Rating of different olfactory judgements in Alzheimer's disease.
(25/1353)
Using simple successive tasks we assessed the influence of Alzheimer's disease on the processing of different odours. Fifteen patients with Alzheimer's disease, 15 old control subjects and 15 young control subjects were tested. The experiment included two sessions. Initially 12 odorants were presented, one odorant every minute. For each odour the subjects were asked to rate intensity, pleasantness, familiarity and edibility using linear rating scales. The odorants were then presented a second time and the subjects were asked to identify them. The results show that the intensity scores were lower in old control subjects and Alzheimer patients than in the young control subjects and that familiarity and identification scores were lower in Alzheimer patients than in old control and young control subjects. When we compared the five olfactory tasks the impairment of performance in Alzheimer patients was relatively higher for identification than familiarity, itself higher than the intensity judgement. No difference was observed between the three groups of subjects for pleasantness and edibility judgements. (+info)
Background considerations to facial aesthetics.
(26/1353)
This paper examines the nature of our objectives in attempting to improve facial appearance. Questions are addressed concerning the basis for any collective agreement on "improvement" and the nature of an agreed "ideal", including an exploration of the reasons for its existence. The discussion focuses on the concept of "averageness", as well as supplementary hypotheses. Finally, the origins and validity of contemporary clinical guidelines are addressed. (+info)
Categorizing sex and identity from the biological motion of faces.
(27/1353)
Head and facial movements can provide valuable cues to identity in addition to their primary roles in communicating speech and expression [1-8]. Here we report experiments in which we have used recent motion capture and animation techniques to animate an average head [9]. These techniques have allowed the isolation of motion from other cues and have enabled us to separate rigid translations and rotations of the head from nonrigid facial motion. In particular, we tested whether human observers can judge sex and identity on the basis of this information. Results show that people can discriminate both between individuals and between males and females from motion-based information alone. Rigid head movements appear particularly useful for categorization on the basis of identity, while nonrigid motion is more useful for categorization on the basis of sex. Accuracy for both sex and identity judgements is reduced when faces are presented upside down, and this finding shows that performance is not based on low-level motion cues alone and suggests that the information is represented in an object-based motion-encoding system specialized for upright faces. Playing animations backward also reduced performance for sex judgements and emphasized the importance of direction specificity in admitting access to stored representations of characteristic male and female movements. (+info)
The extent of patients' understanding of the risk of treatments.
(28/1353)
The scientific understanding of how people perceive and code risks and then use this information in decision making has progressed greatly in the last 20 years. There is considerable evidence that people employ simplifying heuristics in judgement and decision making. These heuristics may lead to bias in how people interpret information. However, much of our understanding of risk perception is based on laboratory studies. It is much less clear whether risk perception in the real world (as in the case of medical treatments) exhibits the same patterns and biases. This paper reviews the published literature on risk perception in patients who face substantial treatment risks. It examines how accurate patients' perception of risk is, what factors affect the perception of risk, and several possible explanations for why patients' risk perception is not always accurate. (+info)
New Evidence for Distinct Right and Left Brain Systems for Deductive versus Probabilistic Reasoning.
(29/1353)
Deductive and probabilistic reasoning are central to cognition but the functional neuroanatomy underlying them is poorly understood. The present study contrasted these two kinds of reasoning via positron emission tomography. Relying on changes in instruction and psychological 'set', deductive versus probabilistic reasoning was induced using identical stimuli. The stimuli were arguments in propositional calculus not readily solved via mental diagrams. Probabilistic reasoning activated mostly left brain areas whereas deductive activated mostly right. Deduction activated areas near right brain homologues of left language areas in middle temporal lobe, inferior frontal cortex and basal ganglia, as well as right amygdala, but not spatial-visual areas. Right hemisphere activations in the deduction task cannot be explained by spill-over from overtaxed, left language areas. Probabilistic reasoning was mostly associated with left hemispheric areas in inferior frontal, posterior cingulate, parahippocampal, medial temporal, and superior and medial prefrontal cortices. The foregoing regions are implicated in recalling and evaluating a range of world knowledge, operations required during probabilistic thought. The findings confirm that deduction and induction are distinct processes, consistent with psychological theories enforcing their partial separation. The results also suggest that, except for statement decoding, deduction is largely independent of language, and that some forms of logical thinking are non-diagrammatic. (+info)
An fMRI investigation of emotional engagement in moral judgment.
(30/1353)
The long-standing rationalist tradition in moral psychology emphasizes the role of reason in moral judgment. A more recent trend places increased emphasis on emotion. Although both reason and emotion are likely to play important roles in moral judgment, relatively little is known about their neural correlates, the nature of their interaction, and the factors that modulate their respective behavioral influences in the context of moral judgment. In two functional magnetic resonance imaging (fMRI) studies using moral dilemmas as probes, we apply the methods of cognitive neuroscience to the study of moral judgment. We argue that moral dilemmas vary systematically in the extent to which they engage emotional processing and that these variations in emotional engagement influence moral judgment. These results may shed light on some puzzling patterns in moral judgment observed by contemporary philosophers. (+info)
Dissociating memory retrieval processes using fMRI: evidence that priming does not support recognition memory.
(31/1353)
We employed event-related fMRI to constrain cognitive accounts of memory retrieval. Studies of explicit retrieval reveal that lateral and medial parietal, dorsal middle frontal gyrus, and anterior prefrontal cortex respond more for studied than new words, reflecting a correlate of "retrieval success." Studies of implicit memory suggest left temporal cortex, ventral and dorsal inferior frontal gyrus respond less for studied than new words, reflecting a correlate of "conceptual priming." In the present study, responses for old and new items were compared during performance on explicit recognition (old/new judgement) and semantic (abstract/concrete judgement) tasks. Regions associated with priming were only modulated during the semantic task, whereas regions associated with retrieval success were modulated during both tasks. These findings constrain functional-anatomic accounts of the networks, suggesting that processes associated with priming do not support explicit recognition judgments. (+info)
Frontopolar and anterior temporal cortex activation in a moral judgment task: preliminary functional MRI results in normal subjects.
(32/1353)
OBJECTIVE: To study the brain areas which are activated when normal subjects make moral judgments. METHOD: Ten normal adults underwent BOLD functional magnetic resonance imaging (fMRI) during the auditory presentation of sentences that they were instructed to silently judge as either "right" or "wrong". Half of the sentences had an explicit moral content ("We break the law when necessary"), the other half comprised factual statements devoid of moral connotation ("Stones are made of water"). After scanning, each subject rated the moral content, emotional valence, and judgment difficulty of each sentence on Likert-like scales. To exclude the effect of emotion on the activation results, individual responses were hemodynamically modeled for event-related fMRI analysis. The general linear model was used to evaluate the brain areas activated by moral judgment. RESULTS: Regions activated during moral judgment included the frontopolar cortex (FPC), medial frontal gyrus, right anterior temporal cortex, lenticular nucleus, and cerebellum. Activation of FPC and medial frontal gyrus (BA 10/46 and 9) were largely independent of emotional experience and represented the largest areas of activation. CONCLUSIONS: These results concur with clinical observations assigning a critical role for the frontal poles and right anterior temporal cortex in the mediation of complex judgment processes according to moral constraints. The FPC may work in concert with the orbitofrontal and dorsolateral cortex in the regulation of human social conduct. (+info)