scholarly journals Induction of Activity Synchronization among Primed Hippocampal Neurons out of Random Dynamics is Key for Trace Memory Formation and Retrieval

2019 ◽  
Author(s):  
Yuxin Zhou ◽  
Liyan Qiu ◽  
Haiying Wang ◽  
Xuanmao Chen
Keyword(s):  
Memory Retrieval ◽  
Fear Memory ◽  
Memory Formation ◽  
Activity Levels ◽  
Ca1 Neurons ◽  
Random Dynamics ◽  
Highly Active ◽  
Random Activity ◽  
Marked Activity ◽  
Trace Fear

AbstractMemory is thought to be encoded by sparsely distributed neuronal ensembles in memory-related regions. However, it is unclear how memory-eligible neurons react incrementally during learning to encode trace fear memory, and how they respond to cues to retrieve the memory. We implemented fiber-optic confocal fluorescence endoscopy to directly visualize calcium dynamics of hippocampal CA1 neurons in freely behaving mice, which were subjected to trace fear conditioning. Here we report that the overall activity levels of CA1 principal neurons showed a right-skewed lognormal-like distribution. A small portion of highly active neurons (termed Primed Neurons) exhibited high sensitivity to sensory stimuli and marked activity plasticity. The Primed Neurons maintained random activity status for at least 5 hours in multiple contexts, including those prior to training and prior to recall. Repetitive training induced Primed Neurons to shift from random activity to a well-tuned synchronization. Importantly, the emergence of activity synchronization coincided with the appearance of mouse freezing behaviors. In recall, a partial synchronization among the same population of Primed Neurons was induced from originally random activity, which also coincided with mouse freezing behaviors. Additionally, training-induced synchronization facilitated robust calcium entry into individual Primed Neurons. In contrast, most CA1 neurons stayed silent and did not respond significantly to tone and foot-shock throughout the training and recall testing cycles. In conclusion, highly active Primed Neurons are preferably recruited to encode trace fear memory, and induction of activity synchronization among Primed Neurons out of random dynamics is critical for trace memory formation and memory retrieval.Significance StatementThe overall activity levels of hippocampal principal CA1 neurons show a right-skewed lognormal-like distribution.A small portion of CA1 neurons (termed Primed Neurons) exhibit high activity and marked activity plasticity during learning and recall.Primed Neurons in the hippocampus are preferably recruited to encode trace fear memory, whereas the majority of CA1 neurons show little activity and little activity change during fear conditioning and recall testing.Induction of activity synchronization among Primed Neurons out of random dynamics is critical for trace memory formation and memory retrieval.Training-induced synchronization drastically increases calcium entry into Primed Neurons, which may promote memory consolidation.

scholarly journals The entorhinal cortex modulates trace fear memory formation and neuroplasticity in the mouse lateral amygdala via cholecystokinin

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Hemin Feng ◽  
Junfeng Su ◽  
Wei Fang ◽  
Xi Chen ◽  
Jufang He
Keyword(s):  
Entorhinal Cortex ◽  
Neural Plasticity ◽  
Long Term Potentiation ◽  
Fear Memory ◽  
Memory Formation ◽  
Loss Of Function ◽  
Trace Fear Conditioning ◽  
Term Potentiation ◽  
Auditory Response ◽  
Trace Fear

Although fear memory formation is essential for survival and fear-related mental disorders, the neural circuitry and mechanism are incompletely understood. Here, we utilized trace fear conditioning to study the formation of trace fear memory in mice. We identified the entorhinal cortex (EC) as a critical component of sensory signaling to the amygdala. We adopted both loss-of-function and gain-of-function experiments to demonstrate that release of the cholecystokinin (CCK) from the EC is required for trace fear memory formation. We discovered that CCK-positive neurons project from the EC to the lateral nuclei of the amygdala (LA), and inhibition of CCK-dependent signaling in the EC prevented long-term potentiation of the auditory response in the LA and formation of trace fear memory. In summary, high-frequency activation of EC neurons triggers the release of CCK in their projection terminals in the LA, potentiating auditory response in LA neurons. The neural plasticity in the LA leads to trace fear memory formation.

scholarly journals The entorhinal cortex modulates trace fear memory formation and neuroplasticity in the lateral amygdala via cholecystokinin

2021 ◽  
Author(s):  
Hemin Feng ◽  
Junfeng Su ◽  
Wei Fang ◽  
Xi Chen ◽  
Jufang He
Keyword(s):  
Entorhinal Cortex ◽  
Neural Plasticity ◽  
Long Term Potentiation ◽  
Fear Memory ◽  
Memory Formation ◽  
Loss Of Function ◽  
Sensory Stimuli ◽  
Sensory Signals ◽  
Term Potentiation ◽  
Trace Fear

Although the neural circuitry underlying fear memory formation is important in fear-related mental disorders, it is incompletely understood. Here, we utilized trace fear conditioning to study the formation of trace fear memory. We identified the entorhinal cortex (EC) as a critical component of sensory signaling to the amygdala. Moreover, we used the loss of function and rescue experiments to demonstrate that release of the neuropeptide cholecystokinin (CCK) from the EC is required for trace fear memory formation. We discovered that CCK-positive neurons extend from the EC to the lateral nuclei of the amygdala (LA), and inhibition of CCK21 dependent signaling in the EC prevented long-term potentiation of sensory signals to the LA and formation of trace fear memory. Altogether, we suggest a model where sensory stimuli trigger the release of CCK from EC neurons, which potentiates sensory signals to the LA, ultimately influencing neural plasticity and trace fear memory formation.

scholarly journals Contextual fear memory retrieval by correlated ensembles of ventral CA1 neurons

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jessica C. Jimenez ◽  
Jack E. Berry ◽  
Sean C. Lim ◽  
Samantha K. Ong ◽  
Mazen A. Kheirbek ◽  
...  
Keyword(s):  
Memory Retrieval ◽  
Fear Memory ◽  
Ca1 Neurons ◽  
Contextual Fear ◽  
Contextual Fear Memory

scholarly journals Extra-cellular signal-regulated kinase 1/2 (ERK1/2) activated in the hippocampal CA1 neurons is critical for retrieval of auditory trace fear memory

2010 ◽  
Vol 1326 ◽  
pp. 143-151 ◽  
Author(s):  
Ching-Hsun Huang ◽  
Yu-Wei Chiang ◽  
Keng-Chen Liang ◽  
Richard F. Thompson ◽  
Ingrid Y. Liu
Keyword(s):  
Fear Memory ◽  
Ca1 Neurons ◽  
Hippocampal Ca1 Neurons ◽  
Hippocampal Ca1 ◽  
Cellular Signal ◽  
Trace Fear

Role of gonadal hormones in anxiety and fear memory formation and inhibition in male mice

2012 ◽  
Vol 105 (5) ◽  
pp. 1168-1174 ◽  
Author(s):  
Carmel M. McDermott ◽  
Dana Liu ◽  
Laura A. Schrader
Keyword(s):  
Fear Memory ◽  
Gonadal Hormones ◽  
Memory Formation ◽  
Male Mice ◽  
Anxiety And Fear

scholarly journals Augmenting brand community identification for inactive users: a uses and gratification perspective

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Laurence Dessart ◽  
Cleopatra Veloutsou
Keyword(s):  
Social Media ◽  
Strong Predictor ◽  
Information Value ◽  
Activity Levels ◽  
Brand Community ◽  
Content Type ◽  
Uses And Gratification ◽  
Highly Active ◽  
Community Identification ◽  
Facebook Pages

Purpose In an era where companies shift a part of their marketing budget to support their social media presence, very little is known about the antecedents and effects of participant identification in a social media community. This paper aims to examine the antecedents of community identification in a Facebook company-managed brand community, for inactive members, using the uses and gratification theory. Brand community identification is also expected to lead to higher levels of brand loyalty for these members. Design/methodology/approach This research reports the results of a quantitative with survey data from 389 members of a variety of different official Facebook pages. Findings The results reveal that inactive members of Facebook pages can be influenced to act in a way that is beneficial for a company. Perceived human and information value of the brand Facebook page lead members to identify with a brand community and identification is a strong predictor of loyalty to the brand. Practical implications This paper provides suggestions to managers on the development of brand community value that can increase brand community identification and loyalty of apparently inactive brand community members. Originality/value By showing that brand community identification and loyalty exist for users with low activity levels, this research challenges the widely accepted idea that only highly active members are valuable in online brand communities. Specifically, it reveals the most important motivations for these members to identify with the community and be loyal to the brand.

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