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At least 613 records · Page 34Linked to original sources
PubMed2003

Olfactory discrimination learning deficit in heterozygous reeler mice.

Adult mice heterozygous for the 'reeler' mutation (HR mice) have been found not to have a reeler phenotype but to express a number of abnormal traits including reduced sensorimotor gating, lower density of dendritic spines in frontoparietal cortex and hippocampus, and selectively decreased expression of one form of glutamic acid decarboxylase (GAD67). Since reelin is expressed in olfactory areas of the adult mouse brain, we have tested for olfactory functions in HR mice that express only half of the reelin found in wild-type (WT) mice. HR and WT mice were trained to criterion performance of 90% correct in a block of 20 trials on eight distinct simultaneous-cue, two-odor discriminations. HR mice required significantly more training sessions and made more errors than did WT mice in acquiring the first olfactory discrimination. Subsequent discriminations were learned equally rapidly by both HR and WT mice. Memory retention for the final discrimination was tested 1 week after training and was equally good for both groups. Both HR and WT mice showed equivalent sensitivity in discriminating low concentrations of either ethyl acetate or butanol from non-odorized air. Whether or not the olfactory learning deficit observed in HR mice is related to the low dendritic spine density or GAD67 reduction observed in hippocampus and cortex are currently under investigation.

Animals↗
PubMed1968

Discrimination learning as the summation of excitation and inhibition.

Pigeons received either excitatory, inhibitory, or combined excitatory and inhibitory (intradimensional) training to discriminate line-tilt stimuli. Algebraic summation of relative-generalization gradients obtained after separate excitatory and inhibitory training sessions was used to predict characteristics of gradients after intradimensional training. The good agreement between obtained and predicted gradients provided support for gradient-interaction theory.

Animals↗
PubMed1980

Discrimination learning of an instrumental response in individual Drosophila melanogaster.

By using a unique methodology and a versatile series of choice points in two distinct apparatuses, individual Drosophila were shown to possess the ability to learn. This behavior can be controlled by a discriminative stimulus (substrate texture). Following a correct response in the presence of the discriminative stimulus at a horizontal choice point, fruit flies bred for negative geotaxis were given the opportunity to ascend a vertical alley leading to another choice point. When cues were consistent, reliable learning occurred. When cues were inconsistent, learning did not occur. Cue reversal produced the classic temporary increase in "incorrect" responses. The success of this paradigm is due, in large part, to the reduction of noxious and competing stimuli.

Animals↗
PubMed2002

Quokkas (Setonix brachyurus) demonstrate tactile discrimination learning and serial-reversal learning.

Two male quokkas (Setonix brachyurus: a herbivorous macropod marsupial) were trained to discriminate pairs of stimuli in the laboratory. Quokkas indicated their choice by pulling on 1 of 2 simultaneously presented cords. The quokkas' discrimination abilities were tested on 6 tactile and 6 visual discrimination tasks. Correct responses were rewarded with food. For both quokkas, all tactile tasks were learned to a criterion of 75% correct in up to 4 20-trial sessions. No visual task maintained criterion performance in 4 sessions. One tactile discrimination was reversed 10 times. After the 1st reversal, the error rate declined sharply and fell to a level well below the initial discrimination.

Animals↗
PubMed1993

Absence of impairments in spatial and temporal discrimination learning in Lewis rats after chronic ethanol consumption.

Many studies reported that chronic ethanol consumption leads to cognitive dysfunction in rodents. It has been suggested that the effects of chronic ethanol consumption resemble those of aging because of the behavioral and neurochemical similarities between the two processes. The present study examined the effects of a chronic ethanol treatment (20% aqueous solution) in Lewis rats on performance in three different tasks: the Morris spatial navigation task, a cone-field task, and a temporal discrimination task. Although an age-related deficit was found in water escape learning, chronic ethanol consumption did not affect the performance of adult and old rats. The results of this experiment were, however, not conclusive. No differences between old control and ethanol-treated rats were found for spatial (cone-field task) and temporal discrimination learning. However, old ethanol-treated rats showed a transient tendency to perseverate in the temporal discrimination task. The present results are at variance with the generally found cognitive impairments after chronic ethanol consumption using aqueous solutions. It is suggested that the effects of ethanol could be related to strain of rat, task complexity, method of ethanol administering, and housing conditions and may explain the discrepancy between results.

Aging↗