Developmental grey matter changes in superior parietal cortex accompany improved transitive reasoning

The neural basis of developmental changes in transitive reasoning in parietal regions was examined, using voxel-based morphometry. Young adolescents and adults performed a transitive reasoning task, subsequent to undergoing anatomical magnetic resonance imaging (MRI) brain scans. Behaviorally, adults reasoned more accurately than did the young adolescents. Neural results showed (i) less grey matter density in superior parietal cortex in the adults than in the young adolescents, possibly due to a developmental period of synaptic pruning; (ii) improved performance in the reasoning task was negatively correlated with grey matter density in superior parietal cortex in the adolescents, but not in the adult group; and (iii) the latter results were driven by the more difficult trials, requiring greater spatial manipulation. Taken together, the results support the idea that during development, regions in superior parietal cortex are fine-tuned, to support more robust spatial manipulation, resulting in greater accuracy and efficiency in transitive reasoning.     

Understanding Goal Motivations in Deprived Contexts: Perspectives of Adults in Two Rural South African Communities

The aim of the present study was to explore and describe the goals and motivations underlying them for adults living in rural African contexts using an inductive approach. Seventy participants (n = 25 males, n = 45 females) between 43 and 89 years (mean age 60.85 years) were selected from a total of N = 537 residing in the rural Ganyesa and Tlakgameng communities in South Africa. Participants were asked to indicate the three most important goals in their present lives and then provide reasons why each of these goals was important to them. Themes emerging from the data analysis referred to financial security, meeting social needs, environmental considerations, generative caring, and relational goals. Goal motivations were not mere intrinsic processes aimed at personal need satisfaction, but had a strong interdependent focus embedded in existing relational ties. Based on the findings we conceptualise an integration of key constructs found in diverse perspectives used in goal research and emphasise the unique role of contextual factors in the understanding of goals and motivations underlying them. These findings highlight important considerations in the enhancement of the quality of life of rural residents of Ganyesa and Tlakgameng.

     

Dynamics of human postural transitions

In the present study, the authors examined transitions between postural coordination modes involved in human stance. The analysis was motivated by dynamical theories of pattern formation, in which coordination modes and transitions between modes are emergent, self-organized properties of the dynamics of animal-environment systems. In 2 experiments, standing participants tracked a moving target with the head. Results are consistent with the hypothesis that changes in body coordination follow typical nonequilibrium phase transitions, exhibiting multistability, bifurcation, critical fluctuations, hysteresis, and critical slowing down. The findings suggest that posture may be organized in terms of dynamical principles and favor the existence of general and common principles governing pattern formation and flexibility in complex systems.     

On the role of familiarity with units of measurement in categorical accentuation: Tajfel and Wilkes (1963) revisited and replicated

The present article provides evidence for the role of participants' familiarity with units of measurement in categorical accentuation with unidimensional physical estimates. Belgian and American participants estimated the lengths of lines varying in length. Depending on the condition, the lines were or were not systematically associated with categorical labels, and the estimates were made either in inches or in centimeters. Consistent with our predictions, (a) categorical accentuation was higher when the lines were systematically categorized than when they were not, and (b) this effect was stronger when participants reported their estimates in an unfamiliar measurement unit (i.e., Belgian participants using inches, and American participants using centimeters). These findings support the view that people's reliance on categorical information is more likely to emerge given uncertain contexts of judgment. Additionally, they may help explain why researchers have had difficulties replicating the categorical accentuation effect in the past.     

Treatment dynamics in sensorimotor disorders: the contribution of electrophysiology]

In the field of sensorimotor activities, progresses achieved over the last fifty years have been largely driven by the Reaction Time (RT) paradigm. Information processing models are set in the context of a global breakdown of sensorimotor activities in multiple concatenated stages, each aggregated in many fundamental operations that are functionally linked. If there is a consensus today about this breakdown, the way stages organize themselves in time however is still much debated. According to one hypothesis, there is no temporal overlap between each stages: the process occurs sequentially. According to another theory, the stages overlap over in time: the process occurs in a parallel manner. A behavioral analysis does not allow to determine between these two hypothesis because the RT represents the final product of the whole sensorimotor pathway, while the temporal organization of the processing of information depends on the nature of the transfer between individual stages. An all-or-nothing information transfer, also called discrete, leads to a sequential organization, while a progressive or continuous transfer brings about a parallel organization. Moreover, contrary to a preconceived notion, data obtained from classical neurophysiology are compatible with both a sequential organization and a parallel organization. Particularly, the great number of connections between the different elements of the nervous system has often seemed difficult to conciliate with a sequential organization. In fact, this argument is inadmissible because it stems from confusion between a temporal organization and an anatomical organization of the processing of information. More generally, our knowledge of the functional anatomy of sensorimotor activities imposes but few constraints on the temporal organization patterns of the processing of information. The lack of interest for the neurophysiological argument seems essentially due to the fact that theses arguments rest on research which is not aimed at the temporal organization of the sensorimotor information processing. Recently, approaches that integrate concepts and methods used in experimental psychology and neurosciences have contributed to putting in perspective the organization of information processing. Electromyography, EEG, reflexology and neuronal recording techniques have been used in the context of two inference logics. The first logic, that we call "factual", is based on the study of functional relations between RT and certain neuronal events. The second logic, that we call "chronometric", is based on the study of the relationships between RT and intervals resulting from the breakdown of the RT in relation to certain neuronal events. Generally speaking, most studies suggest that in tasks where the stimulus is composed of numerous attributes, information processing operates in parallel. On the other hand, when the stimulus is made up of a single attribute, information processing could be operating in a sequential manner. One weakness of this electrophysiological approach is that it has so far only examined relationships between physiological indicators and means RT. We propose here to offset these weaknesses by examining functional relationships between RT distribution variances and certain neuronal events linked to information processing.     

Involvement of the medial prefrontal cortex in two alternation tasks using different environments

Spatial alternation performance in rats is usually evaluated with the T-Maze. The first aim of this study was to analyze the effect of a selective lesion of medial prefrontal cortex (mPFC) on performance in a T-maze. Second, we wanted to validate a new test using alternation in a water maze (AWM). The mPFC of 21 male Sprague-Dawley rats was lesioned bilaterally using in situ microinjection of ibotenic acid. Thirteen control rats received injections of the vehicle only. Results show that mPFC lesioned rats were significantly impaired in the T-Maze as well as in the AWM compared to controls. These results validate the AWM as a frontal cortex dependent task probing working memory and/or behavioral flexibility. We suggest that the AWM may be more powerful than the T-maze as an investigational tool, given that is can be easily compared to other water maze tasks that evaluate other (nonfrontal) cognitive modules.     

Application of stochastic modeling to the assessment of group and individual differences in cognitive functioning

This article begins with a guiding schema of relations among cognitive science, clinical science, and assessment technology. Emphasis is placed on stochastic modeling of cognitive processes. Basic models are adjusted so as to parsimoniously accommodate performance deviations occurring with psychopathology. Modified portions of models indicate functions affected by disorder, whereas portions remaining intact indicate spared functions. Findings from clinical cognitive science are applied to the individual case using Bayesian procedures. Methods are instantiated with respect to cognitive psychopathology of paranoid schizophrenia. The authors address observations and issues arising from this application, including integration of these methods with current assessment practices.