Effects on locomotion and memory in 2 models of cerebral hypoperfusion in male Wistar rats.

INTRODUCTION: Cerebral ischaemia is one of the most common neurological diseases worldwide. Its many sequelae range from motor and sensory symptoms to cognitive decline and dementia. Animal models of cerebral ischaemia/hypoperfusion elicit effects on long term memory; however, the effects of these procedures on short term memory are not clearly understood and effects induced by alternative hypoperfusion models are completely unknown. METHODS: We evaluated the effects of 2 cerebral hyperperfusion models on memory in 3-month-old male rats. Episodic memory and working memory were assessed using the new object recognition test and the spontaneous alteration test, respectively. Neurological assessment was also performed, along with an open field test to evaluate locomotor activity. RESULTS: Rats in both hyperperfusion models displayed no cognitive changes. Rats with unilateral left-sided ligation plus temporary ligation of the right carotid tended to show slightly impaired performance on the new object recognition test on the second day after the procedure. In contrast, the group with permanent unilateral ligation tended to display alterations in working and episodic memory 9 days after the procedure, but they subsequently recovered. CONCLUSION: Despite these differences, both hypoperfusion groups displayed clear signs of motor impairment 2 days after the procedure, as reflected by their decreased locomotor activity during the open field test.

Multivariate effects of demand characteristics on the analogue assessment of heterosocial competence.

The present study assessed the effects of a contextual demand manipulation (pretreatment assessment versus experiment) and an instructional demand manipulation (high demand for competent behavior versus neutral demand) on the analogue assessment of heterosocial competence. Also assessed was the interaction between each demand manipulation and subject characteristics (high-frequency dating/low heterosocially anxious versus low-frequency dating/high heterosocially anxious college males). Students were assigned randomly to one of four groups receiving differential information and instructions. Students completed a battery of five standard paper-and-pencil questionnaires, responded out loud to 10 taped social situations, and conversed with a female confederate while being videotaped for five minutes. Multivariate analyses revealed highly significant differences between subject groups and between contextual manipulation groups. Univariate analyses revealed that only 3 of the 16 dependent measures, including 2 of the self-reports, were significantly affected by the contextual demand. Results are discussed in light of previous studies of phobic behavior and social skills. Various avenues for future research were presented.