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PubMed1979

Stimulus properties of conspecific behavior.

Two experiments identified the conditions in which the behavior of one bird acquired discriminative control of the behavior of a second bird. The schedule-controlled behaviors of the "stimulus" bird were differentially correlated with the components of a multiple schedule according to which the pecking of an "experimental" bird produced food. In Experiment 1, three pairs of pigeons acquired a successive discrimination and two reversals with the conspecific stimuli. Experiment 2 included a control condition in which no systematic relationship existed between the conspecific stimuli and the component schedules. While differential responding during the components of the multiple schedule was again found when the conspecific stimuli were available, differential responding did not occur in the control condition. Test conditions included in the experiments indicated that (a) the differential responding was not dependent on the discriminative properties of reinforcement, (b) the pecking of the stimulus and experimental birds was temporally interrelated, (c) the visual conspecific stimuli were critical to the maintenance of the discrimination, and (d) the observed stimulus control immediately generalized to an unfamiliar conspecific.

Journal Article↗
PubMed1992

Inverse relations between preference and contrast.

Pigeons were trained on a multiple schedule in which two target components with identical reinforcement schedules were followed by either the same-valued schedule or by extinction. Response rate increased in both target components but was higher in the target component followed by extinction, replicating previous findings of positive anticipatory contrast. A similar design was used to study negative contrast, in that the two target components were followed either by the same-valued schedule or by a higher valued schedule. Negative contrast occurred equally, on average, in both target components, thus failing to demonstrate negative contrast that is specifically anticipatory in nature. When the stimuli correlated with the two target components were paired in choice tests, the pattern of preference was in the opposite direction. For the positive contrast procedure, no significant preference between the two target stimuli was evident. But for the negative contrast procedure, preference favored the stimulus followed by the higher valued schedule. The results demonstrate a functional dissociation between positive and negative contrast in relation to stimulus value. More generally, the results demonstrate an inverse relation between response rate and preference and challenge existing accounts of contrast in terms of the concept of relative value.

Journal Article↗
PubMed2004

Management of insomnia in patients with chronic pain conditions.

The management of insomnia in patients experiencing chronic pain requires careful evaluation, good diagnostic skills, familiarity with cognitive-behavioural interventions and a sound knowledge of pharmacological treatments. Sleep disorders are characterised by a circular interrelationship with chronic pain such that pain leads to sleep disorders and sleep disorders increase the perception of pain. Sleep disorders in individuals with chronic pain remain under-reported, under-diagnosed and under-treated, which may lead--together with the individual's emotional, cognitive and behavioural maladaptive responses--to the frequent development of chronic sleep disorders. The moderately positive relationship between pain severity and sleep complaints, and the specificity of pain-related arousal and mediating variables such as depression, illustrate that insomnia in relation to chronic pain is multifaceted and poorly understood. This may explain the limited success of the available treatments. This article discusses the evaluation of patients with chronic pain and insomnia and the available pharmacological and nonpharmacological interventions to manage the sleep disorder. Non-pharmacological interventions should not be considered as single interventions, but in association with one another. Some non-pharmacological interventions especially the cognitive and behavioural approaches, can be easily implemented in general practice (e.g. stimulus control, sleep restriction, imagery training and progressive muscle relaxation). Hypnotics are routinely prescribed in the medically ill, regardless of their adverse effects; however, their long-term efficacy is not supported by robust evidence. Antidepressants provide an interesting alternative to hypnotics, since they can improve pain perception as well as sleep disorders in selected patients. Sedative antipsychotics can be considered for sleep disturbances in those patients exhibiting psychotic features, or for those with contraindications to benzodiazepines. Low doses of sedative antipsychotics may improve chronic insomnia in the elderly. However, no intervention is likely to be effective unless a good physician-patient relationship is developed.

Analgesics↗
PubMed1999

The effect of sex differences on event-related potentials in young adults.

Female/male cognitive differences have been studied for some time; however, such differences in Turkish population is unknown. Evoked potentials (EPs) of the brain have been applied as an index of information processing in a wide variety of normal and cognitive impaired subjects. Scalp event-related potentials (ERP) evoked by auditory stimuli were recorded in 20 male and 18 female neurologically and audiologically normal young Turkish subjects of 18-25 years (Av. 20.6) of age. Standard auditory "Oddball" paradigm involving simple discrimination task of concentrating on infrequent (target) stimulus and ignoring frequent (non-target) stimulus was employed. EEG activity was recorded at the Fz, Cz, Pz and Oz electrode sites of the 10-20 system using Ag/AgCl electrodes. Wave forms were collected and averaged off-line by a Pentium 100 computer, which also controlled the stimulus presentation. In general, significant main effects of gender and electrode site on evoked potential components were found. The interpeak amplitudes N1-P2 and N2-P3 were higher in the male subjects than in the female subjects at Cz. N2-P3 were higher in the male subjects than in the female subjects at Oz. The latencies of N1, P2, N2, P3 components were not different between both sex. For both sexes we found that N1-P2 amplitude was higher at Fz and Cz than Pz and Oz. N2-P3 amplitude was higher at Fz than Oz for only female subject. In male subjects, latency of N2 was longer at Fz than Oz. There were no significant differences in the latencies of N1, P2, and P3 components between electrode sites in both sexes. We suggest that ERP components could be affected by sex, electrode site, and cognitive performance.

Adolescent↗
PubMed1993

Experimental autoimmune prostatitis (EAP): enhanced release of reactive oxygen intermediates (ROI) in peritoneal macrophages.

The metabolic state of peritoneal macrophages is defined quantitatively for spontaneous ROI release and compared with those produced after cell contact with phorbol myristate acetate (PMA) or zymosan (OZ) particles. Peritoneal exudate cells (PEC) from EAP animals spontaneously released significantly more ROI than cells from controls rats, indicating that mononuclear phagocytes from autoimmune rats were more activated than populations cells arising from rats injected with BSA, with CFA or non-injected. These findings could indicate an in vivo activation state in PEC from autoimmune rats different from that obtained with heterologous antigens or CFA immunization procedures. The release of ROI induced after in vitro stimulus was, in general, higher in cells from autoimmune than in BSA or CFA treated rats. This differential responsiveness between the MAG, BSA and CFA injected macrophage populations could indicate that during the autoimmune process the autoantigen/s could amplify the inflammatory response triggered by them. Although release of oxygen metabolites represents only one of many potential mechanisms of tissue injury, this together with the lesions observed in the prostate gland indicate that oxygen radicals could be involved in this autoimmune disease.

Animals↗
PubMed2002

Transfer of learning across durations and ears in auditory frequency discrimination.

Frequency-discrimination thresholds (FDTs) for 1-kHz tone pips with durations of 40, 100, and 200 msec were measured in the left and right ears of 10 normal-hearing listeners, before and after six 2-h frequency-discrimination training sessions involving, exclusively, the 200-msec duration and the right ear. In the trained ear, highly significant improvements in FDTs were observed at all durations. Further inspection of the data suggested complete generalization between 200 and 100 msec, but not at 40 msec. Posttraining FDTs were not found to differ between the two ears for the two untrained durations, but proved significantly smaller in the right (trained) than in the left (untrained) ear at the trained (200-msec) duration only. A control experiment involving 10 additional subjects allowed us to establish the absence of intrinsic differences in pretraining FDTs between the right and left ears. Overall, these findings indicate that frequency-discrimination learning generalizes widely across stimulus durations and across ears, but that part of the improvement is specific to the range of durations and to the ear used in training.

Adult↗
PubMed1991

Hippocampal inputs to identified neurons in an in vitro slice preparation of the rat nucleus accumbens: evidence for feed-forward inhibition.

The aim of the present study was to analyze responses of nucleus accumbens neurons to stimulation of the fornix. The recorded neurons were labeled with biocytin and identified as medium spiny neurons. A large majority of cells generated a depolarizing postsynaptic potential in response to stimulation of the fornix. Using intracellular current injection, this depolarizing response was dissociated into an EPSP reversing at -6 +/- 6 mV and an IPSP reversing at -71 +/- 4 mV. Both the EPSP and IPSP were abolished by 6-cyano-7-nitroquinoxaline-2,3-dione. In addition, the IPSP was blocked by bicuculline and picrotoxin. The onset latency of the EPSP was constant in spite of varying stimulus intensities. In contrast, the onset latency of the IPSP increased with decreasing stimulus intensity. Notably, the stimulus threshold for evoking IPSPs was generally lower than for EPSPs. At stimulus intensities well above threshold, the IPSP onset was only slightly delayed with respect to the EPSP onset. These results indicate that the EPSP can be characterized as a monosynaptic and glutamate-mediated synaptic response. The IPSP, however, appears to be mediated by a disynaptic feed-forward pathway involving both glutamate and GABAA receptors. Recurrent and lateral inhibitory interactions have previously been proposed to be predominant organizational principles in the caudate-putamen and nucleus accumbens. This study indicates that feed-forward inhibition is an additional principle governing the activities of striatal neural networks.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1987

Osteoarthritis, insulin and bone density.

We earlier explored the crush and shear forces, associated with periarticular fibrous thickening, in nodal and other forms of osteoarthritis (OA). Looking for a generally acting growth stimulus, we described an association between hyperinsulinemia and DISH. In this study this association was confirmed, and a similar association between low insulin values and osteopenia emerged. A strong association between insulin levels and body weight was confirmed, which explained much of the difference in insulin levels between males and females. Very different kinds of OA were found in robust, hyperinsulinemic subjects as compared with osteopenic, hypoinsulinemic individuals, in which the arthropathy was more deforming, inflammatory, and erosive.

Adult↗
PubMed1985

Postnatal development of the phase-locked response to low frequency tones of auditory nerve fibers in the cat.

The maturation of the auditory nerve's ability to encode temporal information in an acoustic signal was studied in young kittens, 7 to 23 days old, and in adult cats by measuring the degree to which auditory nerve fiber responses are synchronized (phase locked) to low frequency tones. The major findings include the following. In 7- to 10-day-old kittens thresholds are high (around 100 dB), and secure phase locking is observed only at frequencies below about 600 Hz. The upper frequency limit for phase locking in the adult, around 4 kHz, is reached gradually toward the end of the third postnatal week, a time when thresholds also reach their adult levels. The time course of development of the phase-locked response is similar for fibers with different characteristic frequencies (CFs). At all ages studied, the maximal phase synchrony at any given low frequency is generally obtained at stimulus intensities less than 20 dB above the rate threshold and some 10 to 30 dB below the saturation firing level of the fiber. Time delays, estimated from phase-versus-frequency plots, were similar across ages, although they tended to be longer and more variable at lower CFs during the first 2 postnatal weeks. Comparing the phase-locked response of auditory nerve fibers with that of the anteroventral cochlear nucleus neurons from a previous study suggested that the upper frequency limit for phase synchrony was reached later in the nucleus than in the nerve.

Acoustic Stimulation↗
PubMed1985

Color discrimination as a function of saturation, field size, and adaptation level.

The purpose of our research was to investigate color discrimination under conditions of ambient illumination that may reduce CRT display saturation and contrast. Our research measured both the variability of color matching and the offsets from a match necessary for a 100% discrimination difference. We did this for four dominant wavelengths each at five saturation levels. Our subjects were tested at low, medium, and high adaptation levels for both large and small test stimulus sizes. In general, our results for the low luminance color matching conditions are in agreement with the published literature. For the high luminance and small field conditions, our data suggest that color discrimination should not be predicted from the 1960 CIE Uniform Chromaticity Space data. Color discrimination varies dramatically with dominant wavelength; reds and greens are more difficult to discriminate than yellows and yellow-greens.

Adaptation, Physiological↗
PubMed1985

Behavior therapy techniques applied to eating, exercise, and diet modification in childhood obesity.

Behavior therapy techniques are receiving increasing attention in the treatment of childhood obesity. This paper provides a selective review of experimental studies of childhood obesity that have utilized behavior therapy techniques with preadolescent populations. It further defines and describes specific behavior therapy techniques utilized in the modification of eating, exercise, and diet patterns in childhood obesity, including stimulus control, stimulus and response generalization, prompting, positive reinforcement, shaping, contingency contracting, and generalization and maintenance strategies.

Behavior Therapy↗
PubMed1974

Conditioned blink reflex and neuronal activity in the auditory cortex of the cat.

The present study is concerned with conditioned reflex changes in background and evoked activity of the neuronal population of the auditory cortex (AI) in three waking cats. For the elaboration of a conditioned blink reflex, a series of eight clicks was used as the signal. The unconditional stimulus was rhythmic blowing of air at the eye. During the elaboration of a positive conditioned reflex there was a significant increase in the level of background activity. During conditioned reflex extinction, background activity showed a further increase. When extinguishing inhibition became profound, it was equivalent to sleep, and there was a strong fall in the level of background activity. During the restoration of an extinguished conditioned reflex, background activity fell to the level observed during conditioned reflex extinction, at the stage of consolidation. Application of an acoustic stimulus elicited a general, sometimes a slight increase in the number of spike discharges. Within the range of 300-350 ms - the time of appearance of the evoked response - neuronal activity underwent a reorganization, sometimes with a tendency to phasic variations. Phasic variations of the given population in response to sound were observed at all stages of the study.

Acoustic Stimulation↗
PubMed1984

Sympathetic nervous system response to mechanical stress of the spinal column in rats.

The effects of mechanical stimulation of the spine on blood pressure, heart rate and the activity of selected sympathetic nerves (renal and adrenal) were examined in alpha-chloralose/urethane anesthetized rats. Spinal segments from T10 to T13 or from L4 to L7 were isolated from surrounding muscle and the upper and lower segments of the four segment units were fixed by means of spinal clamps. Forces from 0.5 to 3.0 kg were applied to the lateral aspect of the two mobile segments. Stimulations of the thoracic or the lumbar region produced large decreases in blood pressure (-29.8 +/- 3.1 mmHg) along with small decreases in heart rate (6.1 +/- 1.6 beats/min). Additionally, large and immediate decreases were observed in renal nerve activity. While responses attenuated during the course of stimulation, they generally outlasted the stimulus. The adrenal nerve, after an initial decline in activity, showed subsequent increases which were attributed to baroreceptor effects, since bilateral lesion of the vagi and carotid sinus nerves abolished them. After baroreceptor denervations only initial decreases in activity were observed by mechanical stimulation of the spine. The observed responses were found not to be due to spinal cord compression, but rather were ascribed to afferent fiber mediated reflexes. Cutting dorsal (sensory) roots T10 to L2, bilaterally, abolished the response to lower lumbar stimulation. Additionally, in recording from the peripheral end of the severed dorsal roots, large increases in afferent activity were observed by spine stimulation. The present study has demonstrated potent somatovisceral reflexes from mechanical stimulation of the spinal column. These results are discussed in relation to other studies of somatovisceral responses and with regard to various clinical reports.

Adrenal Glands↗
PubMed1987

A role for receptors of N-methyl-D-aspartic acid in the discriminative stimulus properties of phencyclidine.

Ketamine and (+)-N-allylnormetazocine ((+)-NANM) were found to generalize in a rat operant drug discrimination paradigm to the interoceptive stimulus induced by phencyclidine (PCP). Intraperitoneal administration of the non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, MK-801, and intracerebroventricular injection of the competitive antagonist, 2-DL-amino-7-phosphonoheptanoic acid (2-APH), also resulted in a dose-dependent generalisation to the PCP discriminative stimulus. The results suggest that NMDA receptor antagonism may play an important role in the mediation of the discriminative stimulus properties of PCP. The low potency of MK-801 and 2-APH to displace [3H](+)-NANM binding in vitro argues against an involvement of the haloperidol-sensitive sigma recognition site in the behaviour.

Animals↗
PubMed1984

Synthesis and evaluation of substituted 2-phenylcyclobutylamines as analogues of hallucinogenic phenethylamines: lack of LSD-like biological activity.

cis- and trans-2-(2,4,5-trimethoxyphenyl)cyclobutylamine and trans-2-(2,5-dimethoxy-4-methylphenyl)cyclobutylamine were synthesized as conformationally restricted analogues of hallucinogenic phenylisopropylamines. In rats trained to discriminate saline from LSD (0.08 mg/kg, ip) in a two-lever drug discrimination paradigm, no generalization of the LSD stimulus to the cis trimethoxy compound occurred at doses up to 20 mg/kg. For both of the trans compounds, partial generalization of the LSD cue occurred at doses of 5 mg/kg or greater. In contrast, complete generalization occurred with trans-2-(2,5-dimethoxy-4-methylphenyl)cyclopropylamine. The ED50 for this compound and the doses of the trans cyclobutyl homologues at which significant drug-appropriate responding occurred indicate that the latter are on the order of 50-75 times less potent than the cyclopropylamine analogue. The lack of generalization to the cyclobutylamines indicates either that their discriminative stimulus properties differ from LSD or that they lack discriminative effects.

Animals↗
PubMed2000

Characterization of the discriminative stimulus effects of gamma-hydroxybutyric acid as a means for unraveling the neurochemical basis of gamma-hydroxybutyric acid actions and its similarities to those of ethanol.

The present paper reviews the drug discrimination studies, both from the literature and from this laboratory, conducted to investigate the pharmacological profile of the discriminative stimulus effects of gamma-hydroxybutyric acid. Collectively, the results of these studies suggest that: (1) the discriminative stimulus effects of gamma-hydroxybutyric acid are composed of different cues, each one being the effect of gamma-hydroxybutyric acid on a specific receptor system; (2) the proportion of each component cue varies as the training dose of gamma-hydroxybutyric acid is increased; (3) the gamma-aminobutyric acid B-mediated cue is a major ingredient of the mixed stimulus of gamma-hydroxybutyric acid, but it is more prominent at high training doses than at low training doses of gamma-hydroxybutyric acid; and (4) positive modulation of the gamma-aminobutyric acid A receptor is a relevant part of the discriminative stimulus effects of low gamma-hydroxybutyric acid doses. Finally, data indicating symmetrical generalization between the discriminative stimulus effects of a specific range of doses of gamma-hydroxybutyric acid and those of ethanol are discussed in regard to their further support of the hypothesis that gamma-hydroxybutyric acid may exert its antialcohol effects through a substitution mechanism.

Animals↗
PubMed1994

A framework for assessing the relative efficiency of stimulus sequences in evoked response measurements.

A general matrix-based framework for characterizing the performance of cross-correlation techniques for recovering the response to an arbitrary stimulus sequence is presented. In general an infinite number of recovery sequences can be identified for any given stimulus sequence. The recovery sequence that minimizes the noise in the recovered response is derived and the effect of the recovery operation on the noise is analyzed. This general framework is employed to develop analytic expressions for the relative efficiencies of conventional signal averaging and binary MLS based methods for the most commonly used recovery operation and the one that optimizes SNR assuming the background noise is uncorrelated. The results depend on the ratio of response length to MLS minimum pulse interval and the amplitude loss as a function of stimulus rate. Examples based on measured amplitude loss functions for ABR recordings are employed to evaluate the relative efficiencies of MLS techniques. When the noise is uncorrelated conventional signal averaging is from two to five times as efficient as MLS techniques. The relative advantage of averaging is shown to decrease when the noise is dominated by low-frequency components.

Evoked Potentials, Auditory, Brain Stem↗
PubMed1991

The effect of stimulus repetition rate on the diagnostic efficacy of the auditory nerve-brain-stem evoked response.

This study investigates the hypothesis that an increase in the click presentation rate during diagnostic testing with the auditory nerve-brain-stem response (ABR) will increase the efficiency with which lesions may be detected in the nervous system. Cats were exposed to conditions of hypoxia, hypercapnia and acidemia, and hypoglycemia was induced in rats. ABR was recorded using the standard 10/sec click rate and also a higher (55/sec) rate during both the control state and experimental state. Various parameters of the ABR were compared at the two click rates in the control and experimental states to see if the higher click rate was more effective in detecting pathology in the nervous system. It was found that in only a very few cases was the higher stimulus presentation rate more effective, and that in general ABR recordings at one stimulus rate only is quite sufficient for work in a clinical setting.

Acidosis↗