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In view of the substantial preclinical evidence that supports a seminal role of central corticotropin-releasing factor (CRF) neuronal systems in the physiology and pathophysiology of stress and anxiety, it is reasonable to suggest that the anxiolytic properties of benzodiazepines are mediated, at least in part, via regulation of CRFergic function. To begin to test this complex hypothesis, we examined the effects of acute and chronic administration of the triazolobenzodiazepine agonist alprazolam on CRF peptide concentrations, receptor-binding density, and mRNA expression in the CNS. Additionally, we measured mRNA expression for urocortin, a recently discovered neuropeptide that is generally considered to be a second endogenous ligand for CRF receptors. Both acute and chronic alprazolam administration was found to decrease CRF concentrations within the locus coeruleus. Furthermore, chronic alprazolam decreased basal activity of the hypothalamic-pituitary-adrenal axis, CRF mRNA expression in the central nucleus of the amygdala, and CRF(1) mRNA expression and receptor binding in the basolateral amygdala. In marked contrast, urocortin mRNA expression in the Edinger-Westphal nucleus and CRF(2A) receptor binding in the lateral septum and ventromedial hypothalamus were increased. Similar findings of an inverse relationship between the CRF(1) and CRF(2A) receptor systems have been reported in an anxiety model based on adverse early-life experience, suggesting the intriguing possibility that CRF neuronal systems may be comprised of two separate, but interrelated, subdivisions that can be coordinately and inversely regulated by stress, anxiety, or anxiolytic drugs.

The fairness or appropriateness of measures of aptitude or achievement have long been of interest and theoretical concern, but more recently have surfaced as variables requiring empirical investigation. One of the first instruments that addressed these concerns was a purported culture fair test devised by Eells, Davis, Havighurst, Herrick and Tyler (1951). From that time through the present, these issues continue to stir controversy for test developers, researchers and the legal profession (Williams, Mosby and Hinson, 1978).In an attempt to provide a framework for reducing or minimizing bias in educational assessment, several methods which address the problems of either test bias or item bias have been proposed. Investigations of test bias have used models ~hich determine whether a test unfairly favors examinees of particular groups, e.g., cultural or linguistic groups. Invesigations of item bias seek to identify specific items within a test which exhibit dissimilar response patterns for examinees having equal ability but different group memberships. The first type of investigation is of primary interest to test users who need to choose intact existing tests for particular applications. The second is of interest to test developers for use in their attempts to identify and eliminate biased items.The present study focused on several models for detecting item bias and the differential performance of these models when applied to a variety of bias structures likely to be encountered in educational assessment data. The data in this investigation were produced with a Monte Carlo procedure in which the amount and type of item bias were specified a priori. TECHNIQUES INVESTIGATEDInvestigations of item bias provide an empirical basis for the identification and elimination of items which appear to measure different traits for different population groups. This study applied two transformed item difficulties approaches, three item characteristic curve (1CC) approaches, and two chi-square approaches to obtain measures of the degree of bias for each item within generated item pools. The procedures used for the application of these approaches are described in the following paragraphs.