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PubMed1996

The orbitofrontal cortex.

The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight of objects from the temporal lobe cortical visual areas, and is involved in learning and in reversing stimulus-reinforcement associations. The stimulus might be a visual or olfactory stimulus, and the primary (unlearned) reinforcer a taste or touch. Damage to the orbitofrontal cortex impairs the learning and reversal of stimulus-reinforcement associations, and thus the correction of behavioural responses when these are no longer appropriate because previous reinforcement contingencies change. The information which reaches the orbitofrontal cortex for these functions includes information about faces, and damage to the orbitofrontal cortex can impair face expression identification. This evidence thus shows that the orbitofrontal cortex is involved in decoding some primary reinforcers such as taste; in learning and reversing associations of visual and other stimuli to these primary reinforcers; and plays an executive function in controlling and correcting reward-related and punishment-related behaviour, and thus in emotion.

Amygdala↗
PubMed1978

Contingency learning in chronic schizophrenia and its relevance to social motivation deficit.

The present study investigates the ability of chronic schizophrenic patients to learn to obtain social rewards when the incentive value of the contingent social event is known. From a group of 40 chronic patients tested for responsivity to social rewards, socially responsive and socially unresponsive patients were selected and compared on a learning task. Patients who were highly motivated to obtain social reinforcement did not emit the reinforced response during 300 learning trials any more frequently than did patients who were not motivated by social rewards. It was only when the experimental contingency was specified that responsive and unresponsive patients could be differentiated. The implications of these findings for social motivation theories of schizophrenia are discussed.

Adult↗
PubMed2003

Amphetamine increases aversive conditioning to diffuse contextual stimuli and to a discrete trace stimulus when conditioned at higher footshock intensity.

Amphetamine can increase conditioning to poor predictors of reinforcement in selective learning tasks (e.g. latent inhibition, LI). In the present study, a noise stimulus was contiguous with footshock or presented at a trace interval. A flashing light background stimulus was used to measure contextual conditioning. Experiment 1 used 1.5 mg/kg and 6 mg/kg dl-amphetamine. Experiments 2 and 3 used 0.5 mg/kg and 1.5 mg/kg d-amphetamine. Unconditioned stimuli parameters (intensity, number, duration) were also manipulated from one experiment to the next. Amphetamine consistently increased conditioning to the background stimulus, and increased conditioning to the trace stimulus at higher footshock intensity (Experiment 3). Thus, amphetamine increased conditioning only to relatively uninformative predictors. The effect on conditioning to trace conditioned stimuli depended on the level of reinforcer but increased conditioning to background did not. Throughout, there was no effect of amphetamine on conditioning of the contiguous stimulus. Thus, the results did not simply arise because amphetamine increased conditioning under any condition in which conditioning without amphetamine was poor. The results are discussed in terms of amphetamine effects on breadth of attention and LI to context.

Amphetamine↗
PubMedDate not supplied

The 60-Second Nurse Educator: Creative strategies to inspire learning.

Educational content that is presented, attended to, remembered, and reinforced in a "fun setting" will have a greater likelihood of being learned. Creative strategies integrated throughout the learning environment are effective in increasing retention of information. Some obstacles to creative teaching methods include lack of class time and preparation time, teaching habits, divergent learning styles of students, and devotion to covering all the content in class. This article presents "60-second strategies" that can be incorporated into large and small classes and clinical teaching. The strategies are quick, easy to implement, and transferable to a wide range of teaching topics.

Clinical Competence↗
PubMed1989

Differential influences of corticotropin-releasing factor on memory retention of aversive learning and appetitive learning in rats.

The effects of intraamygdala injections of corticotropin-releasing factor (CRF) on memory retention of aversive and appetitive learnings were examined in the present study. Other than confirming the results of a previous study that a moderate dose of CRF (0.1 microgram) injected into the amygdala facilitated retention performance of an inhibitory avoidance task (electric shock punishment) 24 h after training, we have further found that this effect lasted for a week. However, CRF produced a differential dose-response effect upon memory of an appetitive learning paradigm (sexual reinforcement). CRF at 0.01 microgram enhanced retention at both 24-h and 1-week intervals, while CRF at 0.1 microgram impaired retention in the same task at 1 week only. These results confirm that the amygdala is important in memory processing and suggest that the mechanisms involved in the action of CRF on memory retention of aversive and appetitive learnings are different. The possible differences are also discussed.

Amygdala↗
PubMedDate not supplied

Students take the professor home.

The nursing process is used to provide a rationale for substituting formal lectures on maternal-child nursing theory with audiotapes included in instructional packages provided to students prior to scheduled classroom time. Five objectives for this teaching strategy are presented and evaluated. Although test scores were not used for evaluation, students were found to listen to the tapes and benefit from the experience. Faculty used classroom time to reinforce content with active learning methods. The audiotaped lectures and handouts were a form of distributed learning, which provided more time for faculty-student interaction and reinforcement of pertinent concepts.

Education, Nursing, Baccalaureate↗
PubMed1996

Cyclic responding by pigeons on the peak timing procedure.

The present experiment examined whether discrimination learning shapes the single-peaked response distributions usually obtained with the peak procedure. Two sources of learning in pigeons were disclosed: learning to respond near the time of reinforcement on fixed interval (FI) trials and learning to withhold responding once the FI duration had elapsed on peak interval (PI) trials. Pigeons also produced a highly unexpected second peak in responding on nonreinforced PI trials at 3 times the FI duration. Follow-up experiments showed that a 1:4 FI:PI duration ratio supported double peaks, but only 1 peak was obtained with a 1:8 FI:PI duration ratio. Finally, 4 peaks could be observed on extra-long PI trials under a 1:4:8 FI:PI:PI ratio procedure. The multiple-peaked response distributions are an unprecedented finding that present a major challenge to any theory of time perception.

Animals↗
PubMed1981

[Effect of etimizol on the RNA synthesizing activity of brain cell nuclei during the learning process in rats].

A study was made of the effect of the central nervous system stimulant ethymizol on RNA-polymerase activity of cell nuclei of the rat cerebral cortex and hippocampus during learning with different reinforcements. Ethymizol stimulated the incorporation of 3H-UTP in the TCA-insoluble fraction of hippocampal nuclei during training of the animals in the avoidance response to the light in a Y-shaped mize and training in the reaction of spontaneous alternation of food reinforcements in a complex mize, and decreased the ratio brain cortex/hippocampus RNA-polymerase activity. The data obtained are discussed from the standpoint that the action of ethymizol is consequent on the activation of the genome of nervous cells.

Animals↗
PubMed2004

Conditioning and cognition.

Animals' abilities to use internal representations of absent objects to guide adaptive behavior and acquire new information, and to represent multiple spatial, temporal, and object properties of complex events and event sequences, may underlie many aspects of human perception, memory, and symbolic thought. In this review, two classes of simple associative learning tasks that address these core cognitive capacities are discussed. The first set, including reinforcer revaluation and mediated learning procedures, address the power of Pavlovian conditioned stimuli to gain access, through learning, to representations of upcoming events. The second set of investigations concern the construction of complex stimulus representations, as illustrated in studies of contextual learning, the conjunction of explicit stimulus elements in configural learning procedures, and recent studies of episodic-like memory. The importance of identifying both cognitive process and brain system bases of performance in animal models is emphasized.

Animals↗
PubMed2003

Behavioral analysis of the consequences of chronic blockade of NMDA-type glutamate receptors in the early postnatal period in rats.

Considering data on the possible glutamatergic nature of the pathogenesis of schizophrenia, we attempted to model cognitive derangements in animals by chronic blockade of NMDA glutamate receptors. Wistar rats received daily s.c. injections of the non-competitive NMDA glutamate receptor antagonist MK-801 (0.05 mg/kg) from days 7 to day 49 of postnatal life. One day after the antagonist injections given on days 27 and 28 of life, animals of the experimental group showed decreased levels of spontaneous movement and orientational-investigative activity as compared with controls, where there was no change in the elevated locomotor reaction produced in response to the direct action of MK-801. These animals showed decreases in the level of anxiety (on day 40 of life) and derangement in spatial learning with food reinforcement (days 50-54 of life). It is suggested that early neonatal blockade of NMDA glutamate receptors leads to the development in animals of disturbances to situational perception and assessment of incoming sensory information.

Animals↗
PubMed1994

Value-dependent selection in the brain: simulation in a synthetic neural model.

Many forms of learning depend on the ability of an organism to sense and react to the adaptive value of its behavior. Such value, if reflected in the activity of specific neural structures (neural value systems), can selectively increase the probability of adaptive behaviors by modulating synaptic changes in the circuits relevant to those behaviors. Neuromodulatory systems in the brain are well suited to carry out this process since they respond to evolutionarily important cues (innate value), broadcast their responses to widely distributed areas of the brain through diffuse projections, and release substances that can modulate changes in synaptic strength. The main aim of this paper is to show that, if value-dependent modulation is extended to the inputs of neural value systems themselves, initially neutral cues can acquire value. This process has important implications for the acquisition of behavioral sequences. We have used a synthetic neural model to illustrate value-dependent acquisition of a simple foveation response to a visual stimulus. We then examine the improvement that ensues when the connections to the value system are themselves plastic and thus become able to mediate acquired value. Using a second-order conditioning paradigm, we demonstrate that auditory discrimination can occur in the model in the absence of direct positive reinforcement and even in the presence of slight negative reinforcement. The discriminative responses are accompanied by value-dependent plasticity of receptive fields, as reflected in the selective augmentation of unit responses to valuable sensory cues. We then consider the time-course during learning of the responses of the value system and the transfer of these responses from one sensory modality to another. Finally, we discuss the relation of value-dependent learning to models of reinforcement learning. The results obtained from these simulations can be directly related to various reported experimental findings and provide additional support for the application of selectional principles to the analysis of brain and behavior.

Animals↗