Math anxiety and the shifting function: An event-related potential study of arithmetic task switching.

Why is math anxiety usually related to less efficient math processing? According to attentional control theory, anxiety leads to reduced attentional control, which often entails a greater investment of resources (e.g., more time or effort) to carry out a cognitive task. The executive functions mainly affected by anxiety are inhibition and shifting. Previous studies suggest that math anxiety may impair the inhibitory function. In the present study, the relationship between math anxiety and shifting efficiency when switching between two-digit additions and subtractions was examined. Twenty highly math-anxious and 20 low math-anxious individuals participated in an event-related potential (ERP) transition-cueing experiment. Math anxiety was expected to delay the shifting process, leading to a larger switch cost in response time and no centroparietal cue-locked switch-specific positivity registered in the electroencephalogram during the cue-target interval. Highly math-anxious individuals showed a larger switch cost than their low math-anxious peers. Asymmetrical switch effects between operations in response time were found in both groups, which might be due to larger sequential difficulty effects after subtractions than after additions. The cue-locked switch-specific positivity was present only in the low math-anxious group. The present results suggest that highly math-anxious individuals take longer to shift task sets. Additionally, the highly math-anxious group showed a more positive frontal P2 after the cue that announced a switch to subtraction, probably indicating stronger attentional capture by this cue, because the most threatening condition is anticipated. Taken together, these data suggest that math anxiety also impairs attentional control when switching between arithmetic tasks.

Use of Rapid Drug Desensitization in Delayed Hypersensitivity Reactions to Chemotherapy and Monoclonal Antibodies.

Background: Rapid drug desensitization (RDD) allows first-line therapies in patients with immediate drug hypersensitivity reactions (DHR) to chemotherapeutic drugs (ChD) and monoclonal antibodies (mAb). Desensitization in delayed drug reactions has traditionally used slow protocols extending up to several weeks; RDD protocols have been scarcely reported. Patients and Method: We retrospectively analyzed the patients referred to the Allergy Department, who had experienced a delayed DHR (> 6 h) related to a ChD or mAb and underwent an RDD protocol. The rate of successful administration of the offending drug and the presence of adverse reactions were evaluated. Results: A total of 93 RDDs were performed in 11 patients (including 6 men and 5 women, with a median age of 61 years). The primary DHR were maculopapular exanthema (MPE) (8), generalized delayed urticaria (1), MPE with pustulosis and facial edema (1), and facial edema with desquamative eczema (1). The meantime for the onset of symptoms was 3 days (range 1-16 days). RDD was performed using a protocol involving 8-13 steps, with temozolomide (25), bendamustine (4), rituximab (9), infliximab (24), gemcitabine (23), and docetaxel (8), within 4.6-6.5 h. Sixteen breakthrough reactions were reported during the RDD (17.2 %) in 5 patients; all were mild reactions including 11 delayed and 5 immediate reactions. All patients completed their treatment. Conclusions: RDD is a potentially safe and effective procedure in patients suffering from delayed reactions to ChD and mAb. It allows them to receive full treatment in a short period, thereby reducing time and hospital visits.

Spatial processing in a mental rotation task: Differences between high and low math-anxiety individuals.

Previous studies suggested that highly math-anxious (HMA) individuals invest more attentional resources than their low math-anxious (LMA) peers in numerical tasks, and have worse spatial skills. We aimed to explore whether they also need to apply more resources in spatial tasks. In this study, HMA and LMA individuals saw normal or mirror-reversed letters in six orientations and made mirror-normal decisions. In both groups, response times and errors increased with angular deviation from upright and the ERP mental rotation effect was found. However, HMAs were slower to respond than their LMA counterparts. Interestingly, the HMA group showed a larger P3b in greater deviations for normal letters and in all mirrored letters. Since P3b amplitude reflects the attentional resources invested in the categorization of relevant stimuli, HMA individuals may need to devote more processing effort than their LMA peers when performing mental rotation. This finding is consistent with the Attentional Control Theory.

Post-error response inhibition in high math-anxious individuals: Evidence from a multi-digit addition task.

The aim of the study was to investigate how high math-anxious (HMA) individuals react to errors in an arithmetic task. Twenty HMA and 19 low math-anxious (LMA) individuals were presented with a multi-digit addition verification task and were given response feedback. Post-error adjustment measures (response time and accuracy) were analyzed in order to study differences between groups when faced with errors in an arithmetical task. Results showed that both HMA and LMA individuals were slower to respond following an error than following a correct answer. However, post-error accuracy effects emerged only for the HMA group, showing that they were also less accurate after having committed an error than after giving the right answer. Importantly, these differences were observed only when individuals needed to repeat the same response given in the previous trial. These results suggest that, for HMA individuals, errors caused reactive inhibition of the erroneous response, facilitating performance if the next problem required the alternative response but hampering it if the response was the same. This stronger reaction to errors could be a factor contributing to the difficulties that HMA individuals experience in learning math and doing math tasks.

Efficiency of Arithmetic Procedures Modulates the Problem-Size Effect in Subtraction.

The aim of this study was to examine whether differences in strategy selection and/or strategy efficiency can explain the modulation of the problem-size effect by arithmetic skill. More specifically, we wondered whether arithmetic skill increases the use of retrieval strategy in large problems, and/or enhances the efficiency of either retrieval or procedural strategies. The performance of highly-skilled (HS) and less highly-skilled (LS) individuals on a subtraction verification task was analyzed according to problem size and to the strategy reported on a trial-by-trial basis after each problem. The problem size effect was larger for LS individuals than for their HS peers, both in response time and in hit rate. Nevertheless, groups did not differ regarding the strategy reported for each subtraction size. As expected, problems in which retrieval strategy was reported were solved more quickly and more accurately than problems solved by procedural strategies. Responses using retrieval strategy were equally fast in the two groups, but HS individuals performed better than LS when using procedural strategies. The results therefore suggest that the differences in behavioral measures between groups might specifically be due to differences in the efficiency of procedural strategies.

Less precise representation of numerical magnitude in high math-anxious individuals: an ERP study of the size and distance effects.

Numerical comparison tasks are widely used to study the mental representation of numerical magnitude. In study, event-related brain potentials (ERPs) were recorded while 26 high math-anxious (HMA) and 27 low math-anxious (LMA) individuals were presented with pairs of single-digit Arabic numbers and were asked to decide which one had the larger numerical magnitude. The size of the numbers and the distance between them were manipulated in order to study the size and the distance effects. The results showed that both distance and size effects were larger for the HMA group. As for ERPs, results showed that the ERP distance effect had larger amplitude for both the size and distance effects in the HMA group than among their LMA counterparts. Since this component has been taken as a marker of the processing of numerical magnitude, this result suggests that HMA individuals have a less precise representation of numerical magnitude.

Individual differences in arithmetic skill reflected in event-related brain potentials.

We used event-related brain potentials (ERP) to study the problem-size effect in individuals with high and low arithmetic skill. Participants were presented with a classic equality verification task, and problem size was manipulated by using small (e.g., 3+4), medium (e.g., 7+8) and large problems (e.g., 16+29). ERP analyses were time-locked to the onset of the second operand in order to address brain potentials during the production phase. High-skill individuals showed a positive slow wave when solving large problems and no differences in the ERP pattern when solving small and medium problems. In contrast, low-skill individuals showed a positive slow wave when solving medium and large problems. Given that differences between high and low skill individuals have been related to differences in calculation strategies, these results provide further support to the utility of using ERP as a signature of arithmetic strategy.

Mental rotation of mirrored letters: evidence from event-related brain potentials.

Event-related brain potentials (ERPs) were recorded while participants (n=13) were presented with mirrored and normal letters at different orientations and were asked to make mirror-normal letter discriminations. As it has been suggested that a mental rotation out of the plane might be necessary to decide on mirrored letters, we wanted to determine whether this rotation occurs after the plane rotation in mirror rotated letters. The results showed that mirrored letters in the upright position elicited a negative-going waveform over the right hemisphere in the 400-500 ms window. A similar negativity was also present in mirrored letters at 30 degrees, 60 degrees, and 90 degrees, but in these cases it was delayed. Moreover, the well-known orientation effect on the amplitude of the rotation-related negativity was also found, although it was more evident for normal than for mirrored letters. These results indicate that the processing of mirrored letters differs from that of normal letters, and suggest that a rotation out of the plane after the plane rotation may be involved in the processing of mirror rotated letters.

Probing thymine with laser ablation molecular beam Fourier transform microwave spectroscopy.

Laser ablation in combination with molecular beam Fourier transform microwave spectroscopy has been used to establish unambiguously the presence of the diketo form of thymine in the gas phase and to obtain its structure.

The shape of beta-alanine.

The combination of Fourier transform microwave spectroscopy in a pulsed supersonic jet with laser ablation has made beta-alanine amenable to a structural study in the gas phase. Two new conformers of beta-alanine have been identified together with the two previously observed by McGlone and Godfrey [J. Am. Chem. Soc. 1995, 117, 1043]. The comparison between the experimental rotational and 14N nuclear quadrupole coupling constants and those calculated ab initio provide a definitive test for molecular structures and confirm unambiguously the identification of all conformers. For the two most abundant conformers, an intramolecular hydrogen bond between the amino group and carbonyl oxygen (N-H...O=C) is established, and the COOH adopts a cis-COOH configuration. The next conformer in order of abundance presents an O-H...N intramolecular hydrogen bond with a trans configuration for the COOH group. The high sensitivity of the experiment has allowed us to detect for the first time a conformer uniquely stabilized by an n-pi* hyperconjugative interaction between the nucleophile N: of the amino group and the pi* orbital at the carbonyl group. Partial conformational relaxation has been observed in the supersonic expansion.

N400 and category exemplar associative strength.

The main purpose of this study was to examine if the N400 amplitude can be considered an index of category exemplar strength of association in a semantic categorization task. Series of six words from a particular semantic category were used as context, and the strength of association between the seventh word and the category was manipulated. Moreover, subjects were asked to perform two different tasks: one consisting of reading the words for comprehension and the other of making a decision regarding the congruence of the ending word. Results showed that the N400 component was elicited by whichever word that was not the best exemplar for the category (atypical members and nonmember of the category). No interaction between type of ending word and type of task was found around 400 ms poststimuli although the P3b component was present for infrequent stimuli in the decision task. It is concluded that the N400 amplitude is sensitive to category membership although no specific attention to the semantic relationship between words was required.

Problem size effect in additions and subtractions: an event-related potential study.

The psychophysiological basis of problem size effect in the arithmetical processing of additions and subtractions was studied with event-related brain potentials (ERP). Subjects were presented sequences of seven numbers, and ERPs elicited to the sixth number were analyzed. Two variables were manipulated: operation type (addition and subtraction) and problem size (by adding or subtracting 2, 3 or 4). Results showed two phases in the ERP pattern: an early phase, appearing to reflect automatic processing involved in stimulus identification, and a positive slow wave, believed to be a computing indicator of the subsequent calculation. The amplitude of this positive slow wave was modulated by the problem size (the more problem size, the larger the amplitude), suggesting that the amplitude of this slow wave indexes the activation of the cerebral network underlying problem size effect.

P600 related to rule violation in an arithmetic task.

The goal of the present paper was to study if a similar neurophysiological process is required for treating violations of both arithmetical rules and linguistic syntactic structures. It has been shown that syntactic violations elicit the P600/syntactic positive shift (SPS) component, reflecting secondary parsing processes or repairing of an incorrect syntactic structure. However, late positivities, similar to the P600/SPS component, are also elicited by other types of violations (e.g. harmonic anomalies or violations in non-linguistic abstract rules), so this component is thought to be an index of detection for any anomaly in rule-governed sequences. We carried out an experiment where violations of arithmetic rules were presented. These violations were evident to a greater or lesser degree (a number very different or very similar to that which correctly completed a series of seven numbers). The type of rule was also manipulated, and increasing and decreasing series were presented. Results showed a late centro-parietal positivity related to arithmetic violations, whose amplitude was larger, the more evident the violation presented was, in both addition and subtraction. It is concluded that a similar neurophysiological process could be required for the processing of violations in numerical sequences and in linguistic syntactic structures. When the rule was broken, another component was present for the adding operation: an early negativity peaking between 250- and 300-ms post-stimulus. Regarding this negative peak, although some possible explanations are drawn, further research needs to be carried out in order to gather more knowledge about it.