Reactivation of Neural Ensembles during the Retrieval of Recent and Remote Memory

Tayler, Kaycie K.; Tanaka, Kazumasa Z.; Reijmers, Leon G.; Wiltgen, Brian J.

doi:10.1016/j.cub.2012.11.019

Cited by 248 publications

(262 citation statements)

References 48 publications

Supporting

Mentioning

220

Contrasting

Unclassified

Order By: Relevance

“…Consistent with Reijmers et al (2007), we found robust reactivation of the BLA when mice retrieved a context fear memory 2 d after training (Tayler et al 2013). At this same interval, we also observed reactivation of neurons in the dentate gyrus and CA1 subregions of the hippocampus.…”

Section: Identification Of Reactivated Neuronssupporting

confidence: 72%

“…For example, 90% of labeled CA1 neurons were reactivated when rats explored the same environment twice (Guzowski et al 1999). In contrast, exposure to two identical environments in TetTag mice induces reactivation of only 20%-40% of CA1 neurons (Nakazawa et al 2013;Tayler et al 2013). There are many differences between these experiments (species, procedure, intervals between tests, background labeling) that could account for this difference.…”

Section: Alternative Tagging Methodsmentioning

confidence: 99%

“…First, gene expression is dependent on the removal of doxycycline, which can take several days (Glazewski et al 2001;Reijmers et al 2007). Active neurons can be labeled anytime during this period, which results in elevated background expression levels relative to other methods (Milanovic et al 1998;Guzowski et al 1999;Liu et al 2012;Tayler et al 2013). A recent paper addressed this issue by using a novel approach called TRAP: targeted recombination in active populations (Guenthner et al 2013).…”

Section: Alternative Tagging Methodsmentioning

confidence: 99%

“…In these tasks, inactivation of the hippocampus impairs memory retrieval shortly after learning, but has no effect when performed weeks or months later (Kim and Fanselow 1992;Anagnostaras et al 1999;Clark et al 2002;Takehara et al 2002Takehara et al , 2003Maviel et al 2004;Ross and Eichenbaum 2006;Lesburgueres et al 2011;Tayler et al 2013; but see Clark et al 2005;Sutherland et al 2010). In addition, several regions of the neocortex become more important for memory retrieval with the passage of time.…”

Section: Animal Models Of Systems Consolidationmentioning

confidence: 99%

“…To examine reactivation of hippocampal and neocortical neurons during context fear conditioning, our laboratory used a transgenic mouse that expresses a long-lasting, activity-dependent form of GFP (Tayler et al 2011(Tayler et al , 2013. In these mice, GFP was fused with the human histone protein HIST1H2BJ (Kanda et al 1998).…”

Section: Identification Of Reactivated Neuronsmentioning

confidence: 99%

See 4 more Smart Citations

New methods for understanding systems consolidation

Tayler

Wiltgen

2013

Learn. Mem.

View full text Add to dashboard Cite

According to the standard model of systems consolidation (SMC), neocortical circuits are reactivated during the retrieval of declarative memories. This process initially requires the hippocampus. However, with the passage of time, neocortical circuits become strengthened and can eventually retrieve memory without input from the hippocampus. Although consistent with lesion data, these assumptions have been difficult to confirm experimentally. In the current review, we discuss recent methodological advances in behavioral neuroscience that are making it possible to test the basic assumptions of SMC for the first time. For example, new transgenic mice can be used to monitor the activity of individual neurons across the entire brain while optogenetic approaches provide precise control over the activity of these cells using light stimulation. These tools can be used to examine the reactivation of neocortical neurons during recent and remote memory retrieval and determine if this process requires the hippocampus.

show abstract

Section: Identification Of Reactivated Neuronssupporting

confidence: 72%

Section: Alternative Tagging Methodsmentioning

confidence: 99%

Section: Alternative Tagging Methodsmentioning

confidence: 99%

Section: Animal Models Of Systems Consolidationmentioning

confidence: 99%

Section: Identification Of Reactivated Neuronsmentioning

confidence: 99%

See 3 more Smart Citations

New methods for understanding systems consolidation

Tayler

Wiltgen

2013

Learn. Mem.

View full text Add to dashboard Cite

show abstract

An update on memory formation and retrieval: An engram‐centric approach

Bostancıklıoğlu

2020

Alzheimer's & Dementia

View full text Add to dashboard Cite

Objective We explore here that memory loss observed in the early stage of Alzheimer's disease (AD) is a disorder of memory retrieval, instead of a storage impairment. This engram‐centric explanation aims to enlarge the conceptual frame of memory as an emergent behavior of the brain and to propose a new treatment strategy for memory retrieval in dementia‐AD. Background The conventional memory hypothesis suggests that memory is stored as multiple traces in hippocampal neurons but recent evidence indicates that there are specialized memory engrams responsible for the storage and the retrieval of different memory types. Updated Memory Hypothesis There are specialized memory engram neurons for each memory type and when information will be stored as a memory arrives in the hippocampus through afferent neurons finds its neuron according to the excitability states of engram neurons. The excitability level in engram neurons seems like a code canalizing the interactions between engrams and information. Therefore, to enhance the excitability of memory engram neurons improves memory loss observed in AD. In addition, we suggest that the hippocampus creates an index for information stored in memory engram cells in specialized regions for different types of memory, instead of storing all information; and different anatomic locations of engram cells and their roles in memory retrieval point out that memory could be an emergent behavior of the brain, and the interaction between serotonin fluctuation and engram neurons could be neural underpinnings of terminal lucidity. Major Challenges for the Model The major challenge for this engram‐centric memory retrieval model is the translation from bench to patient, specifically the delivery of optogenetic tools in patients. Engram neurons can be specifically activated by optogenetic tools, but optogenetics is an invasive technique which requires optic fiber implantation into the brain. In addition, light can overheat the tissue and thus induce damage in tissue. Furthermore, light is a foreign object and its direct implantation into the brain may cause neuroinflammation, the main trigger of neurodegenerative diseases. Therefore, to test the engram hypothesis in human, new tools to allow specific engram activation should be discovered.

show abstract

Improved specificity of hippocampal memory trace labeling

et al. 2016

View full text Add to dashboard Cite

Recent studies have focused on the identification and manipulation of memory traces in rodent models. The two main mouse models utilized are either a CreERT2/loxP tamoxifen (TAM)- or a tetracycline transactivator (tTA)/tetracycline-response element (TRE) doxycycline (DOX)-inducible system. These systems, however, could be improved to label a more specific population of activated neurons corresponding to behavior. Here, we sought to identify an improved selective estrogen receptor (ER) modulator (SERM) in which we could label an individual memory trace in ArcCreERT2 mice. We found that 4-hydroxytamoxifen (4-OHT) is the most selective SERM in the ArcCreERT2 x ROSA26-CAG-stopflox-channelrhodospin (ChR2)-enhanced yellow fluorescent protein (eYFP) mice. The half-life of 4-OHT is also shorter than TAM, allowing for more specificity of memory trace labeling. Furthermore, 4-OHT allowed for context-specific labeling in the dentate gyrus (DG) and CA3. In summary, we believe 4-OHT improves the specificity of memory trace labeling and will allow for refined memory trace studies in the future.

show abstract

Reactivation of Neural Ensembles during the Retrieval of Recent and Remote Memory

Abstract: Retrieving a recently formed context fear memory reactivates neurons in the hippocampus, amygdala, and cortex. Several weeks after learning, the degree of reactivation is altered in hippocampal and amygdala networks but remains stable in the cortex.

Cited by 248 publications

References 48 publications

New methods for understanding systems consolidation

New methods for understanding systems consolidation

An update on memory formation and retrieval: An engram‐centric approach

Improved specificity of hippocampal memory trace labeling

Contact Info

Product

Resources

About