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At least 1,315 records · Page 73Linked to original sources
PubMed1979

Recovery of memory and learning functions following traumatic brain injury.

Twenty-four traumatically brain-injured males, of whom eight had sustained right-sided, eight left-sided, and eight bilateral or diffuse closed head injuries, took a battery of neuropsychological tests within the first six months, the second six months, the second year and the third year post injury. Performances on WAIS Digits Forward and Backward and Rey's Auditory-Verbal Learning Test were classified as within or below normal range. Comparisons were made (1) between time periods and tests and (2) between subgroups formed by severity, site of lesion, and age. The findings give an overall picture of wide performance variability with consistent improvement in immediate memory span and learning. Recovery varied with the specific nature of the tested function, task complexity, and severity of injury. Neither age, site of injury, not recency were associated with improvement.

Adult↗
PubMed1986

Learning and memory for personality prototypes.

Although personality traits are commonly assumed to be represented in memory as schemata, little research has addressed whether such schemata can be learned from observation. Subjects in three studies classified 60 person instances into group members and nonmembers as defined by the instances' match to a complex personality prototype. To simulate learning of fuzzy categories, each person instance provided conflicting cues to group membership. Learning for instances' group membership was excellent across studies. In Study 1, frequency of cues indicating group membership was greatly overestimated among nongroup instances. In Study 2, schema-consistent memory bias was revealed for person instances. In Study 3, schemata of consistently positive (or negative) traits were learned faster than arbitrary schemata. The findings implicated frequency sensitivity of memory (Estes, 1986), and a model of probabilistic cued-memory retrieval was developed to account for the effects. The findings were then discussed in relation to everyday cognitive performance.

Adult↗
PubMed1967

Effects of thiopental sedation on learning and memory.

Subjects who were administered thiopental showed a loss of memory for events discussed while they were under sedation. We tested the subjects for recognition memory of pictures and recall of associated pairs of letters and words, and found that the subsequent memory loss was correlated with the concentration of thiopental in the venous blood at the time the material was learned. Retention did not appear to be state-dependent because the subject, while under sedation, could recall material learned prior to sedation, and because recall was not facilitated by reinstatement of the sedation.

Female↗
PubMed1998

Effect of RGH-2716 on learning and memory deficits of young and aged rats in water-labyrinth.

RGH-2716 is a novel 1-oxa-3,8-diazaspiro[4.5] decan 2-one, which was published to have potent inhibitory effect on neuronal Na and Ca movement and stimulatory action on nerve growth factor (NGF)-production, as well as to show significant antiamnesic activity in experimental amnesia models. The aim of the present experiments was to study the effect of the compound on the learning process and on the different stages of memory using water-labyrinth in normal and memory impaired young animals, as well as to study cognitive effect of RGH-2716 on aged animals. At the doses of 0.5 mg/kg i.p. or 3 mg/kg p.o. given before daily swimming, this compound improved the learning process of young animals impaired by either diazepam (DIA) or scopolamine (SCOP). In retrograde amnesia model RGH-2716 (3 mg/kg p.o.) significantly ameliorated consolidation process and retrieval of information impaired by SCOP or DIA. Nimodipine and vinpocetine (10 mg/kg p.o.) showed moderate effect compared to RGH-2716. Aged rats pretreated with daily i.p. RGH-2716 performed the tasks with significantly fewer errors and shorter swimming time than untreated aged rats. When aged animals had to solve a new labyrinth problem, treated aged rats showed significantly better learning ability than aged controls. One month of oral treatment of aged rats with 3 mg/kg dose of RGH-2716 two times daily resulted in a "tendency-like" improvement in learning of aged Fischer 344 and spontaneously hypertensive (SH) rats. The present results make RGH-2716 an interesting compound for the treatment of cognitive disorders.

Aging↗
PubMed2002

Vocal memory and learning in adult Bengalese Finches with regenerated hair cells.

Critical learning periods are common in vertebrate development. In many birds, song learning is limited by a critical period; juveniles copy songs from adult birds by forming memories of those songs during a restricted developmental period and then using auditory feedback to practice their own vocalizations. Adult songs are stable over time regardless of exposure to other birds, but auditory feedback is required for the maintenance of stable adult song. A technique was developed to reversibly deafen Bengalese Finches by destruction and regeneration of inner ear auditory hair cells. With this approach, we asked two questions about the plasticity of song information stored in the adult brain. First, do adult birds store memories or "templates" of their songs that exist independent of auditory reinforcement? Such memories could be used to control vocal output by acting as fixed models of song to which ongoing vocalizations are matched. Second, can adult song learning, which does not normally occur in this species, be induced by removing and then restoring hearing? Studying changes in adult song behavior during hair cell loss and regeneration revealed two findings: (1) adult birds store memories or templates of their songs that exist independent of auditory input and can be used to restore normal vocal behavior when hearing is restored; (2) under experimental circumstances, adult birds can be induced to acquire song material from other birds. Results suggest that, in Bengalese Finches, the degree of behavioral and neural plasticity in juvenile and adult birds may be less distinct that previously thought.

Animals↗
PubMed2004

Isoform-specific knockout of FE65 leads to impaired learning and memory.

FE65 is a multimodular adapter protein that is expressed predominantly in brain. Its C-terminal phosphotyrosine interaction domain (PID) binds to the intracellular tail of the beta-amyloid precursor protein (betaPP), a protein of central importance to the pathogenesis of dementias of the Alzheimer type. To study the physiological functions of FE65, we generated a line of FE65 knockout mice via gene targeting. By Western analysis with a panel of FE65-specific antibodies, we demonstrate that the 97-kDa full-length FE65 (p97) was ablated in the mutant mice, and that a previously undescribed FE65 isoform with apparent molecular mass of 60 kDa (p60) was expressed in both wild-type and mutant mice. p60 had a truncated N-terminus and was likely to be generated through alternative translation. Expressions of the two isoforms appeared to be brain region distinct and age dependent. The p97FE65(-/-) mice were viable and showed no obvious physical impairments or histopathological abnormalities. However, p97FE65(-/-) and p97FE65(+/-) mice exhibited poorer performances than wild-type mice on a passive avoidance task when tested at 14 months (P <.05). p97FE65(-/-) mice at 14 months also exhibited impaired hidden-platform acquisition (P <.05) and a severe reversal-learning deficit (P <.002) but normal visual-platform acquisition in the Morris water maze tests. Probe trials confirmed impairments in p97FE65(-/-) mice in relearning of new spatial information, suggesting a hippocampus-dependent memory-extinction deficit. Reduced secretion of Abeta peptides was observed in primary neuronal cultures of hybrids of p97FE65(-/-)/betaPP transgenic (Tg2576) mice. These studies suggest an important and novel function of FE65 in learning and memory.

Aging↗
PubMed1989

Learning and memory effects of four newly-synthesized aniracetam analogues.

Four new analogues of the pyrolidine derivative with nootropic action--aniracetam--were synthesized using classical methods. The effects of the newly-synthesized compounds were tested using the step-through method for passive avoidance with negative reinforcement and the method of habituation of exploratory activity in the Opto-Varimex apparatus. Two series of experiments were performed using the step-through method: in one series aniracetam (Anc) and its analogues p-H and p-Cl were applied twice daily in a dose of 50 mg/kg for 7 days prior to the training session; retention tests were made 3 h, 24 h and 7 days after the training session. In the other series of experiments the Anc analogues p-P (in single daily doses of 10, 50 and 250 mg/kg) and p-F (in a single daily dose of 50 mg/kg) were applied for 5 days prior to the training session; memory tests were performed 24 h and 7 days after the training session. In one of the experimental series in Opto-Varimex, after 5-min recording of the horizontal, vertical and rotatory movements of each rat, the various groups of animals received 20, 100 or 300 mg/kg from each of the agents tested (Anc, p-Cl and p-H). Tests for habituation were performed 7 days later. The other series of experiments in Opto-Varimex included groups of rats receiving 50 mg/kg Anc, p-Cl and p-H twice daily for 7 days. The three types of movement were recorded for 5 min in the Opto-Varimex after the last dose of the substances tested. All substances were administered orally. The results obtained (longer time spent by the animals in the illuminated section when the step-through method was used and enhanced habituation in the Opto-Varimex experiments) suggest that the substances tested improve the memory, mainly through improving the process of consolidation of the memory traces.

Animals↗
PubMed2001

Neural-network models of learning and memory: leading questions and an emerging framework.

Real-time neural-network models provide a conceptual framework for formulating questions about the nature of cognition, an architectural framework for mapping cognitive functions to brain regions, a semantic framework for defining terms, and a computational framework for testing hypotheses. This article considers key questions about how a physical system might simultaneously support one-trial learning and lifetime memories, in the context of neural models that test possible solutions to the problems posed. Model properties point to partial answers, and model limitations lead to new questions. Placing individual system components in the context of a unified real-time network allows analysis to move from the level of neural processes, including learning laws and rules of synaptic transmission, to cognitive processes, including attention and consciousness.

Journal Article↗
PubMed1989

Significance of the cerebral dopaminergic neurotransmission for the individual differences in learning and memory (experiments on rats).

Using the step-down method for passive avoidance with punishment electroshock reinforcement, the experimental rats were divided according to their individual differences in the capacity for learning and retention into two groups: good learners (GL) and poor learners (PL). Stereotypy and catalepsy methods were used in order to clarify the role of the central dopaminergic (DA-ergic) transmitter mechanisms for the individual differences. Stereotypic motor behaviour was induced by applying the following DA-ergic agonists: apomorphine (2 mg/kg. i.p.), amphetamine (6 mg/kg, s.c.) and elymoklavine (2 mg/kg, i.p.). The stereotypic behaviour was recorded on a 5-point scale. A set of catalepsy tests was used to determine the cataleptic effect of the DA-ergic antagonist haloperidol (1 mg/kg, i.p.). Our experimental results showed that the intensity and duration of the stereotypy caused by the three agents were significantly increased in GL compared with PL. Catalepsy in the PL group appeared later than in the GL group, and its total duration was shorter. The data obtained suggest that in the GL group there is a marked tendency towards a higher level of sensitivity of the brain dopamine receptors, compared with the PL group.

Animals↗