Reasoning about visibility

We consider properties of sequences of spatial regions, as seen from a viewpoint. In particular, we concentrate on two types of regions: (1) general domains in which a region is any subset of the space, and (2) axis-parallel domains, where the regions are boxes in an N-dimensional space. We introduce binary relations allowing to express properties of these sequences and present two approaches to process them. First, we show that constraints on these relations can be solved in polynomial time for general domain and that the same problem is NP-complete in the axis-parallel case. Second, we introduce a modal logic on these relations, called Visibility Logic, and show that model-checking on a finite sequence of regions can be done in polynomial time (both in the general and axis-parallel cases). Finally, we present applications to image processing and firewall filtering.     

The influence of surgical stress,anxiety and benzodiazepine intravenous sedation on recall of oral surgery

Abstract

This study, part of a larger investigation of the efficacy and safety of intravenous sedation in dentistry, reports the prevalance of failure to recall information during third molar impaction surgery and attempts to differentate the effects of stress and benzodiazepines on recall. Both recognition of neutral pictures and the recall of surgical procedures were assessed. Recall failure in the drug groups ranged from zero for recall of stressful procedures, completed before drug titration, to 92 percent of subjects for recognition of the neutral picture presented at 5 minutes after the surgical procedure began. Placebo condition subjects had almost no recall loss. Recall failure was demonstrated to be primarily a function of the volume of midazolam employed. However, operative stress and trait and state anxiety explained some of the findings.     

How to explain receptivity to conjunction-fallacy inhibition training: Evidence from the Iowa Gambling Task

Intuitive predictions and judgments under conditions of uncertainty are often mediated by judgment heuristics that sometimes lead to biases. Using the classical conjunction bias example, the present study examines the relationship between receptivity to metacognitive executive training and emotion-based learning ability indexed by Iowa Gambling Task (IGT) performance. After completing a computerised version of the IGT, participants were trained to avoid conjunction bias on a frequency judgment task derived from the works of Tversky and Kahneman. Pre- and post-test performances were assessed via another probability judgment task. Results clearly showed that participants who produced a biased answer despite the experimental training (individual patterns of the biased → biased type) mainly had less emotion-based learning ability in IGT. Better emotion-based learning ability was observed in participants whose response pattern was biased → logical. These findings argue in favour of the capacity of the human mind/brain to overcome reasoning bias when trained under executive programming conditions and as a function of emotional warning sensitivity.     

Models of habituation in infancy

Research on infant cognition using habituation methods has sparked considerable controversy in recent years. At the core of the debates is the issue of whether infants have early (and possibly innate) conceptual understandings. This article reviews a range of computational models of habituation that might provide insights into such discussions. The models are assessed against key behavioral and neural features of habituation: temporal unfolding, exponential decrease, familiarity-to-novelty shift, habituation to repeated testing, discriminability of habitual items, selective inhibition and cortical-subcortical interactions. The review suggests that current models fail to offer comprehensive explanations of the behavioral phenomena.     

Perception-Movement Coupling in the Regulation of Step Lengths When Approaching an Obstacle

Experiment 1 showed that the control mechanism based on a perception–movement coupling observed in certain goal-directed movement tasks (De Rugy, Montagne, Buekers, & Laurent, 2000 De Rugy, A., Montagne, G., Buekers, M. J. and Laurent, M. 2000. The study of locomotor pointing in virtual reality: The validation of a test set-up. Behavior Research Methods, Instruments, & Computers, 32: 515–520.  [Google Scholar]; Montagne, Cornus, Glize, Quaine, & Laurent, 2000 Montagne, G., Cornus, S., Glize, D., Quaine, F. and Laurent, M. 2000. A perception-action coupling type of control in long-jumping. Journal of Motor Behavior, 32: 37–44. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) can be extended to a stepping across an obstacle task. Regardless of the specificity of tasks, the initiation of regulations is a function of the amount of adjustment. Our participants organized their regulation later than long jumpers. Two additional experiments were conceived to investigate whether this control mechanism could be generalized to goal-directed locomotor displacements, with different constraints. The aim of Experiments 2 and 3 was to address the adaptation of this control mechanism by manipulating the obstacle width and the walking speed in a stepping across task. The results showed that the functioning of this control mechanism could be influenced by the spatiotemporal constraints. Participants' behavior depended on a perception–movement coupling. This study suggests the existence of a generic control mechanism based on a perception–movement coupling, and it emphasizes the adaptation of this type of control mechanism involved in goal-directed displacements.     

Short-term music training enhances verbal intelligence and executive function

Researchers have designed training methods that can be used to improve mental health and to test the efficacy of education programs. However, few studies have demonstrated broad transfer from such training to performance on untrained cognitive activities. Here we report the effects of two interactive computerized training programs developed for preschool children: one for music and one for visual art. After only 20 days of training, only children in the music group exhibited enhanced performance on a measure of verbal intelligence, with 90% of the sample showing this improvement. These improvements in verbal intelligence were positively correlated with changes in functional brain plasticity during an executive-function task. Our findings demonstrate that transfer of a high-level cognitive skill is possible in early childhood.     

Whole word morphologizer: expanding the word-based lexicon: a nonstochastic computational approach

Whole Word Morphologizer is a small computer implementation of word-based morphology. The program automatically identifies morphological relations in a small word-based lexicon, literally learning its morphology, and uses the knowledge it acquires to generate new words. It is based on a model of the mental lexicon in which all entries are whole, entire, fully fledged words and relies solely on basic cognitive principles (differentiation and generalization) for the automatic acquisition of morphological relations and the population of the lexicon.     

A positron emission tomography study of short- and long-term treatment effects on functional brain activation in adults who stutter

Previous studies have shown that fluency-inducing techniques, such as choral speech, result in changes in neural activation as measured by functional neuroimaging. In the present study, positron emission tomography was used to investigate the effects of intensive behavioural treatment, followed by a 1-year maintenance program, on the pattern of cortical and subcortical activation in stuttering adults during silent and oral reading of single words. The results indicate changes in activation lateralisation, as well as a general reduction in overactivation, especially in the motor cortex, following treatment. The results are discussed in light of previous functional imaging studies with stuttering adults.

Educational objectives: The reader will learn about and be able to describe the: (1) use of functional neuroimaging PET in the study of stuttering; (2) differences in neural activation between stuttering and non-stuttering adults; and (3) effects of behavioural fluency treatment on cortical and subcortical activations in stuttering speakers.