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PubMed1984

Effects of pimozide on escape and discrimination performance in a water-escape task.

The effects of pimozide (0.2 and 0.4 mg/kg) on discrimination learning were evaluated by a water-escape paradigm in which the degree of motor difficulty was manipulated by varying water temperature. Treatment with the drug marginally affected escape latencies in relatively warm water (25 degrees C) but markedly disrupted escape latencies when the task was more demanding (e.g., 15 degrees C and 20 degrees C water). The escape deficits, however, were not accompanied by disturbances in the acquisition of a position discrimination response or of a cue discrimination response when mice were required to make the highly prepared response of swimming to light or the contraprepared response of swimming to dark. These data were taken to suggest that in tasks involving aversive motivation pimozide influences performance through its effects on response maintenance but does not appear to affect either associative or motivational processes.

Animals↗
PubMed1994

A new operant discrimination test procedure for resident rats.

An automated method for testing visual discrimination with water reinforcement using a modified residential Y-maze is described. The visual stimulus is presented above one of two water holes. Rats have been tested with different lengths of water periods and different intervals between the periods. During the 10 days of testing, overall activity decreased. Activity on the initial days was low during daytime, with few drinking attempts. Discrimination learning acquisition was measured as the increase in the percentage of water periods with drinking attempts in which the first attempt occurred on the correct side, and/or as the increase in the number of correct drinking attempts as a percentage of all drinking attempts. Acquisition was observed both when light indicated water and when it indicated no water. This test model may offer a useful method for standardized measurement of left/right, light on/off discriminations.

Acoustic Stimulation↗
PubMed1978

Protein deprivation in primates. X. Test performance of juveniles born of deprived mothers.

Forty juvenile rhesus monkeys whose mothers were fed semisynthetic diets containing 13.4, 6.7, or 3.35% protein during pregnancy were tested as juveniles on four tests of perceptual-discrimination learning. All juveniles were well fed since birth. No significant differences in proficiency due to diet could be detected. It is concluded that thanks to the mother's proficient adaptation to the diet the fetus is well protected, and not deprived.

Animals↗
PubMed1975

A comparison of the effects of cytosine arabinoside and adenine arabinoside on some aspects of brain growth and development in the rat.

1. Treatment of pregnant rats with cytosine arabinoside (ara-C, 50 mg/kg, i.p.)at 14 days of gestation severely impaired both prenatal and postnatal whole brain growth in their offspring, although the cerebellum was relatively less affected than whole brain. 2. Rats treated at 5 days of age with ara-C (250 mg/kg, i.p.) showed an impairment in growth of the cerebellum relative to the rest of the brain. 3. Adenine arabinoside (ara-A) treatment, either prenatally or postnatally, had negligible effect on brain growth, even at doses considerably higher than those of ara-C. 4. Adult rats, previously treated with ara-C (50 mg/kg, i.p.) at 14 days of gestation, showed an impairment in discrimination learning when tested in a water T-maze. 5. These results are discussed in relation to the proposed use of ara-C or ara-A as antiviral agents, particularly against intrauterine infection with cytomegalovirus.

Age Factors↗
PubMed1976

A possible essential role for dietary linolenic acid in the development of the young rat.

Female rats were fed semi-purified diets containing 10% safflower oil or 10% soybean oil for six weeks prior to mating and through-out pregnancy and lactation. The progeny were weaned to the diet of the dam. Physical, neuromotor and reflex development was monitored in the progeny prior to weaning and learning ability of the mature progeny was assessed in a simple Y-maze test. Brain lipid analyses were conducted in the progeny at birth, 21 and 210 days of age. Inclusion of soybean oil in the diet resulted in higher levels of 22:6omega3 and lower levels of 22:5omega6 in the brain ethanolamine glycerophosphatides. The nature of the dietary fat exerted no effect on the physical development, onset of reflexologic responses or onset of neuromotor co-ordination in the pups. The soybean oil-fed animals spent more time in certain neuromotor activities possibly associated with explorative drive than did their safflower oil-fed counterparts. The performance of the mature soybean oil-fed progeny in the discrimination-learning test was superior to that of progeny fed safflower oil. The association of superior learning capacity with dietary soybean oil-induced incorporation of omega3 fatty acids into the brain glycerophosphatides is offered as support for an essential role for dietary linolenic acid for the young rat.

Animals↗
PubMed1998

Perirhinal cortex ablation impairs visual object identification.

Impairments in both recognition memory and concurrent discrimination learning have been shown to follow perirhinal cortex ablation in the monkey. The pattern of these impairments is consistent with the hypothesis that the perirhinal cortex has a role in the visual identification of objects. In this study we compared the performance of a group of three cynomolgus monkeys with bilateral perirhinal cortex ablation with that of a group of three normal controls in two tasks designed to test this hypothesis more directly. In experiment 1 the subjects relearned a set of 40 familiar concurrent discrimination problems; the stimuli in each trial were digitized images of real objects presented in one of three different views. After attaining criterion they were tested on the same problems using similar, but previously unseen, views of the objects. In experiment 2 the subjects were tested on their ability to perform 10 of these familiar discriminations with each problem presented in the unfamiliar context of a digitized image of a unique complex scene. The subjects with ablations were significantly impaired on both tasks. These results demonstrate that the role of the perirhinal cortex is not restricted to memory, and they support the hypothesis that the perirhinal cortex is involved in visual object identification. We suggest that the perirhinal cortex is crucially involved in processing coherent concepts of individual objects. A deficit of this nature could underlie the pattern of impairments that follow perirhinal cortex damage in both visual object recognition memory and visual associative memory.

Animals↗
PubMed2004

The importance of awareness for eyeblink conditioning is conditional: theoretical comment on Bellebaum and Daum (2004).

Eyeblink conditioning entails a variety of paradigms that differ in terms of the brain systems that support conditioning and the importance of awareness. In this issue, C. Bellebaum and I. Daum (2004) that reports that conditional discrimination learning depends on awareness. Their findings, along with other recent work, suggest a framework whereby the temporal features of the conditioning paradigm are critical in determining the ability of the cerebellum to support conditioning and, as a result, the role of awareness in conditioning.

Awareness↗
PubMed1977

Ontogeny of behavior in two inbred lines of selected mice.

The development over 11 ages of 14 reflex responses, 26 behavioral components, jumpiness, and left-right discrimination learning was studied in 2 strains of mice genetically selected for high (SRH) and low (SRL) rearing response frequency. Significant age-dependent differences between the strains were found mainly, but not exclusively, in the behavioral components, e.g., rearing, jumping, scratching, defecating. Two-week-old pups of both strains showed good acquisition and retention in learning tests without shock, but the "jumpy" behavior disturbed performance to a certain degree in the SRH strain. Although less active initially, SRH mice were ahead at later developmental stages. Whether these differences are determined by the gene controlling rearing frequency or by other genes remains undecided.

Age Factors↗
PubMed2002

Stimulus control by same-versus-different relations among multiple visual stimuli.

The authors devised a go/no-go discrimination learning task that allowed but did not require pigeons to report (a) from which of 2 different sets a collection of visual items was drawn and (b) the relations between or among the items as being the same as or different from one another. The results of 2 experiments using this task disclosed stimulus control by the particular items in the arrays and by the same-different relations exemplified by those items. Relational and item control depended on how many items were in the arrays. Same-different discrimination was evident with 2-item displays, but it was much stronger with 6 or more items. These findings help to define the substrates of advanced conceptual behavior.

Analysis of Variance↗
PubMed1978

Complex learning and information processing by pigeons: a critical analysis.

THREE MODELS OF CONDITIONAL DISCRIMINATION LEARNING BY PIGEONS ARE DESCRIBED: stimulus configuration learning, the multiple-rule model, and concept learning. A review of the literature reveals that true concept learning is not characteristic of the behavior of pigeons in matching-to-sample, oddity-from-sample, or symbolic matching studies. Instead, pigeons learn a set of sample-specific S(D) rules. Transfer of the discrimination to novel stimuli, at least along the hue dimension, is predicted by a "coding hypothesis", which holds that pigeons make a unique, but usually unobserved response, R(1), to each sample, and that the comparison stimulus chosen depends on which R(1) was emitted in the presence of the sample. Convincing evidence is found that pigeons do code sample hues, but there is little evidence that allows one to infer that the "coding event" must have behavioral properties. Parameters of the conditional discrimination paradigm are identified, and it is shown that by appropriate parametric manipulation, a variety of analogous tasks may be generated for both human and animal subjects. The tasks make possible the comparative study of complex learning, attention, memory, and information processing, with the added advantage that behavior processes may be compared systematically across tasks.

Journal Article↗
PubMed1986

[A neurochemical study of rat brain maldevelopment induced by MAM treatment at different stages of gestation].

The regional levels of several cell marker proteins in the brain and the ability of operant discrimination learning on a multiple fixed ratio (FR), fixed interval (FI) schedule were determined in rats with microencephaly induced by prenatal treatment with methylazoxymethanol (MAM), an antimitotic agent, on the 11 th to 13 th days (Group A) or on the 15 th day (Group B) of gestation. The cell marker proteins were determined with a sensitive enzyme immunoassay. Neuron-specific enolase (NSE; gamma gamma-enolase) had a significantly lowered level in the neocortex anterior in Group A. Non-neuronal enolase (NNE; alpha alpha-enolase) was significantly reduced in the superior colliculus, lateral geniculate body and optic nerve, but increased 1.5 fold in the retina in Group A. S-100b protein, a marker of astroglial cells, showed no significant change. As for the learning performance, the Group B animals showed an elevated behavioral activity and made evident discrimination between the FI and FR schedule. But Group A animals had prolonged FR components requiring responses to light on, and their spontaneous activity counts recorded by Automex showed an inhibition of behavior in light environments. These findings suggest a causative role of some developmental abnormality in the central visual system, indicated by the aberrant cell marker levels, in the disturbed learning ability of the Group A animals.

Abnormalities, Drug-Induced↗
PubMed1998

Effects of neocortical ectopias upon the acquisition and retention of a non-spatial reference memory task in BXSB mice.

BXSB mice have a 40-60% incidence of small, focal, neocortical dysplasias called ectopias. Ectopics and non-ectopics were compared on horizontal-vertical discrimination learning, a non-spatial cognitive task. No differences were found during acquisition. Ectopic mice, however, were superior when retested 8 weeks later. The results support prior findings that ectopic mice have better long-term spatial memory and extend this conclusion to the non-spatial domain.

Animals↗
PubMed1974

Group behavior of rats under schedules of reinforcement.

Groups of three rats were placed in a chamber containing one response lever and one water dispenser. A variety of schedule conditions were explored including fixed ratio, extinction, satiation, fixed interval, fixed time, differential reinforcement of low rates, and discrimination learning. Each group was treated as a single unit, with the collective lever responses emitted by the three rats being the main dependent variable. Group responding was found to be controlled by the reinforcement schedules in an orderly and consistent manner. However, the groups often paused less and responded faster than individual rats working under identical conditions.

Animals↗
PubMedDate not supplied

An animal model of auditory cortex prostheses.

Experiments aimed at rehabilitating deaf and blind patients with cortical prostheses were first conducted decades ago, but epicortical electrodes allowed only crude information transfer. Here we report that in Mongolian gerbils with electrodes implanted in input layers of the primary auditory cortex, spatial, temporal and spatiotemporal variations in intracortical stimulation all lead to perceptual differences as evidenced by discrimination training. For some stimulus regimes discrimination learning was as fast as with intracochlear stimulation in this animal. Intracortical stimulation induced field potentials and 2-deoxyglucose labeling patterns in primary auditory cortex similar to those induced by auditory click or tone stimuli, respectively. Given the common organization principles of neocortical areas, these results are presumably also of significance to prostheses interfacing with visual cortex.

Animals↗
PubMedDate not supplied

Memory consolidation for the discrimination of frequency-modulated tones in mongolian gerbils is sensitive to protein-synthesis inhibitors applied to the auditory cortex.

Differential conditioning of Mongolian gerbils to linearly frequency-modulated tones (FM) has recently received experimental attention. In the study of the role of cerebral protein synthesis for FM discrimination memory, gerbils received post-training bilateral injections of anisomycin into the auditory cortex under light halothane anesthesia. Compared with saline-treated controls, anisomycin-treated gerbils showed a discrimination decrement during the subsequent three days of training. They markedly improved their performance within training sessions, but started each session at low levels. When repeatedly trained gerbils received post-session injections of anisomycin, discrimination performance during subsequent sessions was similar to the pre-injection performance, indicating that retention, retrieval, reconsolidation, and expression of the established reaction were not affected. However, the improvement of a partially established discrimination reaction was impaired after this treatment. Intracortical injections of emetine confirmed this finding. Neither drug affected FM discrimination learning when given several days before the initial training. Our results suggest that protein-synthesis inhibitors applied to the auditory cortex of gerbils during the post-acquisition phase interfered with learning and memory-related aspects of FM processing. The resulting deficit was evident for a number of post-injection training days. This effect was probably due to impaired consolidation, i.e., processes required for long-term stabilization or retrieval of the memory trace while leaving short-term memory intact.

Acoustic Stimulation↗
PubMed1995

New infrared spectroscopic technique as a tool to reveal roles of unsaturated fatty acids in diseases and synaptic functions.

Newly developed Fourier-transform infrared spectroscopic analysis (FTIR) techniques were applied to diagnosis of adulthood disease and to reveal the role of unsaturated fatty acids in neuronal function. A new FTIR technique was developed to monitor the change of lipid content in the human oral mucosa noninvasibly. By this technique the infrared spectrum of oral mucosa was found to change in good relation to that of triglyceride level in blood of adult volunteers. This indicates that the new infrared technique may be useful for future diagnoses of hyperlipidemia or triglyceridemia noninvasively. It was found that the deficiency of n-3 polyunsaturated fatty acids in brain membranes decreased the bright-ness-discrimination learning performance in rats, and a change of membrane surface structures was detected nondestructively by FTIR after the learning task in comparison with the structure of membrane surfaces before the learning. The evidence obtained from this technique suggested that a change of sialic acid binding form in the brain membranes occurred after the learning task in rats fed n-3 rich diet but not in rats fed n-3 deficient diet. This was further confirmed by a chemical analysis of sialidase-sensitive sialic acid contents in the membrane. These evidences show that the newly developed infrared spectroscopic techniques are useful not only for the noninvasive diagnoses for human adulthood diseases but also for the nondestructive analysis of biomembrane.

Adult↗
PubMed2003

Elemental and configural encoding of the conditioned stimulus.

Five experiments explored the effect of conditioning AB and CD compounds on responding to transfer AD and BC compounds and to elements. These experiments used several conditioning procedures: flavour aversion and instrumental discriminative learning in rats and autoshaping in pigeons. All of the experiments found greater responding to the trained AB and CD than to the transfer AD and BC compounds, a result that agrees with some configural models, but not with an elemental model. All experiments also found greater responding to the transfer AD and BC compounds than to the elements, a result that agrees with elemental, but not configural, models.

Animals↗
PubMed1975

Relative effectiveness of various letter discrimination procedures in directionality pretraining.

Two investigations were conducted to provide information relevant to programming basic reading skills for retarded individuals. Both experiments utilized various procedures to teach subjects to discriminate between the letters b and d. The role of feedback and task format conditions was investigated in Experiment 1. Results indicated that two-choice discrimination learning was significantly more difficult than either oddity or matching-to-sample conditions. In Experiment 2 the effects of problem type and sample reduncancy were examined. Analyses indicated that simultaneous matching-to-sample procedures were significantly easier than successive matching-to-sample procedures. Performance with a delayed matching-to-sample transfer task did not reflect differential effects of training in either study.

Adolescent↗