Differences In Learning Ability Research Articles

Protein and Molecular Characterization of Hippocampal Protein Kinase C in C57BL/6 and DBA/2 Mice

Measures of protein kinase C (PKC) in C57BL/6 and DBA/2 mice using [3H]phorbol 12,13-dibutyrate binding to tissue homogenates and brain slices demonstrated that levels of activated, membrane-bound PKC were greater in C57BL hippocampus than in DBA hippocampus. Western analysis of alpha-, beta I-, beta II-, gamma-, delta-, and epsilon-PKC using isozyme-specific antibodies indicated that the increase observed in C57BL hippocampus was due primarily to the gamma-PKC protein, whose immunoreactivity was greater in the membrane-bound fraction in C57BL mice. Characterization of alpha-, beta I,II-, and gamma-PKC hippocampal mRNA using northern analysis and isozyme-specific nucleic acid probes did not reveal differences between the strains in levels of gene expression. Restriction fragment length polymorphisms (RFLP) were found in the alpha- and gamma-, but not beta-PKC genomic DNA. The RFLPs appeared to be located in noncoding, nonregulatory regions of the gene. These findings suggest that the gamma-PKC isozyme is largely responsible for the PKC activity difference in C57BL and DBA hippocampus that has been reported previously and may be closely associated with differences in learning ability observed in these strains.

The Differences in Learning Abilities between Spontaneously Hypertensive (SHR) and Wistar Normotensive Rats Are Cue Dependent

We examined the performance of spontaneously hypertensive (SHR) and Wistar normotensive (NT) rats in acquisition, retention after a 2-month interval, and reversal learning in two tasks: simultaneous brightness discrimination (Experiment I) and conditional discrimination of directional locomotor responses (Experiment II). In both tasks food reinforcement was used. In Experiment I both SHR and NT groups comprised younger (3-month-old) and older (10-month-old) rats. In each experimental stage SHRs of both age groups mastered the task earlier and made fewer errors than the respective NT groups. Reversal learning took longer than acquisition of discrimination in both age groups of NT rats. Conversely, reversal learning was an easier task for SHR. In Experiment II only younger rats were used. The forced turn at the start in the modified T-maze was utilized as the cue to guide performance at the choice point of the maze. In acquisition and retention, rats were trained to select at the choice point the arm in the same direction as in the forced turn; in the reversal, opposite contingencies were applied. At all stages the choice accuracy of SHR was the same as that in NT rats. The contrasting findings of Experiment I and Experiment II indicate that SHR learned better than NT when exteroceptive visual stimuli were used, but performed at the same level as NT rats in the task where interoceptive kinesthetic cues were relevant. We suggest that SHR pay more attention to visual stimuli than NT rats.

Tsukuba High- and Low-Emotional strains of rats (Rattus norvegicus): An overview

This report compiles the results of a series of studies on the Tsukuba High- and Low-Emotional strains (THE and TLE) of rats (Rattus norvegicus) established at the University of Tsukuba, Japan. The THE and TLE strains have been selected, respectively, for low and high activity in a runway test. During the course of selection, defecation has increased in the THE strain and decreased in the TLE strain. These strain differences were not affected by maternal influences, early experience, or psychotropic drugs. THE rats were consistently inactive in all novel situations examined, while TLEs were very active. The level of spontaneous activity, however, was similar between the two strains. It was remarkable that THE rats showed more burrowing activity than TLE animals, whereas the latter displayed more aggression than the former. Differences in learning ability, concentration of neural transmitters, and social behavior were examined.

Differences in learning ability of two strains of Hemigrammus caudovittatus

With the purpose of determining interstrain differences in learning ability of fishes, two aquarial strains of Buenos Aires tetra, Hemigrammus caudovittatus (Characinidae)—normally colored (25 subjects) and albino (13 subjects)—were tested. To determine learning ability, active avoidance in the shuttlebox was conditioned. The number of good and poor learners in each strain was determined, taking into account both the speed of appearance and the consolidation of the active avoidance response. Normally colored subjects had a higher percentage of good learners than did albino animals. However, these two strains did not differ in motor activity. Since the strains are easily distinguished visually, they are convenient for use in experiments in which comparision of behavior in good and poor learners living in a group together is the aim of study.

Discrimination of natural contact calls by two strains of canary and the budgerigar

Animals and their communication signals make up a unique environmental world. The sender of the signal, the signal itself, and the receiver interact to produce a complex communication system. Evidence is accumulating that many species of animal are especially adapted not only for producing species-specific communication signals, but also for perceiving such signals (Marler 1984; Dooling & Hulse 1989). We recently reported an experiment in which budgerigars and Belgian Waterslager canaries were trained to discriminate both budgerigar and canary calls in an operant procedure (Park, Okanoya & Dooling 1985). Budgerigars were equally adept at learning to discriminate among canary calls as well as budgerigar calls. The canaries were more adept at discriminating among canary calls than budgerigar calls, but the canaries' overall discrimination rate was much lower than the budgerigars'. Furthermore, the 2 species were equally adept at learning to discriminate among pure tones biologically irrelevant acoustic stimuli for both species. While these results could be used to support the notion of species-specific perceptual adaptation in canaries, they also reveal that canaries may be far less adept at learning to discriminate among complex calls than budgerigars. One possible explanation might be that the auditory sensitivity of canaries is not as good as that of budgerigars. Okanoya & Dooling (1985, 1987) found that a population from the Waterslager strain of canary expressed an elevation in auditory sensitivity. Waterslagers have auditory thresholds 30 to 40 dB higher in the middle to high frequency region of the audiogram compared to other strains of canaries, including German Rollers and American Singers tested with the same procedures. Though Belgian Waterslager canaries have poor high frequency sensitivity, birds from our colony and colonies in other laboratories have no difficulty in breeding. This means that males of the strain are apparently able to use auditory information to learn and successfully use song to elicit reproductive behaviors from females. Still, because a great deal of information on neurophysiological correlates to song development has come from Waterslager canaries (Nottebohm 1984), the recent finding 'of abnormal hearing in the strain raises important questions. For instance, do the elevated thresholds affect reproductive success by hindering or even facilitating learning and reproductive behaviors? The present experiments were designed to further explore the effects of poor high-frequency hearing on perceptual learning of biologically relevant stimuli in an experimental situation. We wanted to know if the species differences we originally reported were due to differences in learning ability or due to species differences in high-frequency auditory sensitivity. To this end, we tested canaries from a strain with normal hearing and compared the results to the same budgerigars and Waterslager canaries used in the previous study. Method Subjects

A tuna fish diet influences cat behavior

When observed in their home cages, cats fed commercial tuna fish cat food were less active, vocalized less, and spent more time on the floor and more time eating than cats fed commercial beef cat food. There were no differences in response to human handling between the two groups. There were no differences in learning ability on a two-choice point maze or in reversal learning in the same maze between beef- and tuna-fed cats. The behavior of the groups differed in a 15-min open field test only in the number of toys contacted. Cats fed the tuna had elevated tissue levels of mercury and selenium.

Maze-learning behavior in early adrenalectomized rats

Rats adrenalectomized (ADX) on day 11 of life display enhanced brain growth due, at least in part, to a stimulation of cell proliferation and myelinogenesis. The present study investigated some functional consequences of this treatment. Rats were ADX or sham-operated (SHAM) on postnatal day 11 and then tested in adulthood for their problem-solving ability in a Hebb-Williams maze. The mean number of errors committed by ADX rats was lower than that of the SHAM controls on every test problem of the maze. ADX subjects also left the start box more quickly and ran the maze faster than the controls. When a subset of these same subjects was tested for running wheel activity, the ADX animals showed greater baseline running behavior and also learned more readily to respond to a fixed-interval schedule of reinforcement. The remaining animals were subjected to carcass analysis, which revealed that ADX rats under the food-restricted conditions necessary for maze testing had a lower percentage of body fat and a higher relative water content than SHAMs. Although there may be some relationship between enhanced maze-learning performance and altered activity or motivation in the ADX animals, the overall results suggest that the performance of these subjects reflects a real difference in learning ability. The neural mechanisms underlying this difference remain to be elucidated.

Learning ability of young rats is unaffected by repeated exposure to a static electromagnetic field in early life.

Infant albino rats were exposed to a static electromagnetic field of 0.0 Tesla (control) or 0.5 Tesla (experimental) for 14 postnatal days. Following a 1-month rest period, the experimental (13 males and 10 females) and control (11 males and 14 females) rats were trained on four successive reversals of a position habit in a single-unit enclosed T-maze that was adapted for the use of escape-avoidance of mild foot shock as a motive. There was no significant difference in learning ability between the experimental and control groups in terms of total (initial combined with repetitive) errors committed over the four reversal problems. While the females tended to make more errors than the males, this difference was likewise insignificant.

High proline levels in the brains of mice as related to specific learning deficits

Hyperprolinemic PRO/Re mice have been studied as potential models for hyperprolinemia in man. In addition to high proline levels, some heretofore unreported amino acid abnormalities in the brains of PRO/Re mice are described. The T-maze and shuttlebox learning abilities of PRO/Re mice were compared with those of CD-1 mice having normal proline levels. PRO/Re mice had a significant deficit for T-maze learning, but a significantly greater aptitude for shuttlebox learning when compared to CD-1 mice. By studying the F3 progency of the PRO/Re × CD-1 cross, these strain-specific differences in learning ability for different tasks were shown to be unrelated to the differences in brain proline levels. F3 mice could be subdivided into two distinct groups: those with high proline (HP+) and low proline (HP−) titers. Other amino acids in brain tissues were essentially identical in both groups. A comparison of learning abilities of these HP+ mice with their HP− littermates showed no meaningful differences. However, the slightly slower rate at which HP+ mice acquired shuttlebox learning was sufficiently consistent over the 8 day training period so that it became significant. These results do not support the hypothesis that high levels of proline in brain tissues and blood are necessarily accompanied by impaired learning and memory, but are in agreement with those studies of hyperprolinemia in man that suggest no consistent learning deficits in hyperprolinemic subjects. The results seem to validate the suitability of the PRO/Re mouse as a model for hyperprolinemia in man. The data suggest also that the altered amino acid pattern in brains of PRO/Re mice has multiple etiologies. The possibility remains that in PRO/Re mice, the differences in ability to learn the T-maze and shuttlebox are the result of the interaction of high proline levels with some of the other biochemical abnormalities in the brain tissues of this mouse strain.

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Strain differences in learning ability in [formula omitted

Effect of brain growth stages on T‐maze acquisition in mice

Recently, it has been shown that brain growth is characterized by periods of especially large increases in growth, with "plateaus" in growth between these "spurt" periods. In humans, these spurts in brain growth are correlated with spurts in mind growth, collectively termed phrenoblysis. Brain growth spurts in rodents occur at 0-6, 8-12, and 17-23 days of age with plateaus in-between. We examined two questions. First, are there differences in learning ability associated with spurts and plateaus in brain growth? Second, can learning during these stages be altered through genetic and environmental manipulations? We employed the high and low lines of the Fuller brain weight selection mice, which are known to have different developmental patterns, and early handling procedures, known to alter growth rates. The results showed that animals tested during a proposed brain growth spurt were superior to animals tested during a brain growth plateau in learning a shock-escape T-maze.

Analysis of hippocampal RNA in rats with genetically determined differences in learning ability.

1. Breeding for speed of formation of a food-getting motor conditioned reflex in the course of 12 generations led to an increase in the intensity of synthesis of nuclear and cytoplasmic fractions of hippocampal RNA in quick-learning animals compared with slow-learning. 2. Electrophoretic analysis of nuclear and cytoplasmic fractions of hippocampal RNA revealed the presence of a similar series of classes of RNA in the initial and trained groups of specially bred animals. 3. In the region of high-molecular-weight classes of nRNA incorporation of radioactive precursor was at a higher level in quick-learning animals than in slow-learning. 4. In connection with training an increase was observed in the incorporation of radio-active precursors in the region of high-molecular-weight classes of nRNA and in the 18S-4S RNA region of cRNA. 5. Incorporation of3H-uridine into polyA-RNA and changes in incorporation of label connected with training were significantly greater in quick-learning animals.

Effects of early protein malnutrition on learning in the rat

Animals were reared on a diet of commercially available corn grits from weaning to approximately 120 days of age. Littermate controls were fed Purina Laboratory Chow. The subjects’ learning ability was tested in a two-way active avoidance task and a black-white visual discrimination task. The grits-fed animals did not develop physically and remained as small as weanling rats throughout the study. The data from the learning tasks indicate that there were no differences in learning ability between the protein-malnourished animals and the normal littermates.

On learning and living in holes by mantis shrimp

Mantis shrimp (Stomatopoda, Crustacea) that normally occupy holes in coral were presented with novel burrows (Erlenmeyer flasks painted black) in the laboratory. Individuals learn to recognize characteristics of the flask and enter, the burrow increasingly rapidly with repeated exposure to the flask. Individuals show consistently fast or slow learning curves, suggesting individual differences in learning ability. Three to seven days appears to be a critical period during which the stimulus must be re-encountered, or else the response is partially forgotten. However, a partial response remains after 14 days, and subsequent re-exposure to the stimulus is associated with more rapid re-acquisition of the entry behaviour than in naive animals. Field observations support the interpretation that individuals learn characteristics of their burrows and the environment. Further studies are needed to investigate the relationship of learning ability to the ritualized behaviour repertoire and to social interactions.

Policy Implications of Individual Differences in Learning Ability: a Comparative Perspective

Abstract Husen, Torsten 1978. Policy Implications of Individual Differences in Learning Ability: A Comparative Perspective. Scandinavian Journal of Educational Research 22, 173‐191. Educational policy implications of individual differences are of particular relevance in societies with a certain social mobility where status is increasingly achieved instead of being ascriptive. Problems of differentiation and uniformity of educational provisions are products of the era of emphasis on equality of educational opportunity. The diversity/uniformity problem has been dealt with in different ways in various national systems of education. Three typical solutions are dealt with in this paper: the American comprehensive model, the Western European elitist model, and the Eastern European model of a unitary school. It is pointed out that an element of meritocracy runs through all the three systems, irrespective of the social and economic order in which they operate.

Comparative Investigation of the Relationship between Cerebral Indices and Learning Abilities

Indices of cerebral development were computed for 23 different species in order to assess their capacity to accurately reflect differences in learning ability. The resulting correlations between index values and performance on a variety of tasks strongly suggest that this approach may offer the best type of continuum for the comparative study of learning. It was further suggested that if the index proposed by Jerison were expanded to reflect possible neuronal connections, a more powerful measure might be obtained.

THE COLOUR OF CONCEPTUAL LEARNING

In this chapter I should like to discuss some aspects of psychology and education that have interested me for a number of years but which have recently attracted particular attention through the work of Jensen. I refer to questions concerned with children’s learning and the problem of improving this learning in school. This pedagogical orientation is, of course, different from Jensen’s main preoccupation which seems to be with ethnic differences in learning ability or intelligence. However, he has suggested pedagogical procedures on the basis of his work and it is this aspect of his work that I wish to focus on.

Memory and Transfer of Information

Memory and Transfer of Information

Spatial and non-spatial discrimination reversal (SDR) learning in the guinea pig

Spatial and non-spatial serial discrimination reversal performance was investigated in guinea pigs over eleven reversals. Difference in learning ability between albino and pigmented strains was not evident on spatial or non-spatial SDR tasks. The guinea pigs' ability to learn rapidly successive spatial and non-spatial reversals with increasing proficiency corresponds well with previous published findings using other mammalian species. These studies also demonstrated behavioural research with the guinea pig to require extended periods of intensive experimental management.

Influence of Age and Sex on the Amount and Rate of Learning Two Motor Tasks

Abstract One hundred and ninety-two subjects were tested on two large muscle motor tasks in order to determine the influence of age and sex on the amount and rate of learning. One required the maintenance of immobility of a stabilometer; the other involved climbing a free standing ladder. Learning curves of six groups of male subjects and six groups of female subjects ranging in age from 26 to 50 years were obtained on the stabilometer and the free standing ladder climb. Variance analyses showed that rate of learning was not influenced by sex over the range 26 to 50 years and that it may also be independent of age over this same range. The amount of learning was unrelated to age but sex differences in learning ability in the range 26 to 50 were dependent upon the task.