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.     

Validity and utility of computer-based test interpretation

Computers have been important to applied psychology since their introduction, and the application of computerized methods has expanded in recent decades. The application of computerized methods has broadened in both scope and depth. This article explores the most recent uses of computer-based assessment methods and examines their validity. The comparability between computer-administered tests and their pencil-and-paper counterparts is discussed. Basic decision making in psychiatric screening, personality assessment, neuropsychology, and personnel psychology is also investigated. Studies on the accuracy of computerized narrative reports in personality assessment and psychiatric screening are then summarized. Research thus far appears to indicate that computer-generated reports should be viewed as valuable adjuncts to, rather than substitutes for, clinical judgment. Additional studies are needed to support broadened computer-based test usage.     

Effect of altered instructions on the MMPI-2 profiles of college students who are not motivated to distort their responses

Research has shown that when the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) is administered with instructions designed to make people aware of the validity indexes and when people are encouraged to respond honestly rather than invalidate the test through defensiveness, their scores on validity scales suggest a more candid responding. Before such modified administration procedures can be broadly used to increase the validity of the MMPI (Hathaway & McKinley, 1943) profiles, it is necessary to have more information about the effect of the altered instructions on test performance of people in general. This study involved administering the MMPI-2 to a group of 218 "normals" (college students) with instructions that differed from traditional instructions. Specifically, the test instructions were altered to explain more about the test and the presence of validity scales to apprise participants that disingenuous responding can be detected. The responses of college students taking the test under altered instructions were compared with those of a similar sample of 150 college students who took the test under standard instructions. Although under altered conditions there was a statistically significant tendency for measures assessing defensiveness (L, K, and S) to be lower for some participants (women but not men), the differences were trivial. Modified instructions made little practical difference in test performance when people who were not motivated to deceive on the test were informed of the presence of validity checks on the test.