Neural correlates of lexical and sublexical processes in reading

The purpose of the present study was to compare the brain regions and systems that subserve lexical and sublexical processes in reading. In order to do so, three types of tasks were used: (i). silent reading of very high frequency regular words (lexical task); (ii). silent reading of nonwords (sublexical task); and, (iii). silent reading of very low frequency regular words (sublexical task). All three conditions were contrasted with a visual/phonological baseline condition. The lexical condition engaged primarily an area at the border of the left angular and supramarginal gyri. Activation found in this region suggests that this area may be involved in mapping orthographic-to-phonological whole word representations. Both sublexical conditions elicited significantly greater activation in the left inferior prefrontal gyrus. This region is thought to be associated with sublexical processes in reading such as grapheme-to-phoneme conversion, phoneme assembly and underlying verbal working memory processes. Activation in the left IFG was also associated with left superior and middle temporal activation. These areas are thought to be functionally correlated with the left IFG and to contribute to a phonologically based form of reading. The results as a whole demonstrate that lexical and sublexical processes in reading activate different regions within a complex network of brain structures.     

Habitual Prospective Memory and Aging: Remembering Intentions and Forgetting Actions

Routine or habitual prospective memory tasks (e.g., taking medication) have the potential for creating confusions regarding whether or not an action has already been performed. We developed a laboratory paradigm for examining the kinds of processes thought to be operating in these kinds of tasks. Younger and older participants were asked to perform an action once and only once on each of 11 trials. The results showed that age and divided attention contributed to both omission and repetition errors. This new paradigm reveals memory failures in a habitual prospective memory task, and the results demonstrate that older adults are particularly susceptible to these memory problems.     

Results of treatment of leg paraspasm cases following longitudinal frontal myelotomy

Follow-up examinations of 14 patients on whom longitudinal frontal myelotomy had been performed because of extreme leg spasms, showed consistently good results as far as spasm removal was concerned. Effective rehabilitation is possible only if the basic condition is stationary, if the operation is made at an early stage and followed by a comprehensive rehabilitation programme. For patients with an advancing condition the operation can alleviate the subjective discomfort felt, and it can make care easier.     

Dimensionality and the dynamics of human unstable equilibrium

Maintaining an unstable equilibrium requires that multiple joints be coordinated so that the center of mass is kept above the base of support. The authors' aim in the present study was to discover the underlying dynamics of local (foot, hip, or head) and global (center of mass) components involved in balance control and how those dynamics are affected by changes in the available information. Participants (N = 6) had to maintain their balance on an unstable platform. Using dimensional analyses (largest Lyapunov exponent and correlation dimension), the authors examined the active degrees of freedom involved in balance control. Results indicated a similarity in dimension between local (joints) and global (center of mass) components, between a fixed point and a limit cycle. The behavior of the center of mass was found to be more predictable than the behavior of its local constituents. In addition, the available visual information affected the predictability of the postural behavior, which suggests that vision is used in the stabilization of the low-dimensional dynamics underlying balance control.     

Semi‐parametric proportional hazards models with crossed random effects for psychometric response times

The semi‐parametric proportional hazards model with crossed random effects has two important characteristics: it avoids explicit specification of the response time distribution by using semi‐parametric models, and it captures heterogeneity that is due to subjects and items. The proposed model has a proportionality parameter for the speed of each test taker, for the time intensity of each item, and for subject or item characteristics of interest. It is shown how all these parameters can be estimated by Markov chain Monte Carlo methods (Gibbs sampling). The performance of the estimation procedure is assessed with simulations and the model is further illustrated with the analysis of response times from a visual recognition task.     

Comparing perceptual and preferential decision making

Perceptual and preferential decision making have been studied largely in isolation. Perceptual decisions are considered to be at a non–deliberative cognitive level and have an outside criterion that defines the quality of decisions. Preferential decisions are considered to be at a higher cognitive level and the quality of decisions depend on the decision maker’s subjective goals. Besides these crucial differences, both types of decisions also have in common that uncertain information about the choice situation has to be processed before a decision can be made. The present work aims to acknowledge the commonalities of both types of decision making to lay bare the crucial differences. For this aim we examine perceptual and preferential decisions with a novel choice paradigm that uses the identical stimulus material for both types of decisions. This paradigm allows us to model the decisions and response times of both types of decisions with the same sequential sampling model, the drift diffusion model. The results illustrate that the different incentive structure in both types of tasks changes people’s behavior so that they process information more efficiently and respond more cautiously in the perceptual as compared to the preferential task. These findings set out a perspective for further integration of perceptual and preferential decision making in a single ramework.     

Cognitive style in attainment of an upside-down posture in water with and without vision

It is well known that adopting a posture required by the central nervous system takes into account a frame of reference. This frame of reference is built on sensory information and, more particularly, on vision, which is often considered to be the main input. The contribution of vision varies by participant and defines their cognitive style. This study investigates the contribution of visual information and cognitive style to postural strategy and, more precisely, to the construction of an upside-down posture in an underwater condition. Eight synchronized swimmers performed the Rod-and-Frame Test (RFT) to assess their cognitive style and practiced upside-down posture in water to measure their body inclination. The Rod-and-Frame Test scores did not distinguish the participants, as the results of the test showed that most of them were visual-field independent. However, in a closed-eyes condition, participants achieved a more precise vertical position than when using translucent goggles.