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PubMed2006

Motivating behavioral persistence: the self-as-doer construct.

Why do some people persist in goal pursuit, even in the face of boredom or setbacks, whereas others quickly give up their goals? In this research, the authors introduce a new motivational construct, the "self-as-doer," to explore this question. Studies 1 and 2 found longitudinal evidence that those who more strongly endorse doer statements regarding their goals (i.e., exerciser, dieter, runner) show greater behavioral persistence and attainment regarding such goals, even controlling for other relevant constructs such as expectancy, self-concordance, commitment, and neuroticism. Study 3 used priming to make the self-as-doer momentarily accessible, finding an interaction such that those who read The Little Engine That Could (vs. Curious George) and wrote an essay applying the story's message to themselves (vs. others) showed the greatest persistence in physically demanding tasks. Implications for sustained motivation of all kinds are discussed.

Adolescent↗

PubMed1998

Protein N-glycosylation: molecular genetics and functional significance.

Protein N-glycosylation is a metabolic process that has been highly conserved in evolution. In all eukaryotes, N-glycosylation is obligatory for viability. It functions by modifying appropriate asparagine residues of proteins with oligosaccharide structures, thus influencing their properties and bioactivities. N-glycoprotein biosynthesis involves a multitude of enzymes, glycosyltransferases, and glycosidases, encoded by distinct genes. The majority of these enzymes are transmembrane proteins that function in the endoplasmic reticulum and Golgi apparatus in an ordered and well-orchestrated manner. The complexity of N-glycosylation is augmented by the fact that different asparagine residues within the same polypeptide may be modified with different oligosaccharide structures, and various proteins are distinguished from one another by the characteristics of their carbohydrate moieties. Furthermore, biological consequences of derivatization of proteins with N-glycans range from subtle to significant. In the past, all these features of N-glycosylation have posed a formidable challenge to an elucidation of the physiological role for this modification. Recent advances in molecular genetics, combined with the availability of diverse in vivo experimental systems ranging from yeast to transgenic mice, have expedited the identification, isolation, and characterization of N-glycosylation genes. As a result, rather unexpected information regarding relationships between N-glycosylation and other cellular functions--including secretion, cytoskeletal organization, proliferation, and apoptosis--has emerged. Concurrently, increased understanding of molecular details of N-glycosylation has facilitated the alignment between N-glycosylation deficiencies and human diseases, and has highlighted the possibility of using N-glycan expression on cells as potential determinants of disease and its progression. Recent studies suggest correlations between N-glycosylation capacities of cells and drug sensitivities, as well as susceptibility to infection. Therefore, knowledge of the regulatory features of N-glycosylation may prove useful in the design of novel therapeutics. While facing the demanding task of defining properties, functions, and regulation of the numerous, as yet uncharacterized, N-glycosylation genes, glycobiologists of the 21st century offer exciting possibilities for new approaches to disease diagnosis, prevention, and cure.

Animals↗

PubMed2004

Attentional influences on functional mapping of speech sounds in human auditory cortex.

BACKGROUND: The speech signal contains both information about phonological features such as place of articulation and non-phonological features such as speaker identity. These are different aspects of the 'what'-processing stream (speaker vs. speech content), and here we show that they can be further segregated as they may occur in parallel but within different neural substrates. Subjects listened to two different vowels, each spoken by two different speakers. During one block, they were asked to identify a given vowel irrespectively of the speaker (phonological categorization), while during the other block the speaker had to be identified irrespectively of the vowel (speaker categorization). Auditory evoked fields were recorded using 148-channel magnetoencephalography (MEG), and magnetic source imaging was obtained for 17 subjects. RESULTS: During phonological categorization, a vowel-dependent difference of N100m source location perpendicular to the main tonotopic gradient replicated previous findings. In speaker categorization, the relative mapping of vowels remained unchanged but sources were shifted towards more posterior and more superior locations. CONCLUSIONS: These results imply that the N100m reflects the extraction of abstract invariants from the speech signal. This part of the processing is accomplished in auditory areas anterior to AI, which are part of the auditory 'what' system. This network seems to include spatially separable modules for identifying the phonological information and for associating it with a particular speaker that are activated in synchrony but within different regions, suggesting that the 'what' processing can be more adequately modeled by a stream of parallel stages. The relative activation of the parallel processing stages can be modulated by attentional or task demands.

Adult↗

PubMed2005

Dishabituation of the BOLD response to speech sounds.

BACKGROUND: Neural systems show habituation responses at multiple levels, including relatively abstract language categories. Dishabituation - responses to non-habituated stimuli - can provide a window into the structure of these categories, without requiring an overt task. METHODS: We used an event-related fMRI design with short interval habituation trials, in which trains of stimuli were presented passively during 1.5 second intervals of relative silence between clustered scans. Trains of four identical stimuli (standard trials) and trains of three identical stimuli followed by a stimulus from a different phonetic category (deviant trials) were presented. This paradigm allowed us to measure and compare the time course of overall responses to speech, and responses to phonetic change. RESULTS: Comparisons between responses to speech and silence revealed strong responses throughout the extent of superior temporal gyrus (STG) bilaterally. Comparisons between deviant and standard trials revealed dishabituation responses in a restricted region of left posterior STG, near the border with supramarginal gyrus (SMG). Novelty responses to deviant trials were also observed in right frontal regions and hippocampus. CONCLUSION: A passive, dishabituation paradigm provides results similar to studies requiring overt responses. This paradigm can readily be extended for the study of pre-attentive processing of speech in populations such as children and second-language learners whose overt behavior is often difficult to interpret because of ancillary task demands.

Journal Article↗

PubMed2004

Evolutionary fuzzy modeling human diagnostic decisions.

Fuzzy CoCo is a methodology, combining fuzzy logic and evolutionary computation, for constructing systems able to accurately predict the outcome of a human decision-making process, while providing an understandable explanation of the underlying reasoning. Fuzzy logic provides a formal framework for constructing systems exhibiting both good numeric performance (accuracy) and linguistic representation (interpretability). However, fuzzy modeling--meaning the construction of fuzzy systems--is an arduous task, demanding the identification of many parameters. To solve it, we use evolutionary computation techniques (specifically cooperative coevolution), which are widely used to search for adequate solutions in complex spaces. We have successfully applied the algorithm to model the decision processes involved in two breast cancer diagnostic problems, the WBCD problem and the Catalonia mammography interpretation problem, obtaining systems both of high performance and high interpretability. For the Catalonia problem, an evolved system was embedded within a Web-based tool-called COBRA-for aiding radiologists in mammography interpretation.

Breast Neoplasms↗

PubMed2000

Verbal fluency and repetition skills in healthy older Spanish-English bilinguals.

The influence of bilingualism on cognitive test performance in older adults has received limited attention in the neuropsychology literature. The aim of this study was to examine the impact of bilingualism on verbal fluency and repetition tests in older Hispanic bilinguals. Eighty-two right-handed participants (28 men and 54 women) with a mean age of 61.76 years (SD = 9.30; range = 50-84) and a mean educational level of 14.8 years (SD = 3.6; range 2-23) were selected. Forty-five of the participants were English monolinguals, 18 were Spanish monolinguals, and 19 were Spanish-English bilinguals. Verbal fluency was tested by electing a verbal description of a picture and by asking participants to generate words within phonemic and semantic categories. Repetition was tested using a sentence-repetition test. The bilinguals' test scores were compared to English monolinguals' and Spanish monolinguals' test scores. Results demonstrated equal performance of bilingual and monolingual participants in all tests except that of semantic verbal fluency. Bilinguals who learned English before age 12 performed significantly better on the English repetition test and produced a higher number of words in the description of a picture than the bilinguals who learned English after age 12. Variables such as task demands, language interference, linguistic mode, and level of bilingualism are addressed in the Discussion section.

Aged↗

PubMed2001

Seeing trees but not the forest: limited perception of large configurations in PD.

OBJECTIVE: To learn if Parkinson's disease (PD) is associated with a restricted attentional "floodlight." BACKGROUND: Different visual tasks may have different attentional requirements. Focused attention may be needed for some tasks; other tasks demand spatially distributed attention. Neglect after right cortical injury and dopamine depletion may limit the area over which attention can be spread. Although subjects with PD have dopamine depletion and can perform poorly on tests of visuospatial function, it is unclear if their attentional floodlight is restricted. METHODS: Eleven subjects with PD and 11 control subjects viewed different-sized letters on five printed stimulus sheets, 43 x 56 cm. On each sheet, four different large letters (14 cm2) were composed of four different medium-sized letters (2.5 cm2), which in turn were composed of four different small letters (0.4 cm2). Stimulus sheets were presented at 30- and 75-cm viewing distances. Subjects named "all the letters they could see." RESULTS: Subjects with PD named small- and medium-sized letters comparably to control subjects, but PD subjects named fewer large letters than control subjects (control = 65.68%, PD = 24.55%; group-by-letter-size interaction, p < 0.05). Subjects with PD who had undergone stereotactic pallidotomy named more letters than prepallidotomy PD subjects (p = 0.05). CONCLUSIONS: PD may affect the patient's ability to perceive large spatial configurations. As global configurations in subjects may be perceived preferentially over local patterns, it is possible that DA depletion induces an aberrant perceptual-attentional bias, such that patients have a narrowed attentional floodlight.

Aged↗

PubMed1997

Mental rotation in a California sea lion (Zalophus californianus).

Mental rotation is a widely accepted concept that suggests an analogue mode of visual information-processing in certain visuospatial tasks. Typically, these tasks demand the discrimination between the image and mirror-image of rotated figures, for which human subjects need an increasing reaction time depending on the angular disparity between the rotated figures. In pigeons, tests of this kind yielded a time-independent rotational invariance, suggested as being the result of a non-analogue information-processing that has evolved in response to the horizontal plane that birds perceive from above while flying. Given that marine mammals use the water surface as the horizontal plane for orientation while diving, the ability of a California sea lion to mentally rotate two-dimensional shapes was tested. Using a successive two-alternative matching-to-sample procedure, the animal had to decide between the image and mirror-image of a previously shown sample. Both stimuli were rotated by a multiple of 30 degrees with respect to the sample. The animal's reaction time was measured by a computer-controlled touch-screen device, rewarding the animal for pressing its snout against the stimulus matching the sample. A linear regression analysis of the animal's mean reaction time against the angular rotation of the stimulus yielded a significant correlation coefficient. Thus, the present data can be explained by the mental rotation model, predicting an image-like representation of visual stimuli in this species. The present results therefore correspond well with those found for human subjects, but are inconsistent with the data reported for pigeons.

Animals↗

PubMed2004

Computer-based detection and prompting of mammographic abnormalities.

Mammographic film reading is a highly demanding task, particularly in screening programmes where the reader must perform a detailed visual search of a large number of images for early signs of abnormality, which are often subtle or small, and which occur very infrequently. False negative cases, where signs of abnormality are missed by a film reader, are known to occur. Computer based algorithms can be used to detect abnormal patterns in images, but it is not possible to reliably detect all signs of abnormality in mammograms, so screening cannot yet be fully automated. The most successful detection algorithms are, however, incorporated in computer-aided detection (CAD) systems which indicate potentially abnormal locations to the reader in a process known as prompting. CAD systems have the capacity to reduce the frequency of false negative errors by ensuring that suspicious regions of the images are thoroughly searched and by increasing the weighting attached to subtle signs that may otherwise have been dismissed. One of the areas currently being researched is the effect of prompting on human performance. This is complex, since readers are presented with prompts generated by multiple detection algorithms, each of which has a different sensitivity and specificity. This paper reviews progress in abnormality detection, the strengths and the weaknesses of CAD, and the methodologies used to evaluate CAD in a clinical setting.

Algorithms↗

PubMed2003

When can a lack of structure facilitate strategic processing of information?

BACKGROUND: Researchers examining the effectiveness of an elaboration strategy (answering 'why') for learning new information have been concerned with the familiarity of the materials and how that affects learning. It may be, however, that both how information is organised and familiarity impact on the potency of the strategy. AIMS: We examined the influence of presentation structures (i.e., organisation of information) on the effectiveness of an elaboration strategy. SAMPLES: All participants were undergraduates (78 females, 67 males) enrolled in a first-year psychology course. Fifteen students participated in Experiment One, 42 students in Experiment Two, and 88 students in Experiment Three. METHODS: In Experiment One, preference for conceptual organisation was assessed. In Experiments Two and Three, students answered 'why' questions when different presentation structures were used. RESULTS: Students' preferred method of organisation did not match the imposed structure found in past research, suggesting that students may have been restricted in their ability to process the information distinctively. Students who were presented with the information in a random order achieved the largest memory scores. CONCLUSIONS: When students have to reconstruct as well as encode the information, these added task demands provide an added benefit for learning.

Adult↗

PubMed2005

Knowledge accessibility, achievement goals, and memory strategy maintenance.

BACKGROUND: An important aim of educational psychology is to account for the difficulties in cognitive strategy maintenance. Possible explanations may be found in developmental studies concerning the interdependence of knowledge accessibility and strategy use, and in current achievement goal models which assume that individuals with a learning goal use deeper strategies than those with a performance goal. AIMS: The purpose of this study was to examine how knowledge accessibility and achievement goals separately or conjointly affect the maintenance of a categorization strategy, recall performance, and perception of the strategy (utility, difficulty, effort) in a free recall task. SAMPLE: Participants were 93 first-year students from a human science university in France. METHOD: In the first phase, the students were taught how to use a categorization strategy in a recall task involving highly accessible (typical) items. In a subsequent transfer task, the same students were assigned to one of four experimental conditions where they were asked to recall a typical or atypical list and where a learning or performance goal was induced. RESULTS: Analysis showed that whatever the typicality of the list, a learning goal promoted maintenance of the categorization strategy, and of perception of its utility. Performance goal participants only maintained this strategy and its perceptions on typical lists, while on atypical lists they display less clustering and found the strategy less useful. CONCLUSION: Results suggest that maintenance of a cognitive strategy is facilitated when there is compatibility between a performance goal and the task demands, or when the participants are learning-goal oriented.

Achievement↗

PubMed2003

The effects of morphology on the processing of compound words: evidence from naming, lexical decisions and eye fixations.

The use of lexemes during the recognition of spatially unified familiar English compounds was examined in naming, lexical decision and sentence-reading tasks by manipulating beginning and ending lexeme frequencies while controlling overall compound frequencies. All tasks revealed robust ending lexeme frequency effects, with compound processing being more effective when the ending lexeme was a high-frequency word. Beginning lexeme frequency effects were more elusive and dependent on task demands. Eye movements, recorded during sentence reading, also indicated that the effects of ending lexemes occurred after the first fixation during compound viewing. Together, the results suggest either that the ending lexeme is used as an access code to locate the meaning of the full compound word or that its meaning is coactive with the meaning of the full compound.

Adolescent↗

PubMed2005

Mood, dissociation and false memories using the Deese-Roediger-McDermott procedure.

Who is likely to have a false memory? Does being in a certain transient state, such as a negative mood, mean that a person is more like to have a false memory? These important questions are examined using the Deese-Roediger-McDermott (DRM) procedure. The amount of false memories was compared with people's score on a dissociation measure and by mood. Unlike past research, which has used different procedures to explore false memories, we found that dissociation was not associated with false memories. We argue that this is because the DRM procedure requires two processes for a false memory (the generation of the critical lure and mistaking its source), while most false memory procedures only require one process (source monitoring error) because the errant information is suggested to the participant. This pattern of results suggests that only errors with the source monitoring process are associated with dissociation. We found that mood was related to false memories, but it was dependent on the specific task demands. If participants were told to recall as many words as they could, then people in a negative mood had more false memories. However, if they were told to recall as many words as they felt like recalling, then there were more false memories for people in a positive mood. This can be explained by the mood-as-input hypothesis. Results are discussed in relation to both theories and applications of memory.

Acoustic Stimulation↗

PubMed1988

Age and visual search: expanding the useful field of view.

The useful field of view is defined as the visual area in which information can be acquired within one eye fixation. We studied visual search within this context and found a reduction in the size of the field as a function of age. This loss, however, was recovered partially with practice. Standard acuity and perimetric tests of visual field, although diagnostic of disease, underestimate the degree of difficulty experienced by visually healthy older adults in everyday activities requiring the use of peripheral vision. To aid in predicting such performance, a model incorporating the effects of distractors and secondary task demands was developed.

Adult↗

PubMed2005

Primary visual cortex activity along the apparent-motion trace reflects illusory perception.

The illusion of apparent motion can be induced when visual stimuli are successively presented at different locations. It has been shown in previous studies that motion-sensitive regions in extrastriate cortex are relevant for the processing of apparent motion, but it is unclear whether primary visual cortex (V1) is also involved in the representation of the illusory motion path. We investigated, in human subjects, apparent-motion-related activity in patches of V1 representing locations along the path of illusory stimulus motion using functional magnetic resonance imaging. Here we show that apparent motion caused a blood-oxygenation-level-dependent response along the V1 representations of the apparent-motion path, including regions that were not directly activated by the apparent-motion-inducing stimuli. This response was unaltered when participants had to perform an attention-demanding task that diverted their attention away from the stimulus. With a bistable motion quartet, we confirmed that the activity was related to the conscious perception of movement. Our data suggest that V1 is part of the network that represents the illusory path of apparent motion. The activation in V1 can be explained either by lateral interactions within V1 or by feedback mechanisms from higher visual areas, especially the motion-sensitive human MT/V5 complex.

Adult↗

PubMed2006

An unexpected sequence of events: mismatch detection in the human hippocampus.

The ability to identify and react to novelty within the environment is fundamental to survival. Computational models emphasize the potential role of the hippocampus in novelty detection, its unique anatomical circuitry making it ideally suited to act as a comparator between past and present experience. The hippocampus, therefore, is viewed to detect associative mismatches between what is expected based on retrieval of past experience and current sensory input. However, direct evidence that the human hippocampus performs such operations is lacking. We explored brain responses to novel sequences of objects using functional magnetic resonance imaging (fMRI), while subjects performed an incidental target detection task. Our results demonstrate that hippocampal activation was maximal when prior predictions concerning which object would appear next in a sequence were violated by sensory reality. In so doing, we establish the biological reality of associative match-mismatch computations within the human hippocampus, a process widely held to play a cardinal role in novelty detection. Our results also suggest that the hippocampus may generate predictions about how future events will unfold, and critically detect when these expectancies are violated, even when task demands do not require it. The present study also offers broader insights into the nature of essential computations carried out by the hippocampus, which may also underpin its unique contribution to episodic memory.

Adolescent↗

PubMed2006

Lifestyle counseling in type 2 diabetes prevention: a case study of a nurse's communication activity to produce change talk.

As a case study, this article describes a nurse's communication activity, focusing on change talk during lifestyle counseling in primary healthcare. All videotaped counseling sessions with a single patient within a period of two years were transcribed verbatim. In the analysis, an emphasis was placed on the nurse's communication activity that produced change talk, how the nurse initiated change talk, and how the patient received it. The observations provide evidence that the dilemma of simultaneously maintaining professional authority and patient perspective leads to sensitivity in lifestyle counseling. Three categories of change talk were identified: rejected, restrictive, and expansive change talk. Producing change talk is a very demanding task for counselors. It is best produced when the nurse stays within the patient's frame of reference with a combination of reflective, change-inducing questions, encouraging assessments and conversational space. On the basis of our results, we suggest that nurses need training to identify and to encourage patients' change talk and to communicate flexibly according to patients' values during lifestyle counseling. In addition, in order to insist on change talk, we need to demonstrate how change talk could be carried out so that nurses could orient to it.

Communication↗

PubMed2003

Managing core resources for genomics and proteomics.

Recent years have seen an explosive growth in biological data, which is often not published in a conventional sense but rather deposited in a database. This trend and the need for computational analyses of the data make databases essential tools for biological research. Data from a variety of sources, covering a wide range of biological information, are stored in different, often quite specialized, databases. The provision of such databases as useful resources for the scientific community is a demanding task since the data not only have to be stored in a consistent way, but also have to be easily accessible and highly integrated with other databases. Furthermore, it is necessary to provide users with effective tools to search the databases and to analyze the data. At the European Bioinformatics Institute (EBI), we develop and maintain a number of biological databases and provide a variety of bioinformatics tools to facilitate database and similarity searches and data analysis. In this review, we will provide examples of the core resources maintained at the EBI and summarize important issues of database management of such resources.

Computational Biology↗