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At least 37 records · Page 2Linked to original sources
PubMed1978

A behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in Macaca mulatta.

Ten Macaca mulatta monkeys were operantly conditioned to perform three motor paradigms designed to evaluate single and combination finger movements. Eight of these monkeys were retested after left medullary pyramidotomy; 2 monkeys underwent left medullary pyramidotomy prior to conditioning. All animals were tested for three years after operation. Monkeys with a completely sectioned medullary pyramid could, with time, perform difficult motor paradigms that required: (1) both individual and combination finger movements; (2) proximal upper extremity motor control; (3) thumb and index finger pincer grasp; and (4) the ability to preprogram and then execute a precision hand movement. The greater the extent of pyramidal tract destruction, the longer the time necessary for recovery of both discrete finger movement and pincer grasp, the greater the effort needed to attain recovery of hand function, and the weaker the affected musculature. The 2 animals in which pyramidotomy of at least 70% of the tract preceded efforts at operant conditioning learned and performed difficult motor paradigms. In all animals, neurological examination revealed that the most enduring and functionally most important deficit that interferes with hand function following pyramidotomy is loss of contactual hand orienting responses and failure of reflex sensorimotor adjustments.

Animals↗
PubMed1976

Simulation studies of learning in an informon network.

A single informon reproduces classical conditioning to compound stimuli under a wide range of conditions during reinforcement and non-reinforcement; it also reproduces simple operant conditioning. A network of 210 informons with 8400 simultaneouslly varying pathways has been simulated; it can learn to recognize handprinted numerals. The networks studied must be more richly interconnected before they can reproduce more detailed behaviour of animals.

Animals↗
PubMedDate not supplied

[Indices of detection in integral radiophotographic examinations in rural areas].

Integral radiophotographic detection was carried out in the territories of 5 randomly selected village dispensaries in 5 different counties. The action was performed in strictly operational conditions, without external experimental interferences. Stress was laid on the strict following of the methodological letter concerning radiophotography. The performing of integral radiophotographic detection in strictly operational conditions in the rural environment demonstrated the utility of these examinations in the present stage. The output obtained can be considered as satisfactory; local variations can be noted and this indicates the possibility of differentiating the conduct in various geographical areas.

Humans↗
PubMed1976

Conditioned EEG desynchronization and seizure occurrence in patients.

Five patients with seizures poorly controlled by standard anticonvulsant medication, underwent EEG operant conditioning. The operant paradigm reinforced the production of low voltage fast activity while decreasing frequencies below 10 c/sec. Seizure frequency decreased in 2 patients, seizure severity was attenuated in 2 others, and one patient who was only given reinforecement for scalp EMG suppression whowed no change in seizure parameters. Pseudoconditioning and control periods ruled out placebo effects. A rationale for this phenomenon is proposed.

Adult↗
PubMed1976

[Anesthesia and the postoperative period in non-urgent tracheal surgery. Apropos of 36 patients].

The authors report 36 cases of resection and suture for stenosis or tumour of the trachea and give details of their technique of anaesthesia, the post-operative follow-up and their results. The development of fiber endoscopy and simplification of intubation, increases the security of the patient, facilitates the task of the anaesthetist and thus improves greatly the operative conditions and post-operative period.

Adolescent↗
PubMed1979

Operant control of precentral neurons in monkeys: evidence against open loop control.

Four normal monkeys were operantly conditioned to change the firing pattern of 111 precentral neurons from phasic to tonic using an operant paradigm which quantifies the control of single neurons. Two monkeys then had their contralateral pyramidal tract (PT) sectioned and one monkey had C5-7 ventral rhizotomies. Postlesion data were: (1) contralateral C1-2PT lesions did not encumber the monkeys' control of precentral PTNs: (2) contralateral C5-7 ventral rhizotomies completely abolished accurate control of precentral neurons which received proprioceptive feedback from flaccid arm regions. These results indicate that precentral neurons are operantly controlled through proprioceptive feedback from peripheral mechanoreceptors. The output of the mechanoreceptors is probably dependent upon discrete joint angles and/or muscle tension which is maintained through non-PT pathways. These data do not support the concept that precentral neurons are operantly controlled directly from a central; 'open loop', pathway.

Animals↗
PubMed1976

[Conditioning of the avoidance to the contact call in the red face lovebird (Agapornis roseicollis, Aves, Psittacidae)].

Two experiments were run on 10 lovebirds to test the reinforcing effect of the social call in an operant conditioning task. In the first experiment, the reinforced behavior (perching) which provoked the occurence of the call decreased. In the second experiment, where the same behavior stopped the continuous emission of the call, the behavior increased. This behavior may results from an avoidance to the call recorded from a lovebird which do not belong to the group of our experimental birds.

Animals↗
PubMed1977

Behavioral and hippocampal electrical changes during operant learning in cats and effects of stimulating two hypothalamic--hippocampal systems.

The electrical activity of the dorsal and ventral hippocampus and of the anterior and posterior neocortex is described and illustrated during the development of trained operant behavior in water-deprived cats learning to bar-press for water reward under three operant conditioning schedules: (a) continuous reinforcement; (b) alternating 10 sec periods of reinforcement and non-reinforcement; and (c) mixed reinforcement and non-reinforcement with special auditory and visual cues. In addition, the contrasting effects of 100 c/sec electrical stimulation of the medial and lateral hypothalamic systems upon hippocampal electrical activity and operantly trained behavior are reported. During the early stages of learning to bar-press for water reward, when close attention to the bar and water-well are required, hippocampal electrical activity manifests synchrony (theta rhythm) and neocortical electrical activity is desynchronized. Subsequently, as bar-pressing performance improves and requires little attention to the manipulanda, the pattern of hippocampal and neocortical electrical activity is one of irregular slow waves mixed with low voltage high frequency activity, characteristic of relative inattention and automatic performance. During alternating or mixed reinforcement and non-reinforcement schedules of operant training differential effects are observed during reinforcement and non-reinforcement periods, the latter being characterized generally by lower voltage, mixed low and high frequency activity, except when orienting and shifting of attention occurred with associated theta rhythm bursts. Stimulation of the medial hypothalamic system has a striking inhibitory effect upon bar-pressing for water reward. Bar-pressing ceases for many minutes but its eventually resumed at the pre-stimulation rate. In contrast, stimulation of the lateral hypothalamic system only interrupts bar-pressing for a matter of seconds. Possible causes of these differential effects, and especially the prolonged inhibition of bar-pressing induced by medial hypothalamic stimulation, are discussed.

Animals↗
PubMed1978

Effects of chronic epileptic foci on control of pyramidal tract neurons in monkeys.

Five Macaca mulatta monkeys were operantly conditioned to control the firing patterns of single precentral pyramidal tract neurons. The accuracy with which the monkeys could control normal PTNs from within the focus was significantly poorer than PTNs from contralateral, homotopic cortex. In comparison to nonepileptic monkeys, there was no significant difference in the accuracy with which PTNs from cortex contralateral to interictal foci were controlled. By contrast, comparison of the time necessary to gain accurate control over individual PTNs from contralateral cortex showed the epileptic monkeys to be significantly encumbered when compared to nonepileptic monkeys. These data suggest that interictal foci produce "noise" in remote regions of brain that are involved in an operant task requiring a high degree of discrimination.

Aluminum Hydroxide↗
PubMed1976

[Behavior therapy in disorders of dietary behavior].

Behaviour therapies using conditioning principles have been successful in the treatment of some psychopatological eating behaviours. Such have been the cases for anorexia nervosae in adolescents and adults, refusal to eat in the young child and difficulties of swallowing. Some of these cases are described. Research has been done in different countries on the applications of these methods to the treatment of obesity caused by overeating which appears very frequently in our societies. Systematic and covert desensitization and operant conditioning using positive reinforcements are more frequently used in these behaviour modification procedures than aversive methods. More recently, researches on self-control (self-reward and self-punishment) have shown it as a very efficient tool for inducing weight loss. These methods using self-control have been applied to large populations: after a first, careful examination of the patient's eating behaviour, the program of reinforcement is established. It can be partially controlled by written instructions and letters. Results are already encouraging although they need to be followed up. But more research should be done on overeating behaviours, the way they appear and are maintained and on different programs of reinforcement for weight loss.

Adolescent↗
PubMed1978

Menstrual cycle influences on operant behavior of female rhesus monkeys.

Nine female rhesus monkeys were paired with males throughout 63 menstrual cycles. The females' motivation to approach males was studied with an operant conditioning paradigm that required the female to press a lever 250 times to gain access to the male. Sexual behavior was scored during standard 60-min tests that followed the attainment of access (17 pairs, 1,440 tests). In the overall data, mean times to access were shortest at mid-cycle and longest just before and after the onset of menstruation, and a model-fitting method showed that 45% of cycles from individual pairs were significantly correlated with a V-shaped model of the overall pattern. Male sexual activity was highest at mid-cycle and lowest in the last quarter of the cycle, but the changes in access times could not be attributed entirely to the rewarding effects of the ejaculations. In the combined data from five females (9 pairs, 33 cycles), high estradiol levels and low progesterone levels were statistically associated with short access times and short ejaculation times. The overall effect was for operant performance and sexual activity to be synchronized and maximized in the periovulatory period of the menstrual cycle.

Animals↗
PubMed2026

The impact of routine traffic encounters that include procedural justice on police perceptions.

OBJECTIVES: Despite procedural justice in police-citizen interactions being widely studied, there is limited research regarding police perceptions of these interactions. This study addresses this by exploring police perceptions of two different types of random breath test (RBT) - standard and procedurally just - in an experimental trial. Officers were asked to report on whether they believe that their RBT interaction with drivers and riders changed behaviour, developed more positive perceptions of police and resulted in slower travel. Additionally, they were asked if they thought that the RBT interaction took too long. METHODS: This study was a six month randomised control trial with two operational conditions: a control condition with a standard (n = 18 days) and an experimental condition with a procedurally just (n = 17 days) RBT. Police officers completed post-operation surveys (n = 80). RESULTS: Police officers incorporating the principles of procedural justice into RBT had limited impact on officer perceptions. However, those officers who were more open to innovation believed that the interaction would result in more positive perceptions of police. Police officers who believed that their RBTs with motorcycle riders would make a difference perceived that the riders would both change their behaviour and travel more slowly after the interaction. There were no differences in perceived interaction length by police officers across both conditions. CONCLUSIONS: This study has shown that police officer openness to innovation has an important role to play in police officers having more positive perceptions regarding the outcomes of RBT interactions. As such police organisations should undertake activities, such as training, to improve innovation. The lack of perceived differences in RBT length between standard and procedurally just interactions suggests that these enhanced interactions can be implemented without concerns that police officers believe that they 'take too long'.

Humans↗
PubMed1975

Catalytic converters for exhaust emission control of commercial equipment powered by internal combustion engines.

The development of PTX, monolithic catalytic exhaust purifiers, is outlined, and their first use for exhaust emissions control of commercial equipment is described. The main use of PTX converters is on forklift trucks. The purification achievable with PTX-equipped fork-lift trucks under various operational conditions is discussed, and examples from the field are given. During more than ten years of operation, no adverse health effects have been reported, and PTX-equipped internal combustion engines appear safe for use in confined areas.

Automobiles↗
PubMed1976

A two-pathway informon theory of conditioning and adaptive pattern recognition.

A neural network theory is proposed which offers an explanation of many of the facts of classical and operant conditioning and adaptive pattern recognition. Interconnected networks of units have been studied and simulated which embody only two rules; firstly, units have inputs from pathways of variable and of fixed conductivity; secondly, the conductivity of a variable pathway is made proportional to the negative of the mutual information function between the signals at its input and output. The signal in a fixed pathway indicates whether the total input to the variable pathways is a member or not of some class. After a learning phase in which the unit, called an informon, receives such labelled inputs, it is able to predict the class of future unlabelled inputs. Such units are stable and their steady state can be calculated.

Conditioning, Psychological↗
PubMed1978

[Lymphographic investigations of oedema of the extremities following reconstructive vascular surgery in the femoro-popliteal territory (author's transl)].

In 37 patients, oedema of the legs was observed following successful femoro-popliteal surgery; lymphangiograms were performed between the third and ninth post-operative days and the intact lymph vessels at the knee and at the groin were counted. In 27 patients there was partial to total disruption of the lymphatic vessels. There was a clear correlation between the degree of swelling of the leg and thigh with the number of not divided lymphatic vessels at the knee and groin. In the presence of more than three intact lymph vessels, swelling amounted to only 1 to 2 cm., whereas if all lymph vessels had been divided, swelling amounted to 7 cm. Extensive soft tissue trauma and repeat surgery resulted in a greater reduction in intact lymph vessels and correspondingly more oedema than was found with more conservative surgery and after initial operations. The pre-operative condition of the arteries, the presence of venous disease and the postoperative blood-flow in the leg had no influence on postoperative oedema. In order to avoid post-operative lymphoedema, it is necessary to preserve the lymphatics during surgery. Marked oedema requires treatment consisting of compression bandages and medicaments.

Arterial Occlusive Diseases↗
PubMed1979

Spectra of cells in flow cytometry using a vidicon detector.

A TV type vidicon detector was interfaced to a flow cytometer (FCM) to obtain spectra of fluorophores in cells during flow. The normal operations of the FCM are undisturbed. A spectrograph spreads 320 nm of the fluorophore fluorescence emission across the 500 channels of the detector. Spectra of fluorescamine (a surface labeling agent) and of propidium iodide (a nuclear stain) were obtained from Balb 3T3 cells, and the chlorophyll and phycobilin peaks were resolved from flowing blue-green algae in the FCM. Under typical flow conditions, operation of the vidicon in the continuous mode gives for these fluorophores a S/N of several hundred to one in approximately 3 sec. The vidicon was also gated to obtain spectra of single cells and of cells in selected portions of the cell cycle. For example, the spectrum of fluorescamine was obtained from cells in the G1 phase of the growth cycle by using as a gate trigger the FCM discriminator output derived from the propidium iodide signal.

Animals↗
PubMed2026

Engineering copper ferrite (CuFe2O4) nanocomposites for enhanced eco-friendly photocatalysis: a systematic critical review on mechanisms, performance, and environmental applications.

Water pollution caused by organic and inorganic contaminants, particularly dyes and pharmaceuticals, represents a major environmental challenge. Advanced oxidation processes based on photocatalysts have emerged as efficient and sustainable approaches for water and wastewater treatment. Copper ferrite (CuFe2O4) is considered a promising photocatalyst owing to its narrow bandgap, visible-light activity, chemical stability, and magnetic properties. Despite extensive experimental investigations, a comprehensive systematic comparison of CuFe2O4-based photocatalysts under diverse operational conditions has remained limited. In this study, a systematic review following PRISMA guidelines was conducted using studies published between January 2014 and November 2025 indexed in Scopus, PubMed, Web of Science, and ScienceDirect. From an initial pool of 397 studies, 98 articles met the inclusion criteria. Key parameters - including pollutant type, pH, catalyst dosage, initial pollutant concentration, irradiation time, light source, and degradation efficiency - were quantitatively compared to identify performance trends and operational optima. The results demonstrate that CuFe2O4-based nanocomposites, particularly heterojunction, Z-scheme, and S-scheme architectures combined with TiO2, g-C3N4, graphene, and metal oxides, achieve high degradation efficiencies (often >90 %) for a wide range of organic pollutants and selected inorganic contaminants (e.g., Cr(VI)). Enhanced charge separation and suppressed electron-hole recombination were identified as the primary factors contributing to improved photocatalytic activity. In addition, the intrinsic magnetic properties of these nanocomposites enable facile catalyst recovery and reuse. In conclusion, CuFe2O4-based nanocomposites, especially those incorporating advanced heterojunction architectures, emerge as highly efficient and magnetically recoverable photocatalytic platforms for sustainable water and wastewater treatment, with strong potential for scalable implementation and real-wastewater applications.

Catalysis↗