Aposematic coloration of prey enhances memory retention in an agamid lizard

The current study aimed at comparing the effect of three placements of the re-exposure episodes on memory retention (interpolated-small, interpolated-medium, postponed), depending on whether retrieval practice or re-reading was used, and on retention interval (one week vs one month).

Download Full-text

It’s all about who you know: Memory retention of a rat’s cagemates during infancy negatively predicts adulthood hippocampal FGF2

Neurobiology of Learning and Memory ◽

10.1016/j.nlm.2021.107448 ◽

2021 ◽

pp. 107448

Author(s):

Sylvia K. Harmon-Jones ◽

Bronwyn M. Graham ◽

Gabrielle King ◽

Rick Richardson

Keyword(s):

Memory Retention

Download Full-text

A study of effect of Centella asiatica on oxidative markers in the hippocampus of offsprings born to alcohol-fed pregnant rats and the correlation with their cognitive functions

Journal of Complementary and Integrative Medicine ◽

10.1515/jcim-2020-0472 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Mitha K.V. ◽

Saraswati Jaiswal Yadav ◽

Ganaraja Bolumbu

Keyword(s):

Brain Damage ◽

Water Extract ◽

Centella Asiatica ◽

Protein Carbonyl ◽

Memory Retention ◽

Pregnant Rats ◽

Shuttle Box ◽

Cognitive Efficiency ◽

Beneficial Effects ◽

Oxidative Markers

Abstract Objectives Alcohol consumption causes several harmful effects on the organs, which is hugely understated. Many deformities occur in the fetus when pregnant mothers indulge in alcoholism. Alcohol is a known teratogen, hence organ formation, particularly development of parts brain critical for cognitive function may be affected. The oxidative brain damage also could contribute to reduced cognitive efficiency of brain exposed to alcohol. In this study, effect of Centella asiatica in relieving the oxidative brain damage in offspring of alcohol fed mother rats was evaluated. Methods In this study we fed alcohol (5 g/kg body weight, 30% w/v) to a group of pregnant Wistar rats during gestation period, and another group served as control. Four groups of rats (n = 6 each) were selected from the offspring of these mother rats. The groups were, control, positive (treated) control, untreated and treated from alcohol-fed mother. Their cognitive parameters were tested in water maze, shuttle box and compared. Further their oxidative status was evaluated by estimating malondialdehyde (MDA), protein carbonyl, total antioxidants and glutathione reductase (GSH) in hippocampus. Results The results suggested that there was significantly high cognitive performance in maze test and shuttle box memory retention in rats treated with C. asiatica water extract and the antioxidant levels were high in their hippocampus. Conclusions The outcome of the study suggested that C. asiatica produced beneficial effects in reversing the alcohol induced brain damage in pregnancy.

Download Full-text

Investigating the Effects of Seizures on Procedural Memory Performance in Patients with Epilepsy

Brain Sciences ◽

10.3390/brainsci11020261 ◽

2021 ◽

Vol 11 (2) ◽

pp. 261

Author(s):

Frank J. van Schalkwijk ◽

Walter R. Gruber ◽

Laurie A. Miller ◽

Eugen Trinka ◽

Yvonne Höller

Keyword(s):

Temporal Lobe ◽

Declarative Memory ◽

Memory Performance ◽

Total Sample ◽

Learning Task ◽

Procedural Memory ◽

Memory Retention ◽

Motor Sequence ◽

Performance Improvements ◽

Patients With Epilepsy

Memory complaints are frequently reported by patients with epilepsy and are associated with seizure occurrence. Yet, the direct effects of seizures on memory retention are difficult to assess given their unpredictability. Furthermore, previous investigations have predominantly assessed declarative memory. This study evaluated within-subject effects of seizure occurrence on retention and consolidation of a procedural motor sequence learning task in patients with epilepsy undergoing continuous monitoring for five consecutive days. Of the total sample of patients considered for analyses (N = 53, Mage = 32.92 ± 13.80 y, range = 18–66 y; 43% male), 15 patients experienced seizures and were used for within-patient analyses. Within-patient contrasts showed general improvements over seizure-free (day + night) and seizure-affected retention periods. Yet, exploratory within-subject contrasts for patients diagnosed with temporal lobe epilepsy (n = 10) showed that only seizure-free retention periods resulted in significant improvements, as no performance changes were observed following seizure-affected retention. These results indicate general performance improvements and offline consolidation of procedural memory during the day and night. Furthermore, these results suggest the relevance of healthy temporal lobe functioning for successful consolidation of procedural information, as well as the importance of seizure control for effective retention and consolidation of procedural memory.

Download Full-text

Nectar non-protein amino acids (NPAAs) do not change nectar palatability but enhance learning and memory in honey bees

Scientific Reports ◽

10.1038/s41598-021-90895-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Daniele Carlesso ◽

Stefania Smargiassi ◽

Elisa Pasquini ◽

Giacomo Bertelli ◽

David Baracchi

Keyword(s):

Amino Acids ◽

Learning And Memory ◽

Honey Bees ◽

Feeding Preference ◽

Memory Retention ◽

Floral Nectar ◽

Olfactory Conditioning ◽

Specific Memory ◽

Protein Amino Acids ◽

Valuable Compounds

AbstractFloral nectar is a pivotal element of the intimate relationship between plants and pollinators. Nectars are composed of a plethora of nutritionally valuable compounds but also hundreds of secondary metabolites (SMs) whose function remains elusive. Here we performed a set of behavioural experiments to study whether five ubiquitous nectar non-protein amino acids (NPAAs: β-alanine, GABA, citrulline, ornithine and taurine) interact with gustation, feeding preference, and learning and memory in Apis mellifera. We showed that foragers were unable to discriminate NPAAs from water when only accessing antennal chemo-tactile information and that freely moving bees did not exhibit innate feeding preferences for NPAAs. Also, NPAAs did not alter food consumption or longevity in caged bees over 10 days. Taken together our data suggest that natural concentrations of NPAAs did not alter nectar palatability to bees. Olfactory conditioning assays showed that honey bees were more likely to learn a scent when it signalled a sucrose reward containing either β-alanine or GABA, and that GABA enhanced specific memory retention. Conversely, when ingested two hours prior to conditioning, GABA, β-alanine, and taurine weakened bees’ acquisition performances but not specific memory retention, which was enhanced in the case of β-alanine and taurine. Neither citrulline nor ornithine affected learning and memory. NPAAs in nectars may represent a cooperative strategy adopted by plants to attract beneficial pollinators.

Download Full-text

GluN2B and GluN2A-containing NMDAR are differentially involved in extinction memory destabilization and restabilization during reconsolidation

Scientific Reports ◽

10.1038/s41598-020-80674-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Andressa Radiske ◽

Maria Carolina Gonzalez ◽

Diana A. Nôga ◽

Janine I. Rossato ◽

Lia R. M. Bevilaqua ◽

...

Keyword(s):

Inhibitory Avoidance ◽

Receptor Subtypes ◽

Memory Recall ◽

Memory Retention ◽

Local Protein Synthesis ◽

Memory Recovery ◽

Male Wistar Rats ◽

Extinction Memory ◽

The Moment ◽

Local Protein

AbstractExtinction memory destabilized by recall is restabilized through mTOR-dependent reconsolidation in the hippocampus, but the upstream pathways controlling these processes remain unknown. Hippocampal NMDARs drive local protein synthesis via mTOR signaling and may control active memory maintenance. We found that in adult male Wistar rats, intra dorsal-CA1 administration of the non-subunit selective NMDAR antagonist AP5 or of the GluN2A subunit-containing NMDAR antagonist TCN201 after step down inhibitory avoidance (SDIA) extinction memory recall impaired extinction memory retention and caused SDIA memory recovery. On the contrary, pre-recall administration of AP5 or of the GluN2B subunit-containing NMDAR antagonist RO25-6981 had no effect on extinction memory recall or retention per se but hindered the recovery of the avoidance response induced by post-recall intra-CA1 infusion of the mTOR inhibitor rapamycin. Our results indicate that GluN2B-containing NMDARs are necessary for extinction memory destabilization whereas GluN2A-containing NMDARs are involved in its restabilization, and suggest that pharmacological modulation of the relative activation state of these receptor subtypes around the moment of extinction memory recall may regulate the dominance of extinction memory over the original memory trace.

Download Full-text