Post-training brain catecholamine levels: lack of response to water-motivated training

Rats were trained in a one-trial appetitive task using water motivation. Brain catecholamine and metabolite levels were assessed in samples collected 10 min after training. There was no evidence that brain NE levels were modified by training, although catecholamine levels increased when the animals were placed in a novel environment. These results differ from those obtained after avoidance training where the extent of a post-training decrease in brain norepinephrine predicts later retention performance.     

The marginal notes of José Gaos inIdeas I

This paper is dedicated to Dr. Fernando Salmerón. I. wish to thank Mark Platts for his help with the English, and William McKenna for his kind and attentive reading.     

AIDS knowledge among black drug users: an issue of reliability

This study examined the reliability of an inventory measuring AIDS-related knowledge among 553 black drug users. Data were collected from a socially high-risk community in Birmingham, Alabama. The KR-20 reliability scores were computed from the inventory for each drug-use group. The KR-20 reliabilities ranged from .39 to .57. These findings may suggest that the inconsistent reports of the predictive power of AIDS knowledge among drug users reported in previous studies might be related to the low internal consistencies of the inventory.     

Are the Tabloids Always Wrong or Is That Just What We Think? Need for Cognition and Perceptions of Articles in Print Media

This study examines how need for cognition, source credibility, and communication strength influence perceptions of a print-media communication. Participants read a strong or weak communication about an evolutionary theory, presented as an article from the Washington Post (high credibility) or the National Enquirer (low credibility). Results revealed a significant Need for Cognition × Source × Communication Strength interaction. Low-need-for-cognition participants who read the weak communication rated the article more positively when it was attributed to the high-credibility source than to the low-credibility source. Source credibility did not affect impressions of the article and theory among participants high in need for cognition or reading the strong communication. However, articles from the Washington Post were rated as more believable, factual, accurate, and true than those from the National Enquirer.     

pCREB in the neonate rat olfactory bulb is selectively and transiently increased by odor preference-conditioned training

Early olfactory preference learning in rat pups occurs when novel odors are paired with tactile stimulation, for example stroking. cAMP-triggered phosphorylation of cAMP response element binding protein (pCREB) has been implicated as a mediator of learning and memory changes in various animals (Frank and Greenberg 1994). In the present study we investigate whether CREB is phosphorylated in response to conditioned olfactory training as might be predicted given the proposed role of the phosphorylated protein in learning. On postnatal day 6, pups were trained for 10 min using a standard conditioned olfactory learning paradigm in which a conditioned stimulus, Odor, was either used alone or paired with an unconditioned stimulus, Stroking (using a fine brush to stroke the pup). In some instances stroking only was used. The pups were sacrificed at 0, 10, 30, or 60 min after the training. Using Western blot analysis, we observed that the majority of olfactory bulbs in conditioned pups (Odor + Stroking) had a greater increase in pCREB activation at 10 min after training than pups given nonlearning training (Odor only or Stroking only). The phosphorylated protein levels were low at 0 min and at 60 min after training. This is in keeping with the slightly delayed and short-lived activation period for this protein. The localization of pCREB increases within the olfactory bulb as seen by immunocytochemistry. Naive pups were not exposed to odor or training. There was a significantly higher level of label in mitral cell nuclei within the dorsolateral quadrant of the bulb of pups undergoing odor-stroke pairing. No significant differences were observed among nonlearning groups (Naive, Odor only, or Stroking only) or among any training groups in the granule or periglomerular cells of the dorsolateral region. The localized changes in the nuclear protein are consistent with studies showing localized changes in the bulb in response to a learned familiar odor. The present study demonstrates that selective increases in pCREB occur as an early step following pairing procedures that normally lead to the development of long-term olfactory memories in rat pups. These results support the hypothesized link between pCREB and memory formation.     

Functional versus structural social support, desirable events, and positive affect in older adults.

The independent contributions of structural social support versus functional support to positive affect in older adults were compared in this prospective design. Four social support models were translated from the stress-symptoms literature into promotional models for positive mental health and for relationships to desirable challenge events. A total of 1,031 older adults were interviewed 5 times at 6-month intervals, and events were measured across the middle 18-month period. The 2 support variables made quite different contributions. Functional support was directly related to positive affect 2 years later, independent of events; structural support had more transitory direct effects. Structural support, but not functional support, was related to the subsequent occurrence of challenge events and in turn was strengthened by challenge events, suggesting a dynamic interplay between the social network and desirable events.     

The nontruncated marginal of a truncated bivariate normal distribution

Inference is considered for the marginal distribution ofX, when (X, Y) has a truncated bivariate normal distribution. TheY variable is truncated, but only theX values are observed. The relationship of this distribution to Azzalini's skew-normal distribution is obtained. Method of moments and maximum likelihood estimation are compared for the three-parameter Azzalini distribution. Samples that are uniformative about the skewness of this distribution may occur, even for largen. Profile likelihood methods are employed to describe the uncertainty involved in parameter estimation. A sample of 87 Otis test scores is shown to be well-described by this model.     

Reasons for the trend toward null findings in research on Type A behavior.

The findings of many studies conducted before 1978 suggest that Type A behavior (TAB) contributes to the development of coronary heart disease (CHD). In contrast, many recent studies have found no association between these variables. Through meta-analysis, several reasons for null findings are identified. First, a type of range restriction bias, disease-based spectrum (DBS) bias, produced many null findings. A study is vulnerable to DBS bias when researchers select only high-risk or diseased Ss for study. Second, self-report measures of TAB were often associated with null findings. Finally, null results were found for all studies that used fatal myocardial infarction as a disease criterion. In addition to identifying the reasons for null findings, this research suggests that TAB, as assessed by the structured interview, is associated with CHD. More Type As (70%) were found in diseased populations of middle-aged men than in healthy populations of middle-aged men (46%).