Correlation and response relevance in sequence learning

We tested the effects of introducing a secondary sequence into the serial reaction time task. Specifically, we examined the role of correlated streams of information and response relevance. In the first experiment, the order of stimulus locations was correlated with the order of key press responses in the conventional way. A symbol-identity sequence, of a different length, was also present but no manual responses were made to it, and it was not correlated with any other stream of information. In the second experiment, two concurrent streams of location-based stimuli were presented. Both were sequenced but only one sequence required responses. Importantly, the sequences were either correlated with one another or not (same vs. different lengths). In the third experiment, the same design was used but with one sequence visual and the other auditory. In all three experiments, participants became sensitive to the sequence that required responses, and resultant knowledge was largely explicit. They were also sensitive to the sequence that did not require responses but only when it was correlated with the sequence that did, and here resultant knowledge was implicit. The findings suggest that the presence of a secondary sequence can affect learning, but only when stimuli in that sequence are integrated, through correlation, with responses made to the primary sequence.     

Validating age-related functional imaging changes in verbal working memory with acute stroke

Functional imaging studies consistently find that older adults recruit bilateral brain regions in cognitive tasks that are strongly lateralized in younger adults, a characterization known as the Hemispheric Asymmetry Reduction in Older Adults model. While functional imaging displays what brain areas are active during tasks, it cannot demonstrate what brain regions are necessary for task performance. We used behavioral data from acute stroke patients to test the hypothesis that older adults need both hemispheres for a verbal working memory task that is predominantly left-lateralized in younger adults. Right-handed younger (age ? 50, n = 7) and older adults (age > 50, n =21) with acute unilateral stroke, as well as younger (n =6) and older (n =13) transient ischemic attack (TIA) patients, performed a self-paced verbal item-recognition task. Older patients with stroke to either hemisphere had a higher frequency of deficits in the verbal working memory task compared to older TIA patients. Additionally, the deficits in older stroke patients were mainly in retrieval time while the deficits in younger stroke patients were mainly in accuracy. These data suggest that bihemispheric activity is necessary for older adults to successfully perform a verbal working memory task.     

Speed during training and anthropometric measures in relation to race performance by male and female open-water ultra-endurance swimmers

The relationship of anthropometric and training characteristics with race time were investigated in 39 male and 24 female open-water ultra-endurance swimmers in a 26.4 km open-water ultra-swim, using bi- and multivariate analyses. For the men, body height, Body Mass Index, length of arm, and swimming speed during training were related to race time in the bivariate analysis. For the women, swimming speed during training was associated with performance in the bivariate analysis. In the multivariate analysis for the men, Body Mass Index and swimming speed during training were related to race time.     

Intra- and inter-judge reliabilities in measuring the skin-fold thicknesses of ultra runners under field conditions

Inter- and intra-judge reliabilities of skinfold measures were investigated in a sample of 27 men and 11 women ultramarathon runners. Two physicians had agreement higher than 90% in field measurements before an ultramarathon race.     

The influence of infant irritability on maternal sensitivity in a sample of very premature infants

The relationship between maternal sensitivity and infant irritability was investigated in a short‐term longitudinal study of 29 very preterm infants. Infant irritability was assessed at term with the Brazelton NBAS, the Mother and Baby Scales (MABS) and the Crying Pattern Questionnaire (CPQ). Maternal sensitivity was assessed by nurses' ratings in the neonatal care unit and at three months during mother–infant interaction observation. Cross‐lagged panel analysis indicated that neonatal irritability did not influence sensitivity at 3 months nor did maternal sensitivity in the newborn period lead to reduced irritability at 3 months. Both irritability and maternal sensitivity showed moderate stability over time (r = 0.55 and r = 0.60, respectively). It is concluded that in early infancy maternal sensitivity shows little influence on infant irritability in very preterm infants. Copyright © 2003 John Wiley & Sons, Ltd.     

Agreeableness and the prolonged spatial processing of antisocial and prosocial information

Previous research has suggested that highly agreeable individuals value positive social relationships to a greater extent than do individual low in agreeableness. The present investigation sought to extend such individual differences to the cognitive level of analysis. It was hypothesized that individual differences in agreeableness would predict the extent to which either antisocial or prosocial words are selected for prolonged processing. Two studies, involving 90 undergraduates, asked participants to encode prosocial and antisocial stimuli, before measuring the speed with which they could spatially disengage attention from such stimuli. As predicted, individuals low in agreeableness exhibited difficulties disengaging from antisocial stimuli, whereas individuals high in agreeableness exhibited difficulties disengaging from prosocial stimuli. This novel finding isolates a particular set of attentional processes that likely contribute to agreeableness-related outcomes such as anger and aggression.     

Watch out! That could be dangerous: valence-arousal interactions in evaluative processing

Seven studies involving 146 undergraduates examined the effects of stimulus valence and arousal on direct and indirect measures of evaluative processing. Stimuli were emotional slides (Studies 1 to 6) or words (Study 7) that systematically varied in valence and arousal. Evaluative categorization was measured by reaction times to evaluate the stimuli (Studies 2, 3, and 7), latencies related to emotional feelings (Study 3), and incidental effects on motor performance (Studies 4 and 5). A consistent interaction was observed such that evaluation latencies were faster if a negative stimulus was high in arousal or if a positive stimulus was low in arousal. Studies 1, 6, and 7 establish that the findings are not due to stimulus identification processes. The findings therefore suggest that people make evaluative inferences on the basis of stimulus arousal.     

Why good guys wear white

Affect is a somewhat abstract concept that is frequently linked to physical metaphor. For example, good is often depicted as light (rather than dark), up (rather than down), and moving forward (rather than backward). The purpose of our studies was to examine whether the association between stimulus brightness and affect is optional or obligatory. In a series of three studies, participants categorized words as negative or positive. The valence of the words and the brightness of the letters were varied orthogonally. In Studies 1, 2, and 3, we found that categorization was inhibited when there was a mismatch between stimulus brightness (e.g., light) and word valence (e.g., negative). Studies 4 and 5 reveal boundary conditions for the effect. The studies suggest that, when making evaluations, people automatically assume that bright objects are good, whereas dark objects are bad.     

CB1 cannabinoid receptors modulate kinase and phosphatase activity during extinction of conditioned fear in mice

Cannabinoid receptors type 1 (CB1) play a central role in both short-term and long-term extinction of auditory-cued fear memory. The molecular mechanisms underlying this function remain to be clarified. Several studies indicated extracellular signal-regulated kinases (ERKs), the phosphatidylinositol 3-kinase with its downstream effector AKT, and the phosphatase calcineurin as potential molecular substrates of extinction behavior. To test the involvement of these kinase and phosphatase activities in CB1-dependent extinction of conditioned fear behavior, conditioned CB1-deficient mice (CB1(-/-)) and wild-type littermates (CB1(+/+)) were sacrificed 30 min after recall of fear memory, and activation of ERKs, AKT, and calcineurin was examined by Western blot analysis in different brain regions. As compared with CB1(+/+), the nonreinforced tone presentation 24 h after auditory-cued fear conditioning led to lower levels of phosphorylated ERKs and/or calcineurin in the basolateral amygdala complex, ventromedial prefrontal cortex, dorsal hippocampus, and ventral hippocampus of CB1(-/-). In contrast, higher levels of phosphorylated p44 ERK and calcineurin were observed in the central nucleus of the amygdala of CB1(-/-). Phosphorylation of AKT was more pronounced in the basolateral amygdala complex and the dorsal hippocampus of CB1(-/-). We propose that the endogenous cannabinoid system modulates extinction of aversive memories, at least in part via regulation of the activity of kinases and phosphatases in a brain structure-dependent manner.