Selection of Neurological Surgery Applicants and the Value of Standardized Letters of Evaluation: A Survey of United States Program Directors.

BACKGROUND: The letter of recommendation (LOR) represents a nonstandardized way to evaluate residency candidates. The goal of this project was to assess the current components of the Electronic Residency Application Service application and to determine and develop support for a standardized letter of evaluation (SLOE) in the resident selection process. METHODS: A 16-question survey was sent to US neurosurgery program directors. In addition to demographic information, respondents were asked to rank 7 aspects of the current application (1-7), evaluate the inclusion of specific standardized questions about applicants (yes or no), note their agreement with statements about LORs (on a 5-point Likert scale), and provide any additional comments. RESULTS: Fifty-three of 113 program directors (47%) completed the survey. The interview (average rank, 2.0 ± 1.4), United States Medical Licensing Exam step 1 score (2.86 ± 1.4), and LOR (2.96 ± 1.5) were ranked as the most important aspects of the application. Agreement was high for items regarding the utility of the current LOR (51%-78% agreement). Almost two-thirds (65%) of program directors agreed that implementing a standardized LOR would improve the resident selection process. Inclusion of questions regarding applicants' work ethic, teamwork, communication, professionalism, and initiative were strongly supported (>80% in favor), whereas including a question on theoretical rank position was mixed (54%). CONCLUSIONS: Most neurosurgical program directors agree that increasing the objectivity of the application would be beneficial, including the addition of standardized questions. However, there is only moderate interest in implementing an SLOE.

Reading skill-fractional anisotropy relationships in visuospatial tracts diverge depending on socioeconomic status.

Low socioeconomic status (SES) has been repeatedly linked with decreased academic achievement, including lower reading outcomes. Some lower SES children do show skills and scores commensurate with those of their higher SES peers, but whether their abilities stem from the same systems as high SES children or are based on divergent strategies is unknown. We here investigated a potential interactive relationship between SES and real-word reading skill in the white matter in 42 typically developing children. SES was determined based on parental education; reading skill and age were not significantly related to SES. There was a significant neural interaction: Clusters in the bilateral inferior longitudinal fasciculus (ILF), left superior longitudinal fasciculus, and left corticospinal tract demonstrated interactive skill-SES relationships in fractional anisotropy. Follow-up analyses demonstrated that higher SES children showed a positive relationship between fractional anisotropy, reflecting tract coherence, and reading skill in left hemisphere tract clusters, whereas lower SES children showed a positive relationship in the right hemisphere homologues. Broadly, the ILF has been demonstrated to support orthographic skill on the left and more general visuospatial processing on the right, so high reading achievement in lower SES children may rely on supplementary visuospatial processing more than for higher SES readers. This pattern is consistent with previous work reporting low SES children's environments to include less rich verbal experience, which may lead them to disproportionately draw on visuospatial skills for success. Further, these results indicate that group SES differences may be best described by an adaptive, not a deficit, model.

The direct segment of the arcuate fasciculus is predictive of longitudinal reading change.

Structural coherence across the arcuate fasciculus has previously been related to reading skill, but the arcuate may be divisible into distinct subtracts which support different functions. Here, we examine longitudinal data from 30 children between the ages of 8 and 14 to determine whether initial coherence in any of the arcuate's subsections is predictive of changes in reading across a longitudinal interval of approximately three years. The arcuate was divided using probabilistic tractography; mean fractional anisotropy across each subtract was extracted for each participant. Time 1 to Time 2 change in reading skill (identification, fluency score average) was significantly and uniquely predicted by only direct fronto-temporal arcuate segment coherence. Participants with lower direct segment FA demonstrated decreases in reading scores, potentially reflecting lessened improvements due to continued inefficient processing. These results were consistent in the older and younger halves of the sample. As such, we demonstrate that it is specifically the direct segment of the arcuate that may support and be predictive of reading skill both initially and longitudinally across development.

Individual differences in crossmodal brain activity predict arcuate fasciculus connectivity in developing readers.

Crossmodal integration of auditory and visual information, such as phonemes and graphemes, is a critical skill for fluent reading. Previous work has demonstrated that white matter connectivity along the arcuate fasciculus (AF) is predicted by reading skill and that crossmodal processing particularly activates the posterior STS (pSTS). However, the relationship between this crossmodal activation and white matter integrity has not been previously reported. We investigated the interrelationship of crossmodal integration, both in terms of behavioral performance and pSTS activity, with AF tract coherence using a rhyme judgment task in a group of 47 children with a range of reading abilities. We demonstrate that both response accuracy and pSTS activity for crossmodal (auditory-visual) rhyme judgments was predictive of fractional anisotropy along the left AF. Unimodal (auditory-only or visual-only) pSTS activity was not significantly related to AF connectivity. Furthermore, activity in other reading-related ROIs did not show the same AV-only AF coherence relationship, and AV pSTS activity was not related to connectivity along other language-related tracts. This study is the first to directly show that crossmodal brain activity is specifically related to connectivity in the AF, supporting its role in phoneme-grapheme integration ability. More generally, this study helps to define an interdependent neural network for reading-related integration.

Brain systems involved in arithmetic with positive versus negative numbers.

Positive number arithmetic is based on combining and separating sets of items, with systematic differences in brain activity in specific regions depending on operation. In contrast, arithmetic with negative numbers involves manipulating abstract values worth less than zero, possibly involving different operation-activity relationships in these regions. Use of procedural arithmetic knowledge, including transformative rules like "minus a negative is plus a positive," may also differ by operand sign. Here, we examined whether the activity evoked in negative number arithmetic was similar to that seen in positive problems, using region of interest analyses (ROIs) to examine a specific set of brain regions. Negative-operand problems demonstrated a positive-like effect of operation in the inferior parietal lobule with more activity for subtraction than addition, as well as increased activity across operation. Interestingly, while positive-operand problems demonstrated the expected addition > subtraction activity difference in the angular gyrus, negative problems showed a reversed effect, with relatively more activity for subtraction than addition. Negative subtraction problems may be understood after translation to addition via rule, thereby invoking more addition-like activity. Whole-brain analyses showed increased right caudate activity for negative-operand problems across operation, indicating a possible overall increase in usage of procedural rules. Arithmetic with negative numbers may thus shows some operation-activity relationships similar to positive numbers, but may also be affected by strategy. This study examines the flexibility of the mental number system by exploring to what degree the processing of an applied usage of a difficult, abstract mathematical concept is similar to that for positive numbers.

Understanding less than nothing: children's neural response to negative numbers shifts across age and accuracy.

We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth-graders and post-instruction seventh-graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth-grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that children who were generally better at working with numbers were better at comparing negatives. In seventh-graders, negative number comparison accuracy significantly predicted their negative number distance effect, indicating that children who were better at working with negative numbers demonstrated a more typical distance effect. Across children, as age increased, the negative number distance effect increased in the bilateral IPS and decreased frontally, indicating a frontoparietal shift consistent with previous numerical development literature. In contrast, as negative comparison task accuracy increased, the parietal distance effect increased in the left IPS and decreased in the right, possibly indicating a change from an approximate understanding of negatives' values to a more exact, precise representation (particularly supported by the left IPS) with increasing expertise. These shifts separately indicate the effects of increasing maturity generally in numeric processing and specifically in negative number understanding.

Imagining the truth and the moon: an electrophysiological study of abstract and concrete word processing.

Previous event-related potential studies have indicated that both a widespread N400 and an anterior N700 index differential processing of concrete and abstract words, but the nature of these components in relation to concreteness and imagery has been unclear. Here, we separated the effects of word concreteness and task demands on the N400 and N700 in a single word processing paradigm with a within-subjects, between-tasks design and carefully controlled word stimuli. The N400 was larger to concrete words than to abstract words, and larger in the visualization task condition than in the surface task condition, with no interaction. A marked anterior N700 was elicited only by concrete words in the visualization task condition, suggesting that this component indexes imagery. These findings are consistent with a revised or extended dual coding theory according to which concrete words benefit from greater activation in both verbal and imagistic systems.

Understanding less than nothing: neural distance effects for negative numbers.

Little work has examined how the mental number system accommodates counterintuitive quantities such as negative numbers, which seem to extend the left end of the mental number line and reverse the established relationship between digit magnitude and value; even less research has been conducted on the neural systems supporting negative number understanding. This study aimed to determine whether adult behavioral and neural responses to negative number paired comparisons were similar to those expected for positive numbers. Mixed pairs (with one positive and one negative number) were also included. Negative number responses demonstrated an increased typical distance effect relative to that for positives, with decreasing response times and intraparietal sulcus activity for comparisons farther apart than those closer together. Negative pairs also showed more activity than positive comparisons across distances in the occipital lobe, inferior and superior parietal lobule, and bilateral caudate and putamen. Mixed pair effect direction varied based on polarity sensitivity, or whether attention to the negative sign was needed for accurate responses, indicating differences in processing strategy. Adults thus draw on brain areas important in numeric processing when dealing with negatives, but also recruit further areas and strategies to support the unique features of negative numbers. The increased distance effect seen may reflect a less mature understanding of negatives. This work expands our knowledge of the flexibility of the mental number system and its ability to represent difficult quantities.

Are historic years understood as numbers or events? An fMRI study of numbers with semantic associations.

While numbers generally cue processing of quantity or order, they can also contain semantic information, as in the case of historic years (e.g., "1492" calls forth associations of Columbus sailing the ocean blue). Whether these dates are processed as quantities or events may depend on the context in which they occur. We examined such "ambiguous number" processing in two different contexts using a paired-comparison task, recording both behavioral responses and brain activity. Participants were either asked to think of all items as numbers and to choose the larger number, or were told to treat the comparators as events and to choose the later event. Behaviorally, all events showed a normal distance effect, establishing that they may be understood and compared in an ordinal sequence. Functional magnetic resonance imaging (fMRI) demonstrated significant differences between years when treated as numbers versus as events. Dates in both contexts shared activity in parietal lobe regions previously implicated in number processing. Dates as numbers showed no extra-numeric activity, while dates thought of as events evoked activity in temporal semantic processing and frontal semantic retrieval areas. These differences suggest that extra-numeric information may be easily accessed and incorporated during processing when supported by even a weak context. This work supports previous studies showing a dissociation between quantity and meaning, and illustrates the brain areas involved in these different aspects.

Tangible words are recognized faster: the grounding of meaning in sensory and perceptual systems.

Sensory experience rating (SER), a new variable motivated by the grounded cognition framework of conceptual processing (e.g., Barsalou, 2008 ), indexes the degree to which a word evokes sensory/perceptual experiences. In the present study, SERs were collected for over 2,850 words. While SER is correlated with imageability, age of acquisition, and word frequency, the latter variables (along with seven others) account for less than 30% of the variance in SER. Reanalyses of two large-scale studies demonstrate that SER significantly predicts lexical decision times when other established predictor variables are statistically controlled. These results suggest that conceptual processing is grounded in sensory systems. Additionally, a major benefit of this variable is that it allows psycholinguistic researchers to examine semantic-perceptual links for all word classes with a single rating.

Age of acquisition's effect on memory for semantically associated word pairs.

This experiment investigated the effects of age of acquisition (AoA) in memory for associated word pairs in a cued recall task. Participants studied a list of frequency-controlled early- and late-acquired words in semantically related pairs and then were asked to recall the second word of the pair when cued with the first. Reaction time effects were found, showing that a late-acquired cue for an early-acquired target word was responded to significantly faster than other combinations. Additionally, late-acquired target words resulted in significantly more accurate responses. As significant differences were found even when frequency was controlled, the effects must therefore stem from the manipulations ofAoA. Given this evidence, the implications for AoA's effects on the organization of semantic memory are explored.