Simvastatin impairs spatial memory in rats at a specific dose level.

Statins, inhibitors of cholesterol synthesis, are used to prevent cardiovascular complications. Moreover, statins have been shown to influence some cognitive functions. The modulating effects of simvastatin, one member of the statin family, on memory-related neurotransmitters and neuronal structures have also been reported. We aimed to investigate the behavioral effects of long-term simvastatin application on daily activity, psychomotor performance and spatial memory using Sprague-Dawley rats. Simvastatin (10 or 30 mg/kg/day) was administered orally to rats, in parallel with a vehicle-treated group. Daily activity test results of both simvastatin groups were found similar to the vehicle group after five weeks of simvastatin or vehicle application. Psychomotor performance was measured with the rotarod test. After 6 weeks of simvastatin or vehicle application, the vehicle-treated group stayed on the rotarod device for a shorter time compared with both simvastatin-treated groups. Spatial memory was evaluated by the Barnes maze test. Four weeks of 10 mg/kg/day simvastatin application led to poorer scores on spatial memory compared to the vehicle group, but surprisingly, this effect was not seen in the 30 mg/kg/day group. Our results revealed that simvastatin administration had no significant effect on daily activity. Psychomotor performance test results suggested that simvastatin alters psychomotor behavior at higher nervous system levels. Spatial memory test results indicate that long-term simvastatin usage impairs spatial memory only at 10 mg/kg/day dose.

Fluvastatin alters psychomotor performance and daily activity but not the spatial memory in rats.

Statins, inhibitors of cholesterol synthesis for treating dyslipidemia and preventing cardiovascular complications, have been shown to alter central nervous system functions. Our aim was to investigate the effects of the fluvastatin, a member of statin family, on psychomotor performance, daily activity and spatial memory. Sprague-Dawley rats were treated with fluvastatin (n = 8) or placebo as a control (n = 11) regardless of sex. Fluvastatin (7.5 mg/kg) was administered orally once a day for four weeks, while the control group was administered only placebo. Psychomotor performance was measured by rotarod tests. No significant difference was observed in the fluvastatin group over the course of weeks, but the control group preferred to stay on the device shorter times (p < 0.05). For the first three weeks of the drug administration there was a statistical difference between the groups, however no difference was found after the 4th week. There was no difference in the Barnes maze spatial memory test between the groups and also within the groups over the course of time. Daily activity tests revealed that stereotypical and vertical movements of the fluvastatin group were significantly less than the control group in all four weeks. Ambulatory movements and the distances taken by the fluvastatin group were decreased significantly over the course of time (p < 0.005 and p < 0.001, respectively), but the control group did not reveal any significant change. Our results suggest that fluvastatin altered psychomotor performance and daily activity in rats, but it did not affect the spatial memory. These behavioral changes might be associated with alterations in the composition of the brain lipids caused by fluvastatin.

Sex differences in verbal and spatial ability reconsidered in relation to body size, lung volume, and sex hormones.

Sex differences in verbal and nonverbal abilities were reconsidered in relation to bodily measures and sex hormones in Turkish university students. Perceptual-verbal ability was evaluated using As Test. To assess the nonverbal abilities, the mental rotation test and Cattell's Culture Fair Intelligence Test were used. As expected, the 53 women performed better than men on the As Test; 79 men had a higher mean than the 53 women on the mental rotation task; there was no sex difference on Cattell's IQ Test. Cattell IQs correlated only with tidal volume of lungs. Scores on the As Test did not show significant correlations with body size and lung capacities. Mental rotation was significantly correlated with height, weight, and lung volume. With covariates of height, weight, and vital capacity, sex differences in mental rotation completely disappeared, but the difference on the As Test increased while Cattell IQ remained sex-neutral. With testosterone as covariate, the sex difference on the As test increased but on the mental rotation task disappeared; Cattell IQ was sex-neutral. With covariates of estradiol and progesterone, sex differences on the As test disappeared; mental rotation scores and Cattell IQ were not influenced. Under a combined covariation of height, weight, and testosterone, sex differences in mental rotation reversed, women scoring better than men; after adding estradiol or progesterone instead of testosterone to this model, sex differences on mental rotation completely disappeared, but verbal ability and Cattell IQ were not changed. These results suggest that Cattell's Culture Fair Intelligence Test is unique in resistance to sex differences; perceptual-verbal ability was the most sex-specific mental trait but with dependence on estradiol; mental rotation, on the contrary, was least sex-specific, depending on body size, lung volume, sex hormones, and their combined actions, which explains women's better performance.

Relationships between nonverbal IQ and brain size in right and left-handed men and women.

This study was designed to evaluate the relationship between nonverbal IQ and brain size in men and women. A significant correlation was found between IQ and brain size in total subjects. There was no significant correlation between these variables in women; men exhibited only a weak relation of brain size to IQ. In both left-handed men and women significant correlations were found between IQ and brain size. The results supported the hypothesis about the relation of IQ to brain size, suggesting that the sex difference in the cranial capacity and cerebral asymmetry might contribute to the diversity in cognitive functions.

Covariation of sex differences in mental rotation with body size.

Sex difference in mental rotation ability was reconsidered. The Vandenberg-Kuse figures were administered to 120 male and 76 female students from the Medical School of BlackSea Technical University in Trabzon, Turkey to assess the mental rotation ability. Students' height and weight were measured. As expected, men outperformed women on this test and had greater height and weight. Number correct on mental rotation test significantly correlated with height and weight for the total sample and for men, but only with weight for women. Using weight as covariate, the sex difference was no longer significant. The mean mental rotation score was significantly higher for heavy women than for light men. There was a positive correlation between weight and mental rotation test scores for heavy women, but height and weight were negatively correlated with mental rotation test scores for light men. These results suggest that there is no sex difference in mental rotation ability as measured.

Sex difference in perceptual-verbal ability in relation to body size.

Sex difference in verbal ability was reconsidered in relation to body size. The perceptual-verbal ability (PVA) was assessed using the A's Test. For the raw data, women excelled men, as expected. PVA positively correlated with height and weight of the subjects, but only for women. As a covariate of height, sex difference increased by increasing the women's score; men's score did not change. Tall women had much higher scores than short men. It was concluded that sex difference in PVA is stable despite the smaller body size of females than males, and body height may be predictive for this ability, but only in women.