A Mini-Review of fMRI Studies of Human Medial Temporal Lobe Activity Associated with Recognition Memory

2005 ◽  
Vol 58 (3-4b) ◽  
pp. 340-360 ◽  
Author(s):  
Richard Henson
Keyword(s):  
Recognition Memory ◽  
Medial Temporal Lobe ◽  
Spatial Information ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Source Information ◽  
Medial Temporal Lobes ◽  
Future Directions ◽  
Temporal Lobes ◽  
Anterior Posterior

This review considers event-related functional magnetic resonance imaging (fMRI) studies of human recognition memory that have or have not reported activations within the medial temporal lobes (MTL). For comparisons both between items at study (encoding) and between items at test (recognition), MTL activations are characterized as left/right, anterior/posterior, and hippocampus/surrounding cortex, and as a function of the stimulus material and relevance of item/source information. Though no clear pattern emerges, there are trends suggesting differences between item and source information, and verbal and spatial information, and a role for encoding processes during recognition tests. Important future directions are considered.

scholarly journals Dissociable medial temporal pathways for encoding emotional item and context information

2018 ◽  
Author(s):  
Maureen Ritchey ◽  
Shao-Fang Wang ◽  
Andrew P. Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Source Memory ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Double Dissociation ◽  
Parahippocampal Cortex ◽  
Hippocampal Activity ◽  
Amygdala Activity

AbstractEmotional experiences are typically remembered with a greater sense of recollection than neutral experiences, but memory benefits for emotional items do not typically extend to their source contexts. Item and source memory have been attributed to different subregions of the medial temporal lobes (MTL), but it is unclear how emotional item recollection fits into existing models of MTL function and, in particular, what is the role of the hippocampus. To address these issues, we used high-resolution functional magnetic resonance imaging (fMRI) to examine MTL contributions to successful emotional item and context encoding. The results showed that emotional items were recollected more often than neutral items. Whereas amygdala and perirhinal cortex (PRC) activity supported the recollection advantage for emotional items, hippocampal and parahippocampal cortex activity predicted subsequent source memory for both types of items, reflecting a double dissociation between anterior and posterior MTL regions. In addition, amygdala activity during encoding modulated the relationships of PRC activity and hippocampal activity to subsequent item recollection and source memory, respectively. Specifically, whereas PRC activity best predicted subsequent item recollection when amygdala activity was relatively low, hippocampal activity best predicted source memory when amygdala activity was relatively high. We interpret these findings in terms of complementary compared to synergistic amygdala-MTL interactions. The results suggest that emotion-related enhancements in item recollection are supported by an amygdala-PRC pathway, which is separable from the hippocampal pathway that binds items to their source context.

scholarly journals Adaptive brain activity changes during tongue movement with palatal coverage from fMRI data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuka Inamochi ◽  
Kenji Fueki ◽  
Nobuo Usui ◽  
Masato Taira ◽  
Noriyuki Wakabayashi
Keyword(s):  
Spatial Information ◽  
Brain Activity ◽  
Motor Impairment ◽  
Angular Gyrus ◽  
Tongue Movement ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Oral Environment ◽  
Motor Dexterity ◽  
The Brain

AbstractSuccessful adaptation to wearing dentures with palatal coverage may be associated with cortical activity changes related to tongue motor control. The purpose was to investigate the brain activity changes during tongue movement in response to a new oral environment. Twenty-eight fully dentate subjects (mean age: 28.6-years-old) who had no experience with removable dentures wore experimental palatal plates for 7 days. We measured tongue motor dexterity, difficulty with tongue movement, and brain activity using functional magnetic resonance imaging during tongue movement at pre-insertion (Day 0), as well as immediately (Day 1), 3 days (Day 3), and 7 days (Day 7) post-insertion. Difficulty with tongue movement was significantly higher on Day 1 than on Days 0, 3, and 7. In the subtraction analysis of brain activity across each day, activations in the angular gyrus and right precuneus on Day 1 were significantly higher than on Day 7. Tongue motor impairment induced activation of the angular gyrus, which was associated with monitoring of the tongue’s spatial information, as well as the activation of the precuneus, which was associated with constructing the tongue motor imagery. As the tongue regained the smoothness in its motor functions, the activation of the angular gyrus and precuneus decreased.

scholarly journals Triple Dissociation in the Medial Temporal Lobes: Recollection, Familiarity, and Novelty

2006 ◽  
Vol 96 (4) ◽  
pp. 1902-1911 ◽  
Author(s):  
S. M. Daselaar ◽  
M. S. Fleck ◽  
R. Cabeza
Keyword(s):  
Medial Temporal Lobe ◽  
Memory Performance ◽  
Parahippocampal Gyrus ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Retrieval Processes ◽  
Individual Trial ◽  
Memory Signals ◽  
Magnetic Resonance Imaging Mri ◽  
Left Parietal Cortex

Memory for past events may be based on retrieval accompanied by specific contextual details (recollection) or on the feeling that an item is old (familiarity) or new (novelty) in the absence of contextual details. There are indications that recollection, familiarity, and novelty involve different medial temporal lobe subregions, but available evidence is scarce and inconclusive. Using functional magnetic resonance imaging (MRI), we isolated retrieval-related activity associated with recollection, familiarity, and novelty by distinguishing between linear and nonlinear oldness functions derived from recognition confidence levels. Within the medial temporal lobes (MTLs), we found a triple dissociation among the posterior half of the hippocampus, which was associated with recollection, the posterior parahippocampal gyrus, which was associated with familiarity, and anterior half of the hippocampus and rhinal regions, which were associated with novelty. Furthermore, multiple regression analyses based on individual trial activity showed that all three memory signals, i.e., recollection, familiarity, and novelty, make significant and independent contributions to recognition memory performance. Finally, functional dissociations among recollection, familiarity, and novelty were also found in posterior midline, left parietal cortex, and prefrontal cortex regions. This is the first study to reveal a triple dissociation within the MTL associated with distinct retrieval processes. This finding has direct implications for current memory models.

scholarly journals Dissociating Confidence and Accuracy: Functional Magnetic Resonance Imaging Shows Origins of the Subjective Memory Experience

2004 ◽  
Vol 16 (7) ◽  
pp. 1131-1142 ◽  
Author(s):  
Elizabeth F. Chua ◽  
Erin Rand-Giovannetti ◽  
Daniel L. Schacter ◽  
Marilyn S. Albert ◽  
Reisa A. Sperling
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Objective Measures ◽  
Correct Identification ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
High Confidence

Successful memory typically implies both objective accuracy and subjective confidence, but there are instances when confidence and accuracy diverge. This dissociation suggests that there may be distinct neural patterns of activation related to confidence and accuracy. We used event-related functional magnetic resonance imaging to study the encoding of novel face–name associations, assessed with a postscan memory test that included objective measures of accuracy and subjective measures of confidence. We showed specific neural activity in the left inferior prefrontal cortex associated with trials when subjects expressed high confidence that they had chosen the correct name for the face and made a correct identification. Moreover, we found that this region was also associated with imparting high confidence when subjects chose the incorrect name. However, medial temporal lobe regions showed activity only for high-confidence correct trials. Many functional magnetic resonance imaging studies have shown that the medial temporal lobe and left prefrontal regions are particularly important for the successful formation of memories by using a combination of subjective and objective measures. Our findings suggest that these regions may be differentially involved in the objective and subjective components of memory and that the origins of confidence–accuracy dissociations may be related to incomplete activation of the neural pattern seen in successful encoding. These findings may also aid understanding of eyewitness misidentifications and memory distortions.

scholarly journals Memorable navigation: Assessing the influence of way-finding in spatial clustering

2020 ◽  
Author(s):  
Alvaro Pastor
Keyword(s):  
Cognitive Abilities ◽  
Spatial Information ◽  
Spatial Clustering ◽  
Recall Performance ◽  
Memory Task ◽  
Correct Recall ◽  
Brain Regions ◽  
Medial Temporal Lobes ◽  
Temporal Lobes

Navigating around an environment and remembering the events that took place within it are crucial cognitive abilities that have been linked to the Hippocampus and medial temporal lobes (MTL). Scene Construction Theory (SCT) has proposed that a function of the Hippocampus is the implicit and continuous construction of scenes to help prediction of upcoming environment. Scenes, as highly efficient means of packaging information, underpin in coordination with other brain regions, episodic memory (EM), spatial navigation, future thinking and perhaps even dreaming and mind-wandering. We examined the conditions in which spatial contiguity of stimuli influences the organization of memory by examining spatial clustering (SC) phenomenon. In this research, an augmented reality (AR) system was used to test 14 participants in a spatially dependent memory task which assessed the SC differences between active navigators and passive spectators. We confirmed our hypothesis that navigators use spatial information as part of the retrieval process in free recall, as they tended to sequentially recall any two neighboring otherwise unrelated items. We also found a significant correlation between SC and correct recall performance supporting our second hypothesis. These results may be valuable for design of learning applications, especially dealing with large amounts of data. Research on Alzheimer's and other neurodegenerative diseases may also benefit from our approach. Future studies may assess the role of encoding and retrieval modality and participant's use of mnemonic strategies.

scholarly journals Hippocampal Volume Influences The Correlations Between White Matter Disruption and Tau Protein in aMCI and mild AD

2020 ◽  
Author(s):  
Thamires Naela Cardoso Magalhães ◽  
Raphael Fernandes Casseb ◽  
Christian Luiz Baptista Gerbelli ◽  
Luciana Ramalho Pimentel-Silva ◽  
Mateus Henrique Nogueira ◽  
...  
Keyword(s):  
White Matter ◽  
Medial Temporal Lobe ◽  
Hippocampal Volume ◽  
Tau Proteins ◽  
Cortical Atrophy ◽  
Medial Temporal Lobes ◽  
Temporal Lobes ◽  
Prodromal Ad ◽  
Transentorhinal Cortex

Abstract Background: Alzheimer’s disease (AD) is classically considered a grey matter (GM) disease that starts in the transentorhinal cortex and spreads to limbic and neocortical regions. However, white matter (WM) damage could be more severe and widespread than expected cortical atrophy. The role of AD biomarkers and WM integrity throughout the brain is unclear, especially in amnestic Mild Cognitive Impairment (aMCI) patients, a possible prodromal AD dementia stage. If WM damage can be detected even before the development of cortical atrophy and overt dementia and in the AD process, Aβ42 Tau (and its phosphorylated form) could directly affect WM. Methods: We analyzed in this study 183 individuals - 48 aMCI in the AD continuum (altered CSF Aβ42), 30 patients with very mild or mild AD dementia and 105 normal controls. All subjects underwent neuropsychological evaluation and MRI exams. aMCI and mild AD individuals were also submitted to CSF puncture to evaluate AD biomarkers.Results: We observed several significant differences in WM integrity regarding the DTI measures between individuals and we found significant correlations between fornix and right cingulum hippocampal tracts and Tau and p-Tau proteins. Conclusions: We hypothesize that significant correlations with tracts anatomically far from more well-established GM atrophic regions, like medial temporal lobes, would support a more direct effect of pathological proteins on WM, whereas medial temporal lobe (MTL) correlations would favor WD and/or a direct spreading of pathology from the hippocampus.

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