Disinhibition account of the conditioned response (DACR).

Pavlovian conditioning is widely used to study the substrates of learning and memory in the mammalian brain. In a standard protocol, subjects are exposed to pairings of a conditioned stimulus (CS; e.g.

Mere Exposure Effect Is Sometimes Insensitive to Mood Inductions.

The mere exposure effect (MEE) is defined as repeated exposures to a stimulus enhancing affective evaluations of that stimulus (Zajonc, 1968). The three prominent explanations of the MEE are Zajonc's "neophobia" account, the uncertainty reduction account, and the perceptual fluency approach. Zajonc's "neophobia" account posits that people have an inherent low level of fear of novel objects and exposure to the objects partially extinguishes this novelty-based fear.

Spatial inference without a cognitive map: the role of higher-order path integration.

The cognitive map has been taken as the standard model for how agents infer the most efficient route to a goal location. Alternatively, path integration - maintaining a homing vector during navigation - constitutes a primitive and presumably less-flexible strategy than cognitive mapping because path integration relies primarily on vestibular stimuli and pace counting. The historical debate as to whether complex spatial navigation is ruled by associative learning or cognitive map mechanisms has been challenged by experimental difficulties in successfully neutralizing path integration.

Recovery of attention with renewal.

One experiment determined the relationship between renewed associative strength and attention. Following cue1-outcome pairings in Context A, cue1 was extinguished in Context B while cue2 was conditioned. On test cue2 was chosen as a predictor of the outcome in Context B.

Associative structure of second-order conditioning in humans.

Second-order conditioning (SOC; i.e., conditioned responding to S2 as a result of S1-US pairings followed by S2-S1 pairings) is generally explained by either a direct S2→US association or by an associative chain (i.

Role of spatial contiguity in sensory preconditioning with humans.

The present study demonstrates the contribution of spatial contiguity in the formation of associations between two neutral stimuli. Using human participants, we used visual conditioned stimuli (CSs) in a sensory preconditioning design in which simultaneous CS2-CS1 pairings and CS4-CS3 pairings were interspersed during Phase 1, followed by sequential CS1-US+ (i.e.

Integration of multiple memories in sensory preconditioning.

The present study demonstrates that humans' response to a single stimulus (S1) is determined by what follows S1's associates. The experiment used a sensory preconditioning (SPC) design where S1 was associated with both S2 and S3 on separate trials before establishing relationships between these latter stimuli with an outcome or its absence in a second phase. When S2 and S3 were associated with the same consequence, either an outcome or its absence, strong consequence-based responding to S1 was observed in a reaction time test.

Attention as an acquisition and performance variable (AAPV).

This article introduces a new model of Pavlovian conditioning, attention as an acquisition and performance variable (AAPV), which, like several other so-called attentional models, emphasizes the role of variation of cue salience, together with associative strength, in accounting for conditioning phenomena. AAPV is primarily (but not exclusively) a performance-focused model in that it assumes not only that both the saliences and associative strengths of cue representations change during acquisition, but also that they are both influential at the time of test in determining responding. Different weights are given to the representations' associative strengths according to the representations' respective saliences at test.

Spatial integration of boundaries in a 3D virtual environment.

Prior research, using two- and three-dimensional environments, has found that when both human and nonhuman animals independently acquire two associations between landmarks with a common landmark (e.g., LM1-LM2 and LM2-LM3), each with its own spatial relationship, they behave as if the two unique LMs have a known spatial relationship despite their never having been paired.

Reaction time as a measure of human associative learning.

Studies of human associative learning have often used causal/predictive learning preparations in which participants decide whether or not a first event is effective in causing or predicting a second event (i.e., an outcome).

Diagnostic accuracy of left ventricular function for identifying sepsis among emergency department patients with nontraumatic symptomatic undifferentiated hypotension.

The hypothesis of this study states that in emergency department (ED) patients with non-traumatic symptomatic hypotension, the presence of hyperdynamic left ventricular function (LVF) is specific for sepsis as the etiology of shock. We performed a secondary analysis of patients with non-traumatic symptomatic hypotension enrolled in a randomized, clinical diagnostic trial. The study was done in an urban tertiary ED with a census over 100,000 visits per year.

Pilot-scale evaluation of separate-stage nitrification using an attached-growth, moving-bed media process.

Submerged attached-growth processes, both fixed and moving bed, are becoming more popular. These processes may or may not be used in combination with suspended-growth treatment. The objective of this project was to evaluate a tertiary attached-growth, moving-bed media nitrification system based on the ammonia-nitrogen removal rates and effluent concentrations that could be achieved.

Effect of dialyzer reuse on complement activation and neutropenia in hemodialysis.

A prospective study of 10 patients undergoing hemodialysis showed that less neutropenia and complement activation occurred with dialyzer reuse. Neutrophil counts fell 95% +/- 5% (SEM) with first use and 66% +/- 8% and 48% +/- 10% with second and third uses, respectively (p less than 0.05).

Ibuprofen inhibits granulocyte responses to inflammatory mediators. A proposed mechanism for reduction of experimental myocardial infarct size.

The use of nonsteroidal antiinflammatory agents to reduce myocardial infarct size has demonstrated a dichotomy between ibuprofen, which reduces myocardial infarct size, and aspirin, which does not. A feline model of coronary ischemia using ligation of the anterior descending artery demonstrated that intravenous ibuprofen (2.5-20 mg/kg) given immediately and 2 h after ligation significantly decreased (by about 40%) myocardial infarct size.

Complement, granulocytes, and shock lung.

Intravascular leukostasis in the pulmonary microvasculature is a cardinal early histologic finding in patients with shock lung. Identical leukostasis is also observed in patients undergoing extracorporeal hemodialysis with cellophane membrane dialyzers, and it has been documented that the accumulation of granulocyte plugs in the lung is mediated by complement activation triggered by dialyzer cellophane. The C5a-desarg so generated causes peripheral blood granulocytes to aggregate, and the aggregates so formed embolize to the lung, where they cause occlusion of the microvasculature and increased capillary leakage, manifested by interstitial and alveolar edema.

Chronic myelogenous leukemia. Development of blast crisis with both lymphoid and myeloid features.

A 50-year-old man had chronic myelogenous leukemia and entered a blast crisis that was both morphologically and histochemically lymphoid. The blasts contained terminal deoxyribonucleotidyl transferase and expressed lymphoblastic leukemia-associated antigen. He rapidly entered remission with vincristine sulfate and prednisone therapy.

Zymosan activation of plasma reduces hypoxic pulmonary vasoconstriction.

Small doses of endotoxin (15 micrograms/kg IV) inhibit the pulmonary vascular pressor response to alveolar hypoxia in the anesthetized dog. One of the actions of endotoxin is to initiate the alternate pathway of complement activation. Incubation of human plasma with zymosan (ZAP) will activate this pathway.

Limbic encephalopathy as a nonmetastatic complication of oat cell lung cancer. Its reversal after treatment of the primary lung lesion.

A 52-year-old white woman presented with dementia, a seizure disorder, and an inappropriate affect characteristic of limbic encephalopathy. Chest x-ray showed a mass lesion that, on biopsy, proved to be oat cell carcinoma. Her central nervous system symptoms improved following radiotherapy limited to the primary lesion and later resolved completely with attainment of a complete remission after chemotherapy with cyclophosphamide, doxorubicin, vincristine, and VP-16--drugs unable to penetrate the cerebrospinal fluid.

Glycogenolysis versus glucose transport in human granulocytes: differential activation in phagocytosis and chemotaxis.

Granulocytes depend primarily on anaerobic glycolysis to supply the necessary energy for locomotion and chemotaxis. Either transmembrane transport of extracellular glucose or catabolism of intracellular glucose can supply glycolytic substrate. In this report, using enzymatic analysis of granulocyte glycogen, we describe conditional requirements for glycogenolysis, namely phagocytosis.

Granulocytes utilize different energy sources for movement and phagocytosis.

Granulocytes depend on anaerobic glycolysis for the energy required for chemotaxis, phagocytosis, and microbial killing. Two potential sources of the needed glucose are available: exogenous glucose and intracellular glycogen. These studies demonstrate that chemotaxin-induced movement of granulocytes induces accelerated uptake of exogenous glucose while phagocytosis does not, presumably utilizing instead the relatively slow process of glycogenolysis.

Activation of plasma complement by perfluorocarbon artificial blood: probable mechanism of adverse pulmonary reactions in treated patients and rationale for corticosteroids prophylaxis.

Perfluorocarbons have shown promise as clinical blood substitutes. Although early experience in Japan with one such product--Fluosol-DA--has been uncomplicated, we observed an adverse pulmonary reaction in the first American patient to receive it and know of similar reactions in two other Americans so treated. Postulating that activation of plasma complement (C) by the perfluorocarbon emulsion might have caused the reaction, we tested the product to determine if it is an activator of complement.