants. The models are built from SPICE sub-circuits representing the key terms in the chemical rate equations. The models include the addition of an ad hoc semi-permeable membrane so the system can achieve steady state fluxes and also to illustrate the need for all the efficient cause agents to be continually replaced. Comments are made about exactly what is being simulated.     

BORES: Behavior observation recording and editing system

This paper describes the use of a Datamyte 900 solid state data collection system for observational research. Data editing and reformatting programs that organize the behavioral data into a consistent format for use with widely available statistical packages and edit the data for logical inconsistencies are discussed. Data collection using both the focal animal observation and group scanning, or scan-sample, techniques are amenable to this approach.     

Functional neuroimaging studies of reading and reading disability (developmental dyslexia)

Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers.     

An integrated circuit for stepwise or continuous microdrive advancement

A circuit for inexpensive automation of a hydraulic microdrive is described. The circuit uses two integrated timing circuits with output periods defined by resistance-capacitance circuits. The output of this circuit operates a relay that controls a small electric motor that runs the microdrive. This system can operate in either a continuous mode for long-term infusion of solutions or in a stepwise fashion for lowering electrodes. When attached to an appropriate microdrive, the circuit can be employed in experiments in which brain-behavior relationships are investigated within anatomical, pharmacological, or electrophysiological paradigms.     

Modulator and filter circuits for EEG biofeedback

Inexpensive designs for two components of an EEG biofeedback system are described. A two-channel modulator accepts a pair of input signals for modulation of two audio carrier frequencies a musical fifth apart. Carrier suppression is obtained with a simple balanced modulator circuit for each channel. The filter circuit is an integrated circuit adaptation of a successful vacuum tube design reported by other investigators a number of years ago. Various configurations of this equipment for two-channel EEG biofeedback are described.     

A low-cost solid state device for producing delayed auditory feedback

This paper presents a design for construction of a relatively low-cost solid state delayed auditory feedback device. The advantages of this unit are that it is reliable, flexible, easy to operate, and it does not require audio tape.     

An eight-channel computer-controlled scanning electromyograph

A measurement system is described for the computerized detection, digitizing, and storage of electromyographic (EMG) signals from up to eight muscle groups. The use of a channel scanning technique allows almost simultaneous multichannel recording with minimal circuit redundancy. Specifically, the scanning electromyograph allows several EMG preamplifiers to share expensive isolation, signal-conditioning, and interface circuitry. The design incorporates monolithic integrated circuit preamplifiers and includes optical isolation of the preamplifier circuitry for protection of the subject. Hybrid active filter modules allow convenient selection of system bandpass characteristics. Key measurement parameters are software programmable. The scanning electromyograph is inexpensively constructed from readily available componentry. Specifications for all functional blocks within the instrument are comparable to those of commercial instrumentation.     

A multiplexed vectored interface logic system for control of behavioral experiments

An interface was constructed which enabled a minicomputer to control operant conditioning experiments with a minimal amount of software recognition and input/output instructions. The hardware consisted of a real-time clock, logic to input a unique number with each change of state of digital input, and logic and solid state drivers to control standard, commercial 24 V behavioral stimuli.     

The state of order in Fe–Al studied by precession electron diffraction

Precession electron diffraction (PED) has been carried out on a fully ordered Fe–40at.%Al solid solution in order to explore its suitability for determining the state of order. The integrated intensity ratio of a superlattice reflection with respect to a fundamental reflection was measured as a function of the sample thickness and the results are well fitted by dynamical simulations. It is proposed that, in addition to conventional X-ray diffraction, PED may provide access to the state of order at microscopic and nanoscopic scales.     

A logarithmic electronic integrator for activity transducers

A solid state integrator having an optional logarithmic or linear input/output function, high input impedance, de input, high sensitivity, low drift, and contact-closure output is described.     

An on-line integrator for alpha quantification

A system for the on-line graphic quantification of alpha frequencies (or other frequency bands extracted from EEG signals) is described. Alpha-frequency components (8 to 13 Hz) are actively filtered from complex EEG waveforms and presented to a laboratory-developed solid state integrator. The high-level output of the integrator, which is compatible with all popular EEG and polygraph recorders, is in the form of an ascending analog voltage ramp, reset at a predetermined level, to provide a rapid quantitative determination of alpha activity and variability. The design of the integrator permits an alternate mode of operation where time-synchronized resets, in lieu of voltage-dependent resets, produce variable height voltage ramps, whose amplitude is a direct function of the accumulated alpha activity per unit time. This method of preprocessing and signal conditioning the alpha components of the EEG waveform provides a simple analog registry of on-line real-time correlation of alpha activity with various physiological and behavioral activity.     

Interfacing the microcomputer: A component-level approach

A method is described for interfacing relatively inexpensive component- and chip-level devices to a standard Intel microcomputer board for providing an on-line physological monitoring system. The system demonstrates basic interfacing techniques and a highly simplified approach for integrating various state-of-the-art peripheral circuit components to a standard microcomputer configuration.