Role of the area postrema in three putative measures of motion sickness in the rat

After thermal cauterization of the area postrema in rats the absence of conditioned taste aversion to sucrose paired with lithium chloride (0.15 M, 3.3 ml/kg) was used as a pharmacologic/behavioral index of area postrema damage. In a subsequent experiment the effects of area postrema lesions on three measures proposed as species-relevant measures of motion sickness were studied, using off-vertical rotation at 150 degrees/s for either 30 or 90 min. Lesions of area postrema did not alter postrotational suppression of drinking or amount of defecation during motion. The initial acquisition of conditioned taste aversion to a novel cider vinegar solution paired with motion was not affected by lesioning of the area postrema, but these taste aversions extinguished more slowly in lesioned rats than in sham-operates or intact controls. Results are discussed in terms of proposed humoral factors which may induce motion sickness and in light of recent data on the role of the area postrema in similar measures in species possessing the complete emetic reflex.     

Electroencephalogram asymmetry during emotionally evocative films and its relation to positive and negative affectivity

The purpose of the present study was to determine if there were differences in hemispheric lateralization during the experience of emotions and if those differences were related to personality style. College-age adult subjects selected for high positive and negative affectivity on Tellegen's Multidimensional Personality Questionnaire (MPQ; Tellegen, 1982) viewed video stimuli selected for their emotionally evocative nature and rated the intensity of the emotions they experienced. The ongoing electroencephalogram (EEG) was recorded while they watched the video clips. Analyses of the EEG data revealed that there were differences in regional activation during the emotional video clips, especially for those stimuli selected to elicit either happy or disgust emotions. These results support the hypothesis that the right hemisphere is specialized for the experience of certain negative affects, whereas the left hemisphere is specialized for the experience of certain positive affects. The findings also indicated some support for the theory that individual differences in personality style are related to differing levels of hemispheric arousal.     

Motor-motor adaptation: preliminary findings

This study investigated the relationship between speech perception and speech production. An experimental technique called motor-motor adaptation was devised. Subjects produced a speech token repeatedly (20 to 40 repetitions), then produced a second token one time. These tokens all contained stop consonants and were subsequently analyzed for voice onset time. The results paralleled previous findings using the experimental procedure, perceptuomotor adaptation. The present study supports the notion of a perception-production link.     

Differential visual field-interhemispheric transfer: can it explain sex and handedness differences in lateralization?

104 men and women were tested for visual field-hemispheric transfer of spatial information on a dot-localization task. Right-handed subjects showed significant improvement when stimuli were presented to the left visual field of the right hemisphere (LVF-RH) after practice on the same task presented to the right visual field of the left hemisphere (RVF-LH) first. No improvement was found when the task was presented in the reverse order (LVF-RH first followed by RVF-LH). It was concluded that, for right-handers, transfer of spatial information to the right hemisphere is facilitated while transfer to the left hemisphere is inhibited. Left-handed subjects demonstrated no significant improvement in either condition, suggesting inhibition or lack of transfer of spatial information in either direction. No sex differences were found in either right-handed or left-handed subjects. The findings suggest that there may be different mechanisms underlying the similarities in functional lateralization of women and left-handers.     

THE PASSIONATE MIND: BRAIN, DREAMS, MEMORY, AND SOCIAL CATEGORIES

Abstract. The intellectualist position held by structuralists does not explain the extremes of emotional reaction to the disruption of social categories. An approach from neuroscience based on the functions of the limbic system in the creation of long-term memory through the role of the hippocampus and REM sleep is proposed to account for the emotive loading of cognitive categories.     

Infants’ identification of three-dimensional form from transformations of linear perspective

The ability of infants to perceive three-dimensional structure from transformations of linear perspective was investigated in two studies. Infants were habituated to the pattern of linear perspective transformations corresponding to a particular three-dimensional object, and their relative preference for that object as compared with a different three-dimensional object was assessed both before and after habituation. The habituation displays showed the distorting shadow cast by a rotating object and therefore provided only transformations of linear perspective as information specifying three-dimensional form. The pre- and posttest displays involved the actual three-dimensional objects and provided binocular, shading, and texture information specifying three-dimensional form, but did not provide informative transformations of linear perspective. In Study 1, 6-month-olds showed changes in preference from pre- to posttest that were related to the identity of the object whose shadow they had seen during habituation; 4-month-olds, however, did not show preference changes related to the habituation object. In Study 2, rhythm information that may have served as a basis for responding in Study 1 was eliminated from the test displays. Six-month-olds again showed changes in preference that were dependent on their habituation experience. It is concluded that, by 6 months of age, infants are able to perceive object structure from the isolated cue of transformations of linear perspective. The findings are discussed with reference to infants’ three-dimensional form perception based on other cues and also with reference to the emergence of certain spatially related moter activities.     

The intergenerational transmission of relationship instability: A focus on emerging adult on-off relationships

This study extends prior research on the intergenerational transmission of relationship instability by examining parents' history of on-off relationships as a predictor of emerging adults' own cycling (i.e., breaking up and renewing with the same romantic partner). Data were collected at a large mid-western university from 702 emerging adults (18–25 years old). Multinomial logistic regression was used to predict the likelihood that participants had cycled in a past or current relationship. Results show that parental cycling increased the likelihood of offspring cycling in a past or current relationship relative to never cycling, and greater uncertainty about the future of the relationship was a mechanism through which such transmission occurred. Findings from this study demonstrate that parental relationship instability can even be consequential for the transient relationships within emerging adulthood, making family history a productive area to explore for practitioners working with cyclical partners and/or emerging adults.     

Examining awareness of privilege among midwestern college students: An analysis of race/ethnicity,gender, and religion

Dominant group members often are not aware of the privileges they benefit from due to their dominant group membership. Yet individuals are members of multiple groups and may simultaneously occupy multiple categories of dominance and marginality, raising the question of how different group memberships work in concert to facilitate or inhibit awareness of multiple forms of privilege. Examining awareness of privilege is important as awareness may be linked to action to dismantle systems of privilege that maintain oppression and inequality. Grounded in intersectional scholarship, in this study we examined how occupying intersecting categories of race/ethnicity, gender, and religion corresponded to an awareness of White, male, and Christian privilege. In a sample of 2321 Midwestern college students, we demonstrated that students from marginalized groups broadly reported greater awareness of all forms of privilege than students from dominant groups, and the difference between marginalized and dominant groups was most pronounced when the specific group category (e.g., gender) aligned with the type of privilege (e.g., male privilege). We also tested interactions among race/ethnicity, gender, and religion, only finding an interaction between race/ethnicity and religion for awareness of White and male privilege. These findings helped to clarify that multiple group memberships tended to contribute to awareness as multiple main effects rather than as multiplicative. Finally, we examined mean differences among the eight intersected groups to explore similarities and differences among groups in awareness of all types of privilege. Taken together, these findings quantitatively demonstrate the ways in which group memberships work together to contribute to awareness of multiple forms of privilege. We discuss study limitations and implications for community psychology research and practice.