The role of the NMDA receptor in the hippocampus in certain forms of learning

Activation of the N-Methyl-D-aspartate (NMDA) receptor is crucial for the induction of hippocampal Long-term potentiation (LTP), a form of synaptic plasticity that has come to be regarded by many neuroscientists as a neural substrate underlying the processing of information during learning. The hippocampus is also a structure that has long been implicated in spatial reference and/or working memory. The aim of this thesis is to test more rigorously, the hypothesis that hippocampal NMDA receptors are involved in "hippocampal learning" through induction of LTP, by investigation the dose-response effect of the NMDA receptor antagonist, AP5 on (i) induction of LTP and spatial learning, tested in individual animals, and (ii) it's effect on working memoryIn the first experiment a range of concentrations (5mM, 13mM, 20mM, 30mM, 40mM) of (D-AP5) were chronically infused (icv) into rats, at a rate of 0. 5^j1 a day for 14 days. Control animals consisted of either sham or unoperated rats, or rats infused with aCSF. During the 14 day experimental period rats were tested on a spatial reference memory task in the open field water maze for 6 days and then an attempt to evoke LTP in each rat was made. At the end of the experiment micro dialysed samples of ecf were taken from the left hippocampus for 2 hours. Finally, tissue samples from 5 brain areas, including the right and left hippocampus were dissected out and the exact content of AP5 in the brain during the experimental period was measured using HPLC. The animals were regrouped according to the whole tissue concentration of AP5 in the hippocampus. The results showed a dose dependent impairment of spatial reference memory that correlated with the dose dependent blockade of LTP. The amount of AP5 recovered from the ecf of the hippocampus was estimated to be compatible with binding studies showing percentage receptor occupancy and electrophysiological studies showing the amount of AP5 required to block LTP in the hippocampal slice.In the second experiment, a single concentration known to impair spatial reference memory and block LTP (30mM D-AP5) was used to test animals ability to learn a spatial working memory task in the open field water maze. AP5 caused no impairment in working memory when the delay between trials was short (30s). When the delay was extended to 2 hours or 5 hours, however, animals infused with AP5 showed a significant impairment. Also at the 5 hour delay, control animals showed a trend towards an impairment in the task.The results from this thesis suggest activation of the hippocampal NMDA receptors are necessary for the processing of spatial information. The high correlation between the learning impairment and the induction of LTP strengthens the hypotheses that the physiological activity underlying learning is a form of plasticity similar to that seen with LTP. Furthermore, from the working memory experiments it can be implied that this type of plasticity occurs when information is required over longer periods of time

Paradoxical Role of an Egr Transcription Factor Family Member, Egr2/Krox20, in Learning and Memory

It is well established that Egr1/zif268, a member of the Egr family of transcription factors, is critical for the consolidation of several forms of memories. Recently, the Egr3 family member has also been implicated in learning and memory. Because Egr family members encode closely related zinc-finger transcription factors sharing a highly homologous DNA binding domain that recognises the same DNA sequence, they may have related functions in brain. Another Egr family member expressed in brain, Egr2/Krox20 is known to be crucial for normal hindbrain development and has been implicated in several inherited peripheral neuropathies; however, due to Egr2-null mice perinatal lethality, its potential role in cognitive functions in the adult has not been yet explored. Here, we generated Egr2 conditional mutant mice allowing postnatal, forebrain-specific Cre-mediated Egr2 excision and tested homozygous, heterozygous and control littermates on a battery of behavioural tasks to evaluate motor capacity, exploratory behaviour, emotional reactivity and learning and memory performance in spatial and non-spatial tasks. Egr2-deficient mice had no sign of locomotor, exploratory or anxiety disturbances. Surprisingly, they also had no impairment in spatial learning and memory, taste aversion memory or fear memory using a trace conditioning paradigm. On the contrary, Egr2-deficient mice had improved performance in motor learning on a rotarod, and in object recognition memory. These results clearly do not extend the phenotypic consequences resulting from either Egr1 or Egr3 loss-of-function to Egr2. In contrast, they indicate that Egr family members may have different, and in certain circumstances antagonistic functions in the adult brain

Spadix Function in the Jack-in-the-Pulpit, Arisaema triphyllum

Aroids are perennial herbs characterized by inflorescences consisting of a finger-like spadix surrounded by a vase-like spathe. A prominent aroid in Georgia is the Jack-in-the-pulpit, Arisaema triphyllum. We assessed the role of the spadix in attracting insect visitors to Arisaema triphyllum. Two study sites near Dahlonega, Georgia, were chosen: one along an unnamed first-order stream and the other along third-order Cane Creek. Plants received either ablation of the distal appendix, removal of the spadix tip, or a sham ablation. Arthropod visitors were captured with a small sticky trap placed inside the spathe. Despite the treatment applied, the number of Diptera captured was not affected. In contrast, ablation reduced the number of Collembola captured to just 29 % of that of the other two treatments (interaction of taxon and treatment after square root transformation: F10,480 = 2.761, P = 0.003). Pollination in A. triphyllum has previously been attributed to fungus gnats (Diptera) and Heterothrips arisaemae (Thysanoptera). Our results suggest that Collembola, which do not fly, may play a role in pollination, perhaps within clustered plants in which long-distance travel is not necessary

Distinct Functions of Egr Gene Family Members in Cognitive Processes

The different gene members of the Egr family of transcriptional regulators have often been considered to have related functions in brain, based on their co-expression in many cell-types and structures, the relatively high homology of the translated proteins and their ability to bind to the same consensus DNA binding sequence. Recent research, however, suggest this might not be the case. In this review, we focus on the current understanding of the functional roles of the different Egr family members in learning and memory. We briefly outline evidence from mutant mice that Egr1 is required specifically for the consolidation of long-term memory, while Egr3 is primarily essential for short-term memory. We also review our own recent findings from newly generated forebrain-specific conditional Egr2 mutant mice, which revealed that Egr2, as opposed to Egr1 and Egr3, is dispensable for several forms of learning and memory and on the contrary can act as an inhibitory constraint for certain cognitive functions. The studies reviewed here highlight the fact that Egr family members may have different, and in certain circumstances antagonistic functions in the adult brain

“My Determination Is To Live”: Narratives of African-American Women Who Have Lived with HIV for 10 or More Years

Exploring the experiences of African-American women who have lived with HIV for many years can inform public health practice on how to better serve high-risk populations along the care continuum. To understand the experiences of African-American women who are HIV positive, the researchers used a narrative approach to guide repeat interviews. Under a theoretical framework of Womanism, we interviewed six African-American women ages 48-66 (M=57) who have lived with HIV for 10 years or longer and conducted analyses of narrative to identify key themes. The primary themes were: recollecting early hardships, HIV infection, and diagnosis; embracing social support; surviving and thriving; meaning making and HIV. The findings highlight the need for programs specific to long-term survivors, including resilience training, education programs on dating and disclosure, and opportunities to engage in meaningful work or volunteer initiatives

Leveraging University-Community Partnerships in Rural Georgia: A Community Health Needs Assessment Template for Hospitals

Background: Under the Affordable Care Act, nonprofit hospitals are required to conduct a Community Health Needs Assessment (CHNA) every three years. Using recommendations proposed by Georgia Watch, students and faculty members from the University of Georgia (UGA) conducted a CHNA for a hospital in a rural county in Georgia. The purpose of the CHNA was to identify community health problems and needs, as well as community assets and resources. The aim of this report is to describe the process for conducting the CHNA, the findings, and the lessons learned. Methods: The CHNA team consisted of students and faculty members from UGA’s College of Public Health and a Public Service and Outreach professional who worked in the community. In completing the CHNA, the team used the following fivestep process: define community, collect secondary data on community health, gather community input and collect primary data, prioritize community health needs, and implement strategies to address community health needs. Primary and secondary data were collected. Results: By triangulating findings across data sources, the CHNA team created a community health profile for the service area of the hospital. Based on these findings, the community identified four main areas for improvement, prioritized these health issues, and developed an implementation strategy for the hospital and community. Conclusions: The process used to conduct this CHNA can serve as a model for other rural communities undergoing similar assessments. Lessons learned from completing this CHNA can be applied to future CHNA efforts

Districts and their Legislators: Do District Demographics Impact the Legislator’s Political Ideology?

Extensive research has been conducted to examine the relationship between district demographics and the political ideology of legislators. In this study, we examine the relationship between district demographics and the ideologies of members in the Ohio State House elected in 2016. Our measures of ideology include legislators’ American Conservative Union scores and the Shor-McCarty ideological measure. The study controls for legislator partisanship, as well as district level characteristics such as median income, and the percent of non-white residents

Occupational Therapy in Primary Care: Determining Receptiveness of Occupational Therapists and Primary Care Providers

Background: Primary care (PC) is an emerging practice setting for occupational therapy; however, few occupational therapists currently practice in this setting due to barriers, including uncertainty about reimbursement and the role of occupational therapists. This pilot study aimed to determine if PC providers and occupational therapists are receptive to occupational therapists as integrated interprofessional PC team members if barriers to inclusion are addressed. Method: After a brief educational paragraph explaining potential occupational therapy contributions to PC teams, the participants accessed a link to survey questions regarding their personal level of receptiveness to occupational therapy in PC. The questions comprised Likert scale and open-ended answers. Results: Of the Likert scale responses, 94%-99% provided by occupational therapists and 82%-97% provided by PC providers indicated possibly or yes to the inclusion of occupational therapists on the PC team. The descriptive responses were primarily supportive. Discussion: The majority of the occupational therapists and PC providers surveyed indicated support for including occupational therapists in primary care. This indicates that when barriers are addressed, occupational therapists and PC providers are receptive to the inclusion of occupational therapists as members of the interprofessional PC team

Intergenerational Risk and Resilience Pathways from Discrimination and Acculturative Stress to Infant Mental Health

Preconception and prenatal stress impact fetal and infant development, and women of color are disproportionately exposed to sociocultural stressors like discrimination and acculturative stress. However, few studies examine links between mothers’ exposure to these stressors and offspring mental health, or possible mitigating factors. Using linear regression, we tested associations between prenatally assessed maternal acculturative stress and discrimination on infant negative emotionality among 113 Latinx/Hispanic, Asian American, Black, and Multiethnic mothers and their children. Additionally, we tested interactions between stressors and potential pre- and postnatal resilience-promoting factors: community cohesion, social support, communalism, and parenting self-efficacy. Discrimination and acculturative stress were related to more infant negative emotionality at approximately 12 months old (M = 12.6, SD = .75). In contrast, maternal report of parenting self-efficacy when infants were 6 months old was related to lower levels of infant negative emotionality. Further, higher levels of parenting self-efficacy mitigated the relation between acculturative stress and negative emotionality. Preconception and prenatal exposure to sociocultural stress may be a risk factor for poor offspring mental health. Maternal and child health researchers, policymakers, and practitioners should prioritize further understanding these relations, reducing exposure to sociocultural stressors, and promoting resilience