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A visual learning and memory test for preoperative evaluation of patients with temporal lobe epilepsy.

We used a modified version of the visual DCS (mDCS) test to study patterns of learning, free recall, and recognition capacity in patients with temporal lobe epilepsy (TLE) (N = 24) and controls (N = 38). The patients were under consideration for epilepsy surgery. The mDCS differentiated left from right TLE patients in all aspects of visuospatial learning and delayed recall. The mDCS revealed lower performance for TLE patients as compared with controls. The present results indicate that the mDCS may be a preoperative tool to differentiate left from right TLE.

Adult↗

Memory and learning performances in POW survivors with history of malnutrition and combat veteran controls.

Former prisoners of war (POWs) with histories of malnutrition and body wasting were compared on standardized measures of memory and learning with POW survivors who sustained less confinement body weight loss and combat veterans of similar ages and military assignments. Results showed that POWs who sustained the greatest degree of trauma-induced weight loss, or that exceeding 35% of their precaptivity body weights, performed significantly worse on four of the five Wechsler Memory Scale /3-Revised (WMS-R) indices, showed more rapid rates of forgetting on the Visual Reproduction test, and exhibited slower acquisition rates and less sophisticated mastery of the learning materials on a modified version of the Rey Auditory Verbal Learning Test (AVLT). Given their relatively intact performances on measures of general intelligence and attention-concentration, the POWs with a history of severe malnutrition appeared to evidence a pattern of cognitive limitations qualitatively similar to that associated with alcoholic Korsakoff's syndrome.

Journal Article↗

Development of learning and memory in mice genetically selected for differences in brain weight.

Mice selected for high (H), medium (M), and low (L) brain weight were trained to the goal arm opposite their preference in a shock-escape T-maze at 7, 9, 11, or 13 days of age. Twenty-four hours later, half of the trained groups at each age received additional training to the original goal, whereas the other half was trained to the opposite goal. Maturational control groups without prior training were trained on the selected retest days for the previously trained groups. Improvement in correct choice-point turns during training was suggested for the H-line by 9 days of age and by 11 days of age for the M- and L-lines. During retraining, H-line mice demonstrated 24-hr retention effects by 10 days of age, whereas 24-hr memory was not indicated for M- and L-lines at any of the ages investigated. These results indicate that the onsets of learning and memory were influenced by genes affecting brain weight, in that H-line mice demonstrated more rapid brain growth as well as heavier brain weights at every age studied as compared with M- and L-line mice which showed similar brain growth functions.

Age Factors↗

[Effect of synthetic fragments of thymic peptide hormones on learning and memory processes].

Seven synthetic peptide fragments of thymic hormones were investigated using behavioral and electrophysiological methods. Splenopentin was shown to increase markedly learning capacities and memory. In contrast, alpha 1-thymosin fragment decreased them. Other peptides only slightly affected the capacities. Two active peptides seem to affect the level of activation of subcortical structures responsible for the excitation and inhibition.

Animals↗

Inwardly rectifying Kir3.1 subunit knockdown impairs learning and memory in an olfactory associative task in rat.

Inward-rectifier potassium channels gated by the direct action of G proteins are activated or inhibited by numerous neurotransmitters and they modulate neuronal excitability. Using an olfactory associative task, the effect of Kir3.1 subunit knockdown was tested on learning and memory. Repeated intracerebroventricular injections of antisense oligodeoxyribonucleotide to the Kir3.1 subunit significantly reduced hippocampal expression of its mRNA target determined by Western blotting. The antisense knockdown had no effect on locomotor and drinking activity or on attention processes. The reduction in Kir3.1 subunit impaired the learning of the odor associations and the procedural side of the task. This reduction correlated with the performance impairment. The results suggest that Kir3.1 channel activity is implicated in the memory processes.

Animals↗

Solcoseryl improves learning and memory in rats.

Our previous experiments have shown that Solcoseryl (S), a protein-free extract of calves' blood stimulates locomotor activity and decreases haloperidol catalepsy in rats. In this study the influence of S on acquisition, consolidation, and recall of both, conditioned avoidance responses (CARs) and passive avoidance behaviour was tested. S at the intraperitoneal (i.p.) dose of 1.25 ml/kg significantly improved acquisition and at the dose of 1.0 ml/kg recall of CARs. In the passive avoidance situation the significant effect on acquisition and recall of information was observed after i.p. injection of 1.0 ml/kg of S, and on consolidation after 0.75 ml/kg. These data indicate that S may positively affect the CNS processes responsible for learning and memory.

Actihaemyl↗

Learning and memory impairments in Kv beta 1.1-null mutants are rescued by environmental enrichment or ageing.

Mice with a null mutation of the K+ channel regulatory subunit Kv beta 1.1 have altered excitability in hippocampal neurons and are impaired in the social transmission of food preferences (STFP) task. It was previously unclear whether this impairment is related to learning and memory (L & M) deficits or to developmental abnormalities. In this study we show that rearing the Kv beta 1.1 mutants in an enriched environment rescues the impairment in the STFP task. Furthermore, we found that STFP performance was impaired in 12-month-old wild-type mice, but not in the Kv beta 1.1 mutants at this age, indicating that the Kv beta 1.1 mutants show an age-related rescue of the deficits observed in the young mutants. Ibotenic acid lesions of the hippocampus in the 12-month-old Kv beta 1.1 mutants caused an impairment in the STFP task. Our findings indicate that performance in the STFP task is age-dependent and involves the hippocampus. Furthermore, we have established that the impairments in the Kv beta 1.1 mutants are related to L & M and not to performance disabilities. Finally, we suggest that the loss of Kv beta 1.1 function is beneficial for L & M in middle age.

Aging↗

Learning and memory in Lymnaea are negatively altered by acute low-level concentrations of hydrogen sulphide.

Hydrogen sulphide (H(2)S) is a common industrial pollutant as well as an endogenous neural transmitter/neural modulator. Experiments were performed on the pond snail Lymnaea stagnalis to determine the acute effects of low-level exposure to H(2)S (50-100 micromol l(-1)) on aerial respiratory behaviour, associative learning, and its subsequent consolidation into long-term memory (LTM). A 3-neuron network whose sufficiency and necessity have been demonstrated drives aerial respiratory behaviour in Lymnaea. In the presence of 100 micromol l(-1) H(2)S the number of bouts of aerial respiration and the total breathing time were significantly increased compared to the control hypoxic situation, but were equivalent to those observed in snails that had been subjected to a 'more intense hypoxic challenge'. In addition, at a concentration of 100 micromol l(-1) H(2)S neither associative learning nor long-term memory (LTM) were observed. However, snails subjected to a 'more intense hypoxic challenge' still had the capacity to learn and form LTM. These snails, in fact, showed statistically the best learning and memory performance of any group. While learning and memory were observed at 50 and 75 micromol l(-1) H(2)S, respectively, they were statistically poorer than the learning and memory exhibited by snails in the standard hypoxia condition. Hence the ability to learn and form memory was compromised by H(2)S. Thus an invertebrate model system with a well-defined neural network can be used to study of the effects of H(2)S on the processes of learning and memory.

Analysis of Variance↗

Neurotoxic basolateral amygdala lesions impair learning and memory but not the performance of conditional fear in rats.

We examined the influence of extensive overtraining (75 trials) on the impact of neurotoxic basolateral amygdala (BLA) lesions on Pavlovian fear conditioning in rats. As we have shown previously, pretraining BLA lesions yielded severe deficits in the acquisition of conditional freezing in rats trained with either 1 or 25 conditioning trials. However, extensive overtraining (50 or 75 trials) mitigated deficits in conditional freezing. Under these conditions the rats with BLA lesions expressed normal and robust freezing behavior, although they required at least 10 times as much training as control rats to reach this level of performance. The ability of rats with BLA lesions to acquire and express conditional freezing after extensive overtraining was modality-specific; conditional freezing in individual rats was acquired to contextual, but not acoustic, conditional stimuli. These results suggest that neural circuitry outside of the amygdala can mediate contextual fear conditioning under some conditions. In contrast to pretraining lesions, post-training BLA lesions eradicated the memory for Pavlovian fear in rats trained with either 1 or 75 trials; this deficit was not modality-specific. Together, these results reveal that impairments in the acquisition and expression of conditional fear in rats with BLA lesions are not attributable to deficits in the performance of the freezing response but are attributable to disruptions in the learning and memory of Pavlovian fear conditioning.

Acoustic Stimulation↗

Effects of a novel compound MCI-225 on impaired learning and memory in rats.

Effects of MCI-225, [4-(2-fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno[2,3-d]pyrimidine monohydrate hydrochloride] on experimental amnesia were studied in rats and compared with those of THA [9-amino-1,2,3,4-tetrahydroacridine]. In the Morris-type water maze task, MCI-225 (1-10 mg/kg, PO) reduced the spatial learning impairment induced by scopolamine (0.5 mg/kg, IP). In a passive avoidance (PA) task, administration of MCI-225 prior to training (1-30 mg/kg, PO) lessened the carbon dioxide (CO2)-induced amnesia in a dose-dependent manner. MCI-225 (1-100 mg/kg) did not affect gross behavior. THA (0.1-3 mg/kg, PO) reduced scopolamine-induced learning deficits in the water maze task, but the effect was not significant. THA (0.3-3 mg/kg, PO) also ameliorated the CO2-induced amnesia, although slightly, in the PA task. THA (10 mg/kg, PO) increased locomotor activity and higher dose of THA (30 mg/kg, PO) induced tremor, hypersalivation, and muscle relaxation. These results suggest that MCI-225 lessens impairments in learning and memory without causing serious behavioral abnormalities.

Animals↗

Effect of bicuculline and angiotensin II fragment 3-7 on learning and memory processes in rats chronically treated with ethanol.

The aim of this study was to determine the possible influence of bicuculline, the antagonist of GABA-A receptor on behavioral activity (recall, acquisition of conditioned reflexes) of angiotension II fragment 3-7 (A II 3-7) in rats chronically treated with ethanol. Long term (9 weeks) ethanol intoxication profoundly impaired learning and memory processes in all testes used. The GABA-A receptor antagonist bicuculline (0.5 mg/kg ip) did not influence exploratory and motor activity in the control rats, but we observed tendency (without significance) to decrease the locomotor activity, in the alcohol-intoxicated groups of animals, when the drug was injected together with A II 3-7 (2 microgram icv). Bicuculline did not influence retrieval process in passive avoidance recall in both investigated groups, and when the drug was given together with AII 3-7 significantly enhanced its action in the control group and in rats chronically treated with ethanol. Bicuculline significantly improved acquisition in the active avoidance test in the control and alcohol-intoxicated groups. Bicuculline injected together with A II 3-7 significantly decreased its action in the control group. Coadministration of bicuculline with A II 3-7 did not significantly change the activity of A II 3-7 in the acquisition of active avoidance test in the alcohol-intoxicated groups of rats.

Angiotensin II↗

Effects of atropine on learning and memory functions in dementia.

The effect of intravenous atropine (1 mg) or saline on mnemonic function was tested in patients with various forms of dementia and age-matched controls. Examinees consisted of 12 subjects having Alzheimer's disease (AD), multi-infarct dementia (MID), Parkinson's disease without dementia or with dementia, and normal aged controls. Wechsler's adult memory scale was used. Orientation, visual reproduction, and associative learning were not affected by this small dose of atropine in any of the subgroups. On the other hand, digit span and logical memory were selectively impaired by atropine in AD. The more sensitive parameters were the improvement on retesting (reflecting learning abilities). This study suggests that cholinergic dysfunction is responsible for abnormalities in logical memory and digit span in AD or the dementia of Parkinson's disease but not in MID.

Alzheimer Disease↗