Right prefrontal cortex and episodic memory retrieval: a functional MRI test of the monitoring hypothesis

The hemispherical encoding retrieval asymmetry (HERA) model, established in 1991, suggests that the involvement of the right prefrontal cortex (PFC) in the encoding process is less than that of the left PFC. The HERA model was previously validated for episodic memory in subjects with brain traumas or injuries. In this study, a revised HERA model is used to investigate long-term memory retrieval from newly learned video-based content for healthy individuals using electroencephalography. The model was tested for long-term memory retrieval in two retrieval sessions: (1) recent long-term memory (recorded 30 min after learning) and (2) remote long-term memory (recorded two months after learning). The results show that long-term memory retrieval in healthy individuals for the frontal region (theta and delta band) satisfies the revised HERA asymmetry model.

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Functional network in the prefrontal cortex during episodic memory retrieval

NeuroImage ◽

10.1016/j.neuroimage.2005.03.004 ◽

2005 ◽

Vol 26 (3) ◽

pp. 932-940 ◽

Cited By ~ 15

Author(s):

Satoshi Umeda ◽

Yoshihide Akine ◽

Motoichiro Kato ◽

Taro Muramatsu ◽

Masaru Mimura ◽

...

Keyword(s):

Prefrontal Cortex ◽

Episodic Memory ◽

Memory Retrieval ◽

Functional Network

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Activation of the basal ganglia in episodic memory retrieval: a functional MRI study

NeuroImage ◽

10.1016/s1053-8119(18)31662-8 ◽

1998 ◽

Vol 7 (4) ◽

pp. S829

Author(s):

S. Dupont ◽

P.F. Van de Mortelle ◽

J.B. Poline ◽

S. Samson ◽

S. Lehéricy ◽

...

Keyword(s):

Basal Ganglia ◽

Episodic Memory ◽

Functional Mri ◽

Memory Retrieval ◽

Mri Study

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Shared and distinct contributions of rostrolateral prefrontal cortex to analogical reasoning and episodic memory retrieval

Human Brain Mapping ◽

10.1002/hbm.23074 ◽

2015 ◽

Vol 37 (3) ◽

pp. 896-912 ◽

Cited By ~ 11

Author(s):

Andrew J. Westphal ◽

Nicco Reggente ◽

Kaori L. Ito ◽

Jesse Rissman

Keyword(s):

Prefrontal Cortex ◽

Episodic Memory ◽

Memory Retrieval ◽

Analogical Reasoning

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The neural dynamics of novel scene imagery

10.1101/429274 ◽

2018 ◽

Author(s):

Daniel N. Barry ◽

Gareth R. Barnes ◽

Ian A. Clark ◽

Eleanor A. Maguire

Keyword(s):

Prefrontal Cortex ◽

Episodic Memory ◽

Temporal Resolution ◽

Memory Retrieval ◽

Brain Regions ◽

Ventromedial Prefrontal Cortex ◽

Neural Dynamics ◽

High Temporal Resolution ◽

Memory Processing ◽

Crucial Component

AbstractRetrieval of long-term episodic memories is characterised by synchronised neural activity between hippocampus and ventromedial prefrontal cortex (vmPFC), with additional evidence that vmPFC activity leads that of the hippocampus. It has been proposed that the mental generation of scene imagery is a crucial component of episodic memory processing. If this is the case, then a comparable interaction between the two brain regions should exist during the construction of novel scene imagery. To address this question, we leveraged the high temporal resolution of magnetoencephalography (MEG) to investigate the construction of novel mental imagery. We tasked male and female humans with imagining scenes and single isolated objects in response to one-word cues. We performed source level power, coherence and causality analyses to characterise the underlying inter-regional interactions. Both scene and object imagination resulted in theta power changes in the anterior hippocampus. However, higher theta coherence was observed between the hippocampus and vmPFC in the scene compared to the object condition. This inter-regional theta coherence also predicted whether or not imagined scenes were subsequently remembered. Dynamic causal modelling of this interaction revealed that vmPFC drove activity in hippocampus during novel scene construction. Additionally, theta power changes in the vmPFC preceded those observed in the hippocampus. These results constitute the first evidence in humans that episodic memory retrieval and scene imagination rely on similar vmPFC-hippocampus neural dynamics. Furthermore, they provide support for theories emphasising similarities between both cognitive processes, and perspectives that propose the vmPFC guides the construction of context-relevant representations in the hippocampus.Significance statementEpisodic memory retrieval is characterised by a dialogue between hippocampus and ventromedial prefrontal cortex (vmPFC). It has been proposed that the mental generation of scene imagery is a crucial component of episodic memory processing. An ensuing prediction would be of a comparable interaction between the two brain regions during the construction of novel scene imagery. Here, we leveraged the high temporal resolution of magnetoencephalography (MEG), and combined it with a scene imagination task. We found that a hippocampal-vmPFC dialogue existed, and that it took the form of vmPFC driving the hippocampus. We conclude that episodic memory and scene imagination share fundamental neural dynamics, and the process of constructing vivid, spatially coherent, contextually appropriate scene imagery is strongly modulated by vmPFC.

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Prefrontal Engagement during Source Memory Retrieval Depends on the Prior Encoding Task

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2006.18.7.1133 ◽

2006 ◽

Vol 18 (7) ◽

pp. 1133-1146 ◽

Cited By ~ 31

Author(s):

Trudy Y. Kuo ◽

Cyma Van Petten

Keyword(s):

Prefrontal Cortex ◽

Episodic Memory ◽

Electrical Activity ◽

Source Memory ◽

Memory Retrieval ◽

Healthy Subjects ◽

Brain Electrical Activity ◽

Object Identity ◽

Prior Work ◽

Memory Tests

The prefrontal cortex is strongly engaged by some, but not all, episodic memory tests. Prior work has shown that source recognition tests—those that require memory for conjunctions of studied attributes—yield deficient performance in patients with prefrontal damage and greater prefrontal activity in healthy subjects, as compared to simple recognition tests. Here, we tested the hypothesis that there is no intrinsic relationship between the prefrontal cortex and source memory, but that the prefrontal cortex is engaged by the demand to retrieve weakly encoded relationships. Subjects attempted to remember object/color conjunctions after an encoding task that focused on object identity alone, and an integrative encoding task that encouraged attention to object/color relationships. After the integrative encoding task, the late prefrontal brain electrical activity that typically occurs in source memory tests was eliminated. Earlier brain electrical activity related to successful recognition of the objects was unaffected by the nature of prior encoding.

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Direct brain recordings identify hippocampal and cortical networks that distinguish successful versus failed episodic memory retrieval

10.1101/2020.05.27.120097 ◽

2020 ◽

Author(s):

Ryan Joseph Tan ◽

Michael D. Rugg ◽

Bradley C. Lega

Keyword(s):

Prefrontal Cortex ◽

Free Recall ◽

Episodic Memory ◽

Memory Retrieval ◽

Right Hemisphere ◽

Brain Regions ◽

Angular Gyrus ◽

Data Set ◽

Functional Connections ◽

Left Angular Gyrus

AbstractHuman data collected using noninvasive imaging techniques have established the importance of parietal regions towards episodic memory retrieval, including the angular gyrus and posterior cingulate cortex. Such regions comprise part of a putative core episodic retrieval network. In free recall, comparisons between contextually appropriate and inappropriate recall events (i.e. prior list intrusions) provide the opportunity to study memory retrieval networks supporting veridical recall, and existing findings predict that differences in electrical activity in these brain regions should be identified according to the accuracy of recall. However, prior iEEG studies, utilizing principally subdural grid electrodes, have not fully characterized brain activity in parietal regions during memory retrieval and have not examined connectivity between core recollection areas and the hippocampus or prefrontal cortex. Here, we employed a data set obtained from 100 human patients implanted with stereo EEG electrodes for seizure mapping purposes as they performed a free recall task. This data set allowed us to separately analyze activity in midline versus lateral parietal brain regions, and in anterior versus posterior hippocampus, to identify areas in which retrieval–related activity predicted the recollection of a correct versus an incorrect memory. With the wide coverage afforded by the stereo EEG approach, we were also able to examine interregional connectivity. Our key findings were that differences in gamma band activity in the angular gyrus, precuneus, posterior temporal cortex, and posterior (more than anterior) hippocampus discriminated accurate versus inaccurate recall as well as active retrieval versus memory search. The left angular gyrus exhibited a significant power decrease preceding list intrusions as well as unique phase-amplitude coupling properties, whereas the prefrontal cortex was unique in exhibiting a power increase during list intrusions. Analysis of connectivity revealed significant hemispheric asymmetry, with relatively sparse left– sided functional connections compared to the right hemisphere. One exception to this finding was elevated connectivity between the prefrontal cortex and left angular gyrus. This finding is interpreted as evidence for the engagement of prefrontal cortex in memory monitoring and mnemonic decision–making.

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Prefrontal cortex and episodic memory retrieval mode

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.97.1.506 ◽

2000 ◽

Vol 97 (1) ◽

pp. 506-511 ◽

Cited By ~ 328

Author(s):

M. Lepage ◽

O. Ghaffar ◽

L. Nyberg ◽

E. Tulving

Keyword(s):

Prefrontal Cortex ◽

Episodic Memory ◽

Memory Retrieval

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Anodal Transcranial Direct Current Stimulation to the Left Rostrolateral Prefrontal Cortex Selectively Improves Source Memory Retrieval

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01421 ◽

2019 ◽

Vol 31 (9) ◽

pp. 1380-1391 ◽

Cited By ~ 4

Author(s):

Andrew J. Westphal ◽

Tiffany E. Chow ◽

Corey Ngoy ◽

Xiaoye Zuo ◽

Vivian Liao ◽

...

Keyword(s):

Prefrontal Cortex ◽

Episodic Memory ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Source Memory ◽

Memory Retrieval ◽

Analogical Reasoning ◽

Anodal Tdcs ◽

Sham Stimulation ◽

Visuospatial Perception

Functional neuroimaging studies have consistently implicated the left rostrolateral prefrontal cortex (RLPFC) as playing a crucial role in the cognitive operations supporting episodic memory and analogical reasoning. However, the degree to which the left RLPFC causally contributes to these processes remains underspecified. We aimed to assess whether targeted anodal stimulation—thought to boost cortical excitability—of the left RLPFC with transcranial direct current stimulation (tDCS) would lead to augmentation of episodic memory retrieval and analogical reasoning task performance in comparison to cathodal stimulation or sham stimulation. Seventy-two healthy adult participants were evenly divided into three experimental groups. All participants performed a memory encoding task on Day 1, and then on Day 2, they performed continuously alternating tasks of episodic memory retrieval, analogical reasoning, and visuospatial perception across two consecutive 30-min experimental sessions. All groups received sham stimulation for the first experimental session, but the groups differed in the stimulation delivered to the left RLPFC during the second session (either sham, 1.5 mA anodal tDCS, or 1.5 mA cathodal tDCS). The experimental group that received anodal tDCS to the left RLPFC during the second session demonstrated significantly improved episodic memory source retrieval performance, relative to both their first session performance and relative to performance changes observed in the other two experimental groups. Performance on the analogical reasoning and visuospatial perception tasks did not exhibit reliable changes as a result of tDCS. As such, our results demonstrate that anodal tDCS to the left RLPFC leads to a selective and robust improvement in episodic source memory retrieval.

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