Hemisphere-specific Episodic Memory Networks in the Human Brain: A Correlation Study between Intracarotid Amobarbital Test and [18F]FDG-PET

2009 ◽  
Vol 21 (3) ◽  
pp. 605-622 ◽  
Author(s):  
Nozomi Akanuma ◽  
Laurence J. Reed ◽  
Paul K. Marsden ◽  
Jozeph Jarosz ◽  
Naoto Adachi ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Frontal Cortex ◽  
Fdg Pet ◽  
Cerebral Metabolism ◽  
Memory Performance ◽  
Anterior Cingulate ◽  
Precentral Gyrus ◽  
Fdg Uptake ◽  
The Right ◽  
Intracarotid Amobarbital Test

The purpose of the present study was to explore the brain regions involved in human episodic memory by correlating unilateral memory performance estimated by the intracarotid amobarbital test (IAT) and interictal cerebral metabolism measured by [18F]fluorodeoxyglucose positron emission tomography ([18F]FDG-PET). Using this method, regional alterations of cerebral metabolism associated with epilepsy pathophysiology are used to predict hemisphere-specific episodic memory function, hence, investigate the differential distribution of memory in each hemisphere. Sixty-two patients with unilateral temporal lobe epilepsy (35 left and 27 right) were studied using [18F]FDG-PET with complementary voxel-based statistical parametric mapping (SPM) and region-of-interest (ROI) methods of analysis. Positive regression was analyzed in SPM with a series of different thresholds (p = .001, .01 or .05) with a correction to 100 voxels. IAT memory performance in which left hemisphere was tested by right-sided injection of amobarbital correlated with [18F]FDG uptake in left lateral and medial temporal regions, and in the left ventrolateral frontal cortex. Right IAT memory performance correlated with [18F]FDG uptake in the right inferior parietal lobule, right dorsolateral frontal cortex, right precentral gyrus, and caudal portion of the right anterior cingulate cortex. ROI analysis corroborated these results. Analyses carried out separately in patients with left (n = 50) and nonleft (n = 12) dominance for language showed that in the nonleft dominant group, right IAT scores correlated with right fronto-temporal regions, whereas left total memory scores correlated with left lateral and medial temporal regions. The findings indicate that (i) episodic memory is subserved by more widespread cortical regions beyond the core mesiotemporal lobe memory structures; (ii) there are different networks functional in the two hemispheres; and (iii) areas involved in memory may be different between patients with left and nonleft dominance for language, particularly in the right hemisphere.

scholarly journals Left frontal cortex connectivity underlies cognitive reserve in prodromal Alzheimer disease

Neurology ◽  
2017 ◽  
Vol 88 (11) ◽  
pp. 1054-1061 ◽  
Author(s):  
Nicolai Franzmeier ◽  
Marco Duering ◽  
Michael Weiner ◽  
Martin Dichgans ◽  
Michael Ewers ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Linear Regression ◽  
Episodic Memory ◽  
Frontal Cortex ◽  
Fdg Pet ◽  
Cognitive Reserve ◽  
Early Stage ◽  
Memory Performance ◽  
Amyloid Pet ◽  
Regression Analyses

Objective:To test whether higher global functional connectivity of the left frontal cortex (LFC) in Alzheimer disease (AD) is associated with more years of education (a proxy of cognitive reserve [CR]) and mitigates the association between AD-related fluorodeoxyglucose (FDG)-PET hypometabolism and episodic memory.Methods:Forty-four amyloid-PET–positive patients with amnestic mild cognitive impairment (MCI-Aβ+) and 24 amyloid-PET–negative healthy controls (HC) were included. Voxel-based linear regression analyses were used to test the association between years of education and FDG-PET in MCI-Aβ+, controlled for episodic memory performance. Global LFC (gLFC) connectivity was computed through seed-based resting-state fMRI correlations between the LFC (seed) and each voxel in the gray matter. In linear regression analyses, education as a predictor of gLFC connectivity and the interaction of gLFC connectivity × FDG-PET hypometabolism on episodic memory were tested.Results:FDG-PET metabolism in the precuneus was reduced in MCI-Aβ+ compared to HC (p = 0.028), with stronger reductions observed in MCI-Aβ+ with more years of education (p = 0.006). In MCI-Aβ+, higher gLFC connectivity was associated with more years of education (p = 0.021). At higher levels of gLFC connectivity, the association between precuneus FDG-PET hypometabolism and lower memory performance was attenuated (p = 0.027).Conclusions:Higher gLFC connectivity is a functional substrate of CR that helps to maintain episodic memory relatively well in the face of emerging FDG-PET hypometabolism in early-stage AD.

Structural Neural Correlates of Memory Performance in Schizoprhenia as Revealed by Cortical Thickness

2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
K. Sergerie ◽  
A.C. Evans ◽  
C. Lepage ◽  
M. Lepage
Keyword(s):  
Episodic Memory ◽  
Cortical Thickness ◽  
Memory Performance ◽  
Recognition Task ◽  
Memory Deficits ◽  
Neural Correlates ◽  
Anterior Cingulate ◽  
Parahippocampal Gyrus ◽  
Brain Abnormalities ◽  
The Right

In addition to the positive and negative symptoms, schizophrenia is associated with a variety of cognitive impairments, and in particular with episodic memory deficits. Functional neuroimaging studies have begun exploring the potential neural correlates of memory deficits but there are few reports of structural brain abnormalities underlying memory impairment in schizophrenia. We investigated the potential association between morphological brain abnormalities as revealed by cortical thickness measures and episodic memory performance on a face recognition task. Differences in regional cortical thickness between 27 patients with a DSM-IV diagnosis of schizophrenia and 28 control matched subjects were investigated using MRI T1 images and computer image analysis (CIVET pipeline; Lerch and Evans, 2005). Cortical thickness was estimated as the shortest distance between the pial surface of the cerebral cortex and the white-matter/gray-matter interface surface at numerous points (40 962 vertices) across the cortical mantle. Consistent with previous studies, a group comparison revealed thinner cortex in the patient group relative to controls in the right prefrontal cortex and parahippocampal gyrus. Interestingly, a significant positive correlation between memory performance and cortical thickness of the anterior cingulate, bilaterally as well as the right parahippocampal gyrus was noted in the schizophrenia group. That is, the thinner the cortex in those regions, the more impaired the patients were in terms of memory performance as compared to healthy participants.

The Effect of Divided Attention on Encoding and Retrieval in Episodic Memory Revealed by Positron Emission Tomography

2000 ◽  
Vol 12 (2) ◽  
pp. 267-280 ◽  
Author(s):  
Tetsuya Iidaka ◽  
Nicole D. Anderson ◽  
Shitij Kapur ◽  
Roberto Cabez ◽  
Fergus I. M. Craik
Keyword(s):  
Positron Emission Tomography ◽  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Divided Attention ◽  
Memory Performance ◽  
Memory Task ◽  
Anterior Cingulate ◽  
Emission Tomography ◽  
Positron Emission ◽  
Encoding And Retrieval

The effects of divided attention (DA) on episodic memory encoding and retrieval were investigated in 12 normal young subjects by positron emission tomography (PET). Cerebral blood flow was measured while subjects were concurrently performing a memory task (encoding and retrieval of visually presented word pairs) and an auditory tone-discrimination task. The PET data were analyzed using multivariate Partial Least Squares (PLS), and the results revealed three sets of neural correlates related to specific task contrasts. Brain activity, relatively greater under conditions of full attention (FA) than DA, was identified in the occipital-temporal, medial, and ventral-frontal areas, whereas areas showing relatively more activity under DA than FA were found in the cerebellum, temporo-parietal, left anterior-cingulate gyrus, and bilateral dorsolateral-prefrontal areas. Regions more active during encoding than during retrieval were located in the hippocampus, temporal and the prefrontal cortex of the left hemisphere, and regions more active during retrieval than during encoding included areas in the medial and right-prefrontal cortex, basal ganglia, thalamus, and cuneus. DA at encoding was associated with specific decreases in rCBF in the left-prefrontal areas, whereas DA at retrieval was associated with decreased rCBF in a relatively small region in the right-prefrontal cortex. These different patterns of activity are related to the behavioral results, which showed a substantial decrease in memory performance when the DA task was performed at encoding, but no change in memory levels when the DA task was performed at retrieval.

The Role of the Right Prefrontal Cortex in Self-evaluation of the Face: A Functional Magnetic Resonance Imaging Study

2008 ◽  
Vol 20 (2) ◽  
pp. 342-355 ◽  
Author(s):  
Tomoyo Morita ◽  
Shoji Itakura ◽  
Daisuke N. Saito ◽  
Satoshi Nakashita ◽  
Tokiko Harada ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Face Recognition ◽  
Inferior Frontal Gyrus ◽  
Video Recording ◽  
Imaging Study ◽  
The Self ◽  
Anterior Cingulate ◽  
Precentral Gyrus ◽  
Self Evaluation ◽  
The Right

Individuals can experience negative emotions (e.g., embarrassment) accompanying self-evaluation immediately after recognizing their own facial image, especially if it deviates strongly from their mental representation of ideals or standards. The aim of this study was to identify the cortical regions involved in self-recognition and self-evaluation along with self-conscious emotions. To increase the range of emotions accompanying self-evaluation, we used facial feedback images chosen from a video recording, some of which deviated significantly from normal images. In total, 19 participants were asked to rate images of their own face (SELF) and those of others (OTHERS) according to how photogenic they appeared to be. After scanning the images, the participants rated how embarrassed they felt upon viewing each face. As the photogenic scores decreased, the embarrassment ratings dramatically increased for the participant's own face compared with those of others. The SELF versus OTHERS contrast significantly increased the activation of the right prefrontal cortex, bilateral insular cortex, anterior cingulate cortex, and bilateral occipital cortex. Within the right prefrontal cortex, activity in the right precentral gyrus reflected the trait of awareness of observable aspects of the self; this provided strong evidence that the right precentral gyrus is specifically involved in self-face recognition. By contrast, activity in the anterior region, which is located in the right middle inferior frontal gyrus, was modulated by the extent of embarrassment. This finding suggests that the right middle inferior frontal gyrus is engaged in self-evaluation preceded by self-face recognition based on the relevance to a standard self.

scholarly journals Effects of amnesia on processing in the hippocampus and default mode network during a naturalistic memory task: a case study

2018 ◽  
Author(s):  
Christiane Oedekoven ◽  
James L. Keidel ◽  
Stuart Anderson ◽  
Angus Nisbet ◽  
Chris Bird
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Structural Mri ◽  
Brain Regions ◽  
Left Hippocampus ◽  
Cortical Regions ◽  
The Right ◽  
Encoding And Retrieval

Despite their severely impaired episodic memory, individuals with amnesia are able to comprehend ongoing events. Online representations of a current event are thought to be supported by a network of regions centred on the posterior midline cortex (PMC). By contrast, episodic memory is widely believed to be supported by interactions between the hippocampus and these cortical regions. In this MRI study, we investigated the encoding and retrieval of lifelike events (video clips) in a patient with severe amnesia likely resulting from a stroke to the right thalamus, and a group of 20 age-matched controls. Structural MRI revealed grey matter reductions in left hippocampus and left thalamus in comparison to controls. We first characterised the regions activated in the controls while they watched and retrieved the videos. There were no differences in activation between the patient and controls in any of the regions. We then identified a widespread network of brain regions, including the hippocampus, that were functionally connected with the PMC in controls. However, in the patient there was a specific reduction in functional connectivity between the PMC and a region of left hippocampus when both watching and attempting to retrieve the videos. A follow up analysis revealed that in controls the functional connectivity between these regions when watching the videos was correlated with memory performance. Taken together, these findings support the view that the interactions between the PMC and the hippocampus enable the encoding and retrieval of multimodal representations of the contents of an event.

scholarly journals Depression Is Associated With Preserved Cortical Thickness Relative to Apathy in Frontotemporal Dementia

2020 ◽  
pp. 089198872096425
Author(s):  
Rakshathi Basavaraju ◽  
Xinyang Feng ◽  
Jeanelle France ◽  
Edward D. Huey ◽  
Frank A. Provenzano
Keyword(s):  
Neurodegenerative Disease ◽  
Frontal Cortex ◽  
Frontotemporal Dementia ◽  
Cortical Thickness ◽  
Gray Matter ◽  
Anterior Cingulate ◽  
Parietal Lobes ◽  
Neuroimaging Data ◽  
Rostral Anterior Cingulate Cortex ◽  
The Right

Objectives: To understand the differential neuroanatomical substrates underlying apathy and depression in Frontotemporal dementia (FTD). Methods: T1-MRIs and clinical data of patients with behavioral and aphasic variants of FTD were obtained from an open database. Cortical thickness was derived, its association with apathy severity and difference between the depressed and not depressed were examined with appropriate covariates. Results: Apathy severity was significantly associated with cortical thinning of the lateral parts of the right sided frontal, temporal and parietal lobes. The right sided orbitofrontal, parsorbitalis and rostral anterior cingulate cortex were thicker in depressed compared to patients not depressed. Conclusions: Greater thickness of right sided ventromedial and inferior frontal cortex in depression compared to patients without depression suggests a possible requisite of gray matter in this particular area for the manifestation of depression in FTD. This study demonstrates a method for deriving neuroanatomical patterns across non-harmonized neuroimaging data in a neurodegenerative disease.

Anatomy of Motor Learning. I. Frontal Cortex and Attention to Action

1997 ◽  
Vol 77 (3) ◽  
pp. 1313-1324 ◽  
Author(s):  
M. Jueptner ◽  
K. M. Stephan ◽  
C. D. Frith ◽  
D. J. Brooks ◽  
R.S.J. Frackowiak ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Motor Learning ◽  
Frontal Cortex ◽  
Anterior Cingulate Cortex ◽  
Cingulate Cortex ◽  
Anterior Cingulate ◽  
Critical Feature ◽  
Positron Emission ◽  
New Learning ◽  
The Right

Jueptner, M., K. M. Stephan, C. D. Frith, D. J. Brooks, R.S.J. Frackowiak, and R. E. Passingham. Anatomy of motor learning. I. Frontal cortex and attention to action. J. Neurophysiol. 77: 1313–1324, 1997. We used positron emission tomography to study new learning and automatic performance in normal volunteers. Subjects learned sequences of eight finger movements by trial and error. In a previous experiment we showed that the prefrontal cortex was activated during new learning but not during automatic performance. The aim of the present experiment was to see what areas could be reactivated if the subjects performed the prelearned sequence but were required to pay attention to what they were doing. Scans were carried out under four conditions. In the first the subjects performed a prelearned sequence of eight key presses; this sequence was learned before scanning and was practiced until it had become overlearned, so that the subjects were able to perform it automatically. In the second condition the subjects learned a new sequence during scanning. In a third condition the subjects performed the prelearned sequence, but they were required to attend to what they were doing; they were instructed to think about the next movement. The fourth condition was a baseline condition. As in the earlier study, the dorsal prefrontal cortex and anterior cingulate area 32 were activated during new learning, but not during automatic performance. The left dorsal prefrontal cortex and the right anterior cingulate cortex were reactivated when subjects paid attention to the performance of the prelearned sequence compared with automatic performance of the same task. It is suggested that the critical feature was that the subjects were required to attend to the preparation of their responses. However, the dorsal prefrontal cortex and the anterior cingulate cortex were activated more when the subjects learned a new sequence than they were when subjects simply paid attention to a prelearned sequence. New learning differs from the attention condition in that the subjects generated moves, monitored the outcomes, and remembered the responses that had been successful. All these are nonroutine operations to which the subjects must attend. Further analysis is needed to specify which are the nonroutine operations that require the involvement of the dorsal prefrontal and anterior cingulate cortex.

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 Identification of the cerebral effects of paracetamol in healthy subjects: an fMRI study

2019 ◽  
Vol 14 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Olivier De Coster ◽  
Patrice Forget ◽  
Johan De Mey ◽  
Peter Van Schuerbeek ◽  
Jan Poelaert
Keyword(s):  
Healthy Volunteers ◽  
Regional Blood Flow ◽  
Inferior Frontal Gyrus ◽  
Anterior Cingulate ◽  
Precentral Gyrus ◽  
Posterior Cingulate ◽  
Analgesic Effects ◽  
Volume Of Interest ◽  
Fmri Study ◽  
The Right

Introduction: Paracetamol is commonly used for its antipyretic properties and analgesic effects, but the central mechanism remains elusive. We designed a study in healthy volunteers to detect the central functional working mechanism of paracetamol. Subjects, material and methods: A total of 20 subjects had a baseline functional magnetic resonance imaging (fMRI) before the intake of 1000 mg paracetamol orally; 60 minutes later, a second fMRI was made aiming detection of regional blood flow differences. Results: A decreased connectivity was observed in the ventral volume of interest (VOI), with the posterior cingulate (with both the left anterior cingulate cortex (ACC) and right ACC: respectively, Ke = 576; t = −6.8894 and Ke = 185; t = −4.8178) and the inferior temporal left (Ke = 103; t = −5.0993); in the combined ventral and dorsal VOIs, the posterior cingulate (with the left ACC; Ke = 149; t = −4.5658) and, both with the right ACC, the inferior temporal left (Ke = 88; t = −3.8456) and the inferior frontal gyrus (Ke = 86; t = −4.3937) had a decrease in connectivity. An increase was seen in other regions, including, among others, the middle frontal and temporal gyri (respectively, Ke = 85; t = 4.4256 and Ke = 85; t = 5.6851), the inferior frontal (with the left ACC: Ke = 165; t = 4.4998) and the superior frontal gyrus (with the right ACC; Ke = 281; t = 4.5992), and the post/precentral gyrus (with the right ACC, respectively, Ke = 102; t = 6.0582 and Ke = 105; t = 4.0776). Conclusions: On fMRIs in healthy volunteers, the ingestion of paracetamol affects connections with the ACC. This suggests a central effect of paracetamol in cerebral areas known to be associated with pain. Further studies are needed to demonstrate the same effects in acute and chronic pain states.

Memory Lost and Regained Following Bilateral Hippocampal Damage

1999 ◽  
Vol 11 (6) ◽  
pp. 682-697 ◽  
Author(s):  
Katharina Henke ◽  
Neal E. A. Kroll ◽  
Hamraz Behniea ◽  
David G. Amaral ◽  
Michael B. Miller ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Hippocampal Formation ◽  
Memory Performance ◽  
Carbon Monoxide Poisoning ◽  
Memory Function ◽  
Word Recall ◽  
Hippocampal Damage ◽  
Global Amnesia ◽  
Neuropsychological Study ◽  
The Right

We present a longitudinal neuropsychological study (31 examinations over a period of 18 months) of patient DF. DF demonstrated bilateral atrophy of the hippocampal formation and globus pallidus resulting from carbon monoxide poisoning. Eighteen months after the event, the volume of the hippocampal formation was reduced by 42% on the left side and 28% on the right. The patient initially presented with a severe global amnesia. Then, he showed a gradual, yet selective recovery of episodic memory function. Verbal free recall and spatial memory performance remained reduced, whereas immediate word recall and recognition memory, as well as picture learning and memory, improved to levels at the lower range of normal performance. Interestingly, nonspatial associative learning was never much impaired and recovered completely by the end of testing. These data are taken as evidence that the human hippocampal formation does not equally support different forms of episodic memory.

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