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Selective attention plays an important role in category learning. However, immaturities of top-down attentional control during infancy coupled with successful category learning suggest that early category learning is achieved without attending selectively. Research presented here examines this possibility by focusing on category learning in infants (6-8months old) and adults. Participants were trained on a novel visual category. Halfway through the experiment, unbeknownst to participants, the to-be-learned category switched to another category, where previously relevant features became irrelevant and previously irrelevant features became relevant. If participants attend selectively to the relevant features of the first category, they should incur a cost of selective attention immediately after the unknown category switch. Results revealed that adults demonstrated a cost, as evidenced by a decrease in accuracy and response time on test trials as well as a decrease in visual attention to newly relevant features. In contrast, infants did not demonstrate a similar cost of selective attention as adults despite evidence of learning both to-be-learned categories. Findings are discussed as supporting multiple systems of category learning and as suggesting that learning mechanisms engaged by adults may be different from those engaged by infants.

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The current review focuses on how exposure to linguistic input, and count nouns in particular, affect performance on various cognitive tasks, including individuation, categorization and category learning, and inductive inference. We review two theoretical accounts of effects of words. Proponents of one account argue that words have top-down effects on cognitive tasks, and, as such, function as supervisory signals. Proponents of the other account suggest that early in development, words, just like any other perceptual feature, are first and foremost part of the stimulus input and influence cognitive tasks in a bottom-up, non-supervisory fashion. We then review evidence supporting each account. We conclude that, although much research is needed, there is a large body of evidence indicating that words start out like other perceptual features and become supervisory signals in the course of development.

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While much research has examined the development of facial recognition abilities, less is known about the ability of individuals with and without autism to categorize facial gender. The current study tested gender categorization abilities in high-functioning children (5-7 and 8-12 years), adolescents (13-17 years), and adults (18-53 years) with autism and matched controls. Naturalistic videos depicted faces that were either typical or less typical of each gender. Both groups improved in their performance across development. However, control children reached expertise that was similar to control adults by 8-12 years; whereas, adults with autism never reached this level of expertise, particularly with less typical gender faces. Results suggest that individuals with autism employ different face processing mechanisms than typically developing individuals.

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It has been established that typically developing individuals have a bias to attend to facial information in the left visual field (LVF) more than in the right visual field. This bias is thought to arise from the right hemisphere's advantage for processing facial information, with evidence suggesting it to be driven by the configural demands of face processing. Considering research showing that individuals with autism have impaired face processing abilities, with marked deficits in configural processing, it was hypothesized that they would not demonstrate a LVF bias for faces. Eye-tracking technology was used to show that individuals with autism were not spontaneously biased to facial information in the LVF, in contrast to a control group, while discriminating facial gender.

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The membranes of human red blood cells (RBCs) are a composite of a fluid lipid bilayer and a triangular network of semiflexible filaments (spectrin). We perform cellular microrheology using the dynamic membrane fluctuations of the RBCs to extract the elastic moduli of this composite membrane. By applying known osmotic stresses, we measure the changes in the elastic constants under imposed strain and thereby determine the nonlinear elastic properties of the membrane. We find that the elastic nonlinearities of the shear modulus in tensed RBC membranes can be well understood in terms of a simple wormlike chain model. Our results show that the elasticity of the spectrin network can mostly account for the area compression modulus at physiological osmolality, suggesting that the lipid bilayer has significant excess area. As the cell swells, the elastic contribution from the now tensed lipid membrane becomes dominant.

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Evidence remains mixed about whether individuals with autism look less to eyes and whether they look more at mouths. Few studies have examined how spontaneous attention to facial features relates to face processing abilities. This study tested the ability to discriminate gender from facial features, namely eyes and mouths, by comparing accuracy scores of 17 children with autism and 15 adults with autism to 17 typically developing children and 15 typically developing adults. Results indicated that all participants regardless of diagnosis discriminated gender more accurately from eyes than from mouths. However, results indicated that compared to adults without autism, adults with autism were significantly worse at discriminating gender from eyes.

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The human red blood cell (RBC) membrane, a fluid lipid bilayer tethered to an elastic 2D spectrin network, provides the principal control of the cell's morphology and mechanics. These properties, in turn, influence the ability of RBCs to transport oxygen in circulation. Current mechanical measurements of RBCs rely on external loads. Here we apply a noncontact optical interferometric technique to quantify the thermal fluctuations of RBC membranes with 3 nm accuracy over a broad range of spatial and temporal frequencies. Combining this technique with a new mathematical model describing RBC membrane undulations, we measure the mechanical changes of RBCs as they undergo a transition from the normal discoid shape to the abnormal echinocyte and spherical shapes. These measurements indicate that, coincident with this morphological transition, there is a significant increase in the membrane's shear, area, and bending moduli. This mechanical transition can alter cell circulation and impede oxygen delivery.

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Little is known regarding metacognition in individuals with autism. Specifically, it is unclear how individuals with autism think about their own mental states. The current study assessed memory awareness during a facial recognition task. High-functioning children (M = 13.1 years, n = 18) and adults (M = 27.5 years, n = 16) with autism matched with typically developing children (M = 14.3 years, n = 13) and adults (M = 26.9 years, n = 15) were tested. Children with autism demonstrated less accurate memory awareness for faces and less reliable differentiation between their confidence ratings compared to typically developing children. Subtle impairments in memory awareness for faces were also evident in adults with autism. Results indicate that broader metacognitive deficits may exist in individuals with autism, possibly contributing to other known impairments.

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The remarkable deformability of the human red blood cell (RBC) results from the coupled dynamic response of the phospholipid bilayer and the spectrin molecular network. Here we present quantitative connections between spectrin morphology and membrane fluctuations of human RBCs by using dynamic full-field laser interferometry techniques. We present conclusive evidence that the presence of adenosine 5'-triphosphate (ATP) facilitates non-equilibrium dynamic fluctuations in the RBC membrane that are highly correlated with the biconcave shape of RBCs. Spatial analysis of the fluctuations reveals that these non-equilibrium membrane vibrations are enhanced at the scale of spectrin mesh size. Our results indicate that the dynamic remodeling of the coupled membranes powered by ATP results in non-equilibrium membrane fluctuations manifesting from both metabolic and thermal energies and also maintains the biconcave shape of RBCs.

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Prototype formation is a critical skill for category learning. Research suggests that individuals with autism may have a deficit in prototype formation of some objects; however, results are mixed. This study used a natural category, faces, to further examine prototype formation in high-functioning individuals with autism. High-functioning children (age 8-13 years) and adults with autism (age 17-53 years) and matched controls were tested in a facial prototype formation task that has been used to test prototype formation abilities in typically developing infants and adults [Strauss, 1979]. Participants were familiarized to a series of faces depicting subtle variations in the spatial distance of facial features, and were then given a forced choice familiarity test between the mean prototype and the mode prototype. Overall, individuals in the autism group were significantly less likely to select the mean prototype face. Even though the children with autism showed this difference in prototype formation, this pattern was driven primarily by the adults, because the adults with autism were approximately four times less likely to select the mean prototype than were the control adults. These results provide further evidence that individuals with autism have difficulty abstracting subtle spatial information that is necessary not only for the formation of a mean prototype, but also for categorizing faces and objects.

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BACKGROUND: Recent experimental evidence suggests that fatty acid ethyl esters (FAEE), nonoxidative metabolites of ethanol, mediate ethanol-induced organ damage. A direct association between pancreas-specific toxicity and increased levels of FAEE following inhibition of the oxidative metabolism of ethanol by 4-methylpyrazole (4-MP) has previously been shown in studies with rats. METHODS: We obtained plasma samples from 32 healthy human volunteers who drank ethanol following 4-MP or placebo ingestion to determine whether in vivo inhibition of oxidative metabolism of ethanol causes a shift to nonoxidative metabolism of ethanol and the subsequent production of increased levels of FAEE. Plasma FAEE were isolated by solid-phase extraction and quantified by gas chromatography-mass spectrometry (GC-MS). RESULTS: Plasma FAEE levels in subjects receiving 4-MP treatment before ethanol consumption were elevated compared with plasma FAEE concentrations taken from control subjects who received a placebo before ethanol ingestion. Increased FAEE levels in the 4-MP treatment group occurred after peak blood ethanol, and peak FAEE levels were achieved. There was a correlation between the blood ethanol and the plasma FAEE levels, and the correlation persisted in the presence or absence of 4-MP. The peak FAEE values were greater in men than in women, with or without 4-MP treatment. CONCLUSIONS: Our results indicate that the in vivo inhibition of the oxidative metabolism of ethanol using 4-MP results in an increased circulating concentration of FAEE, products of the nonoxidative metabolism of ethanol.

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Fatty acid ethyl esters (FAEEs), nonoxidative metabolites of ethanol, have been implicated in ethanol-induced heart injury. To assess the in vivo production of FAEEs by myocardial tissue, we used a modified ethanol ablation procedure in pigs. A controlled 60-minute ethanol infusion was administered into the distal left anterior descending coronary artery in seven swine; serial blood sampling of the coronary sinus and peripheral vein before, during, and after infusion allowed measurement of FAEE production and ethanol levels in the coronary sinus and the peripheral circulation. In a single animal, FAEEs were also quantified from nine different sites within the myocardium. FAEEs were produced by the heart within 5 minutes of exposure to ethanol, with very high concentrations of FAEEs detected in coronary sinus blood. Significant variability in amounts of FAEEs was detected in different regions of the heart tissue. A strong correlation was found between coronary sinus FAEEs and ethanol concentration (r = 0.9241, P < 0.00001). FAEE production by the heart after delivery of ethanol into the left anterior descending coronary artery was rapid, reaching levels in the coronary sinus blood 4 to 10 times greater than that found in peripheral blood after ethanol intake. These data demonstrate that FAEEs may be mediators of ethanol-induced cardiotoxicity.

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AIMS: To develop a method to assess the relative binding of fatty acid ethyl esters (FAEE) and free fatty acids (FFA) to albumin, and to determine if binding affinity is related to fatty acid chain length and or degree of saturation. METHODS: Radiolabelled ethyl-[14C] oleate bound to albumin was challenged with various ratios of FFA to FAEE. The displacement of ethyl-[14C] oleate by FFA was visualized and quantitated through a combination of native-PAGE, autoradiography, and liquid scintillation counting (LSC). RESULTS: As the ratio of FFA to FAEE increased from 0:1 to 12:1, for all fatty acids tested (myristate, palmitate, stearate, oleate, linoleate, and arachidonate), ethyl-[14C] oleate displacement increased, when expressed as radioactivity (in DPM) as a percentage of control. In contrast, ethyl oleate did not displace stearate or oleate from albumin at molar ratios up to 5:1 (FAEE:FFA). CONCLUSIONS: The method developed gave reproducible visualization of noncovalent binding of radiolabelled FAEE to albumin. The combination of native-PAGE and autoradiography LSC works well in assessing the binding properties of albumin and radiolabelled FAEE. The data indicate preferential binding of FFA over FAEE to albumin with six different FFA displacing FAEE to an approximately equal extent.

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We present a new quantitative method for investigating red blood cell morphology and dynamics. The instrument integrates quantitative phase microscopy with an inverted microscope, which makes it particularly suitable for the noninvasive assessment of live erythrocytes. In particular, we demonstrate the ability of this approach to quantify noninvasively cell volume and dynamic morphology. The subnanometer path-length sensitivity at the millisecond time scales is exemplified by measuring the hemoglobin flow out of the cell during hemolysis.

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Fatty acid ethyl esters (FAEEs) are nonoxidative ethanol metabolites that have been implicated as mediators of alcohol-induced organ damage. FAEEs are detectable in the blood after ethanol ingestion, and on that basis represent markers of ethanol intake. FAEEs have also been quantitated in human liver and adipose tissue and have been shown to be postmortem markers of premortem ethanol intake. A substantial difference in FAEE concentration was found in liver and adipose tissue of patients with detectable blood ethanol at the time of autopsy vs those with no detectable blood ethanol, who were either chronic alcoholics or social drinkers. Most currently available diagnostic markers for chronic alcoholism have limited clinical utility. Data in this report demonstrate that the amount or type of FAEEs can be used to differentiate a chronic alcoholic from an episodic heavy drinker (binage drinker) at or near peak blood ethanol concentrations and approximately 24 hours after discontinuation of ethanol. Thus, FAEEs are markers of ethanol intake in blood and tissues and can be useful in distinguishing chronic alcoholics from binge drinkers.

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Although alcohol abuse is known to cause an array of ethanol-induced red blood cell (RBC) abnormalities, the underlying molecular mechanisms remain poorly understood. Fatty acid ethyl esters (FAEEs) are toxic, nonoxidative ethanol metabolites that have been found in blood, plasma, and tissues. Because FAEEs have been shown to be incorporated into phospholipid bilayers, we conducted a controlled ethanol intake study to test the hypothesis that FAEEs accumulate and persist within RBCs following ethanol ingestion. We demonstrated that RBC FAEEs account for approximately 5% to 20% of total whole-blood FAEEs, and that the fatty acid composition of FAEEs in RBCs and plasma are different and vary differently over time. These data indicate that a significant percentage of FAEEs in the blood is associated with RBCs and that the metabolism of RBC FAEEs and that of plasma FAEEs (bound to albumin or lipoproteins) are largely independent.

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This report describes the biochemistry of fatty acid ethyl esters (FAEE), non-oxidative metabolites of ethanol, and their clinical significance. We review information regarding the enzymes responsible for FAEE synthesis and degradation, and the mechanisms involved with the intracellular and extracellular transport of FAEE and FAEE-mediated cytotoxicity. Also a summary of reports on the emerging clinical significance and diagnostic utility of FAEE as short and long-term markers of alcohol consumption, and the methodological aspects of FAEE assessment is included.

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Fatty acid ethyl esters (FAEE), esterification products of fatty acids and ethanol, have been shown to be mediators of ethanol-induced cell injury and their presence in the blood and tissues is a marker of ethanol intake. Recently, it has been shown that FAEE are produced within seconds of infusion of ethanol into the heart, when using a protocol similar to that used for myocardial ablation. This raises the possibility that the mechanism for the death of myocytes in cardiac ablation involves the generation of toxic FAEE. It has also been recently demonstrated that chronic alcoholics have a high concentration of a specific FAEE species--ethyl oleate. The use of the serum ethyl oleate concentration may be helpful in differentiating binge drinkers from chronic alcoholics.

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