Mamillary Body Lesions in Monkeys Impair Object-in-Place Memory: Functional Unity of the Fornix-Mamillary System

1997 ◽  
Vol 9 (4) ◽  
pp. 512-521 ◽  
Author(s):  
Amanda Parker ◽  
David Gaffan
Keyword(s):  
Episodic Memory ◽  
Memory Task ◽  
Control Group ◽  
Thalamic Nuclei ◽  
Mamillary Body ◽  
Control Operation ◽  
Place Memory ◽  
Severe Impairment ◽  
Anterior Thalamic Nuclei

Six monkeys were trained preoperatively in an automated object-in-place memory task in which they learned 20 new scenes in each daily session. Three of the six monkeys then received stereotaxically guided bilateral mamillary body lesions, leaving the fornix intact, while the other three received a control operation. Postoperatively the control animals' rate of learning new scenes was unchanged, but the animals with mamillary body lesions showed a severe impairment, equal to that seen in previous experiments after fornix transection. All six animals were then given fornix transection, in addition to the existing mamillary or control operation. The control group now showed, after fornix transection, an impairment equal to that of the animals with mamillary body lesions alone. But the animals with mamillary body lesions did not show any additional impairment following fornix transection. We conclude that (1) the role of the mamillary bodies in a model of human episodic memory is as important as the role of the fornix, (2) the fornix and mamillary bodies form a single functional memory system, since the effect of lesions in both parts is no more severe than the effects of a lesion in one of the parts alone, and (3) the idea that the functional effects of fornix transection result from cholmergic deafferentation of the hippocampus receives no support from the present results; rather, they support the idea that in primates the fornix and mamillary bodies, together with connected structures, including the subiculum, mamillo-thalamic tract, anterior thalamic nuclei, and cingulate bundle, form a cortico-cortical association pathway for episodic memory.

Object, Space, and Object-Space Representations in the Primate Hippocampus

2005 ◽  
Vol 94 (1) ◽  
pp. 833-844 ◽  
Author(s):  
Edmund T. Rolls ◽  
Jianzhong Xiang ◽  
Leonardo Franco
Keyword(s):  
Episodic Memory ◽  
Spatial Information ◽  
Hippocampal Formation ◽  
Memory Task ◽  
Memory System ◽  
Important Advance ◽  
Object Space ◽  
Place Memory ◽  
Human Hippocampus ◽  
Spatial View

A fundamental question about the function of the primate including human hippocampus is whether object as well as allocentric spatial information is represented. Recordings were made from single hippocampal formation neurons while macaques performed an object-place memory task that required the monkeys to learn associations between objects and where they were shown in a room. Some neurons (10%) responded differently to different objects independently of location; other neurons (13%) responded to the spatial view independently of which object was present at the location; and some neurons (12%) responded to a combination of a particular object and the place where it was shown in the room. These results show that there are separate as well as combined representations of objects and their locations in space in the primate hippocampus. This is a property required in an episodic memory system, for which associations between objects and the places where they are seen are prototypical. The results thus provide an important advance by showing that a requirement for a human episodic memory system, separate and combined neuronal representations of objects and where they are seen “out there” in the environment, is present in the primate hippocampus.

scholarly journals Severe episodic memory impairment after strategic infarct: A case report

2017 ◽  
Vol 11 (4) ◽  
pp. 454-458 ◽  
Author(s):  
Francisco Wilson Nogueira Holanda Júnior ◽  
Katie Moraes de Almondes ◽  
Rodrigo Alencar e Silva
Keyword(s):  
Episodic Memory ◽  
Medial Temporal Lobe ◽  
Memory Impairment ◽  
Critical Role ◽  
Current Case ◽  
Ischemic Lesion ◽  
Personal Experiences ◽  
Severe Impairment

ABSTRACT. Brain infarcts located in strategic regions often result in cognitive impairment. Based on a case study, this paper describes unusual and specific clinical and neuropsychological features of a strategic ischemic lesion in the left medial temporal lobe (MTL) structures. Taken together with the literature data, the case illustrates that a unilateral strategic infarct in MTL structures may result in severe impairment of episodic memory (EM), which refers to the ability to encode and retrieve personal experiences, including information about the time and place of an event and detailed description of the event itself. The preservation of other cognitive functions, the severe functional impairment, and the type of visual-verbal deficit in a left-sided lesion were identified as singular features of the case. The current case supports the critical role of the MTL structures in EM formation.

scholarly journals Thanks for the memories: Extending the hippocampal-diencephalic mnemonic system

1999 ◽  
Vol 22 (3) ◽  
pp. 471-479 ◽  
Author(s):  
John P. Aggleton ◽  
Malcolm W. Brown
Keyword(s):  
Prefrontal Cortex ◽  
Recognition Memory ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Thalamic Nuclei ◽  
Target Article ◽  
Anterior Thalamic Nuclei ◽  
Relationship Of ◽  
The Relationship ◽  
Key Questions

The goal of our target article was to review a number of emerging facts about the effects of limbic damage on memory in humans and animals, and about divisions within recognition memory in humans. We then argued that this information can be synthesized to produce a new view of the substrates of episodic memory. The key pathway in this system is from the hippocampus to the anterior thalamic nuclei. There seems to be a general agreement that the importance of this pathway has previously been underestimated and that it warrants further study. At the same time, a number of key questions remain. These concern the relationship of this system to another temporal-lobe/diencephalic system that contributes to recognition, and the relationship of these systems to prefrontal cortex activity.

scholarly journals Episodic memory, amnesia, and the hippocampal–anterior thalamic axis

1999 ◽  
Vol 22 (3) ◽  
pp. 425-444 ◽  
Author(s):  
John P. Aggleton ◽  
Malcolm W. Brown
Keyword(s):  
Episodic Memory ◽  
Temporal Lobe ◽  
Gene Activation ◽  
Temporal Cortex ◽  
Anterograde Amnesia ◽  
Thalamic Nuclei ◽  
Medial Dorsal ◽  
New Information ◽  
Subsequent Recall ◽  
Anterior Thalamic Nuclei

By utilizing new information from both clinical and experimental (lesion, electrophysiological, and gene-activation) studies with animals, the anatomy underlying anterograde amnesia has been reformulated. The distinction between temporal lobe and diencephalic amnesia is of limited value in that a common feature of anterograde amnesia is damage to part of an “extended hippocampal system” comprising the hippocampus, the fornix, the mamillary bodies, and the anterior thalamic nuclei. This view, which can be traced back to Delay and Brion (1969), differs from other recent models in placing critical importance on the efferents from the hippocampus via the fornix to the diencephalon. These are necessary for the encoding and, hence, the effective subsequent recall of episodic memory. An additional feature of this hippocampal–anterior thalamic axis is the presence of projections back from the diencephalon to the temporal cortex and hippocampus that also support episodic memory. In contrast, this hippocampal system is not required for tests of item recognition that primarily tax familiarity judgements. Familiarity judgements reflect an independent process that depends on a distinct system involving the perirhinal cortex of the temporal lobe and the medial dorsal nucleus of the thalamus. In the large majority of amnesic cases both the hippocampal–anterior thalamic and the perirhinal–medial dorsal thalamic systems are compromised, leading to severe deficits in both recall and recognition.

scholarly journals An Event Related Potentials Study of Semantic Coherence Effect during Episodic Encoding in Schizophrenia Patients

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Lâle Battal Merlet ◽  
Alain Blanchet ◽  
Hazlin Lockman ◽  
Milena Kostova
Keyword(s):  
Episodic Memory ◽  
Cognitive Rehabilitation ◽  
Electrophysiological Study ◽  
Memory Performance ◽  
Memory Task ◽  
Event Related Potentials ◽  
Control Group ◽  
Semantic Coherence ◽  
Related Potentials ◽  
Coherence Effect

The objective of this electrophysiological study was to investigate the processing of semantic coherence during encoding in relation to episodic memory processes promoted at test, in schizophrenia patients, by using the N400 paradigm. Eighteen schizophrenia patients and 15 healthy participants undertook a recognition memory task. The stimuli consisted of pairs of words either semantically related or unrelated to a given category name (context). During encoding, both groups exhibited an N400 external semantic coherence effect. Healthy controls also showed an N400 internal semantic coherence effect, but this effect was not present in patients. At test, related stimuli were accompanied by an FN400 old/new effect in both groups and by a parietal old/new effect in the control group alone. In the patient group, external semantic coherence effect was associated with FN400, while, in the control group, it was correlated to the parietal old/new effect. Our results indicate that schizophrenia patients can process the contextual information at encoding to enhance familiarity process for related stimuli at test. Therefore, cognitive rehabilitation therapies targeting the implementation of semantic encoding strategies can mobilize familiarity which in turn can overcome the recollection deficit, promoting successful episodic memory performance in schizophrenia patients.

scholarly journals Role of designed Bio-Geometrical forms in antagonizing neurobehavioral burden of Wi-Fi radiation: Evidence-based experimental study

2019 ◽  
Vol 12 (3) ◽  
pp. 1217-1234
Author(s):  
Nevin E. Sharaf ◽  
Asmaa F. Galal ◽  
Mohamed S. El-Sawy ◽  
Aziza B. Shalby ◽  
Alaa H. Sayed ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Memory Task ◽  
Anxiety Level ◽  
Control Group ◽  
Hsp 70 ◽  
Brain Areas ◽  
Wireless Router ◽  
Geometrical Shapes ◽  
The Impact

This study investigated the impact of Wi-Fi signals exposure on cognitive function and its relevant brain biomarkers and the possible role of designed Bio-Geometrical forms in restoring the neurobehavioral alterations resulting from the exposure to the emerging radiation.Rats were assigned into 3 groups; Gp I control group (away from exposure to radiation); Gp II, III were exposed to wireless router signals for 24 h for 6 months and Gp III was protected by a set of designed BioGeometrical shapes. Animals were tested for spatial memory, anxiety and emotionality in addition to the related neurotransmitters (dopamine, serotonin and acetylcholine) in different brain areas. Melatonin, Heat Shock Protein (HSP-70) and acetylcholine esterase (AchE) were also measured in various brain regions and histopathological examination was carried out as well. Wi-Fi radiation exposed group showed elevated anxiety level and impaired spatial memory. Moreover, significant decline in dopamine, serotonin and acetylcholine levels in the investigated brain areas has been recorded. Melatonin levels were decreased in the cortex, striatum and hippocampus while HSP-70 was depleted in the cortex only. Using Bio-Geometrical forms along with Wi-Fi exposure could combat the burden of Wi-Fi radiation. This was evidenced by the recovery of the anxiety level and the improvement of memory task. In addition, the presence of Bio-Geometrical shapes could retrieve dopamine, serotonin and acetylcholine as well as melatonin and HSP-70 levels This study provides solid foundation for the potential use of Bio-Geometrical shapes to modify the insult of Wi-Fi radiation on brain function and structure.

scholarly journals Anterior thalamic function is required for spatial coding in the subiculum and is necessary for spatial memory

2020 ◽  
Author(s):  
Bethany E. Frost ◽  
Sean K. Martin ◽  
Matheus Cafalchio ◽  
Md Nurul Islam ◽  
John P. Aggleton ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Memory Task ◽  
Hippocampal Function ◽  
Thalamic Nuclei ◽  
Spatial Coding ◽  
Anterior Thalamic Nuclei ◽  
Thalamic Lesions ◽  
Hippocampal Networks ◽  
Thalamic Function ◽  
Spatial Recognition

SummaryHippocampal function relies on the anterior thalamic nuclei, but the reasons remain poorly understood. While anterior thalamic lesions disrupt parahippocampal spatial signalling, their impact on the subiculum is unknown, despite the importance of this area for hippocampal networks. We recorded subicular cells in rats with either permanent (N-methyl-D-aspartic acid) or reversible (muscimol) anterior thalamic lesions. Bayesian and other statistical analyses underscored the notable absence of the diverse spatial signals normally found in the subiculum, including place cells, following permanent anterior thalamic lesions. Likewise, there was marked disruption of these diverse spatial signals during transient lesions. By contrast, permanent anterior thalamic lesions had no discernible impact on CA1 place fields. Anterior thalamic lesions reduced spatial alternation performance (permanently or reversibly) to chance, while leaving a non-spatial recognition memory task unaffected. These findings, which help explain why anterior thalamic damage is so deleterious for spatial memory, cast a new spotlight on the importance of subiculum function and reveal its dependence on anterior thalamic signalling.Graphical Abstract

Tryptophan-Niacin Metabolism in Rat with Puromycin Aminonucleoside-Induced Nephrosis

2006 ◽  
Vol 76 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Yukari Egashira ◽  
Shin Nagaki ◽  
Hiroo Sanada
Keyword(s):  
Body Weight ◽  
Urinary Excretion ◽  
Enzyme Activities ◽  
Treated Group ◽  
Control Group ◽  
Puromycin Aminonucleoside ◽  
Low Level ◽  
Key Enzyme

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.

The Role of Attention in Episodic Memory Impairment During Nicotine Withdrawal

2007 ◽  
Author(s):  
Paul S. Merritt ◽  
Adam Cobb ◽  
Luke Moissinac ◽  
Corpus Christi ◽  
Elliot Hirshman
Keyword(s):  
Episodic Memory ◽  
Memory Impairment ◽  
Nicotine Withdrawal

The Use of Posterior Pericardiotomy Technique to Prevent Postoperative Pericardial Effusion in Cardiac Surgery

2012 ◽  
Vol 15 (2) ◽  
pp. 84 ◽  
Author(s):  
Canturk Cakalagaoglu ◽  
Cengiz Koksal ◽  
Ayse Baysal ◽  
Gokhan Alici ◽  
Birol Ozkan ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Heart Surgery ◽  
Artery Bypass ◽  
Pericardial Tamponade ◽  
Anxiety Level ◽  
Control Group ◽  
Echocardiographic Study ◽  
Number Of Patients ◽  
Hospital Stays

<p><b>Aim:</b> The goal was to determine the effectiveness of the posterior pericardiotomy technique in preventing the development of early and late pericardial effusions (PEs) and to determine the role of anxiety level for the detection of late pericardial tamponade (PT).</p><p><b>Materials and Methods:</b> We divided 100 patients randomly into 2 groups, the posterior pericardiotomy group (n = 50) and the control group (n = 50). All patients undergoing coronary artery bypass grafting surgery (CABG), valvular heart surgery, or combined valvular and CABG surgeries were included. The posterior pericardiotomy technique was performed in the first group of 50 patients. Evaluations completed preoperatively, postoperatively on day 1, before discharge, and on postoperative days 5 and 30 included electrocardiographic study, chest radiography, echocardiographic study, and evaluation of the patient's anxiety level. Postoperative causes of morbidity and durations of intensive care unit and hospital stays were recorded.</p><p><b>Results:</b> The 2 groups were not significantly different with respect to demographic and operative data (<i>P</i> > .05). Echocardiography evaluations revealed no significant differences between the groups preoperatively; however, before discharge the control group had a significantly higher number of patients with moderate, large, and very large PEs compared with the pericardiotomy group (<i>P</i> < .01). There were 6 cases of late PT in the control group, whereas there were none in the pericardiotomy group (<i>P</i> < .05). Before discharge and on postoperative day 15, the patients in the pericardiotomy group showed significant improvement in anxiety levels (<i>P</i> = .03 and .004, respectively). No differences in postoperative complications were observed between the 2 groups.</p><p><b>Conclusion:</b> Pericardiotomy is a simple, safe, and effective method for reducing the incidence of PE and late PT after cardiac surgery. It also has the potential to provide a better quality of life.</p>

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