PubMed Health⌕ Search

Biomedical subjects

G E Robinson

Publications and source records attributed to G E Robinson.

At least 55 records · Page 3Linked to original sources
PubMed1998

Stalking. Part II: Victims' problems with the legal system and therapeutic considerations.

OBJECTIVE: This paper is the second of 2 parts reviewing the topic of stalking. It focuses on victims difficulties with the legal system and the psychotherapeutic tasks for victims and therapists. METHOD: Computerized literature searches were used to identify relevant papers from psychiatric and legal journals. Publications by victims' and women's organizations provided additional information. RESULTS: Victims suffer emotional consequences from being stalked. Additional stress is caused by the legal system's lack of understanding of the causes and consequences of stalking and inadequate and unenforced laws. The treatment of victims requires a comprehensive approach, including education, supportive psychotherapy, and discussion of practical measures. Therapists may overidentify with the patient's powerlessness or hesitate to take on a case out of fear of the stalker. Female therapists may protect themselves against the realization of their own vulnerability by blaming the victim, while male therapists may feel defensive or overprotective. CONCLUSION: Stalking is a crime with major mental health consequences which is often poorly understood by society. Therapists need to be aware of the victim's emotional reactions, the types of legal and practical supports available, and the possible biases of society. Further education and research should be encouraged.

Canada↗
PubMed1997

Expansion of the neuropil of the mushroom bodies in male honey bees is coincident with initiation of flight.

The mushroom bodies (MB), the insect brain structures most often associated with learning, have previously been shown to exhibit structural plasticity during the adult behavioral development of female worker and queen honey bees. We now show that comparable morphological changes occur in the brains of male honey bees (drones). The volume of the MB in the brains of drones was estimated from tissue sections using the Cavalieri method. Brains were obtained from six groups of drones that differed in age and flight experience. Circulating levels of juvenile hormone (JH) in these drones were determined by radioimmunoassay (RIA). There was an expansion of the neuropil of the MB that was temporally associated with drone behavioral development, as in female queens and workers. The observed changes in drones were maintained in the presence of low levels of JH, also as in females. These results suggest that expansion of the neuropil of the MB in honey bees is associated with learning the location of the nest, because this learning is the most prominent aspect of behavioral development common to all members (workers, drones, queen) of the honey bee colony.

Age Factors↗
PubMed1997

Juvenile hormone in adult eusocial Hymenoptera: gonadotropin and behavioral pacemaker.

Studies on the role of juvenile hormone (JH) in adult social Hymenoptera have focused on the regulation of two fundamental aspects of colony organization: reproductive division of labor between queens and workers and age-related division of labor among workers. JH acts as a gonadotropin in the primitively eusocial wasp and bumble bee species studied, and may also play this role in the advanced eusocial fire ants. However, there is no evidence that JH acts as a traditional gonadotropin in the advanced eusocial honey bee or in the few other ant species that have recently begun to be studied. The role of JH in age-related division of labor has been most thoroughly examined in honey bees. Results of these studies demonstrate that JH acts as a "behavioral pacemaker," influencing how fast a worker grows up and makes the transition from nest activities to foraging. Hypotheses concerning the evolutionary relationship between the two functions of JH in adult eusocial Hymenoptera are discussed.

Age Factors↗
PubMed1997

Insect societies and the molecular biology of social behavior.

This article outlines the rationale for a molecular genetic study of social behavior, and explains why social insects are good models. Summaries of research on brain and behavior in two species, honey bees and fire ants, are presented to illustrate the richness of the behavioral phenomena that can be addressed with social insects and to show how they are beginning to be used to study genes that influence social behavior. We conclude by considering the problems and potential of this emerging field.

Animals↗
PubMed1996

Common endocrine and genetic mechanisms of behavioral development in male and worker honey bees and the evolution of division of labor.

Temporal polyethism is a highly derived form of behavioral development displayed by social insects. Hormonal and genetic mechanisms regulating temporal polyethism in worker honey bees have been identified, but the evolution of these mechanisms is not well understood. We performed three experiments with male honey bees (drones) to investigate how mechanisms regulating temporal polyethism may have evolved because, relative to workers, drones display an intriguing combination of similarities and differences in behavioral development. We report that behavioral development in drones is regulated by mechanisms common to workers. In experiment 1, drones treated with the juvenile hormone (JH) analog methoprene started flying at significantly younger ages than did control drones, as is the case for workers. In experiment 2, there was an age-related increase in JH associated with the onset of drone flight, as in workers. In experiment 3, drones derived from workers with fast rates of behavioral development themselves started flying at younger ages than drones derived from workers with slower rates of behavioral development. These results suggest that endocrine and genetic mechanisms associated with temporal polyethism did not evolve strictly within the context of worker social behavior.

Aging↗
PubMed1996

A curriculum on physician-patient sexual misconduct and teacher-learner mistreatment. Part 2: Teaching method.

Medical educators have become increasingly aware of the need for health care professionals to receive more training about the causes and consequences of physician-patient sexual misconduct and teacher-learner mistreatment and harassment. A curriculum in use at the University of Toronto includes a didactic component, consisting of lectures, and an experiential component, consisting of a workshop. This article concerns how, by discussing case vignettes designed to illustrate salient points, the participants have an opportunity to consider their responses in actual clinical and teaching situations. Evaluation of the course by 373 participants shows that the curriculum is considered acceptable and is likely to be of benefit. Of the course participants, 54% (15/28) of those attending the course for faculty and 39% (133/345) of those at subsequent courses stated that they would change their clinical and teaching practices in positive ways as a result of attending. A further 38% (130/345) stated that they already practised in a manner congruent with the model discussed.

Curriculum↗
PubMed1996

A curriculum on physician-patient sexual misconduct and teacher-learner mistreatment. Part 1: content.

Although health care professionals, licensing bodies, governments and the community are paying increasing attention to the negative consequences of sexual misconduct by physicians, education for professionals about this subject is rare and limited. Even less attention has been paid to the adverse effects of violations of boundaries between teachers and learners (students, residents, interns and other trainees). A curriculum now being used at the University of Toronto to teach faculty and students about these topics includes a didactic portion and a workshop component. The didactic portion consists of lectures on the definitions, causes and consequences of physician-patient sexual misconduct and teacher-learner mistreatment and harassment. Relationships after termination of treatment and the complaint and discipline procedures of the College of Physicians and Surgeons of Ontario are also discussed. This article reviews the topics covered in this portion of the curriculum. A subsequent article will discuss the workshop component of the course.

Curriculum↗
PubMed1996

Juvenile hormone, behavioral maturation, and brain structure in the honey bee.

Juvenile hormone regulates metamorphosis in insects, and its effects on the nervous system during the larval-pupal transition have been studied primarily in the hawk moth, Manduca sexta. The effects of juvenile hormone on the nervous system of adult insects have been little studied. Elucidating the role of juvenile hormone during behavioral development in adult honey bees provides an opportunity to study hormone regulation of nervous system structure and function in an insect with a rich behavioral repertoire and social life. A worker honey bee typically lives 30-60 days. During this time, she performs a sequence of different tasks that sustain the colony. A striking behavioral transition typically occurs at about 3 weeks of age. At this time, worker bees stop performing within-hive tasks such as rearing brood and building comb and begin to forage outside the hive. This behavioral development is accompanied by a marked increase in the production of juvenile hormone. The mushroom bodies of the protocerebrum, the region of the insect brain most often associated with learning and memory, also undergo an internal reorganization during behavioral development. High titers of juvenile hormone and an increased volume of neuropil associated with the mushroom bodies are characteristic of the forager. Importantly, the time of the behavioral transition to foraging is not fixed. Individual bees can respond to changing colony or environmental conditions by accelerating or delaying the switch from within-hive tasks to foraging. For example, in the absence of older workers, some bees will undergo precocious development and may forage as early as 4 days of age. These workers also experience a precocious rise in juvenile hormone and an earlier reorganization of the mushroom bodies. Our current studies investigate the roles played by juvenile hormone and experience in shaping the mushroom bodies of the adult honey bee, and the relationship of these changes to the bee's ability to forage successfully. It is proposed that juvenile hormone may mediate neural plasticity in the brains of adult honey bees to support the demanding cognitive task of foraging.

Animals↗
PubMed1995

Neurogenesis is absent in the brains of adult honey bees and does not explain behavioral neuroplasticity.

The mushroom bodies, the insect brain structures most often associated with learning, exhibit structural plasticity during adult behavioral development in honey bees. We have investigated whether adult neurogenesis contributes to the plasticity of the mushroom bodies by labeling the DNA of replicating cells with 5-bromo-2'-deoxyuridine (BrdU). Immunocytochemical analysis of brain sections from bees fed or injected with BrdU as well as from bees treated in vitro with BrdU revealed no labeled neuronal nuclei, regardless of age or behavioral status of the worker bee (1-day old, nurse, or forager). Our results demonstrate that neurogenesis in the adult bee brain is a rare event, if it occurs at all. Therefore, the structural changes observed in the bee brain during adult behavioral development must be explained by developmental processes other than neurogenesis.

Animals↗
PubMed1995

Effects of experience and juvenile hormone on the organization of the mushroom bodies of honey bees.

There is an age-related division of labor in the honey bee colony that is regulated by juvenile hormone. After completing metamorphosis, young workers have low titers of juvenile hormone and spend the first several weeks of their adult lives performing tasks within the hive. Older workers, approximately 3 weeks of age, have high titers of juvenile hormone and forage outside the hive for nectar and pollen. We have previously reported that changes in the volume of the mushroom bodies of the honey bee brain are temporally associated with the performance of foraging. The neuropil of the mushroom bodies is increased in volume, whereas the volume occupied by the somata of the Kenyon cells is significantly decreased in foragers relative to younger workers. To study the effect of flight experience and juvenile hormone on these changes within the mushroom bodies, young worker bees were treated with the juvenile hormone analog methoprene but a subset was prevented from foraging (big back bees). Stereological volume estimates revealed that, regardless of foraging experience, bees treated with methoprene had a significantly larger volume of neuropil in the mushroom bodies and a significantly smaller Kenyon cell somal region volume than did 1-day-old bees. The bees treated with methoprene did not differ on these volume estimates from untreated foragers (presumed to have high endogenous levels of juvenile hormone) of the same age sampled from the same colony. Bees prevented from flying and foraging nonetheless received visual stimulation as they gathered at the hive entrance. These results, coupled with a subregional analysis of the neuropil, suggest a potentially important role of visual stimulation, possibly interacting with juvenile hormone, as an organizer of the mushroom bodies. In an independent study, the brains of worker bees in which the transition to foraging was delayed (overaged nurse bees) were also studied. The mushroom bodies of overaged nurse bees had a Kenyon cell somal region volume typical of normal aged nurse bees. However, they displayed a significantly expanded neuropil relative to normal aged nurse bees. Analysis of the big back bees demonstrates that certain aspects of adult brain plasticity associated with foraging can be displayed by worker bees treated with methoprene independent of foraging experience. Analysis of the overaged nurse bees suggests that the post-metamorphic expansion of the neuropil of the mushroom bodies of worker honey bees is not a result of foraging experience.

Aging↗
PubMed1995

Volume changes in the mushroom bodies of adult honey bee queens.

The volume of the mushroom bodies of the brains of honey bee queens (Apis mellifera) was estimated using the method of Cavalieri. Tissue sampled was obtained from queens in five different behavioral and reproductive states: 1-day-old virgin queens, 14-day-old virgin queens, 14-day-old instrumentally inseminated queens, 9- to 13-day old naturally mated queens, and 5-month-old naturally mated queens. There were significant volume changes within the mushroom bodies during the first 2 weeks of adult life. The volume occupied by the somata of the intrinsic neuronal population (Kenyon cells) of the mushroom bodies decreased by approximately 30% and the volume of the neuropil of the mushroom bodies increased between 25 and 50%. These volume changes are strikingly similar to those previously reported to occur for worker honey bees switching from hive activities to foraging (Withers, Fahrbach, & Robinson, 1993). However, in this study they were found even in queens that had no flight experience. In addition, queens exhibiting these volume changes were found to have low blood levels of juvenile hormone, while previous studies have shown that foraging worker honey bees have high hormone levels. These results suggest that some aspect of behavioral development common to both the queen and the worker castes is fundamental to protocerebral volume changes early in adulthood in honey bees. If juvenile hormone regulates this process, results from queens suggest that it may play an organizational role.

Animals↗
PubMed1995

Seasonal changes in juvenile hormone titers and rates of biosynthesis in honey bees.

Honey bee colonies can respond to changing environmental conditions by showing plasticity in age related division of labor, and these responses are associated with changes in juvenile hormone. The shift from nest tasks to foraging has been especially well characterized; foraging is associated with high juvenile hormone titers and high rates of juvenile hormone biosynthesis, and can be induced prematurely in young bees by juvenile hormone treatment or by a shortage of foragers. However, very few studies have been conducted that study plasticity in division of labor under naturally occurring changes in the environment. To gain further insight into how the environment and juvenile hormone influence foraging behavior, we measured juvenile hormone titers and rates of biosynthesis in workers during times of the year when colony activity in temperature climates is reduced: late fall, winter, and early spring. Juvenile hormone titers and rates of biosynthesis decreased in foragers in the fall as foraging diminished and bees became less active. This demonstration of a natural drop in juvenile hormone confirms and extends previous findings when bees were experimentally induced to revert from foraging to within-hive tasks. In addition, endocrine changes in foragers in the fall are part of a larger seasonally related phenomenon in which juvenile hormone levels in younger, pre-foraging bees also decline in the fall and then increase the following spring as colony activity increases. The seasonal decline in juvenile hormone in foragers was mimicked in summer by placing a honey bee colony in a cold room for 8 days. This suggests that seasonal changes in juvenile hormone are not related to photoperiod changes, but rather to changes in temperature and/or colony social structure that in turn influence endocrine and behavioral development. We also found that active foragers in the late winter and early spring had lower juvenile hormone levels than active foragers in late spring. In light of recent findings of a possible link between juvenile hormone and neuroanatomical plasticity in the bee brain, these results suggest that bees can forage with low juvenile hormone, after previous exposure to some threshold level of juvenile hormone leads to changes in brain structure.

Analysis of Variance↗
PubMed1994

Physiological correlates of division of labor among similarly aged honey bees.

Hormone analyses and exocrine gland measurements were made to probe for physiological correlates of division of labor among similarly aged adult worker honey bees (Apis mellifera L.). Middle-age bees (ca. 2 weeks old) performing different tasks showed significant differences in both juvenile hormone (JH) biosynthesis rates and hemolymph titers; guards and undertakers had high JH, and wax producers and food storers, low JH. Guards and undertakers had similar hormone levels to foragers, even though they were 10 days younger than foragers. No differences in JH were detected among young bees (1-week-old queen attendants and nurses) or older bees (3-4 week-old pollen foragers, non-pollen foragers, and soldiers). Hypopharyngeal gland size was inversely correlated with worker age and rate of JH biosynthesis, but soldiers had significantly larger hypopharyngeal glands than did foragers, despite their similar age and JH level. Results from soldiers indicate that exocrine gland development is not always linked with age-related behavior and endocrine development; they also support the recent claim that soldiers constitute a group of older bees that are distinct from foragers. Hormonal analyses indicate that the current model of JH's role in honey bee division of labor needs to be expanded because high levels of JH are associated with several other tasks besides foraging. JH may be involved in the regulation of division of labor among similarly aged workers in addition to its role in age-related division of labor.

Age Factors↗
PubMed1993

Selective neuroanatomical plasticity and division of labour in the honeybee.

The mushroom bodies in the protocerebrum are believed to be the structures of the insect brain most closely associated with higher-order sensory integration and learning. Drosophila melanogaster mutants with olfactory learning deficits have anatomically abnormal mushroom bodies or altered patterns of gene expression in mushroom body neurons. In addition, anatomical reorganization of the mushroom bodies occurs in adult flies, and possibly in adult honeybees; disturbance of electrical activity in this region disrupts memory formation in honeybees. Little is known, however, about the relationship of naturally occurring anatomical changes in the mushroom bodies to naturally occurring behavioural plasticity. We now report that age-based division of labour in adult worker honeybees (Apis mellifera) is associated with substantial changes in certain brain regions, notably the mushroom bodies. Moreover, these striking changes in brain structure are dependent, not on the age of the bee, but on its foraging experience, thus demonstrating a robust anatomical plasticity associated with complex behaviour in an adult insect.

Aging↗