Behavioral Profiles of Genetically Selected Aggressive and Nonaggressive Male Wild House Mice in Two Anxiety Tests

Artificially selected aggressive (SAL) and non-aggressive (LAL) male house mice were tested in a hexagonal tunnel maze and light-dark preference (LD) box to determine if the bidirectional selection for aggressive behavior leads to a coselection for different levels of trait anxiety. The tunnel maze consists of an open, brightly lit central arena surrounded by a complex system of interconnecting tunnels. As in the LD box, animals which spend less time and are less active in the brightly illuminated section of the maze are considered to have higher anxiety levels. In the tunnel maze, the LAL mice showed more exploration and spent more time in the central arena than the SAL animals, but only during the final 2 min of the 6-min test. This reduced preference for the central arena was not due to general inactivity or a failure of the SAL to find the central arena and indicates a higher level of state anxiety in the aggressive animals. In contrast, no anxiety-like differences were found in the LD box, either for the percentage of time spent in the light compartment or for the number of crossings. SAL males actually showed higher levels of moving and rearing, and lower levels of freezing, than did LAL males.     

Effects of "Below-Zero" Habituation on the Electrodermal Orienting Response to a Test Stimulus

Two experiments were designed to investigate the effect of below-zero habituation training on skin conductance response (SCR) amplitude to a change in auditory stimulus frequency. In both experiments, subjects were trained with a 1000 Hz tone until zero responding and then received 5, 10, or IS further training trials. In Experiment 1 (N=45), subjects then received 1 presentation of a test stimulus of 1400 Hz, while in Experiment 2 (N=45), the test stimulus was a tone of 670 Hz. On the basis of dual-process theory, it was hypothesized that response amplitude to the test stimulus would be inversely related to amount of below-zero training. However, the results of both experiments indicate that SCR amplitude was positively related to amount of below-zero training. These results suggest that in situations of extended habituation training, an expectancy or subjective probability of stimulus occurrence gradient is important in determining response amplitude to a test stimulus.     

Minority mating advantage of certain eye color mutants ofDrosophila melanogaster. I. Multiple-choice and single-female tests

Alleles at the brown locus ofDrosophila melanogaster combined with homozygous scarlet provide a useful model to demonstrate minority advantage of males in mating. Heterozygotes with orange (O) eyes equal in numbers to homozygotes with red (R) eyes (1010 in both sexes) displayed no bias favoring either eye color, but each eye color was favored when males occurred in a minority ratio (218). In direct observation of single females with equal numbers of males (33) as controls,O males courted less and more slowly thanR males, but females mated with either type without bias. When unequal (41), the minority males were successful at more than twice the frequency expected. Whether successful or not, the minority males did not change their level of courtship, and thus cannot be said to compensate for their frequency in any way. The time between first courtship and mating was less for the minority males than for the majority males. We discard the hypothesis that the minority male will be accepted immediately or ahead of a majority male, because the opposite tended to occur: that if a minority male courted first he was less likely to be successful than if he waited until the majority courted. Our results then are in conformity with the hypothesis that a female samples males and their courtship cues, thus becoming habituated to the majority of the first courting male, but she accepts a male with a cue different from that which she originally detected but avoided. That male is most often the minority.This research was supported in part by National Science Foundation Grants GB-34206 to August 31, 1974, and BMS 72-02110 after that date.     

SELECTIVE HABITUATION OF GALVANIC SKIN RESPONSE COMPONENT OF THE ORIENTATION REACTION TO AN AUDITORY STIMULUS

The prediction from Sokolov's (1960) theory that, following OR habituation, size of OR return is proportional to the amount of difference between the new stimulus and the habituating stimulus was tested using an auditory stimulus varying in frequency and intensity. Five Ss were allocated to each of 16 conditions, three conditions involving changes in frequency, three involving changes in intensity, nine involving changes in both frequency and intensity, with one control condition involving a repetition of the habituating stimulus. Following habituation of the GSR component of the OR to a criterion of response failure for three successive trials, magnitude of GSR under the 16 conditions was measured. Contrary to Sokolov's theory, only increase in intensity had a significantly different effect on OR return. More importantly, it was found that Ss habituating rapidly to the initial stimulus were less likely to show OR return to stimulus change. It was concluded that individual differences in habituation rate may be more important than stimulus difference effects in selective habituation.     

Effects of sex and estrous cycle on modulation of the acoustic startle response in mice

Potential sex differences in amplitude, habituation, prepulse inhibition (PPI) and prepulse facilitation (PPF) of the acoustic startle response (ASR) were investigated using male and female mice from the two different inbred mouse strains C57BL/6J (C57) and C3H. Furthermore, the effects of the estrous cycle were tested. The estrous cycle appeared to have no effect on ASR amplitude, habituation, PPF and PPI, the latter being in contrast to results in rats and humans. While sex had no effect on PPI or PPF, males exhibited higher startle amplitudes than females, irrespective of strain, which we discuss to be due to increased male anxiety. In addition, long-term habituation was stronger in C57 males and short-term habituation was weaker in C3H males with respect to females. These results provide evidence for influence of the reproductive hormones on startle reactivity and startle habituation; we therefore conclude that future studies involving genetic influences on behavior using inbred strains are only complete if both sexes are included.     

Repeated Habituation and Overhabituation of the Orienting Response

This investigation was designed to test (a) whether stimuli presented in the form of repeated blocks of habituation trials, as opposed to.1 single continuous series of stimuli, would produce a progressive decline. in amount of spontaneous recovery and trials to rehabituation of the skin conductance component of the orienting response; and (b) whether 30 or 50 post-habituation trials would produce a return of the orienting response which could be related In sensitization effects. Results showed that repeated habituations strengthened habituation as reflected in progressively decreasing spontaneous recovery across blocks, but not in speed of habituations. Further, neither 30 nor 50 post-habituation trials produced a return of the orienting response, although 30 such trials did result in increased skin conductance level. Discussion centers on whether habituation beyond asymptotic levels (‘below-zero’) within sessions was unambiguously obtained; relationships among stimulus intensity, frequency, and the return of the orienting response; and factors affecting measures of retention of habituation within sessions.     

Habituation of the Skin Conductance Response to Strong Stimuli: A Twin Study

Skin conductance responses to a series of loud tones were measured bilaterally in 121 pairs of adult twins, 53 pairs reared together and 68 pairs reared apart. Subjects were given an absorbing task on which to focus their attention and instructed to ignore the meaningless tones. Rangecorrection eliminated hand and sex differences in SCR amplitude and also the correlation with age of this variable. For the combined group of 79 pairs of monozygotic (MZ) twins, the within-pair correlations for Y-intercept, the slope of the habituation curve, and the number of trials to habituation were near the limits of retest reliability for these variables. After range-correction, the correlation for Y-intercept for the 42 pairs of dizygotic (DZ) twins was about half the MZ value, suggesting that initial electrodermal reactivity is strongly genetic and can be interpreted according to a polygenic-additive model. Biometric model testing indicated that stable individual differences in uncorrected SCR amplitude and in habituation slope are primarily determined by non-additive genetic factors. About 40% of the total variance (and most of the stable variance) in number of trials to habituation is genetically determined. Co-twins of MZ twins who were electrodermal nonresponders tended also to be hyporesponsive while co-twins of DZ nonresponders tended to be normoresponsive.     

不同方式前庭习服锻炼对正弦谐波加速度试验的影响

目的研究地面针对性前庭习服锻炼和飞行中前庭习服锻炼两种锻炼方式对正弦谐波加速度试验（sinusoidal harmonic acceleration test，SHAT）的影响。方法地面人员10名，进行7天针对性前庭习服锻炼；男性健康飞行员26名，飞行时间450～1350小时。分别测定在转椅（0．01Hz～0．64Hz）倍频正弦谐波加速度刺激方式下的前庭眼动反射，分析增益、不对称比、相位等参数。结果飞行员的低频增益（0．01Hz、0．02Hz、0．04Hz、0．08Hz、0．16Hz）高于地面人员。结论不同的前庭习服锻炼对正弦谐波加速度试验的影响是不同的．地面针对性前庭习服锻炼在提高前庭功能稳定性上好于飞行员实际飞行中的前庭习服锻炼。     

Novelty,conditioning and attentional bias to sexual rewards

The Internet provides a large source of novel and rewarding stimuli, particularly with respect to sexually explicit materials. Novelty-seeking and cue-conditioning are fundamental processes underlying preference and approach behaviors implicated in disorders of addiction. Here we examine these processes in individuals with compulsive sexual behaviors (CSB), hypothesizing a greater preference for sexual novelty and stimuli conditioned to sexual rewards relative to healthy volunteers. Twenty-two CSB males and forty age-matched male volunteers were tested in two separate behavioral tasks focusing on preferences for novelty and conditioned stimuli. Twenty subjects from each group were also assessed in a third conditioning and extinction task using functional magnetic resonance imaging. CSB was associated with enhanced novelty preference for sexual, as compared to control images, and a generalized preference for cues conditioned to sexual and monetary versus neutral outcomes compared to healthy volunteers. CSB individuals also had greater dorsal cingulate habituation to repeated sexual versus monetary images with the degree of habituation correlating with enhanced preference for sexual novelty. Approach behaviors to sexually conditioned cues dissociable from novelty preference were associated with an early attentional bias to sexual images. This study shows that CSB individuals have a dysfunctional enhanced preference for sexual novelty possibly mediated by greater cingulate habituation along with a generalized enhancement of conditioning to rewards. We further emphasize a dissociable role for cue-conditioning and novelty preference on the early attentional bias for sexual cues. These findings have wider relevance as the Internet provides a broad range of novel and potentially rewarding stimuli.