Influence of a 14-day regimen of electrical stimulation involving large portions of the cerebral mass on later habit acquisition in the rat

Four groups of rats, one of which served as a normal, nonoperated group, were used. The other three groups were operated and fitted with an electrode carrier of eight electrodes of varying lengths arranged in a 7.5 mm X 5 mm rectangle. About 10 or 12 days after surgery, the following groups of animals underwent a 14-day regimen wherein each animal spent 15 min in a deep, metal, electrically insulated cylinder: Group A, normal, nonoperated group, with no intervention; Group B, stimulated each day with 45 trains of rectangular biphasic pulses (3 trains per min) at the rate of 20 pulses per second (pps); Group C, the same but at the rate of 100 pps; Group D, the same but 180 pps. After a 48-hr fast and without benefit of shaping, each animal was placed for 60 min in a lever-pressing device and was rewarded with a pellet after each three to four presses. The resulting performance curves showed no improvement in pressing rate for Group A; marginal improvement for Group B; definite improvement for Group C; and the greatest improvement for Group D, the terminal rate being almost twice that of Group C.     

FUNCTIONAL ANALYSIS AND TREATMENT OF SEVERE PICA

A two-phase functional analysis of a profoundly retarded 19-year-old male's pica facilitated the design of an effective intervention containing no aversive components. In the first analysis, frequent staff-client interaction resulted in 25% and 66% less pica than limited and no interaction, respectively. Paradoxical effects were obtained in the second analysis, where no protective helmet resulted in 38% and 26% less pica than the helmet with face shield and helmet without face shield, respectively. On the basis of these analyses, limited interaction and no helmet conditions were combined in an effective, staff-implemented treatment at a medium-sized institution.     

GENERALIZATION OF OBJECT NAMING AFTER TRAINING WITH PICTURE CARDS AND WITH OBJECTS

Generalization of four retarded children's object naming responses to stimuli in the natural environment was assessed after training with either objects or pictures of the objects. Generalization was typically greater after training with objects. In a second experiment, half of the stimuli that showed little generalization were retrained by alternating the original training object with an object that belonged to the same stimulus class as the training stimulus. The other half were simply retrained using the object. The alternating procedure resulted in substantial increases in generalization to untrained objects.     

The effect of negative stimulus presentations on observing-response rates

Theories of observing differ in predicting whether or not a signal for absence of reinforcement (S−) is capable of reinforcing observing responses. Experiments in which S− was first removed from and then restored to the procedure have yielded mixed results. The present experiments suggest that failure to control for the direct effect of presenting S− may have been responsible. Pigeons and operant procedures were used. Experiment 1 showed that presentations of S−, even when not contingent on observing, can raise the rate of an observing response that was reinforced only by presentations of a signal (S+) that accompanied a schedule of food delivery. Experiment 2 showed that this effect resulted from bursts of responding that followed offsets of S−. Experiment 3 showed that, when the presence of S− was held constant, lower rates occurred when S− was dependent on, rather than independent of, observing. These results support theories that characterize S− as incapable of reinforcing observing responses.     

Preference for less segmented fixed-time components in concurrent-chain schedules of reinforcement

A concurrent-chain procedure was used to examine choice between segmented and less segmented response-independent schedules of reinforcement. A pair of independent, concurrent variable-interval 60-s schedules were presented in the initial link, along with a 1.5-s changeover delay. A chained fixed-interval fixed-time and its corresponding tandem schedule constituted the terminal links. The length of the fixed-interval schedule in the terminal link was varied between 5 s and 30 s while that of the fixed-time schedule was kept at 5 s over conditions. The first components of both terminal-link schedules were accompanied by the same stimulus. Except in the baseline condition, the onset of the second component of the terminal-link chained schedule was accompanied by either a localized (key color) or a nonlocalized (dark houselight) stimulus change. Stimulus conditions were constant during the terminal-link tandem schedule. With three exceptions, pigeons demonstrated a slight preference for the tandem over the chained schedule in the terminal link. Furthermore, this preference varied inversely with the length of the first component. In general, these results are consistent with previous studies that reported an adverse effect on choice by segmenting an interval schedule into two or more components, but they are inconsistent with studies that reported preference for signaled over unsignaled delay of reinforcement.     

Speech-mediated retention in dyslexics

Dyslexics (6 to 9 yr. old) and a control group of 12 normal readers (second-graders) were tested on a memory task with rhyming and non-rhyming items. The most important finding is that both groups were penalized by rhyme, indicating speech coding. It was observed that the dyslexics were not less penalized by rhyme than were controls. The present results are compared with those of other recent studies.     

Influence of age, sex, etiology, and hearing loss on balance performance by deaf children

The purpose of this study was to examine the influence of age, sex, etiology, and degree of hearing loss on the static and dynamic balance performance of hearing impaired children and youth (N = 132), ages 3 to 14 yr. The subjects were individually assessed on Items 2 and 7 of Subtest 2 of the Short Form of the Bruininks-Oseretsky Test of Motor Proficiency. As expected, performance on both tasks improved with chronological age. In comparing the performance of subjects by etiology, only one significant difference emerged; those with genetic deafness were superior on static balance to those whose deafness was idiopathic. However, the mean scores for the genetic group were superior for both balance tasks. The sex of the child as well as extent of hearing loss did not affect performance in either task.     

An ecological approach to mechanisms determining individual differences in perception

In 1982 Satow proposed four hypothetical properties determining mechanisms of individual differences in perceptions; these were supported by results of a factor analysis of responses to a 58-item check list. Present work confirmed the four properties (intense sensitivity, temporal sensitivity, sensory-motor reactivity, and possible range of total stimuli), and obtained a property, preference for intense and prolonged stimuli, from a principal component analysis of data from a 60-item list given to 316 subjects. The 60-item list is a revised version of the 58-item list which asked subjects about their subjective sensitiveness and preferences for environmental sensory stimuli (visual, auditory, olfactory, and tactile). Within subjects relationships among these properties are interindependent, since for individuals correlations of factor-score estimates between pairs of these properties were near zero. This interindepedence supported a model of four hypothetical types of individuals, explaining the individual differences on the grounds of the relations among the properties.     

Behavior of visual evoked potentials (pattern reversal VECP) in smokers

Twenty six clinically healthy smokers were studied with transient pattern visual-evoked potentials. In comparison with a sample of "normal" subjects we found a difference of some parameters (P less than 0.05): the P2-latency and the interocular difference of latency on average were 6-7 ms respectively 2 ms larger. Thirteen subjects have had a prolonged P2-latency (P less than 0.05) and/or a difference in interocular latencies larger than 5 ms. These findings may suggest on subclinical disturbances of visual system and indicators of an special sensitivity of that person. The findings are possibly related to tobacco-alcohol amblyopia.