Why mental arithmetic counts: Brain activation during single digit arithmetic predicts high school math scores

Do individual differences in the brain mechanisms for arithmetic underlie variability in high school mathematical competence? Using functional magnetic resonance imaging, we correlated brain responses to single digit calculation with standard scores on the Preliminary Scholastic Aptitude Test (PSAT) math subtest in high school seniors. PSAT math scores, while controlling for PSAT Critical Reading scores, correlated positively with calculation activation in the left supramarginal gyrus and bilateral anterior cingulate cortex, brain regions known to be engaged during arithmetic fact retrieval. At the same time, greater activation in the right intraparietal sulcus during calculation, a region established to be involved in numerical quantity processing, was related to lower PSAT math scores. These data reveal that the relative engagement of brain mechanisms associated with procedural versus memory-based calculation of single-digit arithmetic problems is related to high school level mathematical competence, highlighting the fundamental role that mental arithmetic fluency plays in the acquisition of higher-level mathematical competence. © 2013 the authors

Investigating the visual number form area: A replication study

© 2019 The Authors. Published by the Royal Society The influential triple-code model of number representation proposed that there are three distinct brain regions for three different numerical representations: verbal words, visual digits and abstract magnitudes. It was hypothesized that the region for visual digits, known as the number form area, would be in ventral occipitotemporal cortex (vOTC), near other visual category-specific regions, such as the visual word form area. However, neuroimaging investigations searching for a region that responds in a category-specific manner to the visual presentation of number symbols have yielded inconsistent results. Price & Ansari (Price, Ansari 2011 Neuroimage 57, 1205–1211) investigated whether any regions activated more in response to passively viewing digits in contrast with letters and visually similar nonsense symbols and identified a region in the left angular gyrus. By contrast, Grotheer et al. (Grotheer, Herrmann, Kovács 2016 J. Neurosci. 36, 88–97) found bilateral regions in vOTC which were more activated in response to digits than other stimuli categories while performing a one-back task. In the current study, we aimed to replicate the findings reported in Grotheer et al. with Price & Ansari’s passive viewing task as this is the most stringent test of bottom-up, sensory-driven, category-specific perception. Moreover, we used the contrasts reported in both papers in order to test whether the discrepancy in findings could be attributed to the difference in analysis

Generalising Deep Learning MRI Reconstruction across Different Domains

We look into robustness of deep learning based MRI reconstruction when tested on unseen contrasts and organs. We then propose to generalise the network by training with large publicly-available natural image datasets with synthesised phase information to achieve high cross-domain reconstruction performance which is competitive with domain-specific training. To explain its generalisation mechanism, we have also analysed patch sets for different training datasets.Comment: Accepted for ISBI2019 as a 1-page abstrac

The length of time's arrow

An unresolved problem in physics is how the thermodynamic arrow of time arises from an underlying time reversible dynamics. We contribute to this issue by developing a measure of time-symmetry breaking, and by using the work fluctuation relations, we determine the time asymmetry of recent single molecule RNA unfolding experiments. We define time asymmetry as the Jensen-Shannon divergence between trajectory probability distributions of an experiment and its time-reversed conjugate. Among other interesting properties, the length of time's arrow bounds the average dissipation and determines the difficulty of accurately estimating free energy differences in nonequilibrium experiments

The role of the left intraparietal sulcus in the relationship between symbolic number processing and children\u27s arithmetic competence

The neural foundations of arithmetic learning are not well understood. While behavioral studies have revealed relationships between symbolic number processing and individual differences in children\u27s arithmetic performance, the neurocognitive mechanisms that bind symbolic number processing and arithmetic are unknown. The current fMRI study investigated the relationship between children\u27s brain activation during symbolic number comparison (Arabic digits) and individual differences in arithmetic fluency. A significant correlation was found between the numerical ratio effect on reaction times and accuracy and children\u27s arithmetic scores. Furthermore, children with a stronger neural ratio effect in the left intraparietal sulcus (IPS) during symbolic number processing exhibited higher arithmetic scores. Previous research has demonstrated that activation of the IPS during numerical magnitude processing increases over the course of development, and that the left IPS plays an important role in symbolic number processing. The present findings extend this knowledge to show that children with more mature response modulation of the IPS during symbolic number processing exhibit higher arithmetic competence. These results suggest that the left IPS is a key neural substrate for the relationship between the relative of precision of the representation of numerical magnitude and school-level arithmetic competence. © 2012 Elsevier Ltd

An offender's perspective of what motivates and deters white-collar criminals in the South African workplace

The aim of this study was to investigate the motives of white-collar criminals so as to gain a better understanding of white-collar crime and develop measures that can help to reduce it. The study involved face-to-face interviews with white-collar offenders imprisoned at a correctional centre in South Africa. The data collected provided evidence to support the existing theory relating to the motives for whitecollar crime; however, a previously unreported theme of race emerged as a key motivator among the respondents. Race was further identified as a key justification for committing the crime. Suggestions from the respondents to employment relations practitioners on how best to mitigate the risks were also collected and reported. The deterrents that were identified as most effective by the respondents revolved around four themes, namely reports and signing authority, working environment, education and matching roles and responsibilities.http://reference.sabinet.co.za/sa_epublication/labouram201

The role of the left intraparietal sulcus in the relationship between symbolic number processing and children\u27s arithmetic competence

The neural foundations of arithmetic learning are not well understood. While behavioral studies have revealed relationships between symbolic number processing and individual differences in children\u27s arithmetic performance, the neurocognitive mechanisms that bind symbolic number processing and arithmetic are unknown. The current fMRI study investigated the relationship between children\u27s brain activation during symbolic number comparison (Arabic digits) and individual differences in arithmetic fluency. A significant correlation was found between the numerical ratio effect on reaction times and accuracy and children\u27s arithmetic scores. Furthermore, children with a stronger neural ratio effect in the left intraparietal sulcus (IPS) during symbolic number processing exhibited higher arithmetic scores. Previous research has demonstrated that activation of the IPS during numerical magnitude processing increases over the course of development, and that the left IPS plays an important role in symbolic number processing. The present findings extend this knowledge to show that children with more mature response modulation of the IPS during symbolic number processing exhibit higher arithmetic competence. These results suggest that the left IPS is a key neural substrate for the relationship between the relative of precision of the representation of numerical magnitude and school-level arithmetic competence. © 2012 Elsevier Ltd

Monitoring Micelle Formation in Mixtures of Linear and Foldon-capped Polypeptides with Light Scattering Spectroscopy

Elastin-like polypeptide (ELP) polymers are ideal for producing environmentally responsive micellar systems because they exhibit a transition from being water-soluble at low temperatures to phase-separated at high temperatures. For application development of drug delivery vehicles and biosensing nanoparticles, it is important to prepare spherical micelles of controlled diameter and shape. Since at a given salt concentration, the headgroup area for each foldon should be constant, the size of the micelles is expected to be proportional to the volume of the linear ELP available per foldon headgroup. Therefore, adding linear ELPs to a system of ELP-foldon should result in changes of the micelle volume. At higher salts the electrostatic repulsion between headgroups is shielded, reducing the effective size of foldon headgroups, increasing the packing factor of micelles which leads to formation of non-spherical micelles. The effects of addition of linear ELPs on size, shape, and molecular weight of micelles at different salt concentrations were studied by a combination of Depolarized Dynamic Light Scattering (DDLS) and Static Light Scattering (SLS) Spectroscopies. The initial results on 50 μM ELPfoldon samples (at 25 mM salt) show that the apparent hydrodynamic radius of mixed micelles increases more than 5-fold as the amount of linear ELP raised from 0 to 50 μM. The size increase is accompanied by significant increase in depolarized scattering indicating the growing geometrical anisotropy of the micelles with increase of added linear ELP. In addition, the increase of the amount of linear ELP in the mixed micelles significantly increased the relative molecular weight of the micelles.https://engagedscholarship.csuohio.edu/u_poster_2014/1024/thumbnail.jp

Controlling Micelle Formation Using Mixtures of Linear and Foldon-capped Polypeptides (ELP): Measurements with UV-vis Spectroscopy

Polymer surfactants developed in our lab have a protein headgroup (foldon) and three elastin-like polypeptide (ELP) tails. They can form micelles smaller than 30 nm, which may be useful in developing targeted drug delivery vehicles. Specifically, ELPs are capped with foldon, which is a 27 amino acid sequence that folds as a homotrimer, resulting in a three-armed star polypeptide. This structure has been shown to form micelles above the transition temperature (Tt) of the ELP. The salt concentration affects the interaction between the headgroups affecting how the micelles assemble. At low salt concentrations the ELP-foldon will form spherical micelles; whereas, at higher salt concentrations the micelles are non-spherical, as is demonstrated by light scattering. When linear ELP is mixed with ELP foldon, it is expected that the ELP-foldon will stabilize small droplets of linear ELP in the form of a microemulsion. Different ratios of ELP-foldon to linear ELP were prepared and their transition behavior was characterized using turbidity measured with UV-vis spectroscopy. The turbidity increased at the Tt of the ELP, and then dropped substantially at the Tt of the ELPfoldon. Increased concentration of the linear ELP increased the measured turbidity level after both transitions, suggesting an increase in aggregate size. Light scattering was utilized to further characterize the size and shape of the aggregates formed.https://engagedscholarship.csuohio.edu/u_poster_2014/1013/thumbnail.jp

The Inferior Temporal Numeral Area distinguishes numerals from other character categories during passive viewing: A representational similarity analysis

A region in the posterior inferior temporal gyrus (pITG) is thought to be specialized for processing Arabic numerals, but fMRI studies that compared passive viewing of numerals to other character types (e.g., letters and novel characters) have not found evidence of numeral preference in the pITG. However, recent studies showed that the engagement of the pITG is modulated by attention and task contexts, suggesting that passive viewing paradigms may be ill-suited for examining numeral specialization in the pITG. It is possible, however, that even if the strengths of responses to different category types are similar, the distributed response patterns (i.e., neural representations) in a candidate numeral-preferring pITG region ( pITG-numerals ) may reveal categorical distinctions, even during passive viewing. Using representational similarity analyses with three datasets that share the same task paradigm and stimulus sets (total N = 88), we tested whether the neural representations of digits, letters, and novel characters in pITG-numerals were organized according to visual form and/or conceptual categories (e.g., familiar versus novel, numbers versus others). Small-scale frequentist and Bayesian meta-analyses of our dataset-specific findings revealed that the organization of neural representations in pITG-numerals is unlikely to be described by differences in abstract shape, but can be described by a categorical digits versus letters distinction, or even a digits versus others distinction (suggesting greater numeral sensitivity). Evidence of greater numeral sensitivity during passive viewing suggest that pITG-numerals is likely part of a neural pathway that has been developed for automatic processing of objects with potential numerical relevance. Given that numerals and letters do not differ categorically in terms of shape, categorical distinction in pITG-numerals during passive viewing must reflect ontogenetic differentiation of symbol set representations based on repeated usage of numbers and letters in differing task contexts