Verbal structure of numerals and digits handwriting: New evidence from kinematics

Two experiments used a digitizing tablet to analyse the temporal, spatial, and kinematic characteristics of handwritten production of arabic numbers. They addressed a specific issue of the numerical domain: Does the lexical and syntactic structure of verbal numerals influence the production of arabic numerals (Experiments 1 and 2), even after enforced semantic processing in a comparison task (Experiment 2)? Subjects had to write multi-digit arabic numerals (e.g., 1200) presented in two different verbal structures: a multiplicative one (e.g., teen-hundred, douze cents (twelve hundred)) or an additive one (e.g., thousand-unit-hundred, mille deux cents (one thousand two hundred)). Results show differences in the inter-digit jumps that reflect the influence of the structure of verbal numerals, even after the semantic task. This finding is discussed with regard to different models of number transcoding (McCloskey, Caramazza, & Basili, 1985; Power & Dal Martello, 1990, 1997).     

Spatiotemporal boundaries of linear vection

Thresholds for the perception of linear vection were measured. These thresholds allowed us to define the spatiotemporal contrast surface sensitivity and the spatiotemporal domain of the perception of rectilinear vection (a visually induced self-motion in a straight line). Moreover, a Weber’s law was found, such that a mean relative differential threshold in angular velocity of about 41% is necessary to perceive curvilinear vection. This visually induced self-motion corresponds to the sensation of moving in a curved path. It is proposed that curvilinear vection is induced when the apparent velocity difference is detectable. The spatiotemporal domain of perception of rectilinear vection and its spatiotemporal contrast surface sensitivity are centered on low spatial frequencies. Concurrently, the values which correspond to the relative differential thresholds of curvilinear vection are low spatial frequencies. Accordingly, the peripheral ambient visual system seems to be involved in perceiving linear vection. It is argued further that the central ambient system might also be involved in the processing of linear vection.     

Diminished heart rate complexity in adolescent girls: a sign of vulnerability to anxiety disorders?

Background and Objectives: Diminished heart rate variability has been found to be associated with high anxiety symptomatology. Since adolescence is the period of onset for many anxiety disorders, this study aimed to determine sex- and anxiety-related differences in heart rate variability and complexity in adolescents.

Methods: We created four groups according to sex and anxiety symptomatology: high-anxiety girls (n?=?24) and boys (n?=?25), and low-anxiety girls (n?=?22) and boys (n?=?24) and recorded their cardiac function while they performed regular school activities. A series of two-way (sex and anxiety) MANOVAs were performed on time domain variability, frequency domain variability, and non-linear complexity.

Results: We obtained no multivariate interaction effects between sex and anxiety, but highly anxious participants had lower heart rate variability than the low-anxiety group. Regarding sex, girls showed lower heart rate variability and complexity than boys.

Conclusions: The results suggest that adolescent girls have a less flexible cardiac system that could be a marker of the girls’ vulnerability to developing anxiety disorders.     

Flanker compatibility effects in patients with Parkinson's disease: impact of target onset delay and trial-by-trial stimulus variation

Parkinson’s disease (PD) patients and healthy controls were administered a flanker task that consisted of the presentation of colored targets and distractors. Participants were required to attend to the center target and identify its color. The stimulus displays were either congruent (i.e., the target and flankers were the same color) or incongruent. The time between the onset of the flanker and the target color (the target onset delay) was either short or long. Results indicated that PD patients and controls did not differ in the magnitude of the flanker effect within individual trials in that both groups demonstrated a typical flanker effect at the short target onset delay and neither group demonstrated a flanker effect at the longer delay. However, when performance was examined on a trial-by-trial basis, PD patients demonstrated a slowing of reaction time relative to controls when having to make the same response across consecutive trials at longer inter-trial intervals when the flankers were incongruent across consecutive trials and the display on the second of two trials was incongruent. These results indicate that PD patients are impaired in inhibiting the distractors over an extended delay and that this deficit may impact motor responding in these patients, suggesting that the basal ganglia contribute to the interface of attention and action.     

The odd-even effect in multiplication: Parity rule or familiarity with even numbers?

This study questions the evidence that a parity rule is used during the verification of multiplication. Previous studies reported that products are rejected faster when they violate the expected parity, which was attributed to the use of a rule (Krueger, 1986; Lemaire & Fayol, 1995). This experiment tested an alternative explanation of this effect: the familiarity hypothesis. Fifty subjects participated in a verification task with contrasting types of problems (even x even, odd x odd, mixed). Some aspects of our results constitute evidence against the use of the parity rule: False even answers were rejected slowly, even when the two operands were odd. We suggest that the odd-even effect in verification of multiplication could not be due to the use of the parity rule, but rather to a familiarity with even numbers (three quarters of products are indeed even).     

The Structure of Idealization in Biological Theories: The Case of the Wright-Fisher Model

In this paper we present a new framework of idealization in biology. We characterize idealizations as a network of counterfactual and hypothetical conditionals that can exhibit different ??degrees of contingency??. We use this idea to say that, in departing more or less from the actual world, idealizations can serve numerous epistemic, methodological or heuristic purposes within scientific research. We defend that, in part, this structure explains why idealizations, despite being deformations of reality, are so successful in scientific practice. For illustrative purposes, we provide an example from population genetics, the Wright-Fisher Model.     

Strengthening Connections: Functional Connectivity and Brain Plasticity

The ascendancy of functional neuroimaging has facilitated the addition of network-based approaches to the neuropsychologist’s toolbox for evaluating the sequelae of brain insult. In particular, intrinsic functional connectivity (iFC) mapping of resting state fMRI (R-fMRI) data constitutes an ideal approach to measuring macro-scale networks in the human brain. Beyond the value of iFC mapping for charting how the functional topography of the brain is altered by insult and injury, iFC analyses can provide insights into experience-dependent plasticity at the macro level of large-scale functional networks. Such insights are foundational to the design of training and remediation interventions that will best facilitate recovery of function. In this review, we consider what is currently known about the origin and function of iFC in the brain, and how this knowledge is informative in neuropsychological settings. We then summarize studies that have examined experience-driven plasticity of iFC in healthy control participants, and frame these findings in terms of a schema that may aid in the interpretation of results and the generation of hypotheses for rehabilitative studies. Finally, we outline some caveats to the R-fMRI approach, as well as some current developments that are likely to bolster the utility of the iFC paradigm for neuropsychology.