scholarly journals The Potentiation of Associative Memory by Emotions: An Event-Related FMRI Study

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
David Luck ◽  
Marie-Eve Leclerc ◽  
Martin Lepage
Keyword(s):  
Performance Improvement ◽  
Entorhinal Cortex ◽  
Associative Memory ◽  
Temporal Lobe ◽  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Emotional Valence ◽  
Neural Correlates ◽  
Fmri Study ◽  
The Right

Establishing associations between pieces of information is related to the medial temporal lobe (MTL). However, it remains unclear how emotions affect memory for associations and, consequently, MTL activity. Thus, this event-related fMRI study attempted to identify neural correlates of the influence of positive and negative emotions on associative memory. Twenty-five participants were instructed to memorize 90 pairs of standardized pictures during a scanned encoding phase. Each pair was composed of a scene and an unrelated object. Trials were neutral, positive, or negative as a function of the emotional valence of the scene. At the behavioral level, participants exhibited better memory retrieval for both emotional conditions relative to neutral trials. Within the right MTL, a functional dissociation was observed, with entorhinal activation elicited by emotional associations, posterior parahippocampal activation elicited by neutral associations, and hippocampal activation elicited by both emotional and neutral associations. In addition, emotional associations induced greater activation than neutral trials in the right amygdala. This fMRI study shows that emotions are associated with the performance improvement of associative memory, by enhancing activity in the right amygdala and the right entorhinal cortex. It also provides evidence for a rostrocaudal specialization within the MTL regarding the emotional valence of associations.

scholarly journals Early stages of tau pathology and its associations with functional connectivity, atrophy and memory

Brain ◽  
2021 ◽  
Author(s):  
David Berron ◽  
Jacob W Vogel ◽  
Philip S Insel ◽  
Joana B Pereira ◽  
Long Xie ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Entorhinal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Memory Impairment ◽  
Memory Performance ◽  
Hippocampal Atrophy ◽  
Tau Pathology ◽  
Β Amyloid ◽  
With Memory

Abstract In Alzheimer’s disease, postmortem studies have shown that the first cortical site where neurofibrillary tangles appear is the transentorhinal region, a subregion within the medial temporal lobe that largely overlaps with area 35, and the entorhinal cortex. Here we used tau-PET imaging to investigate the sequence of tau pathology progression within the human medial temporal lobe and across regions in the posterior-medial system. Our objective was to study how medial temporal tau is related to functional connectivity, regional atrophy, and memory performance. We included 215 β-amyloid negative cognitively unimpaired, 81 β-amyloid positive cognitively unimpaired and 87 β-amyloid positive individuals with mild cognitive impairment, who each underwent [18]F-RO948 tau and [18]F-flutemetamol amyloid PET imaging, structural T1-MRI and memory assessments as part of the Swedish BioFINDER-2 study. First, event-based modelling revealed that the entorhinal cortex and area 35 show the earliest signs of tau accumulation followed by the anterior and posterior hippocampus, area 36 and the parahippocampal cortex. In later stages, tau accumulation became abnormal in neocortical temporal and finally parietal brain regions. Second, in cognitively unimpaired individuals, increased tau load was related to local atrophy in the entorhinal cortex, area 35 and the anterior hippocampus and tau load in several anterior medial temporal lobe subregions was associated with distant atrophy of the posterior hippocampus. Tau load, but not atrophy, in these regions was associated with lower memory performance. Further, tau-related reductions in functional connectivity in critical networks between the medial temporal lobe and regions in the posterior-medial system were associated with this early memory impairment. Finally, in patients with mild cognitive impairment, the association of tau load in the hippocampus with memory performance was partially mediated by posterior hippocampal atrophy. In summary, our findings highlight the progression of tau pathology across medial temporal lobe subregions and its disease-stage specific association with memory performance. While tau pathology might affect memory performance in cognitively unimpaired individuals via reduced functional connectivity in critical medial temporal lobe-cortical networks, memory impairment in mild cognitively impaired patients is associated with posterior hippocampal atrophy.

Medial temporal lobe activation during autobiographical context memory retrieval of time and place and its dependency upon recency

Neurocase ◽  
2013 ◽  
Vol 21 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Silke Lux ◽  
Valeska N. Bindrich ◽  
Hans J. Markowitsch ◽  
Gereon R. Fink
Keyword(s):  
Temporal Lobe ◽  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Context Memory

Temporal Lobe Epilepsy

2017 ◽  
Author(s):  
Edward H. Bertram
Keyword(s):  
Animal Models ◽  
Temporal Lobe Epilepsy ◽  
Entorhinal Cortex ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Focal Epilepsy ◽  
Neural Circuitry ◽  
Human Condition ◽  
Physiological Changes ◽  
Limbic Structures

Temporal lobe epilepsy, as discussed in this chapter, is a focal epilepsy that involves primarily the limbic structures of the medial temporal lobe (amygdala, hippocampus, and entorhinal cortex). In recent years animal models have been developed that mirror the pathology and pathophysiology of this disease. This chapter reviews the human condition, the structural and physiological changes that support the development of seizures. The neural circuitry of seizure initiation will be reviewed with a goal of creating a framework for developing more effective treatments for this disease.

scholarly journals An Exploratory Study of the Relationship between Face Recognition Memory and the Volume of Medial Temporal Lobe Structures in Healthy Young Males

1998 ◽  
Vol 11 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Clare E. Mackay ◽  
Neil Roberts ◽  
Andrew R. Mayes ◽  
John J. Downes ◽  
Jonathan K. Foster ◽  
...  
Keyword(s):  
Face Recognition ◽  
Recognition Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Multiple Comparisons ◽  
Cerebral Hemispheres ◽  
Parahippocampal Gyrus ◽  
Bonferroni Correction ◽  
Temporal Pole ◽  
The Right

A rigorous new methodology was applied to the study of structure function relationships in the living human brain. Face recognition memory (FRM) and other cognitive measures were made in 29 healthy young male subjects (mean age = 21.7 years) and related to volumetric measurements of their cerebral hemispheres and of structures in their medial temporal lobes, obtained using the Cavalieri method in combination with high resolution Magnetic Resonance Imaging (MRI. Greatest proportional variability in volumes was found for the lateral ventricles (57%) for the cerebral hemispheres (8%) in the mean volumes of the hippocampus, parahippocampal gyrus, amygdala, caudate nucleus, temporal pole and temporal lobe on the right and left sides of the brain. The volumes of the right and left parahippocampal gyrus, temporal pole, temporal lobe, and left hippocampus were, prior to application of the Bonferroni correction to take account of 12 multiple comparisons, significantly correlated with the volume of the corresponding hemisphere (p< 0.05). The volumes of all structures were highly correlated (p< 0.0002 for all comparisons) between the two cerebral hemispheres. There were no positive relationships between structure volumes and FRM score. However, the volume of the right amygdala was, prior to application of the Bonferroni correction to take account of 38~multiple comparisons, found to be significantly smaller in the five most consistent high scorers compared to the five most consistent low scorers (t= 2.77,p= 0.025). The implications for possible relationships between healthy medial temporal lobe structures and memory are discussed.

Medial temporal lobe stimulation may disrupt context-dependent memory retrieval

2015 ◽  
Vol 8 (2) ◽  
pp. 355 ◽  
Author(s):  
M.B. Merkow ◽  
J.F. Burke ◽  
A.R. Ramayya ◽  
A. Sharan ◽  
M.J. Kahana ◽  
...  
Keyword(s):  
Temporal Lobe ◽  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Context Dependent

Medial temporal lobe activations during associative memory encoding for arbitrary and semantically related object pairs

2007 ◽  
Vol 1161 ◽  
pp. 46-55 ◽  
Author(s):  
Amélie M. Achim ◽  
Marie-Claude Bertrand ◽  
Alonso Montoya ◽  
Ashok K. Malla ◽  
Martin Lepage
Keyword(s):  
Associative Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Memory Encoding ◽  
Related Object

Lateralization of Prefrontal Activity during Episodic Memory Retrieval: Evidence for the Production-Monitoring Hypothesis

2003 ◽  
Vol 15 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Roberto Cabeza ◽  
Jill K. Locantore ◽  
Nicole D. Anderson
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Item Recognition ◽  
Cued Recall ◽  
Anterior Cingulate ◽  
Episodic Retrieval ◽  
Context Recognition ◽  
Production Monitoring ◽  
The Right

We propose a new hypothesis concerning the lateralization of prefrontal cortex (PFC) activity during verbal episodic memory retrieval. The hypothesis states that the left PFC is differentially more involved in semantically guided information production than is the right PFC, and that the right PFC is differentially more involved in monitoring and verification than is the left PFC. This “production-monitoring hypothesis” differs from the existing “systematic-heuristic hypothesis,” which proposes that the left PFC is primarily involved in systematic retrieval operations, and the right PFC in heuristic retrieval operations. To compare the two hypotheses, we measured PFC activity using positron emission tomography (PET) during the performance of four episodic retrieval tasks: stem cued recall, associative cued recall, context recognition (source memory), and item recognition. Recall tasks emphasized production processes, whereas recognition tasks emphasized monitoring processes. Stem cued recall and context-recognition tasks underscored systematic operations, whereas associative cued recall and item-recognition tasks underscored heuristic operations. Consistent with the production-monitoring hypothesis, the left PFC was more activated for recall than for recognition tasks and the right PFC was more activated for recognition than for recall tasks. Inconsistent with the systematic-heuristic hypothesis, the left PFC was more activated for heuristic than for systematic tasks and the right PFC showed the converse result. Additionally, the study yielded activation differences outside the PFC. In agreement with a previous recall/recognition PET study, anterior cingulate, cerebellar, and striatal regions were more activated for recall than for recognition tasks, and the converse occurred for posterior parietal regions. A right medial temporal lobe region was more activated for stem cued recall and context recognition than for associative cued recall and item recognition, possibly reflecting perceptual integration. In sum, the results provide evidence for the production-monitoring hypothesis and clarify the role of different brain regions typically activated in PET and functional magnetic resonance imaging (fMRI) studies of episodic retrieval.

scholarly journals Dissociating Neural Correlates of Action Monitoring and Metacognition of Agency

2011 ◽  
Vol 23 (11) ◽  
pp. 3620-3636 ◽  
Author(s):  
David B. Miele ◽  
Tor D. Wager ◽  
Jason P. Mitchell ◽  
Janet Metcalfe
Keyword(s):  
Brain Activity ◽  
Dorsal Striatum ◽  
Neural Correlates ◽  
Action Monitoring ◽  
Fmri Study ◽  
Metacognitive Judgments ◽  
The Right ◽  
Reflective Processing ◽  
Increased Activity ◽  
The Brain

Judgments of agency refer to people's self-reflective assessments concerning their own control: their assessments of the extent to which they themselves are responsible for an action. These self-reflective metacognitive judgments can be distinguished from action monitoring, which involves the detection of the divergence (or lack of divergence) between observed states and expected states. Presumably, people form judgments of agency by metacognitively reflecting on the output of their action monitoring and then consciously inferring the extent to which they caused the action in question. Although a number of previous imaging studies have been directed at action monitoring, none have assessed judgments of agency as a potentially separate process. The present fMRI study used an agency paradigm that not only allowed us to examine the brain activity associated with action monitoring but that also enabled us to investigate those regions associated with metacognition of agency. Regarding action monitoring, we found that being “out of control” during the task (i.e., detection of a discrepancy between observed and expected states) was associated with increased brain activity in the right TPJ, whereas being “in control” was associated with increased activity in the pre-SMA, rostral cingulate zone, and dorsal striatum (regions linked to self-initiated action). In contrast, when participants made self-reflective metacognitive judgments about the extent of their own control (i.e., judgments of agency) compared with when they made judgments that were not about control (i.e., judgments of performance), increased activity was observed in the anterior PFC, a region associated with self-reflective processing. These results indicate that action monitoring is dissociable from people's conscious self-attributions of control.

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