scholarly journals Medial prefrontal cortex activity reflects ordinal retrieval modes and hippocampal activity reflects temporal context retrieval modes

2018 ◽  
Author(s):  
Puck C. Reeders ◽  
Amanda G. Hamm ◽  
Timothy A. Allen ◽  
Aaron T. Mattfeld
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Medial Prefrontal Cortex ◽  
Neural Correlates ◽  
Mode Interaction ◽  
Temporal Context ◽  
Hippocampal Activity ◽  
Sequence Memory ◽  
New Evidence ◽  
Spatial Content

ABSTRACTRemembering sequences of events defines episodic memory, but retrieval can be driven by both ordinality and temporal contexts. Whether these modes of retrieval operate at the same time or not remains unclear. Theoretically, medial prefrontal cortex (mPFC) confers ordinality, while the hippocampus (HC) associates events in gradually changing temporal contexts. Here, we looked for evidence of each with BOLD fMRI in a sequence task that taxes both retrieval modes. To test ordinal modes, items were transferred between sequences but retained their position (e.g., AB3). Ordinal modes activated mPFC, but not HC. To test temporal contexts, we examined items that skipped ahead across lag distances (e.g., ABD). HC, but not mPFC, tracked temporal contexts. There was a mPFC and HC by retrieval mode interaction. These current results suggest that the mPFC and HC are concurrently engaged in different retrieval modes in support of remembering when an event occurred.Significance StatementMemory for sequences of events is a defining aspect of everyday episodic memory allowing our brain to separate unique experiences that otherwise have overlapping sensory and spatial content. Sequence memory is impaired in typical aging and in disorders such as Alzheimer’s disease. The results of the current study provide new evidence that two retrieval modes concurrently arise during sequence memory, and they have distinct neural correlates. The medial prefrontal cortex contributes to an ordinal retrieval mode, while at the same time, the hippocampus contributes a gradually-changing temporal context mode of retrieval. These data shed new light on why typical episodic memory requires both the medial prefrontal cortex and the hippocampus, and suggests a functional dissociation between the medial prefrontal cortex and hippocampus across these modes of retrieval.

scholarly journals Neural correlates of integrated self and social processing

2020 ◽  
Vol 15 (9) ◽  
pp. 941-949
Author(s):  
Laura Finlayson-Short ◽  
Christopher G Davey ◽  
Ben J Harrison
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Processing Condition ◽  
Emotional Valence ◽  
Neural Correlates ◽  
Brain Regions ◽  
Affective Processing ◽  
Social Processing ◽  
Referential Processing ◽  
Core Self

Abstract Self-referential and social processing are often engaged concurrently in naturalistic judgements and elicit activity in overlapping brain regions. We have termed this integrated processing ‘self-other referential processing’ and developed a task to measure its neural correlates. Ninety-eight healthy young people aged 16–25 (M = 21.5 years old, 67% female) completed our novel functional magnetic resonance imaging task. The task had two conditions, an active self-other referential processing condition in which participants rated how much they related to emotional faces and a control condition. Rating relatedness required thinking about oneself (self-referential processing) and drawing a comparison to an imagined other (social processing). Self-other referential processing elicited activity in the default mode network and social cognition system; most notably in the ‘core self’ regions of the medial prefrontal cortex and posterior cingulate cortex. Relatedness and emotional valence directly modulated activity in these core self areas, while emotional valence additionally modulated medial prefrontal cortex activity. This shows the key role of the medial prefrontal cortex in constructing the ‘social-affective self’. This may help to unify disparate models of medial prefrontal cortex function, demonstrating its role in coordinating multiple processes—self-referential, social and affective processing—to allow the self to exist in a complex social world.

scholarly journals Lateralized Contributions of Medial Prefrontal Cortex Network to Episodic Memory Deficits in Subjects With Amnestic Mild Cognitive Impairment

2021 ◽  
Vol 13 ◽  
Author(s):  
Qing Ye ◽  
Haifeng Chen ◽  
Renyuan Liu ◽  
Ruomeng Qin ◽  
Caimei Luo ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Prefrontal Cortex ◽  
Executive Function ◽  
Mild Cognitive Impairment ◽  
Episodic Memory ◽  
Medial Prefrontal Cortex ◽  
Memory Deficits ◽  
Amnestic Mild Cognitive Impairment ◽  
Hippocampal Networks ◽  
The Right

Both episodic memory and executive function are impaired in amnestic mild cognitive impairment (aMCI) subjects, but it is unclear if these impairments are independent or interactive. The present study aimed to explore the relationship between episodic memory deficits and executive function deficits, and the underlying functional mechanisms in aMCI subjects. Thirty-one aMCI subjects and 27 healthy subjects underwent neuropsychological tests and multimodal magnetic resonance imaging (MRI) scans. Hippocampal networks and medial prefrontal cortex (MPFC) networks were identified based on resting-sate functional MRI (fMRI) data. AMCI subjects displayed lower episodic memory scores and executive function scores than control subjects, and the episodic memory scores were positively correlated with the executive function scores in aMCI subjects. Brain network analyses showed an interaction between the hippocampal networks and the MPFC networks, and the interaction was significantly associated with the episodic memory scores and the executive function scores. Notably, aMCI subjects displayed higher functional connectivity (FC) of the right hippocampal network with the right prefrontal cortex than did control subjects, but this difference disappeared when controlling for the MPFC networks. Furthermore, the effects of the MPFC networks on the hippocampal networks were significantly associated with the episodic memory scores in aMCI subjects. The present findings suggested that the episodic memory deficits in aMCI subjects could be partially underpinned by the modulation of the MPFC networks on the hippocampal networks.

scholarly journals The Role of Hippocampal–Ventromedial Prefrontal Cortex Neural Dynamics in Building Mental Representations

2021 ◽  
Vol 33 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Anna M. Monk ◽  
Marshall A. Dalton ◽  
Gareth R. Barnes ◽  
Eleanor A. Maguire
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Brain Regions ◽  
Ventromedial Prefrontal Cortex ◽  
High Temporal Resolution ◽  
Cognitive Domains ◽  
Initial Stage ◽  
Hippocampal Activity ◽  
Two Stages

The hippocampus and ventromedial prefrontal cortex (vmPFC) play key roles in numerous cognitive domains including mind-wandering, episodic memory, and imagining the future. Perspectives differ on precisely how they support these diverse functions, but there is general agreement that it involves constructing representations composed of numerous elements. Visual scenes have been deployed extensively in cognitive neuroscience because they are paradigmatic multielement stimuli. However, it remains unclear whether scenes, rather than other types of multifeature stimuli, preferentially engage hippocampus and vmPFC. Here, we leveraged the high temporal resolution of magnetoencephalography to test participants as they gradually built scene imagery from three successive auditorily presented object descriptions and an imagined 3-D space. This was contrasted with constructing mental images of nonscene arrays that were composed of three objects and an imagined 2-D space. The scene and array stimuli were, therefore, highly matched, and this paradigm permitted a closer examination of step-by-step mental construction than has been undertaken previously. We observed modulation of theta power in our two regions of interest—anterior hippocampus during the initial stage and vmPFC during the first two stages, of scene relative to array construction. Moreover, the scene-specific anterior hippocampal activity during the first construction stage was driven by the vmPFC, with mutual entrainment between the two brain regions thereafter. These findings suggest that hippocampal and vmPFC neural activity is especially tuned to scene representations during the earliest stage of their formation, with implications for theories of how these brain areas enable cognitive functions such as episodic memory.

scholarly journals Higher GABA concentration in the medial prefrontal cortex of Type 2 diabetes patients is associated with episodic memory dysfunction

2019 ◽  
Vol 40 (14) ◽  
pp. 4287-4295 ◽  
Author(s):  
Jan‐Willem Thielen ◽  
Sofiya Gancheva ◽  
Donghyun Hong ◽  
Seyedmorteza Rohani Rankouhi ◽  
Bixia Chen ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Medial Prefrontal Cortex ◽  
Gaba Concentration ◽  
Memory Dysfunction ◽  
Diabetes Patients
Sign in / Sign up

Export Citation Format

Share Document