Chronic stress and sex differences on the recall of fear conditioning and extinction

Chronic stress effects and sex differences were examined on conditioned fear extinction. Male and female Sprague–Dawley rats were chronically stressed by restraint (6 h/d/21 d), conditioned to tone and footshock, followed by extinction after 1 h and 24 h delays. Chronic stress impaired the recall of fear extinction in males, as evidenced by high freezing to tone after the 24 h delay despite exposure to the previous 1 h delay extinction trials, and this effect was not due to ceiling effects from overtraining during conditioning. In contrast, chronic stress attenuated the recall of fear conditioning acquisition in females, regardless of exposure to the 1 h extinction exposure. Since freezing to tone was reinstated following unsignalled footshocks, the deficit in the stressed rats reflected impaired recall rather than impaired consolidation. Sex differences in fear conditioning and extinction were observed in nonstressed controls as well, with control females resisting extinction to tone. Analysis of contextual freezing showed that all groups (control, stress, male, female) increased freezing immediately after the first tone extinction trial, demonstrating contextual discrimination. These findings show that chronic stress and sex interact to influence fear conditioning, with chronic stress impairing the recall of delayed fear extinction in males to implicate the medial prefrontal cortex, disrupting the recall of the fear conditioning acquisition in females to implicate the amygdala, and nonstressed controls exhibiting sex differences in fear conditioning and extinction, which may involve the amygdala and/or corticosterone levels.     

Beyond the two-strategy model of skilled spelling: Effects of consistency, grain size, and orthographic redundancy

Most models of spelling assume that people rely on two procedures when engaging in spelling: a lexical look-up procedure that retrieves spellings in their entirety, and a nonlexical procedure that constructs spellings with a set of phoneme-grapheme rules. In the present research, we investigated whether larger sized subsyllabic relationships also play a role in spelling, and how they compare to small-sized phoneme-grapheme relationships. In addition, we investigated whether purely orthographic units can explain some of the variance typically attributed to the mapping between sound and spelling. To do this, we ran five spelling experiments, two using real words and three using nonwords. Results from the experiments showed that there were independent contributions of both phoneme-grapheme and larger sized subsyllabic sound-spelling relationships, although the effect of phoneme-grapheme-sized relationships was always stronger and more reliable than larger sized subsyllabic sound-spelling relationships. Purely orthographic effects were also shown to affect word spelling, but no significant effects were found with nonword spelling. Together, the results support the hypothesis that a major constraint on spelling comes from phoneme-grapheme-sized relationships.     

Female Body Image as a Function of Themes in Rap Music Videos: A Content Analysis

A content analysis of rap music videos taken from the end of year countdowns aired on U.S. cable outlets (i.e. BET, MTV, and VH1) was undertaken. The analysis examined the body images of 258 female characters (87.6% Black, 5.8% White, 6.6% other) as a function of the thematic content in the videos (e.g., violence, sex). It was found that, overall, “thin” females were overrepresented in the videos. More interestingly, the body sizes of the female characters varied by three of the four video themes. When the music videos were high in sex, or high in materialism, women were more likely to have smaller body sizes. In contrast, when the videos were high in political awareness, women were more likely to have larger body sizes.     

Simple Co‐Occurrence Statistics Reproducibly Predict Association Ratings

What determines human ratings of association? We planned this paper as a test for association strength (AS) that is derived from the log likelihood that two words co‐occur significantly more often together in sentences than is expected from their single word frequencies. We also investigated the moderately correlated interactions of word frequency, emotional valence, arousal, and imageability of both words (r's ≤ .3). In three studies, linear mixed effects models revealed that AS and valence reproducibly account for variance in the human ratings. To understand further correlated predictors, we conducted a hierarchical cluster analysis and examined the predictors of four clusters in competitive analyses: Only AS and word2vec skip‐gram cosine distances reproducibly accounted for variance in all three studies. The other predictors of the first cluster (number of common associates, (positive) point‐wise mutual information, and word2vec CBOW cosine) did not reproducibly explain further variance. The same was true for the second cluster (word frequency and arousal); the third cluster (emotional valence and imageability); and the fourth cluster (consisting of joint frequency only). Finally, we discuss emotional valence as an important dimension of semantic space. Our results suggest that a simple definition of syntagmatic word contiguity (AS) and a paradigmatic measure of semantic similarity (skip‐gram cosine) provide the most general performance‐independent explanation of association ratings.     

Neurocognitive profiles of preterm infants randomly assigned to lower or higher hematocrit thresholds for transfusion

Objective: Preterm infants are frequently transfused with red blood cells based on standardized guidelines or clinical concerns that anemia taxes infants' physiological compensatory mechanisms and thereby threatens their health and well-being. The impact of various transfusion guidelines on long-term neurocognitive outcome is not known. The purpose of this study is to evaluate long-term neurocognitive outcome on children born prematurely and treated at birth with different transfusion guidelines.

Methods: Neurocognitive outcomes were examined at school age for 56 preterm infants randomly assigned to a liberal (n?=?33) or restrictive (n?=?23) transfusion strategy. Tests of intelligence, achievement, language, visual-spatial/motor, and memory skills were administered. Between-group differences were assessed.

Results: Those in the liberal transfusion group performed more poorly than those in the restrictive group on measures of associative verbal fluency, visual memory, and reading.

Conclusions: Findings highlight possible long-term neurodevelopmental consequences of maintaining higher hematocrit levels.     

The crystal structure of Al20.6Ta22.4 and its relation to Frank–Kasper phases

The monoclinic phase in the Al–Ta system has been identified by means of X-ray single-crystal structure analysis as Al_{19+ x} Ta_{24? x} (x?=?1.6), Pearson symbol mP86. Al_20.58Ta_22.42 crystallizes in the space group P2₁/n, with a?=?987.86?pm, b?=?990.12?pm, c?=?1489.45?pm and β?=?99.958°. Twinned crystals of the title compound can be obtained by iodine-promoted reactions of the elements. In the experiments described here, the reactions took place in sealed tantalum ampoules at 1400°C. Single-phase samples were obtained by a metallurgical powder method, which minimizes aluminium loss by incongruent vapourization. The composition was found to span the range 0.51?≤?x _Ta?≤?0.53. Al_{19+ x} Ta_{24? x} decomposes in the solid state at 1450°C into Al₆₉Ta₃₉ and σ-AlTa₂. The crystal structure is analyzed in relation to tetrahedral close-packed structures. The kinship with Cr₃Si-type and H-type structures is accentuated.     

Organisms,machines, and societies: From the vertical structure of adaptability to the management of information

The adaptability of organisms and human societies depends on the synergistic orchestration of processing modes at many different levels of organization, each with unique informational characteristics. Digital information technology is a narrow transect of this spectrum. Adaptability theory provides a tool for analyzing the interactions between these fundamentally different modes of processing and for delineating the factors that can lead to either positive or negative consequences for human life.     

Learning artificial phonotactic constraints: time course, durability, and relationship to natural constraints

G. S. Dell, K. D. Reed, D. R. Adams, and A. S. Meyer (2000) proposed a "breadth-of-constraint" continuum on phoneme errors, using artificial experiment-wide constraints to investigate a putative middle ground between local and language-wide constraints. The authors report 5 experiments that test the idea of the continuum and the location of the experiment-wide constraints within it. Experiments 1 and 2 replicated the findings of Dell et al. on the experiment-wide constraints but showed only chance adherence to the local positional constraints. Experiment 3 showed that the latter constraints are uniquely affected by the form of practice used. Experiments 4 and 5 investigated the time course and robustness of the experimental constraints by reversing them during testing. This caused no difficulty when occurring between blocks (Experiment 4) but caused short-lived disruption when occurring within block (Experiment 5). The authors propose that the results do not support the idea of a continuum, but that the experiment-wide constraints reflect a local biasing of language-wide constraints, probably related to the need for rapid learning.     

Effects of syllable-frequency in lexical decision and naming: an eye-movement study

In three experiments we explored task-specific effects of syllable-frequency, following Perea and Carreiras' (1998) findings of a facilitative effect during naming and an inhibitory effect during lexical decision. In Experiment 1, an inhibitory effect of first syllable-frequency on articulation duration suggested a process-specific effect during naming: a facilitative effect on construction of phonological output, but an inhibitory effect on lexical access. Eye-movement recording was used in Experiment 2 to disentangle these two processes. An inhibitory effect on eye-movement parameters during both lexical decision and naming supported the assumption that higher first syllable-frequency inhibits lexical access. Implications of a general inhibitory effect of syllable-frequency for computational models of word recognition, specifically for the multiple-trace memory (MTM) model of polysyllabic word naming (Ans, Carbonnel, & Valdois, 1998), are discussed.