scholarly journals Distributed plasticity in ant visual pathways following colour learning

2019 ◽  
Vol 286 (1896) ◽  
pp. 20182813 ◽  
Author(s):  
Ayse Yilmaz ◽  
Kornelia Grübel ◽  
Johannes Spaethe ◽  
Wolfgang Rössler
Keyword(s):  
Learning And Memory ◽  
Light Exposure ◽  
Visual Pathways ◽  
Memory Formation ◽  
Central Complex ◽  
Insect Brain ◽  
Long Term Memory ◽  
Neuronal Circuits ◽  
Efficient Design

Colour processing at early stages of visual pathways is a topic of intensive study both in vertebrate and invertebrate species. However, it is still unclear how colour learning and memory formation affects an insect brain in the peripheral processing stages and high-order integration centres, and whether associative colour experiences are reflected in plasticity of underlying neuronal circuits. To address this issue, we used Camponotus blandus ants as their proven colour learning and memory capabilities, precisely controllable age and experience, and already known central visual pathways offer unique access to analyse plasticity in neuronal circuits for colour vision in a miniature brain. The potential involvement of distinct neuropils—optic lobes (OLs), mushroom body (MB) input (collar) and output (vertical lobe), anterior optic tubercle (AOTU) and central complex (CX)—in associative colour experiences was assessed by quantification of volumetric and synaptic changes (MB collar) directly after colour conditioning and, 3 days later, after the establishment of long-term memory (LTM). To account for potential effects of non-associative light exposure, we compared neuronal changes in the brain of colour-naive foragers with those of foragers that had been exposed to light in a non-associative way. The results clearly show that the OLs, AOTU, and CX respond with plastic changes after colour learning and LTM formation. This suggests a complex neuronal network for colour learning and memory formation involving multiple brain levels. Such a colour-processing network probably represents an efficient design promoting fast and accurate behavioural decisions during orientation and navigation.

scholarly journals Mushroom body-specific profiling of gene expression identifies regulators of long-term memory in Drosophila

2017 ◽  
Author(s):  
Yves F Widmer ◽  
Adem Bilican ◽  
Rémy Bruggmann ◽  
Simon G Sprecher
Keyword(s):  
Gene Expression ◽  
Learning And Memory ◽  
Mushroom Body ◽  
Memory Formation ◽  
Long Term Memory ◽  
Transcriptional Program ◽  
Term Memory ◽  
New Genes ◽  
Memory Traces

AbstractMemory formation is achieved by genetically tightly controlled molecular pathways that result in a change of synaptic strength and synapse organization. While for short-term memory traces rapidly acting biochemical pathways are in place, the formation of long-lasting memories requires changes in the transcriptional program of a cell. Although many genes involved in learning and memory formation have been identified, little is known about the genetic mechanisms required for changing the transcriptional program during different phases of long-term memory formation. With Drosophila melanogaster as a model system we profiled transcriptomic changes in the mushroom body, a memory center in the fly brain, at distinct time intervals during long-term memory formation using the targeted DamID technique. We describe the gene expression profiles during these phases and tested 33 selected candidate genes for deficits in long-term memory formation using RNAi knockdown. We identified 10 genes that enhance or decrease memory when knocked-down in the mushroom body. For vajk-1 and hacd1, the two strongest hits, we gained further support for their crucial role in learning and forgetting. These findings show that profiling gene expression changes in specific cell-types harboring memory traces provides a powerful entry point to identify new genes involved in learning and memory. The presented transcriptomic data may further be used as resource to study genes acting at different memory phases.

scholarly journals Disruption of the astrocyte–neuron interaction is responsible for the impairments in learning and memory in 5XFAD mice: an Alzheimer’s disease animal model

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Moonseok Choi ◽  
Sang-Min Lee ◽  
Dongsoo Kim ◽  
Heh-In Im ◽  
Hye-Sun Kim ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Animal Model ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Stat3 Phosphorylation ◽  
Neuron Interactions ◽  
5Xfad Mice

AbstractThe morphological dynamics of astrocytes are altered in the hippocampus during memory induction. Astrocyte–neuron interactions on synapses are called tripartite synapses. These control the synaptic function in the central nervous system. Astrocytes are activated in a reactive state by STAT3 phosphorylation in 5XFAD mice, an Alzheimer’s disease (AD) animal model. However, changes in astrocyte–neuron interactions in reactive or resting-state astrocytes during memory induction remain to be defined. Here, we investigated the time-dependent changes in astrocyte morphology and the number of astrocyte–neuron interactions in the hippocampus over the course of long-term memory formation in 5XFAD mice. Hippocampal-dependent long-term memory was induced using a contextual fear conditioning test in 5XFAD mice. The number of astrocytic processes increased in both wild-type and 5XFAD mice during memory formation. To assess astrocyte–neuron interactions in the hippocampal dentate gyrus, we counted the colocalization of glial fibrillary acidic protein and postsynaptic density protein 95 via immunofluorescence. Both groups revealed an increase in astrocyte–neuron interactions after memory induction. At 24 h after memory formation, the number of tripartite synapses returned to baseline levels in both groups. However, the total number of astrocyte–neuron interactions was significantly decreased in 5XFAD mice. Administration of Stattic, a STAT3 phosphorylation inhibitor, rescued the number of astrocyte–neuron interactions in 5XFAD mice. In conclusion, we suggest that a decreased number of astrocyte–neuron interactions may underlie memory impairment in the early stages of AD.

scholarly journals Wnt Signaling Is Required for Long-Term Memory Formation

Cell Reports ◽  
2013 ◽  
Vol 4 (6) ◽  
pp. 1082-1089 ◽  
Author(s):  
Ying Tan ◽  
Dinghui Yu ◽  
Germain U. Busto ◽  
Curtis Wilson ◽  
Ronald L. Davis
Keyword(s):  
Wnt Signaling ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory

scholarly journals What's hot: the enhancing effects of thermal stress on long-term memory formation in Lymnaea stagnalis

2012 ◽  
Vol 215 (24) ◽  
pp. 4322-4329 ◽  
Author(s):  
M. L. Teskey ◽  
K. S. Lukowiak ◽  
H. Riaz ◽  
S. Dalesman ◽  
K. Lukowiak
Keyword(s):  
Thermal Stress ◽  
Lymnaea Stagnalis ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory

scholarly journals Habitat and social context affect memory phenotype, exploration and covariance among these traits

2018 ◽  
Vol 373 (1756) ◽  
pp. 20170291 ◽  
Author(s):  
Sarah Dalesman
Keyword(s):  
Individual Differences ◽  
Cognitive Abilities ◽  
Lymnaea Stagnalis ◽  
Memory Formation ◽  
Long Term Memory ◽  
Wild Populations ◽  
In Captivity ◽  
Specific Trait ◽  
Context Specific

Individual differences in cognitive ability are predicted to covary with other behavioural traits such as exploration and boldness. Selection within different habitats may act to either enhance or break down covariance among traits; alternatively, changing the environmental context in which traits are assessed may result in plasticity that alters trait covariance. Pond snails, Lymnaea stagnalis , from two laboratory strains (more than 20 generations in captivity) and F1 laboratory reared from six wild populations were tested for long-term memory and exploration traits (speed and thigmotaxis) following maintenance in grouped and isolated conditions to determine if isolation: (i) alters memory and exploration; and (ii) alters covariance between memory and exploration. Populations that demonstrated strong memory formation (longer duration) under grouped conditions demonstrated weaker memory formation and reduced both speed and thigmotaxis following isolation. In wild populations, snails showed no relationship between memory and exploration in grouped conditions; however, following isolation, exploration behaviour was negatively correlated with memory, i.e. slow-explorers showing low levels of thigmotaxis formed stronger memories. Laboratory strains demonstrated no covariance among exploration traits and memory independent of context. Together these data demonstrate that the relationship between cognition and exploration traits can depend on both habitat and context-specific trait plasticity. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.

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