PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “CONDITIONED LEARNING”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMed1999

Affective distress and implantable cardioverter defibrillators: cases for psychological and behavioral interventions.

The implantable cardioverter defibrillator (ICD) may be associated with some degree of psychological maladjustment, especially in patients experiencing high rates of discharge. This article reviews the psychological literature related to ICDs and presents two case examples illustrating common psychological complications related to multiple discharges. A brief, psychological intervention can be implemented to improve patient adjustment. To explain possible processes by which psychological complications may develop in ICD patients, two well-established psychological theories of learning and behavior, classical conditioning and learned helplessness, are reviewed. Multidisciplinary teams that include consultation with clinical psychologists are suggested for the routine care of ICD patients.

Adjustment Disorders↗
PubMed2003

The CS-preexposure effect in conditioned taste-aversion learning in golden hamsters.

In Experiment 1, golden hamsters were injected with either 0.9% saline or the nausea-inducing agent, lithium chloride (LiCL), immediately after consuming a flavored diet that was either novel or familiar. The LiCl-induced aversion was strong in hamsters for which the flavored diet was novel, but no significant aversion was observed in hamsters that were familiar with the flavored diet. In Experiment 2, the strength of the LiCl-induced aversion was related inversely to the amount of conditioned-stimulus (CS) preexposure and directly to the duration of the preexposure-conditioning interval. Thus, although some previous researchers have suggested that hamsters may not demonstrate the CS-preexposure effect in a conditioned taste-aversion paradigm, they clearly did so under the conditions of the present experiments, and moreover, the characteristics of the CS-preexposure effect in hamsters were generally similar to those observed in rats.

Animals↗
PubMed1999

Olfactory associative learning in Caenorhabditis elegans is impaired in lrn-1 and lrn-2 mutants.

The C. elegans mutants, lrn-1 and lrn-2, are impaired in associative learning using conditioned taste cues. Both mutants are defective in associative learning about appetitive and aversive events, indicating that lrn-1 and lrn-2 exert effects across motivational boundaries. In a new olfactory associative learning paradigm, in which wild type worms learn to avoid a previously attractive diacetyl odor after it has been paired with an aversive acetic acid solution, lrn-1 and lrn-2 are impaired. Although defective in associative learning using a conditioned olfactory cue, nonassociative learning (habituation and dishabituation) using this same olfactory cue is unaffected. The discovery that lrn-1 and lrn-2 are defective in associative learning with both taste and olfactory cues may suggest that associative learning in different sensory modalities converges on a common genetic pathway in C. elegans that is subserved by lrn-1 and lrn-2.

Animals↗
PubMed1984

Vasopressin effect on learning in 6-hydroxydopamine-pretreated rats: correlation with caudate vasopressin levels.

Conditioned avoidance learning was studied at 2 months of age in rats treated with intracisternal 6-OH dopamine (DA) at 5 days of life after desipramine pretreatment. Subcutaneous DDAVP 20 micrograms/rat or LVP 1 microgram/rat improved conditioned avoidance learning in the 6-OH DA-treated rats at least as much as in control rats. Caudate vasopressin levels significantly correlated with learning ability in the shuttle box in control rats (r = 0.69, n = 8), 6-OH DA-treated rats (r = 0.64, n = 8), 6-OH DA plus DDAVP-treated rats (r = 0.60, n = 9), or in the total sample (r = 0.59, n = 25, p less than 0.01).

Animals↗
PubMed1987

Accountability and judgment processes in a personality prediction task.

In this experiment, we investigated the impact of accountability--social pressures to justify one's views to others--on cognitive processing in a personality-prediction task. Subjects were presented with the responses of actual test-takers to 16 items from Jackson's Personality Research Form (PRF) and asked to predict how these individuals responded to an additional set of 16 items from the same test. Subjects were assigned to a no-accountability condition (they learned that all of their responses would be anonymous), a preexposure-accountability condition (they learned of the need to justify their responses before seeing the test-takers' PRF responses), and a postexposure-accountability condition (they learned of the need to justify their responses after seeing the test-takers' PRF responses). Preexposure-accountability subjects reported more integratively complex impressions of test-takers, made more accurate behavioral predictions, and reported more appropriate levels of confidence in their predictions than did either no-accountability or postexposure-accountability subjects. We conclude by considering possible psychological mediators of these effects as well as the broader theoretical implications of the findings for the development of contingency models of judgment and choice.

Humans↗
PubMed1996

Cooperative learning and peer acceptance of students with learning disabilities.

The effects of cooperative learning on 417 regular-education students, acceptance of 41 of their special-education classmates were examined in an 8-month study. The participants were in Grades 5-8 in 21 classes in 2 U.S. schools. The 3 conditions were cooperative learning and competitive learning, taught by the same teachers, and competitive learning, taught by a random sample of teachers. In October and in May, the regular-education students rated each classmate's desirability as a work partner. The students' peer ratings were generally very stable, for both their regular-education classmates and their special-education classmates. Positive changes in peer ratings for both types of classmates occurred more frequently in the cooperative-learning condition than in the competitive-learning conditions.

Adolescent↗
PubMedDate not supplied

Hippocampal activations during repetitive learning and recall of geometric patterns.

Hippocampal activation is required for episodic memory. Encoding and retrieval of novel and memorable items have been related to different locations in the hippocampus; however, the data remain ambiguous. The application of a newly designed keyboard allowed investigation of brain activation during encoding and free immediate and delayed recall with functional magnetic resonance imaging (fMRI) in young healthy controls (n = 12). Because of the repetitive learning and recall conditions, an individual learning gradient was used to contrast neural activity at different individual levels of novelty. During learning, subjects were asked to memorize 10 geometric patterns requiring the establishment of intra-item associations for memorization. After learning, subjects were asked to recall the items actively via the keyboard. Learning and recall were alternated five times. Delayed recall was scanned about 15 min after the fifth immediate recall condition without subjects having seen the items again. Left-sided anterior hippocampal activity was observed during conditions of initial learning as well as maximum recall. Neural activity during delayed recall did not reveal hippocampal responses and was characterized by a transition of neural activity from occipitoparietal regions to bilateral temporal cortices. We conclude that both lateralization and segregation depend on the specific relational characteristics of the stimuli requiring establishment of intra-item associations for encoding as well as retrieval. The absence of hippocampal activation during delayed recall together with the increase of lateral temporal involvement possibly corresponds with an emerging transition from episodic to long-term memory.

Adult↗
PubMed1987

Effects of vasopressin on the brain lipid metabolism during learning and retention of conditioned avoidance behaviour.

Intracerebral vasopressin pretreatment impairs acquisition and consolidation, but delays extinction of conditioned avoidance behaviour. The latter effect of the peptide is associated with a pronounced suppression of the incorporation of labelled precursor in total lipids of the hippocampus. Results suggest that memory-improving effects of vasopressin are probably related to alterations of the brain lipid metabolism.

Animals↗
PubMed2006

Methylphenidate can reduce selectivity in associative learning in an aversive trace conditioning task.

There are good grounds to expect that methylphenidate (MP) should enhance cognitive function. However, experimental evidence on this point is scant. The present study therefore examined the effects of MP on learning the association between a conditioned stimulus (CS, in this case, noise) and an unconditioned stimulus (UCS, in this case, footshock) in an aversive variant of a trace conditioning procedure. Learning was measured off-the-baseline as conditioned suppression of drinking (both latencies to drink, expressed as suppression ratios, and the amount drunk, expressed as the number of licks, in the presence of the CS). In addition to the measures of discrete cue conditioning, MP effects on contextual conditioning were measured as suppression to apparatus cues and an experimental background stimulus. MP was administered at 1 or 5 mg/kg prior to conditioning sessions. As attention deficit hyperactivity disorder (ADHD) has been characterized as involving a ;wide attentional window' (e.g. Shalev and Tsal, 2003), it was predicted that MP, as the treatment of choice for ADHD, should increase selectivity (narrowing the attentional window). This outcome would show as reduced levels of conditioning (compared to control rats) to less informative trace and contextual cues present during conditioning. Contrary to prediction, both 1 and 5 mg/kg MP increased learning about all the available stimuli, including the less informative trace CS and the background stimulus. These findings are consistent with reduced rather than increased selectivity in learning (because of increased rather than decreased conditioning to weak cues) under MP.

Animals↗
PubMed2006

Discrimination learning and reversal of the conditioned eyeblink reflex in a rodent model of autism.

Offspring of rats exposed to valproic acid (VPA) on gestational day (GD) 12 have been advocated as a rodent model of autism because they show neuron loss in brainstem nuclei and the cerebellum resembling that seen in human autistic cases . Studies of autistic children have reported alterations in acquisition of classical eyeblink conditioning and in reversal of instrumental discrimination learning . Acquisition of discriminative eyeblink conditioning depends on known brainstem-cerebellar circuitry whereas reversal depends on interactions of this circuitry with the hippocampus and prefrontal cortex. In order to explore behavioral parallels of the VPA rodent model with human autism, the present study exposed pregnant Long-Evans rats to 600 mg/kg VPA on GD12 and tested their offspring from Postnatal Day (PND26-31) on discriminative eyeblink conditioning and reversal. VPA rats showed faster eyeblink conditioning, consistent with studies in autistic children . This suggests that previously reported parallels between human autism and the VPA rodent model with respect to injury to brainstem-cerebellar circuitry are accompanied by behavioral parallels when a conditioning task engaging this circuitry is used. VPA rats also showed impaired reversal learning, but this likely reflected "carry-over" of enhanced conditioning during acquisition rather than a reversal learning deficit like that seen in human autism. Further studies of eyeblink conditioning in human autism and in various animal models may help to identify the etiology of this developmental disorder.

Analysis of Variance↗
PubMed1987

Effects of naltrexone on learning and performance of conditional fear-induced freezing and opioid analgesia.

In the presence of Pavlovian conditional aversive stimuli rats engage in defensive freezing and exhibit a decreased sensitivity to painful stimulation. Administration of the opioid antagonist naltrexone (7 mg/ml/kg) prior to training in a context fear conditioning procedure using footshock caused an increase in freezing but did not affect suppression of formalin-induced recuperative behaviors relative to controls during a test session 24 hr later. The same dose of naltrexone given during the test session reversed conditional analgesia without altering the level of freezing. These results suggest that full expression of endogenous opioid analgesia during training is not necessary for conditional responding.

Animals↗
PubMed2005

Concurrent conditioned taste aversion: a learning mechanism based on rapid neural versus flexible humoral processing of visceral noxious substances.

Taste aversion learning (TAL) consists of the avoidance of a taste previously associated with a noxious visceral stimulus. Clinical and experimental studies suggest that this adaptive process can be established by different procedures that imply distinct forms of learning and memory, although the final result is analogous, i.e. avoidance of the gustatory stimulus associated with gastrointestinal discomfort. In fact, a double neurobiological system has been anatomically dissociated and, functionally, may be implicated in nausea and emesis, in food selection, and in neuroimmune interactions. Actually, a dual, parallel, and non-redundant gut-brain system has been proposed that sustain two different TAL modalities, concurrent and sequential. Concurrent TAL requires several trials and is inflexible, requiring simultaneity of the stimuli and the participation of the vagus nerve. In contrast, sequential TAL can be acquired in one trial and is flexible, permits long inter-stimulus delays, and is independent of vagal pathways. These two TAL modalities are analyzed in the light of the recent proposal that different acquisition processes are sustained by distinct cerebral systems.

Adaptation, Physiological↗
PubMed1987

Contingency learning and causal detection in Hermissenda: I. Behavior.

The addition of extra light-alone or rotation-alone presentations to sequences of light-rotation pairings reduced the associative suppression of phototaxic behavior for the nudibranch Hermissenda. Training-induced changes in Type B photoreceptor light responses were found to parallel the training-induced behavioral changes in the intact animal. The decremental effects of the degraded contingency treatments upon neural and behavioral changes normally occasioned by light-rotation pairings reflected two processes. One factor was the increased stimulation frequency entailed by degraded contingency training. The second factor reflected the specifically unpaired character of the added light-alone or rotation-alone presentations, independent of frequency changes. The attenuation of phototaxic suppression was not because of a general habituation process or adaptation to the effects of either visual or vestibular stimulation. Instead, attenuation seemed to reflect a local interference effect of interspersed unpaired stimuli. The present experiments demonstrate a sensitivity to stimulus contingencies for Hermissenda similar to that of many vertebrates and indicate that contiguity and contingency relations are both encoded and stored in the Type B photoreceptors. The results indicate that similar neurophysiological mechanisms are involved.

Animals↗