Effect of chronic intermittent immobilization stress on Fos-like immunoreactivity in rat brain and adrenal medulla

The present study examined the influence of short- and long-term chronic intermittent immobilization stress throughout the brain and on the adrenal medulla of intact rats using Fos-like immunoreactivity (Fos-LI) as a marker of cellular activation. The effect of adreno-medullectomy on the central nervous system (CNS) response to chronic immobilization stress was also examined. It was found that control unoperated, unstressed rats had no Fos-LI cells in the brain or in the adrenal medulla. In intact rats, neither short term (1 week) nor long term (4 weeks) chronic intermittent immobilization stress produced significant increases in Fos-LI in the CNS compared with control animals. However, marked increase in the number of Fos-LI cells was observed in the adrenal medulla of animals stressed for 4 weeks compared with control, unstressed animals or those stressed for 1 or 2 weeks. In adreno-medullectomised rats, 4 weeks, but not 1 week, chronic immobilization stress produced significant increases in numbers of Fos-LI neurons in the paraventricular hypothalamic and supraoptic nuclei and the medial amygdala compared with intact animals stressed for a similar period of time. It is concluded that long term stress produces chronic Fos-LI in the adrenal medulla and that adreno-medullectomy increases the Fos response of the PVN, supraoptic nucleus and medial amygdala to long term stress.     

Hypothalamo-pituitary-adrenocortical axis function and hedonic behavior in adult male and female rats prenatally stressed by maternal food restriction

Neuroendocrine activation during stress is affected by many factors contributing to the variability of the stress response. The present study was aimed at evaluating long-term changes in hypothalamo-pituitary-adrenocortical (HPA) axis function and in hedonic behavior in adult offspring prenatally stressed by maternal food restriction, with attention on possible gender differences. Adult offspring were blood sampled via a tail artery cannula. Prenatally stressed females had significantly higher adrenal weights compared to males. Plasma ACTH levels, which rose in response to acute stress induced by handling, were significantly higher in females compared to those in males. A similar pattern was found in plasma corticosterone. The rise in ACTH levels was more pronounced in prenatally stressed rats though the rise in corticosterone failed to be modified. Corticotropin releasing hormone (CRH) and proopiomelanocortin mRNA levels in the hypothalamic paraventricular nucleus and anterior pituitary, respectively, were found to be unchanged. The present experiments failed to reveal a decrease in hedonic behavior in prenatally stressed rats. In contrast, in male offspring a tendency to a higher sucrose preference was observed. These data together with observed changes in hormone and CRH mRNA levels indicate that the gestational stress used did not result in a depression-like state in adult offspring.     

Overt and covert object-based attention

To examine the role of perceptual object representations in the control of eye movements and attention, a pair of experiments adapted the object-cuing paradigm of Egly, Driver, and Rafal (1994) to require eye movements. Displays were pairs of adjacent rectangles, each containing two characters. Observers were asked to make a speeded judgment of a target character’s orientation, and a cue was provided prior to target/distractor onset to indicate the target’s likely location. Gaze-contingent presentation of target and distractors was used to demand overt scanning of displays. Eye movements during task performance evinced two forms of object-based effects. First, saccades following fixation on an invalidly cued item were more likely to be made within the cued rectangle than between rectangles. Second, saccades within the cued rectangle were preceded by shorter dwell times than saccades between rectangles. Extrafoveal processing of stimuli within the cued rectangle, however, was not facilitated, suggesting that covert attention was not allocated more densely within the cued than within the uncued object.     

Recognition memory for single items and for associations is similarly impaired following damage to the hippocampal region

The formation of new associations between items is critical for establishing episodic memories. It has been suggested that the hippocampus is essential for creating such associations but is not involved, or is much less involved, in memory for single items. In Experiment 1, we tested controls and amnesic patients with bilateral lesions thought to be limited primarily to the hippocampal region in both single-item and associative recognition memory tasks. In the single-item task, a conventional recognition memory task was administered in which participants studied either houses or faces and were tested for their ability to recognize the individual items. In the associative task, participants studied paired pictures of houses and faces with instructions that encouraged associating the two stimuli, and were tested for their ability to recognize the specific pairings that were presented at study. Like the controls, the amnesic patients performed more poorly on the associative task. Relative to the controls, the amnesic patients were impaired to a similar extent on the single-item and associative tasks. In Experiment 2, the performance of the amnesic patients was improved by increasing the number of presentations of the study lists (eight presentations instead of one). On both the single-item and associative tests, the performance of the amnesic patients after eight presentations was now identical to the performance of the controls who had been given only one presentation of the study list. Thus, the associative condition was not disproportionally difficult for the amnesic patients. These results are consistent with the idea that the hippocampus is similarly involved in single-item and associative memory.     

Postmodernism Versus Modernism: Rethinking Theoretical Tensions in Social Gerontology

The interconnection of social theory to social aspects of aging has grown in recent years. The theoretical movement entitled structured dependency, couched in social class analysis, has tended to ignore an understanding of aging identity, the body, cultural representations of aging, and positive images of aging, all of which are central features of an emerging postmodern paradigm in gerontological theory. This article argues that the concept of gender can form a useful bridge, a continuity, between structured dependency and postmodernism in theoretical gerontology. Unfortunately, the compartmentalization of these two conceptual approaches has made their links difficult to forge. This article attempts to take a first step in this direction by highlighting the way postmodern ideas can be used to understand a modernist issue—gender in a gerontological context. Also, focusing on the aging body as a primary form of analysis generates some novel insights into the importance of both the theoretical understanding and cultural representations of the body.     

A conceptual model of cultural predictors of anxiety among Japanese American and part-Japanese American adolescents

A model integrating Japanese ethnicity, cultural identity, and anxiety was developed and assessed in Japanese American and part-Japanese American high school seniors (N = 141). Using measures from the Hawaiian High Schools Health Survey, the model incorporated the State-Trait Anxiety Inventory, the Major Life Events Scale, and the Japanese Culture Scale (JCS). Japanese American adolescents scored higher on the JCS and reported fewer anxiety symptoms than part-Japanese American adolescents. Predictors for anxiety were being Japanese American versus part-Japanese American, income, and culturally intensified events. A significant interaction of behavior by self-identification was obtained. The model had good overall fit, suggesting that cultural identity formation may contribute to anxiety experienced particularly by adolescents of mixed heritage.     

Asian American-white American differences in expressions of social anxiety: a replication and extension

This study examined whether Asian American-White American differences on a trait measure of social anxiety extend to nonverbal behavior and to reports of anxiety-related emotions during a 3-min social performance task. Forty Asian Americans and 40 White Americans completed a trait measure of social anxiety and rated their emotions before, and immediately after, a social performance task. Their videotaped behavior was coded using microlevel behavioral codes (e.g., gaze avoidance, fidgeting). Results indicated that Asian Americans reported more anxiety than White Americans on the trait measure and on the emotion rating scales but that they did not differ substantially on microlevel behavioral indexes of social anxiety. Implications of ethnic variations in the patterns of anxious responding are discussed.     

Animal spare parts? A Canadian public consultation on xenotransplantation

Xenotransplantation, or the use of animal cells, tissues and organs for humans, has been promoted as an important solution to the worldwide shortage of organs. While scientific studies continue to be done to address problems of rejection and the possibility of animal-to-human virus transfer, socio-ethical and legal questions have also been raised around informed consent, life-long monitoring, animal welfare and animal rights, and appropriate regulatory practices. Many calls have also been made to consult publics before policy decisions are made. This paper describes the Canadian public consultation process on xenotransplantation carried out by the Canadian Public Health Association in an arm’s length process from Health Canada, the ministry overseeing government health policy and regulation. Focusing on six citizen fora conducted around the country patterned after the citizen jury deliberative approach, the paper describes the citizen panelists’ recommendations to hold off on proceeding with clinical trials and the rationales behind this recommendation. The consultation process is discussed in the context of constructive technology assessment, a framework which argues for broader input into earlier stages of technology innovation, particularly at the technology design stage. This study was supported by a grant to the first author from the Social Sciences and Humanities Research Council in Canada.     

The generalization of deferred imitation in enculturated chimpanzees (Pan troglodytes)

Deferred imitation of object-related actions and generalization of imitation to similar but not identical tasks was assessed in three human-reared (enculturated) chimpanzees, ranging in age from 5 to 9 years. Each ape displayed high levels of deferred imitation and only slightly lower levels of generalization of imitation. The youngest two chimpanzees were more apt to generalize the model's actions when they had displayed portions of the target behaviors at baseline, consistent with the idea that learning is more likely to occur when working within the "zone of proximal development." We argue that generalization of imitation is the best evidence to date of imitative learning in chimpanzees. Electronic Publication