Novel Scenes Improve Recollection and Recall of Words

2008 ◽  
Vol 20 (7) ◽  
pp. 1250-1265 ◽  
Author(s):  
Daniela B. Fenker ◽  
Julietta U. Frey ◽  
Hartmut Schuetze ◽  
Dorothee Heipertz ◽  
Hans-Jochen Heinze ◽  
...  
Keyword(s):  
Specific Activity ◽  
Activity Patterns ◽  
Long Term Potentiation ◽  
Contextual Memory ◽  
Memory Enhancement ◽  
Term Potentiation ◽  
Outdoor Scenes ◽  
Indoor And Outdoor ◽  
Hippocampus Dependent Memory

Exploring a novel environment can facilitate subsequent hippocampal long-term potentiation in animals. We report a related behavioral enhancement in humans. In two separate experiments, recollection and free recall, both measures of hippocampus-dependent memory formation, were enhanced for words studied after a 5-min exposure to unrelated novel as opposed to familiar images depicting indoor and outdoor scenes. With functional magnetic resonance imaging, the enhancement was predicted by specific activity patterns observed during novelty exposure in parahippocampal and dorsal prefrontal cortices, regions which are known to be linked to attentional orienting to novel stimuli and perceptual processing of scenes. Novelty was also associated with activation of the substantia nigra/ventral tegmental area of the midbrain and the hippocampus, but these activations did not correlate with contextual memory enhancement. These findings indicate remarkable parallels between contextual memory enhancement in humans and existing evidence regarding contextually enhanced hippocampal plasticity in animals. They provide specific behavioral clues to enhancing hippocampus-dependent memory in humans.

scholarly journals The fate of hippocampal synapses depends on the sequence of plasticity-inducing events

2018 ◽  
Author(s):  
J. Simon Wiegert ◽  
Mauro Pulin ◽  
Christine E. Gee ◽  
Thomas G. Oertner
Keyword(s):  
Hippocampal Slice ◽  
Specific Activity ◽  
Activity Patterns ◽  
Long Term Potentiation ◽  
Information Storage ◽  
Two Photon ◽  
Term Potentiation ◽  
Hippocampal Synapses ◽  
Activity Dependent

AbstractSynapses change their strength in response to specific activity patterns. This functional plasticity is assumed to be the brain’s primary mechanism for information storage. We used optogenetic stimulation of rat hippocampal slice cultures to induce long-term potentiation (LTP), long-term depression (LTD), or both forms of plasticity in sequence. Two-photon imaging of spine calcium signals allowed us to identify stimulated synapses and to follow their fate for the next 7 days. We found that plasticity-inducing protocols affected the synapse’s chance for survival: LTP increased synaptic stability, LTD destabilized synapses, and the effect of the last stimulation protocol was dominant over earlier stimulations. Interestingly, most potentiated synapses were resistant to depression-inducing protocols delivered 24 hours later. Our findings suggest that activity-dependent changes in the transmission strength of individual synapses are transient, but have long-lasting consequences for synaptic lifetime.

scholarly journals The fate of hippocampal synapses depends on the sequence of plasticity-inducing events

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
J Simon Wiegert ◽  
Mauro Pulin ◽  
Christine Elizabeth Gee ◽  
Thomas G Oertner
Keyword(s):  
Hippocampal Slice ◽  
Specific Activity ◽  
Activity Patterns ◽  
Long Term Potentiation ◽  
Information Storage ◽  
Two Photon ◽  
Term Potentiation ◽  
Hippocampal Synapses ◽  
Activity Dependent

Synapses change their strength in response to specific activity patterns. This functional plasticity is assumed to be the brain’s primary mechanism for information storage. We used optogenetic stimulation of rat hippocampal slice cultures to induce long-term potentiation (LTP), long-term depression (LTD), or both forms of plasticity in sequence. Two-photon imaging of spine calcium signals allowed us to identify stimulated synapses and to follow their fate for the next 7 days. We found that plasticity-inducing protocols affected the synapse’s chance for survival: LTP increased synaptic stability, LTD destabilized synapses, and the effect of the last stimulation protocol was dominant over earlier stimulations. Interestingly, most potentiated synapses were resistant to depression-inducing protocols delivered 24 hr later. Our findings suggest that activity-dependent changes in the transmission strength of individual synapses are transient, but have long-lasting consequences for synaptic lifetime.

scholarly journals  5GABAA Receptor Activity Sets the Threshold for Long-Term Potentiation and Constrains Hippocampus-Dependent Memory

2010 ◽  
Vol 30 (15) ◽  
pp. 5269-5282 ◽  
Author(s):  
L. J. Martin ◽  
A. A. Zurek ◽  
J. F. MacDonald ◽  
J. C. Roder ◽  
M. F. Jackson ◽  
...  
Keyword(s):  
Long Term Potentiation ◽  
Receptor Activity ◽  
Term Potentiation ◽  
Hippocampus Dependent Memory

scholarly journals Intracellular calcium stores mediate a synapse-specific form of metaplasticity at hippocampal dendritic spines

2018 ◽  
Author(s):  
Gaurang Mahajan ◽  
Suhita Nadkarni
Keyword(s):  
Dendritic Spines ◽  
Activity Patterns ◽  
Long Term Potentiation ◽  
Multiple Time Scales ◽  
Calcium Stores ◽  
Multiple Time ◽  
Additional Layer ◽  
Term Potentiation ◽  
Activity Dependent

ABSTRACTLong-term plasticity mediated by NMDA receptors supports input-specific, Hebbian forms of learning at excitatory CA3-CA1 connections in the hippocampus. An additional layer of stabilizing mechanisms that act globally as well as locally over multiple time scales may be in place to ensure that plasticity occurs in a constrained manner. Here, we investigate the potential role of calcium (Ca2+) stores associated with the endoplasmic reticulum (ER) in the local regulation of plasticity dynamics at individual CA1 synapses. Our study is spurred by (1) the curious observation that ER is sparsely distributed in dendritic spines, but over-represented in large spines that are likely to have undergone activity-dependent strengthening, and (2) evidence suggesting that ER motility within synapses can be rapid, and accompany activity-regulated spine remodeling. Based on a physiologically realistic computational model for ER-bearing CA1 spines, we characterize the contribution of IP3-sensitive Ca2+ stores to spine Ca2+ dynamics during activity patterns mimicking the induction of long-term potentiation (LTP) and depression (LTD). Our results suggest graded modulation of the NMDA receptor-dependent plasticity profile by ER, which selectively enhances LTD induction. We propose that spine ER can locally tune Ca2+-based plasticity on an as-needed basis, providing a braking mechanism to mitigate runaway strengthening at potentiated synapses. Our model suggests that the presence of ER in the CA1 spine may promote re-use of synapses with saturated strengths.

scholarly journals Brain is modulated by neuronal plasticity during postnatal development

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Masoumeh Kourosh-Arami ◽  
Nasrin Hosseini ◽  
Alireza Komaki
Keyword(s):  
Activity Patterns ◽  
Long Term Potentiation ◽  
Inhibitory Synapses ◽  
Neural Systems ◽  
Neural Structure ◽  
Term Potentiation ◽  
Study Results ◽  
Development Processes ◽  
Adaptation Processes

AbstractNeuroplasticity is referred to the ability of the nervous system to change its structure or functions as a result of former stimuli. It is a plausible mechanism underlying a dynamic brain through adaptation processes of neural structure and activity patterns. Nevertheless, it is still unclear how the plastic neural systems achieve and maintain their equilibrium. Additionally, the alterations of balanced brain dynamics under different plasticity rules have not been explored either. Therefore, the present article primarily aims to review recent research studies regarding homosynaptic and heterosynaptic neuroplasticity characterized by the manipulation of excitatory and inhibitory synaptic inputs. Moreover, it attempts to understand different mechanisms related to the main forms of synaptic plasticity at the excitatory and inhibitory synapses during the brain development processes. Hence, this study comprised surveying those articles published since 1988 and available through PubMed, Google Scholar and science direct databases on a keyword-based search paradigm. All in all, the study results presented extensive and corroborative pieces of evidence for the main types of plasticity, including the long-term potentiation (LTP) and long-term depression (LTD) of the excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs).

scholarly journals The Longevity of Hippocampus-Dependent Memory Is Orchestrated by the Locus Coeruleus-Noradrenergic System

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Niels Hansen
Keyword(s):  
Locus Coeruleus ◽  
Transcriptional Control ◽  
Dorsal Hippocampus ◽  
Long Term Potentiation ◽  
Memory Storage ◽  
Long Term Memory ◽  
Long Term Depression ◽  
Term Potentiation ◽  
Hippocampus Dependent Memory

The locus coeruleus is connected to the dorsal hippocampus via strong fiber projections. It becomes activated after arousal and novelty, whereupon noradrenaline is released in the hippocampus. Noradrenaline from the locus coeruleus is involved in modulating the encoding, consolidation, retrieval, and reversal of hippocampus-based memory. Memory storage can be modified by the activation of the locus coeruleus and subsequent facilitation of hippocampal long-term plasticity in the forms of long-term depression and long-term potentiation. Recent evidence indicates that noradrenaline and dopamine are coreleased in the hippocampus from locus coeruleus terminals, thus fostering neuromodulation of long-term synaptic plasticity and memory. Noradrenaline is an inductor of epigenetic modifications regulating transcriptional control of synaptic long-term plasticity to gate the endurance of memory storage. In conclusion, locus coeruleus activation primes the persistence of hippocampus-based long-term memory.

scholarly journals Temporal and spatial regulation of the expression of BAD2, a MAP kinase phosphatase, during seizure, kindling, and long-term potentiation.

1994 ◽  
Vol 1 (3) ◽  
pp. 180-188
Author(s):  
Z Qian ◽  
M Gilbert ◽  
E R Kandel
Keyword(s):  
Map Kinase ◽  
Specific Activity ◽  
Long Term Potentiation ◽  
Dual Purpose ◽  
Spatial Regulation ◽  
Term Potentiation ◽  
Map Kinase Phosphatase ◽  
Synaptic Changes

Recent studies indicate that stimulation of NMDA receptors in cultured hippocampal cells activates MAP kinase. Although the pathway whereby MAP kinase is activated has been been characterized, little is known about the mechanisms that shut off MAP kinase. In the course of analyzing several immediate-early genes identified previously by differential screen as inducible by seizure activity, we found that one of them, BAD2, encodes dual purpose, threonine/tyrosine phosphates with specific activity directed against MAP kinase (MKP-1). In situ hybridization of BAD2 demonstrates that stimuli that produce seizure, kindling, and long-term potentiation cause a rapid increase in BAD2 mRNA (within 0.5-1 hr after stimulation) that has, in each case, a distinctive pattern of expression in the brain. In these regions, the induction of a MAP kinase-specific phosphatase may provide a negative feedback control associated with long-term synaptic changes.

scholarly journals Somatostatin-positive interneurons in the dentate gyrus of mice provide local- and long-range septal synaptic inhibition

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Mei Yuan ◽  
Thomas Meyer ◽  
Christoph Benkowitz ◽  
Shakuntala Savanthrapadian ◽  
Laura Ansel-Bollepalli ◽  
...  
Keyword(s):  
Dentate Gyrus ◽  
Spatial Information ◽  
Molecular Layer ◽  
Activity Patterns ◽  
Long Term Potentiation ◽  
Medial Septum ◽  
Perforant Path ◽  
Term Potentiation ◽  
Memory Acquisition

Somatostatin-expressing-interneurons (SOMIs) in the dentate gyrus (DG) control formation of granule cell (GC) assemblies during memory acquisition. Hilar-perforant-path-associated interneurons (HIPP cells) have been considered to be synonymous for DG-SOMIs. Deviating from this assumption, we show two functionally contrasting DG-SOMI-types. The classical feedback-inhibitory HIPPs distribute axon fibers in the molecular layer. They are engaged by converging GC-inputs and provide dendritic inhibition to the DG circuitry. In contrast, SOMIs with axon in the hilus, termed hilar interneurons (HILs), provide perisomatic inhibition onto GABAergic cells in the DG and project to the medial septum. Repetitive activation of glutamatergic inputs onto HIPP cells induces long-lasting-depression (LTD) of synaptic transmission but long-term-potentiation (LTP) of synaptic signals in HIL cells. Thus, LTD in HIPPs may assist flow of spatial information from the entorhinal cortex to the DG, whereas LTP in HILs may facilitate the temporal coordination of GCs with activity patterns governed by the medial septum.

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