Donald I. Tepas

Computer analysis of the electroencephalogram: Evoking, promoting, and provoking

Having a long history of applying analog processing techniques to their data, electroencephalographers were among the first to use the digital computer in the laboratory. Methodological and terminological lessons learned from these applications are discussed in terms of their significance for the psychophysiologist in specific and the psychological laboratory in general.

Auditory evoked brain responses: Intensity functions from bipolar human scalp recordings*

Average evoked brain responses were computed from four simultaneous recordings during binaural tone stimulation at 10 intensity levels. Amplitudes and latencies were measured for the prominent components, and linear regression coefficients were computed. The results indicate that the sensitivity of the evoked response to stimulus intensity is dependent upon the selection of the appropriate measure. Linear amplitude functions were demonstrated. Additional research relating these responses to psychophysical measures is suggested.

Intensity effects of the auditory evoked brain response to stimulus onset and cessation

Average evoked brain responses (EBR) to the onset (ON) and cessation (OFF) of 1-kHz pure-tone stimuli were computed from human scalp recordings. Stimuli of 2,000 msec duration were presented binaurally at 10 intensity levels. The waveform of the OFF EBR is similar to the ON EBR. The ON response is in general larger than the OFF response. Comparable ON and OFF amplitude response measures are both sensitive to changes in stimulus intensity which may be fit by a linear function. Significant differences in slope between ON and OFF amplitude intensity functions were demonstrated, which suggests different physiological systems for these responses.

APE: average potential evaluation software for the LAB-8 system

A paper-tape software system is described which allows the addition and/or subtraction of signal averaging data from the DEC advanced averager program. This pooled averaging data may be plotted, printed, or punched. A DEC LAB-8 system with 4K memory and high-speed reader/punch are required. Several examples of the application of the system to human evoked brain response data are presented, and the application of the system to other problems is discussed.

Gaining access to shiftworkers through labor unions

In this paper, we provide the procedures used to gain access to shiftworkers who served as subjects in a work-sleep study. Our experiences in gaining the cooperation of labor union organizations and their members are described in detail, as are characteristics of the surveyed workers.

Laboratory and field interview methods for the study of shiftworkers

Gordon, Tepas, Stock, and Walsh (1979) describe the manner in which shiftworkers were selected as research subjects through the cooperation of labor union organizations. In this paper, we describe the methods used to select and orient the workers to serve in a laboratory study involving measurement of the psychophysiological correlates of sleep. Procedures used for field interviews with the same subjects are also described. Some of the advantages and disadvantages of using a multimethod (laboratory and field interview) approach to the study of shiftwork effects are detailed.

Computer use in the psychology laboratory: A survey☆

Abstract A survey was conducted to quantify computer use in psychology as well as to evaluate the need for specialized conferences in this area. The questionnaire was mailed to 402 probable computer users in psychology and allied sciences. A 60% response rate was achieved. Respondent access and use of mini computer, remote terminal, and large batch processing systems is presented and discussed in terms of equipment use, programming language use, and specialty area of primary application. The data indicate that the majority of the respondents most frequently use mini computer systems, despite the common availability of both terminal and large batch processing systems. Most respondents do some programming of their own, frequently using languages other than FORTRAN or BASIC for mini computer applications. Equipment, language and specialty area all vary with type of system.

Human evoked brain responses following loud pure tones

The electroencephalogram (EEG) was recorded at the vertex of three subjects following a 5-min exposure to a 720-Hz pure tone at 110 dB or 45 dB SPL. Eight consecutive evoked brain responses (EBRs) to tone bursts were computed from the EEG for a 2-min period following each exposure. The EBRs computed following the 110-dB exposure were initially smaller than those computed following the 45-dB exposure, and this difference became minimal as time after exposure increased. Thus, EBR amplitude data suggest that a temporary threshold shift (TTS) was produced by the 110-dB exposure and that the EBR reflects this change in the listener’s sensitivity.

Teaching maxi- and minicomputer programming at the same time: Is there an advantage?

A course is described that provides concurrent and equal coverage of maxi- and minicomputer systems. The results of student evaluations are provided.

Paradoxical sleep in the rat: Comparison of early and late blinding

Electrophysiological recordings of sleep in adult rats blinded prior to weaning were significantly different from those recorded in littermates blinded after weaning. Behavior on an open-field test failed to indicate any significant differences between these two groups. Thus, it appears that an early reduction of external sensory input can modify brain activity during sleep.