The attribute priming effect in patients with Alzheimer's disease

2018 ◽  
Vol 13 (3) ◽  
pp. 485-502 ◽  
Author(s):  
Roberta Perri ◽  
Giovanni Augusto Carlesimo ◽  
Marco Monaco ◽  
Carlo Caltagirone ◽  
Gian Daniele Zannino
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Priming Effect ◽  
Attribute Priming

Implicit memory for words presented in short texts is preserved in Alzheimer's disease

2002 ◽  
Vol 33 (1) ◽  
pp. 169-174 ◽  
Author(s):  
J.-F. CAMUS ◽  
S. NICOLAS ◽  
E. WENISCH ◽  
I. MORRONE ◽  
F. BLANCHARD ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Implicit Memory ◽  
Explicit Memory ◽  
Priming Effect ◽  
Semantic Processing ◽  
Memory Performance ◽  
Read Aloud ◽  
Healthy Controls ◽  
Perceptual Aspect

Background. The level of efficiency of implicit memory in Alzheimer's disease remains unclear as previous studies using stem completion tasks have led to contradictory results.Method. The present study used target words embedded in significant short texts that subjects were required to read aloud (i.e. to enhance semantic processing). Texts were presented in two perceptual situations: ‘simple’ (blank spaces delimitating words) and ‘complex’ (spaces were filled by ‘8’s). In the completion phase, patients had to write the first word that came to mind in order to complete a three-letter stem. The recognition phase explored explicit memory performance. The performance of 24 Alzheimer patients was compared to a matched sample of healthy controls.Results. Reading times differed between groups and were shorter for healthy controls. Recognition was dramatically lower in patients, thus confirming the alteration of explicit memory in this pathology. However, a significant priming effect (e.g. the tendency to complete the stem with the aid of a previously explored word) was present in both groups and did not differ between patients and healthy controls.Conclusions. The absence of a correlation between priming and recognition scores suggests that this result cannot be explained by an explicit memory bias. Moreover, as the priming level was identical whatever the perceptual aspect of the text, we suggest that the priming effect is not only mediated by perceptual processes but also by lexical and conceptual processes, which to some extent are preserved during the light and moderate stages of this disease.

Cognitive control constrains memory attributions

2019 ◽  
Vol 42 ◽  
Author(s):  
Colleen M. Kelley ◽  
Larry L. Jacoby
Keyword(s):  
Alzheimer’S Disease ◽  
Older Adults ◽  
Alzheimer's Disease ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Cognitive Control

Abstract Cognitive control constrains retrieval processing and so restricts what comes to mind as input to the attribution system. We review evidence that older adults, patients with Alzheimer's disease, and people with traumatic brain injury exert less cognitive control during retrieval, and so are susceptible to memory misattributions in the form of dramatic levels of false remembering.

Formation of paired helical filaments in Alzheimer's disease

1984 ◽  
Vol 42 ◽  
pp. 302-303
Author(s):  
J. Metuzals ◽  
D. F. Clapin ◽  
V. Montpetit
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Frontal Lobe ◽  
Giant Axon ◽  
Paired Helical Filaments ◽  
Normal Brain ◽  
Protein Assemblies ◽  
Electron Microscopic ◽  
Helical Symmetry ◽  
Structural Levels

Information on the conformation of paired helical filaments (PHF) and the neurofilamentous (NF) network is essential for an understanding of the mechanisms involved in the formation of the primary lesions of Alzheimer's disease (AD): tangles and plaques. The structural and chemical relationships between the NF and the PHF have to be clarified in order to discover the etiological factors of this disease. We are investigating by stereo electron microscopic and biochemical techniques frontal lobe biopsies from patients with AD and squid giant axon preparations. The helical nature of the lesion in AD is related to pathological alterations of basic properties of the nervous system due to the helical symmetry that exists at all hierarchic structural levels in the normal brain. Because of this helical symmetry of NF protein assemblies and PHF, the employment of structure reconstruction techniques to determine the conformation, particularly the handedness of these structures, is most promising. Figs. 1-3 are frontal lobe biopsies.

Computer-aided methods for 3-D visualization of serial sections and thick biological specimens

1992 ◽  
Vol 50 (2) ◽  
pp. 1060-1061
Author(s):  
Mark Ellisman ◽  
Maryann Martone ◽  
Gabriel Soto ◽  
Eleizer Masliah ◽  
David Hessler ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Three Dimensional ◽  
Neuritic Plaque ◽  
Dimensional Structure ◽  
Data Sets ◽  
Molecular Physiology ◽  
Research Activities ◽  
Computer Aided ◽  
Dimensional Reconstruction

Structurally-oriented biologists examine cells, tissues, organelles and macromolecules in order to gain insight into cellular and molecular physiology by relating structure to function. The understanding of these structures can be greatly enhanced by the use of techniques for the visualization and quantitative analysis of three-dimensional structure. Three projects from current research activities will be presented in order to illustrate both the present capabilities of computer aided techniques as well as their limitations and future possibilities.The first project concerns the three-dimensional reconstruction of the neuritic plaques found in the brains of patients with Alzheimer's disease. We have developed a software package “Synu” for investigation of 3D data sets which has been used in conjunction with laser confocal light microscopy to study the structure of the neuritic plaque. Tissue sections of autopsy samples from patients with Alzheimer's disease were double-labeled for tau, a cytoskeletal marker for abnormal neurites, and synaptophysin, a marker of presynaptic terminals.

Liquid crystalline ordering of paired helical filaments in neurofibrillary tangles of Alzheimer's disease

1986 ◽  
Vol 44 ◽  
pp. 348-349
Author(s):  
D.F. Clapin ◽  
V.J.A. Montpetit
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurofibrillary Tangles ◽  
Liquid Crystalline ◽  
Amyloid Fibrils ◽  
Geometric Analysis ◽  
Paired Helical Filaments ◽  
Microscopic Level ◽  
Light Microscopic Level ◽  
Regular Spacing

Alzheimer's disease is characterized by the accumulation of abnormal filamentous proteins. The most important of these are amyloid fibrils and paired helical filaments (PHF). PHF are located intraneuronally forming bundles called neurofibrillary tangles. The designation of these structures as "tangles" is appropriate at the light microscopic level. However, localized domains within individual tangles appear to demonstrate a regular spacing which may indicate a liquid crystalline phase. The purpose of this paper is to present a statistical geometric analysis of PHF packing.

Paired helical filaments (PHF) in rats: An experimental animal model for Alzheimer's disease

1987 ◽  
Vol 45 ◽  
pp. 842-843
Author(s):  
V.J.A. Montpetit ◽  
S. Dancea ◽  
S.W. French ◽  
D.F. Clapin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Animal Model ◽  
Paired Helical Filaments ◽  
Ethanol Intoxication ◽  
Drg Neurons ◽  
Critical Difference ◽  
Suitable Animal Model ◽  
The Central Nervous System ◽  
Chronic Ethanol Intoxication

A continuing problem in Alzheimer research is the lack of a suitable animal model for the disease. The absence of neurofibrillary tangles of paired helical filaments is the most critical difference in the processes by which the central nervous system ages in most species other than man. However, restricting consideration to single phenomena, one may identify animal models for specific aspects of Alzheimer's disease. Abnormal fibers resembling PHF have been observed in dorsal root ganglia (DRG) neurons of rats in a study of chronic ethanol intoxication and spontaneously in aged rats. We present in this report evidence that PHF-like filaments occur in ethanol-treated rats of young age. In control animals lesions similar in some respects to our observations of cytoskeletal pathology in pyridoxine induced neurotoxicity were observed.Male Wistar BR rats (Charles River Labs) weighing 350 to 400 g, were implanted with a single gastrostomy cannula and infused with a liquid diet containing 30% of total calories as fat plus ethanol or isocaloric dextrose.

Amyloid β-peptide and Alzheimer's disease

2014 ◽  
Vol 56 ◽  
pp. 99-110 ◽  
Author(s):  
David Allsop ◽  
Jennifer Mayes
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Senile Plaques ◽  
Strong Support ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Cascade Hypothesis ◽  
Sequence Of Events ◽  
Aβ Amyloid ◽  
Amyloid Cascade

One of the hallmarks of AD (Alzheimer's disease) is the formation of senile plaques in the brain, which contain fibrils composed of Aβ (amyloid β-peptide). According to the ‘amyloid cascade’ hypothesis, the aggregation of Aβ initiates a sequence of events leading to the formation of neurofibrillary tangles, neurodegeneration, and on to the main symptom of dementia. However, emphasis has now shifted away from fibrillar forms of Aβ and towards smaller and more soluble ‘oligomers’ as the main culprit in AD. The present chapter commences with a brief introduction to the disease and its current treatment, and then focuses on the formation of Aβ from the APP (amyloid precursor protein), the genetics of early-onset AD, which has provided strong support for the amyloid cascade hypothesis, and then on the development of new drugs aimed at reducing the load of cerebral Aβ, which is still the main hope for providing a more effective treatment for AD in the future.

Proteolytic processing of the amyloid-beta protein precursor of Alzheimer's disease

2002 ◽  
Vol 38 ◽  
pp. 37-49 ◽  
Author(s):  
Janelle Nunan ◽  
David H Small
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Beta ◽  
Alternative Pathway ◽  
Protein A ◽  
Proteolytic Processing ◽  
Gamma Secretase ◽  
Amyloid Beta Protein ◽  
Protein Precursor ◽  
Amyloid Beta Protein Precursor

The proteolytic processing of the amyloid-beta protein precursor plays a key role in the development of Alzheimer's disease. Cleavage of the amyloid-beta protein precursor may occur via two pathways, both of which involve the action of proteases called secretases. One pathway, involving beta- and gamma-secretase, liberates amyloid-beta protein, a protein associated with the neurodegeneration seen in Alzheimer's disease. The alternative pathway, involving alpha-secretase, precludes amyloid-beta protein formation. In this review, we describe the progress that has been made in identifying the secretases and their potential as therapeutic targets in the treatment or prevention of Alzheimer's disease.

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