Barker, Jennifer M.
Person Preferred Name
Jennifer Barker
Person Alternate Names
J.M. Barker
Jennifer Marie Barker
JM Barker
Position
Faculty Member
Field of Activity
Comparative Neurobiology
Endocrinology & Metabolism
Biochemistry & Molecular Biology
Zoology
Website
Email/Contact
barkerj1@douglascollege.ca
Department
Status
current
Education and Credentials
PhD (University of British Columbia)
MSc (University of Toronto)
BSc (University of Toronto)
PhD (University of British Columbia)
MSc (University of Toronto)
BSc (University of Toronto)
Related Works
Content type
Digital Document
Abstract
Since the launch of the BC Open Textbook Project in 2012, the adoption of open textbooks has steadily grown within public post-secondary institutions in British Columbia, Canada. An analysis of adoption records over a five-year period reveals that open textbooks have been adopted across all types of institutions, including research universities, teaching universities, colleges, and institutes, and across a diverse set of disciplines, with the largest numbers in the sciences and social sciences. In this report we identify, describe, and illustrate eight distinct patterns of open textbook adoption. These are: stealth adoption, adoption by infection, committee adoption, sanctioned exceptional adoption, course developer adoption, infection by inter-institutional carrier, creation and adoption, and lone adoption. While these patterns are not intended to be exhaustive, we hope that identifying these patterns provides a useful framework for campus leaders to (a) understand how adoptions occur in their own contexts, (b) identify ways to support further adoptions, (c) recognize that there are multiple ways, and no single path, to supporting the adoption of educational innovations at their institutions, and (d) foster the embrace of wider open educational practices.
Origin Information
Content type
Digital Document
Abstract
Testosterone has been shown to enhance hippocampal neurogenesis through increased cell survival, but which stages of new neuron development are influenced by testosterone remains unclear. Therefore, we tested the effects of sex steroids administered during three different periods after cell division in the dentate gyrus of adult male rats to determine when they influence the survival of new neurons. Adult male rats were bilaterally castrated. After 7 days of recovery, a single injection of bromodeoxyuridine (BrdU) was given on the first day of the experiment (Day 0) to label actively dividing cells. All subjects received five consecutive days of hormone injections during one of three stages of new neuron development (days 1–5, 6–10, or 11–15) after BrdU labeling. Subjects were injected during these time periods with either testosterone propionate (0.250 or 0.500 mg/rat), dihydrotestosterone (0.250 or 0.500 mg/rat), or estradiol benzoate (1.0 or 10 µg/rat). All subjects were euthanized sixteen days later to assess the effects of these hormones on the number of BrdU-labeled cells. The high dose of testosterone caused a significant increase in the number of BrdU-labeled cells in the hippocampus compared to all other groups, with the strongest effect caused by later injections (11-15 days old). In contrast, neither DHT nor estradiol injections had any significant effects on number of BrdU-labeled cells. Fluorescent double-labeling and confocal microscopy reveal that the majority of BrdU-labeled cells were neurons. Our results add to past evidence that testosterone increases neurogenesis, but whether this involves an androgenic or estrogenic pathway remains unclear.
Origin Information
Content type
Digital Document
Abstract
This textbook is a project under development by our Biology faculty to ultimately provide students with all the factual information they need to succeed in the BIOL 1203 and BIOL 1209 courses at Douglas College in BC, Canada. It was developed initially as an adaptation of the OpenStax Anatomy & Physiology textbook, freely available online at http://cnx.org/content/col11496/latest/. The original adaptations of that OpenStax textbook for Douglas College are accessible online at https://pressbooks.bccampus.ca/dcbiol11031109/ and https://pressbooks.bccampus.ca/dcbiol12031209/ In the first edition of the Douglas College adaptations the chapter and section numbers were left as they were in the version of the OpenStax A&P textbook, from which they were largely drawn. However, this second edition has been more extensively edited and rearranged to correspond with the curriculum used at Douglas College, so chapter and section numbers are no longer aligned specifically with the OpenStax A&P textbook.
Origin Information
Content type
Digital Document
Abstract
Poster presentation at the <a href="https://cap.ca/congress-conference/past-congress/"target="_blank" >Canadian Association of Physicists</a> conference at SFU, Burnaby (June 3-7, 2019).
The use of open textbooks is increasing dramatically in first year physics courses. This poster presents the results of scholarly research around student perceptions, the use and impact of open textbooks, as well as suggestions for how instructors might change what they do in their classroom around their use of open textbooks. Comparing and contrasting student’s attitudes in first year physics, astronomy and biology classes to open textbooks is the theme of this poster. It also relates attitudes towards open educational resources (OER) to simple demographic information and the overall cost of textbooks to determine whether there are indicators that can be measured a priori to suggest that students in a particular course may be more or less receptive to the incorporation of OER. More than 300 students were surveyed in 10 courses over two years at Douglas College so there is enough data to form interesting correlations. The questions that were asked included demographic questions as well as questions such as “How often does your instructor encourage you to read your textbook?” and “What is your best estimate of the percentage of exam questions that could be correctly answered using only the textbook?” Results: Student perceive that the open textbook is as good as or better than commercial books. Satisfaction increases as the book is modified to match learning outcomes.
Origin Information
Content type
Digital Document
Abstract
In general, the behavioral and neural effects of estradiol administration to males and females differ. While much attention has been paid to the potential structural, cellular and sub-cellular mechanisms that may underlie such differences, as of yet there has been no examination of whether the differences observed may be related to differential uptake or storage of estradiol within the brain itself. We administered estradiol benzoate to gonadectomized male and female rats, and compared the concentration of estradiol in serum and brain tissue found in these rats to those of gonadectomized, oil-treated rats and intact rats of both sexes. Long-term gonadectomy (3 weeks) reduced estradiol concentration in the male and female hippocampus, but not in the male or female amygdala or in the female prefrontal cortex. Furthermore, exogenous treatment with estradiol increased estradiol content to levels above intact animals in the amygdala, prefrontal cortex and the male hippocampus. Levels of estradiol were undetectable in the prefrontal cortex of intact males, but were detectable in all other brain regions of intact rats. Here we demonstrate (1) that serum concentrations of estradiol are not necessarily reflective of brain tissue concentrations, (2) that within the brain, there are regional differences in the effects of gonadectomy and estradiol administration, and (3) that there is less evidence for local production of estradiol in males than females, particularly in the prefrontal cortex and perhaps the hippocampus. Thus there are regional differences in estradiol concentration in the prefrontal cortex, amygdala and hippocampus that are influenced by sex and hormone status.
Origin Information
Content type
Digital Document
Abstract
The dogmatic view that new neurons are not produced in the adult mammalian brain has been overturned in light of mounting evidence that neurogenesis continues to occur within two neurogenic niches, the subventricular zone and the hippocampus. In mammals, new neurons are incorporated into the hippocampus throughout life and are influenced by environmental and genetic factors. Most studies use captive-bred animals, and no previous studies have examined neurogenesis in free-living rats despite the common use of laboratory rats. In particular, exercise upregulates neurogenesis in the hippocampus and exercise levels would certainly differ between wild and captive populations. Therefore, it is unclear whether results from captive populations can be generalized to natural populations or reflect variations from an artificial and inappropriate "baseline" level. To address this, we compared levels of cell proliferation and the number of immature neurons (using the endogenous markers Ki67 and doublecortin, respectively) in captured wild juvenile and adult Norway rats to three captive strains (Sprague-Dawley, Long-Evans, and Brown Norway) of the same species. Here, we show that the level of cell proliferation and young immature neuron survival in the dentate gyrus of juvenile wild rats is significantly higher than in Sprague-Dawley rats, but not Long-Evans or Brown Norway rats. However, cell proliferation and the number of immature neurons in the hippocampus of adult wild rats are within the normal range of captive-bred rats at all adult ages examined. This finding is surprising given the dissimilar environments, including stressors and opportunities for exercise, encountered by each population. © 2009 Wiley-Liss, Inc.
Origin Information
Content type
Digital Document
Abstract
In canaries, specific phrases of male song (sexy songs, SS) that are difficult to produce are especially attractive for females. Females exposed to SS produce more copulation displays and deposit more testosterone into their eggs than females exposed to non-sexy songs (NS). Increased expression of the immediate early genes c-Fos or zenk (a.k.a. <i>egr-1</i>) has been observed in the auditory forebrain of female songbirds hearing attractive songs. C-Fos immunoreactive (Fos-ir) cell numbers were quantified here in the brain of female canaries that had been collected 30 min after they had been exposed for 60 min to the playback of SS or NS or control white noise. Fos-ir cell numbers increased in the caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM) of SS birds as compared to controls. Song playback (pooled SS and NS) also tended to increase average Fos-ir cell numbers in the mediobasal hypothalamus (MBH) but this effect did not reach full statistical significance. At the individual level, Fos expression in CMM was correlated with its expression in NCM and in MBH but also with the frequency of calls that females produced in response to the playbacks. These data thus indicate that male songs of different qualities induce a differential metabolic activation of NCM and CMM. The correlation between activation of auditory regions and of the MBH might reflect the link between auditory stimulation and changes in behavior and reproductive physiology.
Origin Information
Content type
Digital Document
Abstract
Estradiol has been shown to have neuroprotective effects, and acute estradiol treatment enhances hippocampal neurogenesis in the female brain. However, little is known about the effects of repeated administration of estradiol on the female brain, or about the effects of estradiol on the male brain. Gonadectomized male and female adult rats were injected with 5-bromo-2-deoxyuridine (BrdU) (200 mg/kg), and then 24 h later were given subcutaneous injections of either estradiol benzoate (33 μg/kg) or vehicle daily for 15 days. On day 16, animals were perfused and the brains processed to examine cells expressing Ki-67 (cell proliferation), BrdU (cell survival), doublecortin (young neuron production), pyknotic morphology (cell death), activated caspase-3 (apoptosis), and Fluoro-Jade B (degenerating neurons) in the dentate gyrus. In female rats, repeated administration of estradiol decreased the survival of new neurons (independent of any effects on initial cell proliferation), slightly increased cell proliferation, and decreased overall cell death in the dentate gyrus. In male rats, repeated administration of estradiol had no significant effect on neurogenesis or cell death. We therefore demonstrate a clear sex difference in the response to estradiol of hippocampal neurogenesis and apoptosis in adult rats, with adult females being more responsive to the effects of estradiol than males.
Origin Information
Content type
Digital Document
Abstract
We examined hematological parameters in four related sciurid species in the late summer–autumn to assess the role of habitat, elevation, body size, and behavior in shaping these parameters. Red squirrels (Tamiasciurus hudsonicus) and Arctic ground squirrels (Spermophilus parryii) were sampled in southwestern Yukon, yellow-pine chipmunks (Tamias amoenus) in southern Alberta, and the eastern grey squirrel (Sciurus carolinensis) in southern Ontario. We obtained whole blood samples from each species and compared glucose levels, red blood cell characteristics (hematocrit, red blood cell count, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration), and white blood cell counts (neutrophils, lymphocytes, monocytes, eosinophils, basophils) across species. We found species differences in glucose and red blood cell characteristics that may be a function of activity levels, phylogeny, or elevation, but not of body size, body condition, or adaptations to a semi-fossorial habitat. We also found species differences in white blood cell counts that remain unexplained by any single simple explanation and may be more useful for comparison of individuals within a given species than for interspecies comparisons.
Origin Information
Content type
Digital Document
Abstract
Postnatal hippocampal neurogenesis in wild mammals may play an essential role in spatial memory. We compared two species that differ in their reliance on memory to locate stored food. Yellow-pine chipmunks use a single cache to store winter food; eastern gray squirrels use multiple storage sites. Gray squirrels had three times the density of proliferating cells in the dentate gyrus (determined by Ki-67 immunostaining) than that found in chipmunks, but similar density of young neurons (determined by doublecortin immunostaining). Three explanations may account for these results. First, the larger population of young cells in squirrels may increase the flexibility of the spatial memory system by providing a larger pool of cells from which new neurons can be recruited. Second, squirrels may have a more rapid cell turnover rate. Third, many young cells in the squirrels may mature into glia rather than neurons. The densities of young neurons were higher in juveniles than in adults of both species. The relationship between adult age and cell density was more complex than that has been found in captive populations. In adult squirrels, the density of proliferating cells decreased exponentially with age, whereas in adult chipmunks the density of young neurons decreased exponentially with age. [Abstract from Author]
Origin Information