Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

Estimates of the Validity and Utility of the Conners’ Continuous Performance Test in the Assessment of Inattentive and/or Hyperactive-Impulsive Behaviors in Children

This study evaluated the validity and classification utility of the Conners' Continuous Performance Test (CCPT) in the assessment of inattentive and hyperactive-impulsive behaviors in children. Significant, positive correlations between the CCPT parameters and behavioral ratings of ADHD behaviors were hypothesized. In addition, it was hypothesized that the CCPT parameters would perform better than a random test (chance) and show fair to moderate utility of classification across the different indices. Participants were 104 children between 6 and 12 years of age who were referred for evaluation of attention problems. The first hypothesis was not supported. There were no significant, positive correlations between the CCPT parameters and parent and teacher ratings of inattentive and hyperactive-impulsive behaviors. The second hypothesis was only partially supported. The CCPT Overall Index and the Omission Errors (84th percentile cutoff) performed better than a random test; however, the utility of the CCPT Overall Index only ranged from poor to slight. Receiver operating characteristic analyses showed the accuracy of the CCPT to be low. The implications and limitations of this study and future research directions are discussed.     

The effect of variable delays on self-control

Five pigeons served as subjects in an experiment that examined the effects of variable as opposed to fixed delays on preference in a self-control paradigm (choice between larger, more delayed and smaller, less delayed reinforcers). Nonindependent concurrent variable-interval schedules were used to measure choice. When delays to the larger, more delayed reinforcers were variable as opposed to fixed, the subjects showed an increased preference for that alternative (the self-control alternative). A series of regressions revealed that the hyperbolic decay model and incentive theory provided poor fits to the data, but a modified version of the generalized matching law provided an adequate fit. Together, consistent with a general prediction made by discounting models, the data supported the conclusion that variable delays can increase self-control. However, specific discounting models were not able to explain the present data well.     

Empirical support for the gender‐as‐culture hypothesis.

This investigation provided a test of the gender‐as‐culture, or ‘two cultures’, hypothesis proposed by Maltz and Borker (1982) to explain male/female differences in language use. Analysis of previous empirical investigations located 16 language features that had consistently been shown to indicate communicator gender and these were tested within the framework of the four dimensions of intercultural style proposed by Gudykunst and Ting‐Toomey (1998): direct versus indirect, succinct versus elaborate, personal versus contextual and instrumental versus affective. Study 1 provided preliminary evidence supporting the hypothesized language‐feature‐by‐dimension relationships (e.g., male directives were rated more direct and female uncertainty verbs more indirect). In Study 2, respondents rated multiple exemplars of the 16 language features, as well as 16 contrasting foil sentences, on all four dimensions, finding that nearly all of the variables fell on the hypothesized intercultural dimensions. In Study 3, respondents rated four sets of naturally occurring target sentences and matching foil sentences, representing all language variables, on their appropriate intercultural dimensions in order to establish dimensional polarity. Results across the three studies supported the hypothesized language feature‐by‐stylistic dimension relationship for 15 of the 16 variables: The 6 male language features were rated as more direct, succinct, personal, and instrumental, whereas 9 of the 10 female features were perceived as more indirect, elaborate, and affective. The findings demonstrate that gender preferences for language use function in ways that are consistent with stylistic preferences that distinguish national cultures.     

Anticipatory Processing and Post‐Event Processing in Social Anxiety Disorder: An Update on the Literature

Two repetitive thinking processes that have been proposed in prominent maintenance models of social anxiety disorder (SAD) are anticipatory processing and post‐event processing. Research into these two processes has steadily increased over the last 20 years. This review highlights the main lines of existing research on anticipatory processing and post‐event processing, including studies on the nature of these processes, their association with social anxiety, the predictors, and consequences of these processes, as well as how these processes respond to treatments for SAD. The review also highlights some of the conceptual and methodological issues that have prevented the literature on anticipatory processing and post‐event processing from being more integrated and focused. Finally, the review draws together some new directions in terms of theory and research to further advance the field.     

Effects of response type on pigeons' sensitivity to variation in reinforcer amount and reinforcer delay

Twelve pigeons, divided into two groups, responded on concurrent nonindependent variable-interval schedules to obtain access to grain by either pecking keys or pressing treadles. Either the amount of grain or the delay to the receipt of grain was varied in separate conditions to determine the sensitivity of relative responding to variation in reinforcer amount (s_A), the sensitivity to variation in reinforcer delay (s_D), and s_A/s_D, a measure related to self-control. There were no significant differences between the two groups in the values of s_A, s_D, and s_A/s_D. These results suggest that the values of s_A, s_D, and s_A/s_D for pigeons may be similar across these two types of responses.     

Vagueness as closeness

This paper presents and defends a definition of vagueness, compares it favourably with alternative definitions, and draws out some consequences of accepting this definition for the project of offering a substantive theory of vagueness. The definition is roughly this: a predicate ‘F’ is vague just in case for any objects a and b, if a and b are very close in respects relevant to the possession of F, then ‘Fa’ and ‘Fb’ are very close in respect of truth. The definition is extended to cover vagueness of many-place predicates, of properties and relations, and of objects. Some of the most important advantages of the definition are that it captures the intuitions which motivate the thought that vague predicates are tolerant, without leading to contradiction, and that it yields a clear understanding of the relationships between higher-order vagueness, sorites susceptibility, blurred boundaries, and borderline cases. The most notable consequence of the definition is that the correct theory of vagueness must countenance degrees of truth.