Periodicity within reaction time distributions and electromyograms

This study investigates a periodic component in reaction time frequency distributions, that is, a tendency for responses to occur at regular, discrete intervals of time after stimulus presentation. Reaction time frequency distributions were plotted by a Computer of Average Transients and were obtained under stimulus conditions varying in sense modality stimulated (auditory and visual), and the intensity, colour, and duration of stimulation. The results indicated that there was periodicity in reaction time frequency distributions with a modal period of approximately 25 msec. It was found that the periodicty (a) was most evident when there was considerable variability in reaction time, and (b) tended to attenuate when a large number of reaction times were grouped. Other stimulus conditions appeared to have little effect on the periodicity. A significant correlation was found between the frequency of periodicity in the reaction time distributions and the electromyograms, both having a modal period of 25 msec. It was concluded that the periodicity in reaction time was the result of motor processes.     

Binocular summation in the evoked cortical potential

Computer-averaged evoked potentials were recorded from six subjects presented with flashes under conditions of binocular and monocular viewing, with a device fitted over each eye to produce ganzfeld conditions. Tests were run with red light and with blue. Analysis of the evoked potentials indicates a substantially larger amplitude with binocular stimulation.     

The death crisis and pastoral counseling

Death is an event that presents a crisis to the family system. Conceptualizing death as a stressor event and recognizing the variety of coping resources present in and available to bereaved families and individuals, along with the meaning attached to death, can help interventionists to perceive stategies for providing assistance in time of grief. Pastoral counselors are often needed to interpret death from a faith perspective, yet they may need to interpret the family's reaction to the death crisis in order to facilitate their readjustment. Analysis of the death event using Reuben Hill's crisis equation provides a workable conceptual framework.     

Changeover delay effects on topographically tagged discriminative behavior

In a multiple variable-interval extinction schedule, pigeons' responses on an operant key were differentially reinforced in the presence of discriminative stimuli located on a signal key. Changeover delays of zero, one, two, or four seconds specified the time following a signal-key response within which an operant-key response was not reinforced. Systematic reduction of signal-key response rates with increasing changeover-delay duration indicated that signal-key responding was largely maintained by reinforcement of adventitious signal-key/operant-key response chains.     

The importance of pattern information for the resolution of depth-ambiguous apparent motion

A single apparent motion display can result in the perception of a rigid three-dimensional motion or a plastic, two-dimensional motion. Previous studies have found that the principal determinant of the perceptual outcome is the temporal properties of the apparent motion stimulus. Here it is shown that the form properties of the stimulus are another determinant and that, in some situations, they may become a more powerful determinant than the temporal properties.     

An analysis of 17 catatonic patients diagnosed with neuroleptic malignant syndrome

This study was conducted to show that catatonia is a predisposing factor for neuroleptic malignant syndrome (NMS) and to review the nosological relationship between catatonia and NMS. Seventeen consecutive cases of NMS were analyzed prospectively with reference to clinical and investigative findings before and after exposure to a neuroleptic. The series comprised eight males and nine females, ranging in age from 18 years to 65 years. Prior to neuroleptic exposure, all patients exhibited features compatible with criteria for catatonia (mutism/excitement) according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised, (DSM-III-R). Following neuroleptic administration (single dose in nine cases), patients deteriorated into a febrile, rigid, and obtunded state accompanied by autonomic dysfunction and raised creatine phosphokinase levels. These features were consistent with a diagnosis of NMS. Neuroleptics were discontinued and supportive medical treatment instituted. Benzodiazepines were beneficial in eight cases in relieving stupor, but bromocriptine and dantrolene were generally ineffective. In all patients diagnosed with NMS in the authors' series, catatonia was an invariable prodromal state. It appears that the administration of a neuroleptic intensified the preexisting catatonic state and precipitated a malignant variant of the disorder, which is currently recognized as NMS. The authors, therefore, challenge the separate nosological status of NMS and catatonia and suggest that these syndromes are part of a unitary pathophysiological disorder.     

The structure of self-reported aggression, drug use, and delinquent behaviors during early adolescence

Examined the structure of self-report scales designed to assess the frequency of adolescent problem behaviors. Urban (n = 988) and rural (n = 1,895) middle school students completed the Problem Behavior Frequency Scale (Farrell, Danish, & Howard, 1992a) and measures of other relevant constructs. Confirmatory factor analyses supported a model that included specific factors related to aggression, drug use, and delinquent behaviors, and a higher order problem behavior factor. Findings did not support a distinction between physical and nonphysical aggression. Results were generally consistent across settings (i.e., urban vs. rural) and gender. Other relevant constructs, including peer pressure for drug use and attitudes favoring aggression, had both specific associations with relevant first-order factors and more general associations with the second-order factor. These findings support the construction of separate scales assessing specific domains of problem behaviors in studies of adolescents' problem behaviors.