scholarly journals Impaired spatial learning and suppression of sharp wave ripples by cholinergic activation at the goal location

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Przemyslaw Jarzebowski ◽  
Clara S Tang ◽  
Ole Paulsen ◽  
Y Audrey Hay
Keyword(s):  
Cholinergic Neurons ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Goal Location ◽  
Optogenetic Stimulation ◽  
Sharp Wave ◽  
Network States ◽  
Stimulation Of

The hippocampus plays a central role in long-term memory formation, and different hippocampal network states are thought to have different functions in this process. These network states are controlled by neuromodulatory inputs, including the cholinergic input from the medial septum. Here, we used optogenetic stimulation of septal cholinergic neurons to understand how cholinergic activity affects different stages of spatial memory formation in a reward-based navigation task in mice. We found that optogenetic stimulation of septal cholinergic neurons (1) impaired memory formation when activated at goal location but not during navigation; (2) reduced sharp wave-ripple (SWR) incidence at goal location; and (3) reduced SWR incidence and enhanced theta-gamma oscillations during sleep. These results underscore the importance of appropriate timing of cholinergic input in long-term memory formation, which might help explain the limited success of cholinesterase inhibitor drugs in treating memory impairment in Alzheimer's disease.

scholarly journals Impaired spatial learning and suppression of sharp wave ripples by cholinergic activation at the goal location

2020 ◽  
Author(s):  
Przemyslaw Jarzebowski ◽  
Clara S Tang ◽  
Ole Paulsen ◽  
Y. Audrey Hay
Keyword(s):  
Cholinergic Neurons ◽  
Memory Formation ◽  
Long Term Memory ◽  
Term Memory ◽  
Goal Location ◽  
Optogenetic Stimulation ◽  
Sharp Wave ◽  
Network States ◽  
Stimulation Of

The hippocampus plays a central role in long-term memory formation, and different hippocampal network states are thought to have different functions in this process. These network states are controlled by neuromodulatory inputs, including the cholinergic input from the medial septum. Here, we used optogenetic stimulation of septal cholinergic neurons to understand how cholinergic activity affects different stages of spatial memory formation in a reward-based navigation task in mice. We found that optogenetic stimulation of septal cholinergic neurons (1) impaired memory formation when activated at goal location but not during navigation; (2) reduced sharp wave-ripple (SWR) incidence at goal location; and (3) reduced SWR incidence and enhanced theta-gamma oscillations during sleep. These results underscore the importance of appropriate timing of cholinergic input in long-term memory formation, which might help explain the limited success of cholinesterase inhibitor drugs in treating memory impairment in Alzheimer's disease.

scholarly journals Hippocampal sharp wave-ripples and the associated sequence replay emerge from structured synaptic interactions in a network model of area CA3

2021 ◽  
Author(s):  
András Ecker ◽  
Bence Bagi ◽  
Eszter Vértes ◽  
Orsolya Steinbach-Németh ◽  
Mária Karlócai ◽  
...  
Keyword(s):  
Place Cells ◽  
Data Driven ◽  
Long Term Memory ◽  
Term Memory ◽  
Sharp Wave ◽  
Synaptic Interactions ◽  
Network States ◽  
Area Ca3 ◽  
Reversed Order

Abstract Hippocampal place cells are activated sequentially as an animal explores its environment. These activity sequences are internally recreated (``replayed'), either in the same or reversed order, during bursts of activity (sharp wave-ripples; SWRs) that occur in sleep and awake rest. SWR-associated replay is thought to be critical for the creation and maintenance of long-term memory. In order to identify the cellular and network mechanisms of SWRs and replay, we constructed and simulated a data-driven model of area CA3 of the hippocampus. Our results show that the chain-like structure of recurrent excitatory interactions established during learning not only determines the content of replay, but is essential for the generation of the SWRs as well. We find that bidirectional replay requires the interplay of the experimentally confirmed, temporally symmetric plasticity rule, and cellular adaptation. Our model provides a unifying framework for diverse phenomena involving hippocampal plasticity, representations, and dynamics, and suggests that the structured neural codes induced by learning may have greater influence over cortical network states than previously appreciated.

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
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