scholarly journals Basolateral Amygdala Inputs to the Medial Entorhinal Cortex Selectively Modulate the Consolidation of Spatial and Contextual Learning

2018 ◽  
Vol 38 (11) ◽  
pp. 2698-2712 ◽  
Author(s):  
Krista L. Wahlstrom ◽  
Mary L. Huff ◽  
Eric B. Emmons ◽  
John H. Freeman ◽  
Nandakumar S. Narayanan ◽  
...  
2020 ◽  
Author(s):  
Krista L. Wahlstrom ◽  
Amanda Alvarez-Dieppa ◽  
Christa K. McIntyre ◽  
Ryan T. LaLumiere

AbstractPrevious work from our laboratory suggests that projections from the basolateral amygdala (BLA) to the medial entorhinal cortex (mEC) are a critical pathway by which the BLA modulates the consolidation of spatial learning. Posttraining optogenetic stimulation of this pathway enhances retention of spatial memories. Evidence also indicates that intra-BLA administration of memory-enhancing drugs increases protein levels of activity-regulated cytoskeletal-associated protein (ARC) in the dorsal hippocampus (DH) and that blocking ARC in the DH impairs spatial memory consolidation. Yet, whether optical manipulations of the BLA-mEC pathway after spatial training also alter ARC in the DH is unknown. To address this question, male and female Sprague-Dawley rats received optogenetic stimulation of the BLA-mEC pathway immediately after spatial training using a Barnes maze and, 45 min later, were sacrificed for ARC analysis. Initial experiments found that spatial training increased ARC levels in the DH of rats above those observed in control rats and rats that underwent a cued-response version of the task. Optogenetic stimulation of the BLA-mEC pathway following spatial training, using parameters effective at enhancing spatial memory consolidation, enhanced ARC protein levels in the DH of male rats without affecting ARC levels in the dorsolateral striatum (DLS) or somatosensory cortex. In contrast, similar optical stimulation decreased ARC protein levels in the DLS of female rats without altering ARC in the DH or somatosensory cortex. Together, the present findings suggest a mechanism by which BLA-mEC stimulation enhances spatial memory consolidation in rats and reveals a possible sex-difference in this mechanism.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Caitlin S. Mallory ◽  
Kiah Hardcastle ◽  
Malcolm G. Campbell ◽  
Alexander Attinger ◽  
Isabel I. C. Low ◽  
...  

AbstractNeural circuits generate representations of the external world from multiple information streams. The navigation system provides an exceptional lens through which we may gain insights about how such computations are implemented. Neural circuits in the medial temporal lobe construct a map-like representation of space that supports navigation. This computation integrates multiple sensory cues, and, in addition, is thought to require cues related to the individual’s movement through the environment. Here, we identify multiple self-motion signals, related to the position and velocity of the head and eyes, encoded by neurons in a key node of the navigation circuitry of mice, the medial entorhinal cortex (MEC). The representation of these signals is highly integrated with other cues in individual neurons. Such information could be used to compute the allocentric location of landmarks from visual cues and to generate internal representations of space.


2021 ◽  
pp. 113259
Author(s):  
Jena B. Hales ◽  
Nicole T. Reitz ◽  
Jonathan L. Vincze ◽  
Amber C. Ocampo ◽  
Stefan Leutgeb ◽  
...  

2019 ◽  
Vol 15 ◽  
pp. P598-P598
Author(s):  
Heechul Jun ◽  
Shogo Soma ◽  
Ananya Dasgupta ◽  
Kei Igarashi

2010 ◽  
Vol 30 (46) ◽  
pp. 15695-15699 ◽  
Author(s):  
M. M. Sauvage ◽  
Z. Beer ◽  
M. Ekovich ◽  
L. Ho ◽  
H. Eichenbaum

1993 ◽  
Vol 70 (1) ◽  
pp. 144-157 ◽  
Author(s):  
R. Klink ◽  
A. Alonso

1. Layer II of the medial entorhinal cortex is composed of two electrophysiologically and morphologically distinct types of projection neurons: stellate cells (SCs), which are distinguished by rhythmic subthreshold oscillatory activity, and non-SCs. The ionic mechanisms underlying their differential electroresponsiveness, particularly in the subthreshold range of membrane potentials, were investigated in an "in vitro" slice preparation. 2. In both SCs and non-SCs, the apparent membrane input resistance was markedly voltage dependent, respectively decreasing or increasing at hyperpolarized or subthreshold depolarized potential levels. Thus the neurons displayed inward rectification in the hyperpolarizing and depolarizing range. 3. In the depolarizing range, inward rectification was blocked by tetrodotoxin (TTX, 1 microM) in both types of neurons and thus shown to depend on the presence of a persistent low-threshold Na+ conductance (gNap). However, in the presence of TTX, pronounced outward rectification became manifest in the subthreshold depolarizing range of membrane potentials (positive to -60 mV) in the SCs but not in the non-SCs. 4. The rhythmic subthreshold membrane potential oscillations that were present only in the SCs were abolished by TTX and not by Ca2+ conductance block with Cd2+ or Co2+. Subthreshold oscillations thus rely on the activation of voltage-gated Na+, and not Ca2+, conductances. The Ca2+ conductance block also had no effect on the subthreshold outward rectification. 5. Prominent time-dependent inward rectification in the hyperpolarizing range in the SCs persisted after Na(+)- and Ca2+ conductance block. This rectification was not affected by Ba2+ (1 mM), but was blocked by Cs+ (1-4 mM). Therefore, it is most probably generated by a hyperpolarization-activated cationic current (Q-like current). However, the Q-like current appears to play no major role in the generation of subthreshold rhythmic membrane potential oscillations, because these persisted in the presence of Cs+. 6. On the other hand, in the SCs, the fast, sustained, outward rectification that strongly developed (after Na+ conductance block) at the oscillatory voltage level was not affected by Cs+ but was blocked by Ba2+ (1 mM). Barium was also effective in blocking the subthreshold membrane potential oscillations. 7. In the non-SCs, which do not generate subthreshold rhythmic membrane potential oscillations or manifest subthreshold outward rectification in TTX, Ca2+ conductance block abolished spike repolarization and caused the development of long-lasting Na(+)-dependent plateau potentials at a high suprathreshold voltage level. At this level, where prominent delayed rectification is present, the Na+ plateaus sustained rhythmic membrane potential oscillations.(ABSTRACT TRUNCATED AT 400 WORDS)


2015 ◽  
Vol 42 (11) ◽  
pp. 2974-2984 ◽  
Author(s):  
Yusuke Tsuno ◽  
George W. Chapman ◽  
Michael E. Hasselmo

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