Characteristics of exaggerated sexual behavior induced by electrical stimulation of the medial preoptic area in male rats.

Twenty-two sexually experienced male rats were implanted with lateral preoptic (LPO) and medial preoptic (MPO) electrodes. Following surgery, the 22 MPO and 18 LPO electrodes were screened for the induction of stimulation-bound copulation in the presence of estrus females. Stimulation through 5 of the MPO electrodes induced highly exaggerated, stimulation-bound sexual behaviou. Ten MPO electrodes produced escape behavior, 2 electrodes aggression and one electrode induced sexual behavior intermingled with aggression. The tips of all the electrodes which effected exaggerated copulation were located within a small preoptic region, less than 1 mm lateral to the midline. LPO electrodes had either inhibitory effects on mating behavior or none at all. The increase in copulatory activity by MPO electrodes' stimulation was expressed in a great enhancement in the number of ejaculations, and marked decreases in the latency to ejaculation, the post-ejaculatory refractory period, and in the number of intromissions preceding an ejaculation. It is concluded that the electrical stimulation affected both the sexual arousal mechanism and the intromission-ejaculation mechanism involved in mating behavior.

Copulation in noncopulators: effect of PCPA in male rats.

Twenty eight virgin male rats who failed to mount spontaneously on four successive mating tests were randomly assigned to two equal groups. One group received four daily injections of PCPA (100 mg/kg-IP), and the other, four vehicle injections. About 24 hr after the last injection all rats were subjected to a mating test. Eight rats of the PCPA group and only two of the vehicle, started to copulate. The difference is significant at the 0.05 level (two-tail). The 18 rats that did not start to copulate, failed to do so also on a repeated test a week later, and were then given four additional daily injections of PCPA. Sixteen of them started to copulate on the following mating test. Most of the rats copulated successfully on additional mating tests that took place three to eight weeks later, in the absence of further PCPA treatment.

Detection measures in real-life criminal guilty knowledge tests.

The present study provides a first attempt to compare the validity of the respiration line length (RLL) and skin resistance response (SRR) amplitude in real-life criminal guilty knowledge tests (GKTs). GKT records of 40 innocent and 40 guilty Ss, for whom actual truth was established by confession, were assessed for their accuracy. When a predefined decision rule was used and inconclusive decisions were excluded, 97.4% of the innocent Ss and 53.3% of the guilty Ss were correctly classified with the SRR measure. For the RLL measure, the respective results were 97.2% and 53.1%. The combination of both measures improved detection of guilty Ss to 75.8% and decreased detection of innocent Ss to 94.1%. The combined measure seems to be a more useful means of identifying guilty suspects than each physiological measure alone. The results elaborate and extend those obtained in a previous field study conducted by Elaad (1990).

A multiple-choice version of the sentence completion method.

A sentence completion (SC) measure of children's autonomy was adapted to a multiple choice (MC) form. Criteria were proposed which MC should meet in order to be reasonably equivalent to SC. MC should not be obvious to the child; thus, the means and variances of the two tests should be similar, and MC should not show a congregation around the "good" answers, nor should it correlate positively with a measure of social desirability. Both tests should correlate significantly with one another. Any factor structure present in SC, which suggests a differentiation within the concept of autonomy should be duplicated in MC. Most of these criteria were met, and it was concluded that a multiple choice form corresponding to a sentence completion measure, testing clearly defined personality areas, could be a resonable alternative for many purposes.