Perturbations of human posture: influence of impulse modality on EMG responses and cerebral evoked potentials

Leg muscle EMG responses and cerebral evoked potentials (CP), elicited by perturbations of stance while on a treadmill with split belts, were analyzed in order to study the relationship between compensatory leg muscle responses and afferent input to supraspinal centers. Various conditions of perturbation were used to establish the extent to which compensatory EMG responses and CPs show congruent behavior. Four different treadmill acceleration rates were applied in three different conditions (unilateral perturbation, directed forward or backward; bilateral perturbation, directed forward or backward; and opposing bilateral perturbation). EMG responses and CPs showed parallel increases in amplitude with increasing displacement velocity. The EMG responses showed distinct differences, predominantly in the response amplitude, between the different perturbation conditions, whereas the CPs were affected only to a minor degree. Tibialis anterior EMG responses were more closely related to the CP following forward perturbation than the corresponding gastrocnemius responses were to the CP following backward perturbation. We conclude that the EMG responses are more closely related than the CPs to displacement parameters and suggest that this is due to the further spinal processing of the afferent input needed to generate an appropriate EMG response. The closer relationship between the tibialis anterior response and CP may reflect a predominant central representation and control of tibialis anterior activation in the regulation of posture. The functional implications of these findings are discussed.     

Cognition and Citizen Participation in Social Action1

Citizen participation in social action may depend, in part, on certain beliefs about the world and one's power to initiate change. Existing tests of internality and belief in a just world were modified, creating independent measures of belief in personal power and belief in possible injustices in society. The paper reports data on the reliability and the convergent and discriminant validity of the new Personal Power and Injustice scales. In Studies 1 and 2 the scales predicted outcomes in theoretically relevant experiments. In Study 3 they discriminated among community groups who did, or did not, engage in social action.     

Self-schema for assertiveness: Extending the validity of the self-schema construct

This research attempted to extend the validity of the self-schema concept by examining a previously untested self-attribute and by examining self-schema effects on the interpretation of more realistic stimulus situations than used in past studies. The attribute was a self-schema for assertiveness and the validity of this self-knowledge structure was evaluated in two studies. In Stuty 1 assertion schematics and aschematics were compared for retrieval of schema-relevant information on a laboratory task of incidental recall. In Study 2 schematics and aschematics were compared on five different tasks that required elaboration of information about rights assertion conflict situations. Study 1 results revealed that schematics as compared to aschematics recalled more assertion related adjectives but did not differ in recall of domain-irrelevant words. Results from Study 2 showed that schematics as compared to aschematics recalled more past instances of assertive behaviors when asked to elaborate why an assertion adjective was endorsed as “Like me”. Also, schematics were significantly more certain they would behave assertively both in situations where assertion was appropriate and in those where compromise was more appropriate. On two perceptual factors known to correlate with assertive behavior, schematics were more likely to judge moderately legitimate requests (i.e., ambiguous requests) as more unreasonable and when asked to generate expected consequences for assertive responses focused more on self rather than other person consequences. The consistency of the results with respect to various hypothesized functions of the self-schema construct are discussed.     

Role of interstimulus and stimulus-hemisphere compatibility in the process of interhemispheric integration

Normal subjects had to name German compound nouns which were presented tachistoscopically. The compound nouns were displayed either unilaterally to the left or right visual field, or bilaterally with one element to the left and one to the right visual field. A distinction was made between the bilateral conditions as to whether the representation of the elements, printed and/or pictorial, included a high or low interstimulus and a high or low stimulus-hemisphere compatibility. Analysis indicated firstly a superiority of the left hemisphere for the naming of compound nouns in mixed print and pictorial representation. Secondly, the performance in the bilateral conditions was moderated by stimulus-hemisphere compatibility. In the process of interhemispheric integration stimulus-hemisphere compatibility proved more crucial than interstimulus compatibility. Analyses of errors further illustrated hemispheric behaviour.     

Contrasting lever-press avoidance behaviors of spontaneously hypertensive and normotensive rats (Rattus norvegicus)

Lever-press avoidance performances of Spontaneously Hypertensive (SHR) and Wistar-Kyoto (WKY) rats were observed in two experiments. The first compared them at shock intensities of 1 or 2 mA. The SHRs had the highest percentage of avoidances, made the most coping responses (avoidances plus escapes), and received the fewest shocks (ps less than .05). They also had shorter avoidance and initial-escape latencies (ps less than .05). In the second experiment these strains were trained with signal-shock intervals that produce good (60 s) or poor (10 s) avoidance acquisition. Analysis of the Strain x Conditions x Blocks interaction showed that SHRs performed better with the longer interval (p less than .05), whereas WKYs' performance was similar with both (p greater than .05). Thus WKYs differed from all other strains previously exposed to these conditions. The findings are interpreted in terms that emphasize the SHRs' tendency to move, compared with the WKYs' tendency to freeze in response to aversive stimuli, rather than characterizing SHRs as hyperreactive.     

The making of an adolescent clinic

This paper addresses the nationwide need for comprehensive health care services directed toward adolescents, outlining a multidisciplinary team program designed to provide such services. The national problem of teenage pregnancy is discussed, and the multidisciplinary team's success with family planning counseling is described. The authors strongly encourage the development of more school- or community-based clinics based on a comprehensive health care team model.     

Female delinquency in the emancipation era: A review of the literature

By the mid-1970s studies began to indicate that the era of women's emancipation had been accompanied by changes in the volume and character of female lawbreaking. In this paper, I critically review the growing literature that has attempted to measure and explain the alleged changes in female delinquency. I examine whether females have remained traditional in their delinquency patterns, whether the observed changes (if they exist at all) are real or the result of changing societal reactions, and whether female delinquents have been masculinized or in other ways influenced by the women's liberation movement or changing gender roles. I also review explanations of female delinquency that are derived from social control, power-control, strain, and subcultural theories. Finally, I argue that more attention needs to be given to understanding the role strain inherent in females' attempts to negotiate ambiguous or contradictory gender roles, and that the concept of role strain offers a promising explanation of contemporary patterns of female delinquency.Portions of this paper were adapted from R. J. Berger (Ed.), The Sociology of Juvenile Delinquency, Chicago: Nelson-Hall, 1990 forthcoming.     

Alexithymic traits as predictors of difficulties with adjustment in an outpatient cohort of expatriates in Tokyo

The purpose of this study was to examine whether alexithymic characteristics, which are thought to be related to poor coping with stress, would be associated with variables thought to reflect adjustment to life abroad. The subjects were 56 expatriates living in Tokyo, Japan. The Expatriate Adaptation Inventory, the Toronto Alexithymia Scale, and the Social Support Questionnaire of the Stress and Coping Inventory were given to the subjects. Scores on alexithymia were significantly associated with dissatisfaction with life abroad, higher satisfaction with life in one's home country prior to departure, and higher ratings on the perception of poor social support. An alexithymia variable, difficulty identifying feelings, was a significant predictor of dissatisfaction with life abroad and satisfaction with life in the home country. The results suggest that, because alexithymia was associated with lower satisfaction with life abroad and higher satisfaction in the home country prior to departure, it may be a predictor of adjustment difficulties when individuals live abroad. Empirical confirmation is needed.     

Residential Relocation of People Who Are Older: Relationships Among Life Satisfaction,Perceptions, Coping Strategies,and Other Variables

A model of social stress was used to examine variables associated with life satisfaction of older people who were making residential relocations from one level of independence to another level of independence. Data were collected regarding life satisfaction, perceptions of the relocation, coping strategies, and possible conditioning variables.