Decremental Effect Research Articles

Local excitability in the superior colliculus influences evoked responses of lateral geniculate cells in rabbits

In anesthetized, immobilized rabbits recordings were made simultaneously from cells in the Lateral Geniculate Nucleus (CGL) and Superior Colliculus (CS), in order to study how the CS influences the CGL. The experimental protocol consisted of three steps. In the initial step (first control) the light stimulus was triggered electronically. In the second step (Test), the same stimulus was triggered by a spontaneous spike arising from a collicular cell. Thus the stimulus presentation was time-locked to collicular endogenous activity. The third step was the same as the first and constituted a second control. The frequencies of stimulus application were gated to be approximately the same. The results indicated that the CS exerts two separate effects on CGL units. In 37 pairs (26%), conditioning the stimulus presentation to collicular firing produced a significant enhancement of geniculate responses. In 24 pairs (17%), the geniculate responses declined. In 82 pairs (57%), no significant influence was noted. The colliculo-geniculate inlfuence is transient. The effects peaked between 100 to 200 msec after the collicular spike and returned to their control levels within 300 msec. Collicular cells producing a decline were encountered mostly in the ventral part of the stratum griseum superficiale, and the stratum opticum, whereas collicular cells that were related to an increased geniculate response were more frequently found dorsally. Increments were more pronounced if the distance (D) between receptive fields was short (0° < D < 40°) or if the collicular and geniculate fields were far apart (120° < D < 180°). The decrement effect was attenuated as the distance separating the two receptive fields. This study suggests that the superior colliculus is capable of generating an internal signal powerful enough to modulate at the geniculate nucleus the visual message conveyed toward the visual cortex. A possible role of the CS in the initiation of the corollary discharge is briefly discussed.

Determinants of brood defence in the great tit Parus major L.

Great tits (Parus major) tending nestlings reacted defensively to a live predator (Glaucidium perlatum; domestic cat) and the playback of a mixed species mobbing chorus, or to the latter alone. Defensive behaviour, mainly mobbing, reflected the risk taken and is assessed by five measures. Multivariate and contingency analyses revealed that at least 11 of 16 contextual independent variables affected the risk taken. Incremental effects are due to: Age of young, sex of the defending bird, the expected number of neighbouring mobbers, low temperature, wet canopy, the raptor's distance from cover, coniferous forest, advancing season. A decremental effect is exerted by a large brood that is older. Annual differences in defence arise probably from demographic factors such as fecundity, which in turn affect the parent's benefit-cost ratio (number of young of the same sex as the parent/residual reproductive value of the parent).

Control of wheel running by near-ultraviolet light

Wheel running by mice was compared during incandescent and incandescent plus near-ultraviolet (UV) illumination in three experiments. During the daily 12-hour light period, running rates decreased with supplemental UV compared to previous incandescent only baselines. The decrements were systematically replicated in a second experiment using alternating UV exposure and recovery phases programmed across blocks of sessions. Again, running rates consistently decreased with supplemental UV irradiation of phases two and four compared to preceeding baselines of phases one and three. In comparison, running rates were inconsistently affected during the 12-hour dark period in both experiments. A third experiment compared the relative decremental effects of UV, blue and red illumination. Baseline running rates monotonically decreased as an inverse function of wavelength for all subjects. The data suggest that the spectral composition of ambient illumination may affect behavior.

The Random Stimulus Design

In the 1960s, a methodological advancement of significant proportion occured with the development of single case research designs in the field of appleid behavior analysis. Among the methods popularized were the multiple baseline, reversal, and, more recently, the alternating treatment designs. Despite the flexibility and wide applicability of each of these single subject designs, there are conditions under which none of them are appropriate. For example, when limited subjects are available and when repeated presentation of the same stimuli result in improvement due to practice effects of decremental effects due to boredom or habituation, problems arise. To offset this difficulty, the investigators describe a new single case design, the random stimulus design. This design is so named becuase an item pool of equal stimuli is established and then items are randomly selected and assigned to one of several cohorts. Cohorts are then assessed in the typical withdrawal or reversal manner.

Methodological Investigation of Vibration Effects on Performance of Three Tasks

Twenty young Navy enlisted male volunteers were first rehearsed and then tested before, during, and after whole-body vibration. Fourteen were tested only at 8 Hz, and six were tested at 8 Hz/0.21 g rms, 16 Hz/0.43 g rms and 32 Hz/0.85 g rms, using three paper-and-pencil tasks involving visual, motor, and cognitive skills. The tasks were “Spoke”, a speed of tapping test; “Aiming”, a test of fine motor coordination; and “Coding”, involving mental computation. Results showed an approximately equal decrement effect across conditions in the Spoke and Coding (but not Aiming) tests that conforms with the frequency function embodied in the current international standard (ISO 2631:1978) on human exposure to vibration; but that a modicum of previous vibration experience may be necessary before reliable data are obtained in this kind of testing. Implications for methodology and for the application of the current standard are briefly discussed.

Character of correlation between the anticonvulsant action of phenazepam and its level in the mouse brain

The effect of low doses of haloperidol was studied by means of screening and electrophysiological tests. In doses of 0.05--0.15 mg/Kg haloperidol exerts an activating effect which manifests in the elevation of motility, in the potentiation of the convulsant effect of bicuculline, EEG desynchronization and decrement of test response depression in the recovery cycle of the somatosensory primary response. The data obtained suggest that the activating effect of haloperidol is due to the weakening of inhibitory processes in the brain.

Priming-produced facilitation or diminution of responding to a Pavlovian unconditioned stimulus.

Two experiments, concerned with signal-produced variation of unconditioned response (UR) amplitude, evaluated the roles of US intensity and response measure in determining when signaling the US results in a conditioned diminution or a conditioned facilitation of responding. In Experiment 1, rabbits received discrimination training, in an eye-blink-conditioning preparation, with a 1-mA, 50-msec shock US. In testing, preceding the US by SC+ facilitated the eye blink response compared with preceding the US by CS- or neither CS. In Experiment 2, subjects received discrimination training with a 5-mA US and were tested with 1-, 2-, and 5-mA US. During testing, subjects' eye blink responses (for which robust CRs were observed) and gross body movement responses (for which no CRs were observed) were simultaneously recorded. for the eye blink response, preceding the US by CS+ facilitated responding to the 1-mA US, produced negligible differences in responding to the 2-mA US, and diminished responding to the 5-mA US, compared with preceding the US by CS- or neither CS. For the movement response, preceding the US by CS+ diminished responding at all three US intensities, with the decremental effects increasing with increases in US intensity. The results of Experiments 1 and 2 are discussed in terms of the dual effects of CS+: the diminution of US processing and the contribution of the conditioned response to the measured response.

A multifactor-system dynamics theory of emotion

In multifactor individuality theory, emotion is treated as the product of the interaction of the cognitive and affective systems, where the cognitive system is defined as a multidimensional, hierarchical system that transforms information in order to detect environmental invariants, and the affective system is defined as a multidimensional hierarchical system that transforms information into arousal states. The highest order dimensions of the cognitive system are conceptual, perceptual, and symbolizing; the highest order dimensions of the affective system are emotional independence, introversion — extroversion, and emotional stability. The concept of arousal provides a key to understanding the complex interactions between cognition and affect. It is hypothesized that specifiable subsets of cognitive and affective dimensions conform to either the facilitative or decremental effects of arousal, and that the Yerkes-Dodson inverted-U function is a composite of both effects. An explanation for the differentiation of distinct emotional states is also presented. Essentially, emotions are differentiated by different weightings of the affective and cognitive dimensions. A theoretical framework for studying the temporal sequencing of phases of emotional behavior is presented as well.

Age-Related Differences in Acquisition of a Verbal Habit

10 young (&lt; 40 yr.) and 10 elderly (&gt; 60 yr.) adults recalled previously memorized paired associates over a long series of trials. Practice was either massed or distributed. Reaction time decreased for both groups at the same rate. Spacing of trials did not affect the younger subjects’ pattern of learning. The elderly subjects’ learning curves showed the classical effects of warm-up, reminiscence, and work decrement. Distribution of practice was seen to affect momentary level of performance rather than actual degree of learning.

Spontaneous decay of compulsive urges: Cumulative effects

In a laboratory investigation of compulsive urges (and the associated discomfort) it was confirmed that these phenomena are subject to spontaneously-occurring decrements. These decrements take place within 15–180 min, according to variations in the experimental conditions. The declines in urges and discomfort follow parallel courses. With repetition, the declines in urges and discomfort take place more rapidly. The decremental effects are cumulative and stable. The spontaneous decay curve shrinks with repeated trials.

Information processing and the decremental effect of intermittent reinforcement schedules in human conditioning

Human conditioning performance decreases as a function of decreases in reinforcement ratio. It was shown that this effect is not exclusively a result of trial-by-trial increments and decrements associated with unconditioned stimulus presence vs. absence. Decreases in reinforcement ratio also increase the number of trials required before CRs emerge and decrease the limit of operators employed to describe performance once acquisition begins. The latter two effects were interpreted to mean, first, that more time is required by subjects to develop the associative network requisite to response acquisition and, second, that information about reinforcement schedules beyond trial-by-trial effects determines overall boundary conditions of performance. The results were discussed from an information processing perspective that differentiates between the acquisition of knowledge about the schedules and the trial-by-trial feed-back effects that shape performance.

Short-term changes in responsiveness to models inBetta splendens

In an experiment attempting a detailed analysis of the habituation of aggression in blue male Siamese fighting fish, the fish viewed their mirror images for varying lengths of time, and then the duration of gill-cover erection was measured during a 60-sec presentation of a simplified model. Tests were separated by 24 h. Responsiveness was lower on the first day of testing than on any subsequent day. There was a peak of responsiveness to a blue model following 5-sec mirror exposure, with a decline in responsiveness after longer mirror exposures. Mirror exposure did not affect responsiveness to a green model. These results suggest that there are incremental and decremental effects of responding in this situation, both of which are stimulus-specific.

Delayed partial reinforcement: Length of delay interval and the relationship of independence

In Experiment 1, groups received a 0-, 15-, 30-, or 60-sec delay of reinforcement on the rewarded trials of a partial reinforcement schedule (delayed PR). A 15-sec reinforcement delay did not reduce acquisition speeds compared with no delay. With delays of 30 and 60 sec, decremental effects of delayed PR were obtained for the first time, with a 60-sec delay of reinforcement producing much slower running than the 0- or 15-sec delays and the 30-sec delay group intermediate. In Experiment 2, two groups received a 60-sec delay of reinforcement, combined in one case with PR and in the other with consistent reinforcement (CR). The delayed PR group ran faster than the delayed CR group in acquisition in all alley sections. The results were discussed with reference to the role of inhibition in producing behavioral decrements under delayed reinforcement.

Cardiovascular changes in/of old age.

Although the causes of aging are still unknown, the effects of decrements in anatomic structure and physiologic function have led to wrong concepts and resulting discriminatory policies against old people. Cardiovascular changes are common among the aged but are not necessarily symptomatic; they may be the result of past illnesses or signs of diminished cardiac reserve. In many cases, a cardiac abnormality detected by our modern diagnostic hardware dose not in itself constitute the necessity for treatment. Illustrative cases are cited. A rise in blood pressure with advanced age often is a sign of adaptation to the increased rigidity of the arterial system. Certain heart murmurs mimicking mitral insufficiency may indicate slight papillary muscle dysfunction or a clinically insignificant degree of mitral valve prolapse. On the other hand, the changing clinical status in old age may involve a diminution of symptoms. Therefore, in geriatric medicine, the physician should be on the alert for aberrant manifestations, e.g., painless myocardial infarction or atypical pulmonary embolism. Psychologic evaluation is important. There is no cardiac disorder which is typical for the older age group, but also there is none from which older people are exempt.

Effects of spiperone on self-stimulation and other activities of the Mongolian gerbil.

1 Self-stimulation to lever pressing and capacitance probe touching was obtained in Mongolian gerbils (Meriones unguiculatus) from electrode placements within the medial forebrain bundle. 2 Lever pressing was more sensitive to the decremental effects of a central depressant, pentobarbitone, than capacitance probe touching, suggesting its greater responsiveness to disturbances of motor function. 3 Spiperone (0.005 to 0.05 mg/kg) attenuated capacitance probe touching and lever pressing equally, a finding explained by action on either reward pathways or on the ability to initiate responding. 4 This same dose range of spiperone (0.005 to 0.05 mg/kg) attenuated locomotor activity, whether spontaneous or evoked by non-contingent electrical stimulation, and produced catalepsy. 5 The spiperone-induced attentuation of self-stimulation was not necessarily a result of its action on dopaminergic reward pathways since the effects could equally well be explained by a failure to initiate responding.

Blocking of a taste aversion by prior pairings of exteroceptive stimuli with illness

Although rats preferentially associate gustatory stimuli with illness, this does not imply that other types of stimuli cannot be associated with illness. In Experiment 1, rats consuming tap water in a distinctive environment prior to illness subsequently suppressed ingestion in that environment, whereas rats poisoned or injected with saline 10 hr later did not. It was also found that rats poisoned after drinking saccharin in the environment paired with illness developed weaker saccharin aversions than identically trained rats which drank saccharin in a different location. In Experiment 2, degrading the correlation between injection-related cues and illness by interpolating saline injections between LiCl preexposures attenuated the decremental effects of illness preexposure. The strength of the exteroceptive cue-illness associations observed in these studies suggests that theories based on evolutionary arguments are not the most appropriate frame of reference for analyzing stimulus selection in poison-induced avoidance.

Lateral differences in habituation of ipsilateral head-turning to repeated tactile stimulation in the human newborn.

Lateral differences in habituation of ipsilateral head-turning to repeated tactile perioral stimulation following midline head restriction was studied in 44 full-term neonates. Left-sided stimulation had a significantly greater and faster decremental effect than right-sided stimulation. Even in the absence of tactile stimulation (Control Group), head-turning to the left decreased systematically whereas head-turning to the right did not. The transient efficacy of prior midline head restriction for the elimination of lateral differences in both spontaneous head movements and responsiveness to tactile input suggests that behavioral asymmetry is already well-established in the newborn.

(Abstract) The Effects of Recombination Balmer Decrements of Collisional and Self-Absorption Processes

(Abstract) The Effects of Recombination Balmer Decrements of Collisional and Self-Absorption Processes

Effects of chlordiazepoxide on tail pinch-induced eating in rats

The effects of 5, 10, and 20 mg/kg chlordiazepoxide on tail pinch (TP)-induced behavior were investigated. Five mg/kg enhanced TP-induced eating in terms of both latency and duration. Twenty mg/kg had decremental effects. All doses of the drug reduced the incidence of clip-directed behavior, but increased locomotor activity during the TP trials in a dose-dependent manner. On control trials, the drug increased locomotor activity at the low dose and eating at the high dose. The results are examined in terms of the various behavioral actions of the minor tranquilizers. The implications for the behavioral and neuropharmacological mechanisms underlying TP-induced and other forms of stimulus-bound behavior are discussed.

A note regarding conditioned attention theory

Two experiments employing rats in an Estes-Skinner CER procedure are reported. In Experiment 1, subjects were preexposed to two stimuli in one of two temporal relationships. S1 either preceded S2 or was explicitly unpaired with S2. When subsequently paired with shock, S1 produced greater response suppression in the group for which S1 and S2 had been paired. In Experiment 2, it was demonstrated that the pairing of S1 and S2 did not enhance subsequent conditioning of S1; rather, the ‘unpairing’ of those stimuli appeared to retard conditioning of S1. These findings are consistent with each of two recent accounts of response decrement effects (Lubow, Alek, & Arzy, 1975; Wagner, in press), but also admit to other interpretations.