Recall of 9.11 in Alzheimer's disease: further evidence for intact flashbulb memory.
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Aged↗
Biomedical subjects
M A Conway
Publications and source records attributed to M A Conway.
Persistent Déjà vu: a disorder of memory.
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Aged↗
Sensory-perceptual episodic memory and its context: autobiographical memory.
Episodic memory is reconceived as a memory system that retains highly detailed sensory perceptual knowledge of recent experience over retention intervals measured in minutes and hours. Episodic knowledge has yet to be integrated with the autobiographical memory knowledge base and so takes as its context or referent the immediate past of the experiencing self (or the 'I'). When recalled it can be accessed independently of content and is recollectively experienced. Autobiographical memory, in contrast, retains knowledge over retention intervals measured in weeks, months, years, decades and across the life span. Autobiographical knowledge represents the experienced self (or the 'me'), is always accessed by its content and, when accessed, does not necessarily give rise to recollective experience. Instead, recollective experience occurs when autobiographical knowledge retains access to associated episodic memories. In this reworking of the 'episodic memory' concept autobiographical memory provides the instantiating context for sensory-perceptual episodic memory.
Autobiographies as Topic↗
Cognitive neuroscience: Repression revisited.
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Humans↗
Protection against Bordetella pertussis infection following parenteral or oral immunization with antigens entrapped in biodegradable particles: effect of formulation and route of immunization on induction of Th1 and Th2 cells.
The immunogenicity and protective efficacy of systemically and orally delivered pertussis antigens entrapped in either microparticle poly-lactide-co-glycolide (PLG) or nanoparticle PLG formulations were evaluated in a murine respiratory challenge model for infection with Bordetella pertussis. The results demonstrate that immunization with two parenteral doses of 1 microg or three oral doses of 100 microg of pertussis toxoid (PTd) and filamentous haemagglutinin (FHA) encapsulated in PLG conferred a high level of protection against B. pertussis challenge. Furthermore protection could be generated with a single parenteral immunization with a combined microparticle and nanoparticle formulation. However, the route of immunization and the size of the particles affected the type of T cell response induced. Parenteral immunization with PTd and FHA entrapped in PLG microparticles elicits a potent type 1 T cell response and potent antibody response when given by the intraperitoneal (i.p.) or intramuscular (i.m.) route. In contrast, nanoparticle formulations favoured the induction of Th2 cells.
Adhesins, Bacterial↗
The construction of autobiographical memories in the self-memory system.
The authors describe a model of autobiographical memory in which memories are transitory mental constructions within a self-memory system (SMS). The SMS contains an autobiographical knowledge base and current goals of the working self. Within the SMS, control processes modulate access to the knowledge base by successively shaping cues used to activate autobiographical memory knowledge structures and, in this way, form specific memories. The relation of the knowledge base to active goals is reciprocal, and the knowledge base "grounds" the goals of the working self. It is shown how this model can be used to draw together a wide range of diverse data from cognitive, social, developmental, personality, clinical, and neuropsychological autobiographical memory research.
Age Factors↗
Plasmid DNA encoding influenza virus haemagglutinin induces Th1 cells and protection against respiratory infection despite its limited ability to generate antibody responses.
Direct intramuscular injection of plasmid DNA can generate immune responses against encoded antigens. However, the relative ability of DNA vaccines to induce cellular and humoral immunity after a single or booster immunization and the persistence of this response have not been fully elucidated. In this study, induction and maintenance of antibody and T cell subtypes with different doses of naked DNA encoding the haemagglutinin (HA) gene of influenza virus were examined and compared to the immune responses and protection induced by respiratory tract infection and immunization with a killed virus vaccine. Like natural infection, immunization with HA DNA induced potent Th1 responses. Spleen cells from mice immunized once with HA DNA in the dose range 10 ng to 100 microgram secreted significant levels of IFN-gamma, but low or undetectable IL-5, in response to influenza virus in vitro. Furthermore, CD4(+) HA-specific Th1 clones were generated from spleens of immunized mice. Although T cell responses waned 12 weeks after a single immunization, antigen-specific Th1 cells persisted in the spleen for at least 6 months after two booster immunizations. In contrast, influenza virus-specific ELISA IgG titres were low after a single immunization and required two booster immunizations to reach significant levels. Furthermore, haemagglutination inhibition (HI) antibodies were weak or undetectable after two immunizations. Nevertheless, two doses of HA DNA conferred almost complete protection against respiratory challenge with live virus. Thus, despite the limited ability to induce antibodies, DNA vaccines confer protective immunity against influenza virus infection, which appears to be mediated by Th1 cells.
Animals↗
Mitral regurgitation: impaired systolic function, eccentric hypertrophy, and increased severity are linked to lower phosphocreatine/ATP ratios in humans.
BACKGROUND: A number of phosphorus (31P) magnetic resonance spectroscopy (MRS) studies link alterations of high-energy phosphate metabolism in valvular disease and cardiomyopathy to the clinical severity of heart failure. However, correlations between MRS and indexes of ventricular dysfunction are inconclusive to date. We examined whether changes in 31P MRS are associated with the impaired contractility, which predisposes to chronic congestive heart failure in patients with mitral regurgitation. METHODS AND RESULTS: Thirteen normal control subjects and 22 patients with echocardiographically characterized chronic mitral regurgitation were studied by 31P MRS. The apical phosphocreatine-to-ATP ratio (PCr/ATP) was lower in severe disease (P<.02) and those on therapy (n=13, 1.29+/-0.29, P<.01) in contrast to control subjects (n=13, 1.61+/-0.3). Compared to those with mild mitral regurgitation, patients with more severe incompetence had lower mean myocardial PCr/ATP ratios (mild, n=6, 1.73 [0.17], P<.05 and P<.01; moderate, n=5, 1.49 [0.18], P<.05; and severe, n=1, 1.29 [0.32], P<.01). PCr/ATP in those referred for mitral valve replacement was lower (n=8, 1.17+/-0.23) although not significantly decreased compared with the ratio among subjects on medical therapy alone (n=5, 1.48+/-0.29). PCr/ATP correlated with the end-systolic diameter (r2=.7, P<.001), end-diastolic diameter (r2=.32, P<.05), left ventricular wall thickness (r2=.38, P<.01), left atrial dimension (r2=.36, P<.05), and derived measurements such as the percent fractional shortening (2=.5, P<.01), and left ventricular mass/body surface area (r2=.5, P<.001) but not with wall stress. CONCLUSIONS: These results demonstrate that abnormalities of PCr/ATP in mitral regurgitation are related to disease severity as measured by dimensional indexes of left ventricular dilatation. They suggest that impaired high-energy phosphate metabolism is a marker of hypertrophy and heart failure.
Adenosine Triphosphate↗
Chloride channel blockers inhibit myogenic tone in rat cerebral arteries.
1. We have investigated the role of chloride channels in pressure-induced depolarization and contraction of cerebral artery smooth muscle cells. 2. Two chloride channel blockers, indanyloxyacetic acid (IAA-94) and 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), caused hyperpolarizations (10-15 mV) and dilatations (up to 90%) of pressurized (80 mmHg), rat posterior cerebral arteries. Niflumic acid, a blocker of calcium-activated chloride channels, did not affect arterial tone. 3. Dilatations to IAA-94 and DIDS were unaffected by potassium channel blockers, but were prevented by elevated potassium. IAA-94 and DIDS had no effect on membrane potential or diameter of arteries at low intravascular pressure, where myogenic tone is absent. Reduction of extracellular chloride (60 mM Cl-) increased the pressure-induced contractions. Removal of extracellular sodium did not affect the pressure-induced responses. 4. Our results suggest that intravascular pressure activates DIDS- and IAA-94-sensitive chloride channels to depolarize arterial smooth muscle, thereby contributing to the myogenic constriction.
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
Changes in memory awareness during learning: the acquisition of knowledge by psychology undergraduates.
First-year psychology students took multiple-choice examinations following each of 4 lecture courses and 3 laboratory research methods courses. One lecture course was later retested. Students indicated state of memory awareness accompanying each answer: recollective experience (remember), "just know" (know), feeling of familiarity (familiarity), or guess. On the lecture courses, higher performing students differed from other students because they had more remember responses. On research methods, higher performing students differed because they knew more, and in the delayed retest, higher performing students differed because they now knew rather than remembered more. These findings demonstrate a shift from remembering to knowing, dependent upon level attained, type of course, and retention interval, and suggest an underlying shift in knowledge representation from episodic to semantic memory. The authors discuss theoretical and educational implications of the findings.
Achievement↗
Remembering, familiarity, and source monitoring.
Two experiments investigated recollective experience in a source monitoring task. Subjects saw an array of objects and performed, watched, or imagined actions involving pairs of objects. In a subsequent recognition test, subjects indicated whether their recognition judgements were made on the basis of conscious recollective experience ("remember" responses), or on some other basis such as familiarity ("know" responses). The proportions of correct "remember" responses for both objects and actions decreased from performed, through watched, to imagined actions, whereas the proportions of correct "know" responses were uninfluenced by the source of the memories. In addition, the relationship between recollective experience and accuracy of source judgement varied across sources. Source accuracy for performed actions was obtained only in "remember" responses, whereas source accuracy for performed actions was obtained only in "remember" responses, whereas source accuracy for imagined actions was obtained only in "know" responses. Source accuracy for watched actions was obtained in both "remember" and "know" responses. The findings suggest that the types of memory attributes available at retrieval determine the quality of subsequent memory experience, and it is proposed that memories with strongly self-referential attributes (arising from performed actions) powerfully cue recollective experience during retrieval.
Adult↗
Electrocardiogram monitoring at rest and during exercise in 31P magnetic resonance spectroscopy studies of the human heart at 1.9 tesla.
An electrocardiogram (ECG) monitoring system has been developed and evaluated in normal volunteers (n = 7) and patients with various cardiac diseases (n = 24) in a 1.9 tesla magnet during magnetic resonance spectroscopy studies. To minimize an ECG signal path, and thus to reduce motion-related artifacts on the ECG during a dynamic exercise test, one coaxial cable was used to obtain the ECG signal from two electrodes placed parallel to the longitudinal body axis on the left side of the chest. A fiber optic link and an inductor-capacitor low-pass filter were used to remove extraneous radiofrequency (RF) noise and RF pulse artifacts respectively, and the examination bed was solidly supported on the base of the magnet. The ECG monitoring system provided a useful means for continuous recording of the ECG independently of the R-R interval in the high magnetic field, and permitted reliable monitoring of the QRS complex of the subject at rest and during exercise.
Atrial Fibrillation↗
Pictures, images, and recollective experience.
Five experiments investigated the influence of picture processing on recollective experience in recognition memory. Subjects studied items that differed in visual or imaginal detail, such as pictures versus words and high-imageability versus low-imageability words, and performed orienting tasks that directed processing either toward a stimulus as a word or toward a stimulus as a picture or image. Standard effects of imageability (e.g., the picture superiority effect and memory advantages following imagery) were obtained only in recognition judgments that featured recollective experience and were eliminated or reversed when recognition was not accompanied by recollective experience. It is proposed that conscious recollective experience in recognition memory is cued by attributes of retrieved memories such as sensory-perceptual attributes and records of cognitive operations performed at encoding.
Adult↗
Flashbulb memories in older adults.
In this study of age differences in flashbulb memory, groups of young and older adults gave detailed accounts of how they heard the news of the resignation of the British Prime Minister Margaret Thatcher. They were tested within 14 days after the event and again 11 months later. They also gave ratings for the encoding variables (surprise, emotion, importance, knowledge, and interest) and for frequency of rehearsal. Memories that met a strict criterion of consistency between the original and delayed responses were classified as flashbulb memories. Although 90% of young Ss had flashbulb memories, only 42% of the elderly met the criterion. The age groups also differed in the type of details remembered and in the relationship between the encoding and rehearsal variables and the occurrence of flashbulb memory. The age-related deficit in flashbulb memory is related to source amnesia and to a deficit in memory for context.
Adolescent↗
2-Deoxyglucose-induced vasodilation and hyperpolarization in rat coronary artery are reversed by glibenclamide.
The mechanisms responsible for coronary vasodilation during ischemia or hypoxia are poorly understood. It has recently been suggested that alterations in intracellular ATP may play a role in this response. We examined whether dilation of isolated coronary arteries in response to metabolic blockade by 2-deoxyglucose, which competitively inhibits glycolysis and glycogenolysis, was sensitive to glibenclamide, an inhibitor of ATP-sensitive potassium channels. Pressurized rat coronary arteries with myogenic tone dilated in response to 2-deoxyglucose by an endothelium-independent mechanism. The dilation was accompanied by a substantial hyperpolarization. Addition of glibenclamide partially reversed this vasodilation and abolished the hyperpolarization. We propose that ATP-sensitive potassium channels play a significant role in the dilator response to 2-deoxyglucose. This may have implications both for ischemia-induced coronary vasodilation and for the use of oral hypoglycemic agents in general.
Animals↗
The formation of flashbulb memories.
A large group of subjects took part in a multinational test-retest study to investigate the formation of flashbulb (FB) memories for learning the news of the resignation of the British prime minister, Margaret Thatcher. Over 86% of the U.K. subjects were found to have FB memories nearly 1 year after the resignation; their memory reports were characterized by spontaneous, accurate, and full recall of event details, including minutiae. In contrast, less than 29% of the non-U.K. subjects had FB memories 1 year later; memory reports in this group were characterized by forgetting, reconstructive errors, and confabulatory responses. A causal analysis of secondary variables showed that the formation of FB memories was primarily associated with the level of importance attached to the event and level of affective response to the news. These findings lend some support to the study by R. Brown and Kulik (1977), who suggest that FB memories may constitute a class of autobiographical memories distinguished by some form of preferential encoding.
Affect↗
Neural mechanisms regulating neurohypophysial resistance arteries.
We defined the extent of vasoactive intestinal polypeptide (VIP) and noradrenergic influences on isolated 100- to 200-microns-diameter vessels from the resistance arterial circulation of the neurohypophysis. A dual extracranial (inferior hypophysial) and intracranial (superior hypophysial) arterial supply to the neurohypophysis was confirmed. The inferior hypophysial artery demonstrates noradrenergic and VIP-like perivascular nerves, whereas the superior hypophysial artery shows primarily VIP-like innervation. Pharmacological sensitivity of the inferior hypophysial to VIP [mean effective dose (ED50) = 10(-8.2) M] and to norepinephrine (ED50 = 10(-5.7) M) was demonstrated. The superior hypophysial reacted only to VIP (ED50 = 10(-8.6) M). The physiological relevance of these findings was tested with transmural nerve stimulation. Frequency-dependent vasodilation of both inferior and superior hypophysial arteries was demonstrated. This dilation could not be blocked with atropine or propranolol. Frequency-dependent vasoconstriction was identified in extracranial vessels including the inferior hypophysial artery. This constriction is only partially blocked by prazosin, phentolamine, and guanethidine. When neurohypophysial resistance vessels are compared with larger circle of Willis arteries and similar-size pial vessels of other cerebral regions, they appear to have regionally unique neural mechanisms for regulating blood flow. Specifically whether controlled by periarterial nerves or other tissue influences, the inferior hypophysial artery appears to meet anatomic, pharmacological, and physiological definitions of neural control for both dilator and constrictor activities of flow to the neurohypophysis.
Animals↗