scholarly journals Synaptic Depression of the Hyppocampal to Prefrontal Cortex Pathway during a Spatial Working Memory Task

2000 ◽  
Author(s):  
F. Burette ◽  
T. Jay ◽  
S. Laroche

2017 ◽  
Author(s):  
Samuel S. McAfee ◽  
Yu Liu ◽  
Roy V. Sillitoe ◽  
Detlef H. Heck

AbstractThe cerebellum has long been recognized for its role in tasks involving precise timing, particularly the temporal coordination of movements. Here we asked whether cerebellar might be involved in the temporal coordination of the phases of neuronal oscillations in the medial prefrontal cortex (mPFC) and dorsal hippocampus CA1 region (CA1). These two structures and the cerebellum are jointly involved in spatial working memory. The phases of oscillations in the mPFC and CA1 have been shown to reach a stable alignment (coherence) during the decision making process in a spatial working memory task. Here we report that PC simple spike activity in the cerebellar lobulus simplex in awake, head-fixed mice represents specific phase differences between oscillations in the mPFC and CA1. Most PCs represented phase differences in more than one the conventional frequency bands (delta, theta, beta and gamma). Between the 32 PCs analyzed here, phase differences in all frequency bands were represented. PCs representing phase differences in the theta and low gamma bands showed significant population preference for mPFC phase leading CA1 phase. These findings support the possibility of a cerebellar involvement in the temporal coordination of phase relationships between oscillations in the mPFC and CA1.



eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Claudia Böhm ◽  
Albert K Lee

The prefrontal cortex (PFC)’s functions are thought to include working memory, as its activity can reflect information that must be temporarily maintained to realize the current goal. We designed a flexible spatial working memory task that required rats to navigate – after distractions and a delay – to multiple possible goal locations from different starting points and via multiple routes. This made the current goal location the key variable to remember, instead of a particular direction or route to the goal. However, across a broad population of PFC neurons, we found no evidence of current-goal-specific memory in any previously reported form – that is differences in the rate, sequence, phase, or covariance of firing. This suggests that such patterns do not hold working memory in the PFC when information must be employed flexibly. Instead, the PFC grouped locations representing behaviorally equivalent task features together, consistent with a role in encoding long-term knowledge of task structure.



Author(s):  
Vasiliki Stavroulaki ◽  
Vasileios Ioakeimidis ◽  
Xanthippi Konstantoudaki ◽  
Kyriaki Sidiropoulou


2020 ◽  
Author(s):  
Claudia Böhm ◽  
Albert K. Lee

AbstractThe prefrontal cortex (PFC)’s functions are thought to include working memory, as its activity can reflect information that must be temporarily maintained to realize the current goal. We designed a flexible spatial working memory task that required rats to navigate - after distractions and a delay - to multiple possible goal locations from different starting points and via multiple routes. This made the current goal location the key variable to remember, instead of a particular direction or route to the goal. However, across a broad population of PFC neurons, we found no evidence of current-goal-specific memory in any previously reported form - i.e. differences in the rate, sequence, phase or covariance of firing. This suggests such patterns do not hold working memory in the PFC when information must be employed flexibly. Instead, the PFC grouped locations representing behaviorally equivalent task features together, consistent with a role in encoding long-term knowledge of task structure.



2021 ◽  
Author(s):  
Wei Zhang ◽  
Lei Guo ◽  
Dongzhao Liu ◽  
Guizhi Xu

Abstract Spatial working memory (SWM) refers to a short-term system for temporary manipulation of spatial information and requires the cooperation of multiple brain regions. Despite evidence that hippocampus (HPC) and prefrontal cortex (PFC) are involved in SWM, how PFC and HPC coordinate the neural information during SWM remains puzzling. In this study, local field potentials (LFPs) were recorded simultaneously from rat ventral HPC and medial PFC during SWM tasks. Then cross-frequency coupling algorithm was used as functional connectivity for construction of undirected networks; Grange causality algorithm was used as effective connectivity for construction of directed networks. Finally, information interactions across two brain regions were analyzed based on undirected and directed networks. Experimental results show that LFPs power in PFC and HPC both decreased over learning days and peaked before the reference point during SWM, moreover, LFPs mainly distributed in theta and gamma. From the undirected aspect, undirected PFC subnetwork and HPC subnetwork have the same effect on information transmission for SWM; the PAC between PFC-gamma and HPC-theta in undirected PFC-HPC network is related to SWM formation and contributes to information interactions between PFC and HPC. From the directed aspect, the effect of information transmission in directed HPC subnetwork is greater than PFC subnetwork; the enhancement of coordination between directed PFC and HPC subnetworks contributes to correct execution of SWM tasks; directed HPC→PFC network plays a predominant role in information interaction; with the increasing of learning days, PFC and HPC tend to be the causal sink and causal source of information flow.



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