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PubMed1989

Training and generalization of agrammatic aphasic adults' wh-interrogative productions.

The stimulus and response generalization effects of training wh-interrogative production were examined in 4 agrammatic Broca's aphasic subjects using a multiple baseline design across behaviors and subjects. Throughout treatment, response generalization to untrained questions and stimulus generalization to several nontraining conditions were assessed. Variable response generalization to untrained exemplars of trained wh-interrogative forms and little generalization to grammatically different wh constructions occurred. Stimulus generalization to only one of three conditions was noted. However, generalization treatment involving sequential modification of training across conditions was found to be effective in facilitating generalization to an additional stimulus condition for 2 of the 4 subjects.

Aged↗

PubMed1996

Diazepam enhances conditioned defeat in hamsters (Mesocricetus auratus).

Male hamsters that have been repeatedly defeated by larger, aggressive males subsequently flee from, rather than attack, nonaggressive male intruders that are introduced into their home cages. We have referred to this generalization of flight in response to nonaggressive intruders as "conditioned defeat" (CD). In an attempt to reverse CD pharmacologically, diazepam (DZP) was administered to hamsters at two different time points relative to CD acquisition and subsequent response generalization tests, which involved the exposure of subjects to nonaggressive intruders (NAIs). In Experiment 1, subjects were given a single injection of one of 4 doses of DZP (0, 2, 6, or 20 mg/kg) immediately following CD acquisition. Twenty-four hours later, contrary to expectations, subjects that had received the 6 mg/kg dose displayed elevated flight responses in the presence of an NAI. Flight responding declined over days except in subjects that received the highest dose. In the second experiment, hamsters were administered a single injection of either 0, 2, or 6 mg/kg DZP just prior to a response generalization test occurring 24 h following CD training. Flight responses to the NAIs were again exaggerated in subjects that were given the 6 mg/kg dose, an effect that persisted several days without further drug administration. The present findings suggest the possibility that benzodiazepines can potentiate fear responses under certain stressful conditions.

Agonistic Behavior↗

PubMed1981

Generalization of the effects of teacher- and self-administered token reinforcers to nontreated students.

Ten, black, second-grade boys served in a series of single-subject studies. They were from poor families, did not do well in arithmetic, were deficient in sustained attention, and presented behavior problems at school. One boy was a therapeutic confederate. Of the remaining nine nontreated students, three observed the confederate reinforced by a teacher, three observed the confederate self-reinforce without having an opportunity to use "self-reinforcement" themselves, and three observed self-reinforcement while having an opportunity to use "self-reinforcement." The target behavior was attending. Other measures of outcome were glancing, academic achievement, and accuracy of reinforcement. The basic experimental design consisted of an ABAB withdrawal applied to the confederate while the nontreated students remained on baseline. Generalization was expressed as a ratio (i.e., percent change in the generalization measure divided by percent change in the target behavior). Teacher-administered reinforcers to the confederate did not produce generalization of any kind. Both arrangements of self-administered reinforcers to the confederate produced across-subjects generalization and subject-response generalization. Additionally, the confederate manifested response generalization.

Attention↗

PubMed1990

Haemodynamic aspects of clinical cerebral angiography. Concurrent two vessel monitoring using transcranial Doppler ultrasound.

To overcome the technical limitations which have precluded noninvasive Doppler ultrasound in investigation of rapid cerebral haemodynamic responses in two cerebrovascular beds at the same time, we have modified a commercial 2 MHz pulsed Doppler instrument with online spectrum analysis. Two probes are activated intermittently, recording eight averaged Doppler-shifted spectra from each probe sequentially. Concurrent recordings of blood velocity in both middle cerebral arteries were performed during 25 selective iohexol carotid angiography runs in 13 patients with near normal cerebral vasculature. The technique permitted the differentiation between the specific responses confined to the recipient vascular bed, and the general responses occurring in remote brain areas as well. The specific response to iohexol was biphasic; a significant decrease in blood velocity occurred less than 4 s after the bolus entry, probably due to the high viscocity of iohexol. Between 4 and 12 s. blood velocity was significantly increased, reflecting the cerebrovascular response to hypertonic solutions. The blood velocity on the opposite side increased from less than 4 s through 45 s after iohexol. This concurs with studies using electromagnetic flowmetry, and suggests that these general responses are elicited by anxiety, discomfort and pain. Thus, no general responses were seen during angiography under general anaesthesia. Eight patients investigated during catheter flushing with normal saline showed a biphasic specific response reciprocal to that due to iohexol. A significant blood velocity peak occurred less than 4 s after the bolus entry, followed by a decrease between 4 and 60 s. The saline injections produced no pain and evoked no significant general response.

Adolescent↗

PubMed2006

Impacts of QTL x environment interactions on genetic response to marker-assisted selection.

Genotype x environment (GE) interaction is a common characteristic for quantitative traits, and has been a subject of great concern for breeding programs. Simulation studies were conducted to investigate the effects of GE interaction on genetic response to marker-assisted selection (MAS). In our study we demonstrated that MAS is generally more efficient than phenotypic selection in the presence of GE interaction, and this trend is more pronounced for developing broadly adaptable varieties. The utilization of different QTL information dramatically influences MAS efficiency. When MAS is based on QTLs evaluated in a single environment, the causal QTL x environment (QE) interactions usually reduce general response across environments, and the reduction in the cumulative general response is a function of the proportion of QE interactions for the trait studied. However, MAS using QTL information evaluated in multiple environments not only yields higher general response, but the general response obtained is also reasonably robust to QE interactions. The total response achieved by MAS in a specific environment depends largely on the total heritability of traits and is slightly subject to relative changes between general heritability and GE interaction heritability. Two breeding strategies, breeding experiments conducted in one environment throughout and in two environments alternately, were also examined for the implementation of marker-based selection. It was thus concluded that plant breeders should be cautious to utilize QTL information from only one environment and execute breeding studies in another.

Breeding↗

PubMed2002

Role of the general stress response during strong overexpression of a heterologous gene in Escherichia coli.

The strong overexpression of heterologous genes in Escherichia coli often leads to inhibition of cell growth, ribosome destruction, loss of culturability, and induction of stress responses, such as a heat shock-like response. Here we demonstrate that the general stress response, which is connected to the stress response regulator sigmas (sigma38, rpoS gene product), is suppressed during strong overproduction of a heterologous alpha-glucosidase. The mRNA levels of the rpoS and osmY stress genes drastically decrease after induction of the strong overexpression system. It is shown that an rpoS mutation causes a significant loss of cell viability after induction of the expression system. Furthermore, it is demonstrated that an E. coli c/pP mutant, which could be suggested to improve heterologous protein production, is not a good production host if a tac-promoter is used to control the expression of the recombinant gene. Data from this study suggest that the overexpression of the alpha-glucosidase was greatly decreased by sigma factor competition in the clpP mutant, due to the increased sigmas level in this mutant background.

Bacterial Proteins↗

PubMedDate not supplied

[Peculiarities of immune responses during general anesthesia in otosurgery].

Immune responses were investigated in 118 patients suffering from chronic purulent inflammation of middle ear. All of them were operated under different methods of anesthesia. Immunotherapy preceding intravenous anesthesia with combination of phentanyl and clophelline along with supporting spontaneous breathing was found to be the most optimal from the immunologic point of view. This anesthetic approach has such advantages as IgG, IgA elevation by 50%-100% and sIgA secretory antibodies content increment by 30% in local mucosal immune system, activating the macrophageal-phagocyte system of antigen treatment.

Anesthesia, General↗

PubMed1961

Generalized neocortical responses and corticospinal neuron activity.

Long-latency responses evoked by ipsilateral sciatic nerve and hippocampal-fornix stimulation in barbiturized cats are associated with activation of corticospinal neurons. Differences in latency and configuration of generalized responses and patterns of relayed corticospinal neuron discharges indicate that a variety of extra-thalamic projections are involved in activation of Betz cells.

Animals↗

PubMed1993

Teaching preschool children with disabilities to respond to the lures of strangers.

An investigation was conducted to determine the effectiveness of a constant-time-delay procedure used in combination with multiple exemplars of strangers, lures, and sites to teach a generalized response to the lures of strangers to four preschool children with disabilities. Although the correct response was quickly acquired in the training site, the response failed to generalize to the probe sites until training was conducted in vivo. Instruction in vivo resulted in acquisition, maintenance, and generalization of the response to strangers' lures. Generalization occurred across probes with novel exemplars of lures, strangers, and sites.

Child, Preschool↗

PubMed2003

Stress-induced gene expression in Candida albicans: absence of a general stress response.

We used transcriptional profiling to investigate the response of the fungal pathogen Candida albicans to temperature and osmotic and oxidative stresses under conditions that permitted >60% survival of the challenged cells. Each stress generated the transient induction of a specific set of genes including classic markers observed in the stress responses of other organisms. We noted that the classical hallmarks of the general stress response observed in Saccharomyces cerevisiae are absent from C. albicans; no C. albicans genes were significantly induced in a common response to the three stresses. This observation is supported by our inability to detect stress cross-protection in C. albicans. Similarly, in C. albicans there is essentially no induction of carbohydrate reserves like glycogen and trehalose in response to a mild stress, unlike the situation in S. cerevisiae. Thus C. albicans lacks the strong general stress response exhibited by S. cerevisiae.

Candida albicans↗

PubMed1991

Estimating equations for parameters in means and covariances of multivariate discrete and continuous responses.

Generalized estimating equations are introduced in an ad hoc fashion for the covariance matrix of a multivariate response. These equations are to be solved jointly with score equations from a generalized linear model for mean parameters. A class of quadratic exponential models is used to develop joint estimating equations for mean and covariance parameters in a more systematic fashion, and proposals for the use of such equations are developed. Comments on the relative merits of the ad hoc and model-based approaches to estimation are given and a regression illustration with a bivariate response is provided.

Anticonvulsants↗

PubMed1982

Temporal generalization.

Responses of 26 rats were reinforced following a signal of a certain duration, but not following signals of shorter or longer durations. This led to a positive temporal generalization gradient with a maximum at the reinforced duration in six experiments. Spacing of the nonreinforced signals did not influence the gradient, but the location of the maximum and breadth of the gradient increased with the duration of the reinforced signal. Reduction of reinforcement, either by partial reinforcement or reduction in the probability of a positive signal, led to a decrease in the height of the generalization gradient. There were large, reliable individual differences in the height and breadth of the generalization gradient. When the conditions of reinforcement were reversed (responses reinforced following all signals longer or shorter than a single nonreinforced duration), eight additional rats had a negative generalization gradient with a minimum at a signal duration shorter than the single nonreinforced duration. A scalar timing theory is described that provided a quantitative fit of the data. This theory involved a clock that times in linear units with an accurate mean and a negligible variance, a distribution of memory times that is normally distributed with an accurate mean and a scalar standard deviation, and a rule to respond if the clock is "close enough" to a sample of the memory time distribution. This decision is based on a ratio of the discrepancy between the clock time and the remembered time, to the remembered time. When this ratio is below a (variable) threshold, subjects respond. When three timing parameters--coefficient of variation of the memory time, the mean and the standard deviation of the threshold--were set at their median values, a theory with two free parameters accounted for 96% of the variance. The two parameters reflect the probability of attention to time and the probability of a response given inattention. These parameters were not influenced by stimulus manipulations but were affected by manipulations of reinforcement rate and by individual differences.

Animals↗

PubMedDate not supplied

Sensory stimulation of severely brain-injured patients.

The research reported here consisted of a series of three studies of the use of a sensory stimulation protocol and assessment scale with brain-injured patients at either Level II or Level III on the Ranchos Los Amigos Cognitive Scale. In the first study, a pilot project with six patients addressed the hypotheses that: (1) immediate changes in responsiveness occur as a result of sensory stimulation; (2) variables such as positioning and level of contact have an effect on responsiveness; and (3) these changes can be measured. The second study established acceptable concurrent validity (n = 20), test-retest (n = 20) reliability and inter-rater reliability (n = 19) values for the procedures. The third study assessed whether change in responsiveness occurs over time secondary to sensory stimulation. General Responsiveness measures for 19 patients were obtained and then remeasured after 3 months. No significant differences in mean General Responsiveness values were found using the t-test for related measures procedure. Relationships were reviewed between General Responsiveness and amount of treatment per day, frequency of family visits, pre-morbid education, age, time since injury and neurological status. No differences were found between those patients who improved and those who did not improve.

Adolescent↗

PubMed1984

The hormonal responses to generalized tonic-clonic seizures.

We studied the hormonal responses to a generalized tonic-clonic convulsion in 20 patients with idiopathic or posttraumatic epilepsy (6 patients) or alcohol-withdrawal seizures (14 patients). We found an increase shortly after the seizure in plasma levels of ACTH, beta endorphin, beta lipotropin, prolactin, and vasopressin, and a later increase in plasma cortisol. There was no significant change in levels of growth hormone, luteinizing hormone, follicular stimulating hormone, or plasma renin activity. An increase in plasma ACTH level was accompanied by a rise in beta lipotropin and beta endorphin, and followed by a rise in plasma cortisol. In 2 patients there was no postictal increase in plasma prolactin, despite changes in other hormones. There was no difference in the nature or time course of the hormonal changes in patients with alcohol-withdrawal seizures and those with seizures from other causes. The mechanisms subserving these changes are unknown. Nonspecific stress influences the release of certain hormones, but the absence of a significant growth hormone response suggests that this was probably not responsible for our findings. It is possible that the generalized neuronal discharge of a seizure stimulates the hypothalamus either directly, through specific neurotransmitter changes, or through the release of other substances. One possibility that we are investigating in experimental animals is that endogenous opioids are involved, especially in the release of prolactin.

Adrenocorticotropic Hormone↗

PubMed2002

Recent insights into the general stress response regulatory network in Escherichia coli.

Many bacterial species exhibit a general stress response that can be induced by numerous very different stress conditions and, phenotypically, renders the cells broadly stress resistant. In Escherichia coli, this response is dependent on the sigmaS (RpoS) subunit of RNA polymerase. SigmaS is a close relative of the vegetative sigma factor sigma70 (RpoD) and recognizes very similar promoter sequences. In recent years, significant progress has been made with respect to elucidating (i) the molecular mechanisms that control the cellular sigmaS level, which include translational regulation as well as intricate control of sigmaS proteolysis, and (ii) the molecular function of sigmaS as a transcription initiation factor, where a number of sigmaS-dependent promoters have been studied in great detail, and the mechanisms that generate sigmaS selectivity are now becoming apparent.

Bacterial Proteins↗

PubMed1976

Employing electric shock with autistic children. A review of the side effects.

The use of electric shock in a punishment paradigm has continued to be a highly controversial issue in the treatment of autistic children. While the experimental literature argues for the effectiveness of the procedure for reducing maladaptive behaviors, some clinicians and researchers have expressed fear of possible negative side effects. The reported side effects of contingent electric shock were reviewed in an attempt to evaluate the validity of these fears. The review indicated that the majority of reported side effects of shock were of a positive nature. These positive effects included response generalization, increases in social behavior, and positive emotional behavior. The few negative side effects reported included fear of the shock apparatus, negative emotional behavior, and increases in other maladaptive behavior. The implication of these findings for the use of the shock procedure are discussed in terms of correct usage of the shock, therapist reservations, and alternative procedures.

Autistic Disorder↗

PubMed1994

Eye torsion elicited by oscillating gratings: effects of orientation, wavelength and stationary contours.

We studied binocular cyclorotatory (torsional) eye movements in response to gratings that oscillated sinusoidally in a frontal plane. The square-wave gratings viewed by the right and left eye were presented and controlled separately to induce cycloversion and cyclovergence by oscillation in phase and out of phase. Eye movements were recorded with scleral induction coils. Stimulus oscillation frequency ranged from 0.125 to 1 Hz and the wavelength of the gratings ranged from 0.92 to 25.75 deg of visual angle. Cycloversion and cyclovergence gain were, on average, comparable in magnitude and decreased with increasing oscillation frequency. There was no consistent effect of the wavelength on the magnitude of the responses. In general, responses were considerably higher to gratings that were oriented horizontally than to those oriented vertically. This anisotropy was present both in cycloversion and cyclovergence. It was enhanced in a larger sized stimulus and by presenting stationary, orthogonal contours (mimicking a "shear" movement), but it was not consistently influenced by wavelength. Cyclovergence showed a phase lag, which increased with oscillation frequency but which was independent of wavelength. In contrast, cycloversion showed a slight phase lead which was independent of both oscillation frequency and wavelength.

Adult↗

PubMed1980

[Electro-ophthalmological responses in inflammations of various sections of the orbital visual pathways (author's transl)].

In a study of electro-ophthalmological responses of the EOG, the photopic and scotopic ERG, the OP and the VECP, in combination with fluorescein angiography and computerized perimetry, in 34 patients suffering from uveitis, chorioretinitis (lesions near the macula and at the periphery), papillitis or retrobulbar neuritis, the following results were obtained: Uveitis and chorioretinitis with lesions either near the macula or at the retinal periphery produce different responses; generally, pathologic responses of the EOG and ERG and normal VECP are obtained in cases of uveitis. Peripheral chorioretinal lesions lead to a diminution of the scotopic ERG, OP and EOG, in contrast to lesions near the macula, in which pathologically diminished amplitudes of the photopic ERG and VECP are found. In papillitis and retrobulbar neuritis, however, the most important peculiarity is the increase in latency and the decrease in amplitudes of the VECP, especially in retrobulbar neuritis.

Chorioretinitis↗