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In this paper, it is determined that learning retention decreases with age and there is a linear rate of decrease. In this study, four male Long-Evans Rats were used. The rats were each trained in 4 different tasks throughout their lifetime, using a food reward as motivation to work. Rats

In this paper, it is determined that learning retention decreases with age and there is a linear rate of decrease. In this study, four male Long-Evans Rats were used. The rats were each trained in 4 different tasks throughout their lifetime, using a food reward as motivation to work. Rats were said to have learned a task at the age when they received the highest accuracy during a task. A regression of learning retention was created for the set of studied rats: Learning Retention = 112.9 \u2014 0.085919 x (Age at End of Task), indicating that learning retention decreases at a linear rate, although rats have different rates of decrease of learning retention. The presence of behavioral training was determined not to have a positive impact on this rate. In behavioral studies, there were statistically significant differences between timid/outgoing and large ball ability between W12 and Z12. Rat W12 had overall better learning retention and also was more compliant, did not resist being picked up and traveled more frequently at high speeds (in the large ball) than Z12. Further potential studies include implanting an electrode into the frontal cortex in order to compare neuro feedback with learning retention, and using human subjects to find the rate of decrease in learning retention. The implication of this study, if also true for human subjects, is that older persons may need enhanced training or additional refresher training in order to retain information that is learned at a later age.
ContributorsSpinrad, Amelia (Author) / Si, Jennie (Thesis director) / Thompson, Patrick (Committee member) / Ma, Weichao (Committee member) / Barrett, The Honors College (Contributor)
Created2014-05
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The aim of this study was to determine whether IUD administration, with and without the presence of Levo, and with and without the presence of the ovaries, impacts cognition in a rat model. Rats received either Sham or Ovariectomy (Ovx) surgery (removal of the ovaries), plus either no IUD, a

The aim of this study was to determine whether IUD administration, with and without the presence of Levo, and with and without the presence of the ovaries, impacts cognition in a rat model. Rats received either Sham or Ovariectomy (Ovx) surgery (removal of the ovaries), plus either no IUD, a Blank IUD (without Levo), or a Levo-releasing IUD (Levo IUD), enabling us to evaluate the effects of Ovx and the effects of IUD administration on cognition. Two weeks after surgery, all treatment groups were tested on the water radial arm maze, Morris water maze, and visible platform task to evaluate cognition. At sacrifice, upon investigation of the uteri, it was determined that some of the IUDs were no longer present in animals from these groups: Sham\u2014Blank IUD, Ovx\u2014Blank IUD, and Sham\u2014Levo IUD. Results from the remaining three groups showed that compared to Sham animals with no IUDs, Ovx animals with no IUDs had marginally impaired working memory performance, and that Ovx animals with Levo IUDs as compared to Ovx animals with no IUDs had marginally enhanced memory performance, not specific to a particular memory type. Results also showed that Ovx animals with Levo IUDs had qualitatively more cells in their vaginal smears and increased uterine horn weight compared to Ovx animals with no IUDs, suggesting local stimulation of the Levo IUDs to the uterine horns. Overall, these results provide alternative evidence to the hypothesis that the Levo IUD administers Levo in solely a localized manner, and suggests that the possibility for the Levo IUD to affect reproductive cyclicity in ovary-intact animals is not rejected. The potential for the Levo IUD to exert effects on cognition suggests that either the hormone does in fact systemically circulate, or that the Levo IUD administration affects cognition by altering an as yet undetermined hormonal or other feedback between the uterus and the brain.
ContributorsStrouse, Isabel Martha (Author) / Bimonte-Nelson, Heather (Thesis director) / Glenberg, Arthur (Committee member) / Sirianni, Rachael (Committee member) / Conrad, Cheryl (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Chronic restraint stress leads to apical dendritic retraction in CA3 pyramidal neurons and often no quantifiable changes in CA1 dendritic complexity. When chronic stress ends, a post-stress recovery period results in an enhancement in CA3 dendritic complexity. We investigated the relationship between CA3 and CA1 pyramidal neurons to determine whether

Chronic restraint stress leads to apical dendritic retraction in CA3 pyramidal neurons and often no quantifiable changes in CA1 dendritic complexity. When chronic stress ends, a post-stress recovery period results in an enhancement in CA3 dendritic complexity. We investigated the relationship between CA3 and CA1 pyramidal neurons to determine whether dendritic restructuring in CA3 neurons leads to region-specific changes in the dendritic complexity of CA1 neurons. Adult male Sprague-Dawley rats were restrained (wire mesh, 6h/d/21d) and brains were removed soon after restraint ended (Str-Imm) or after a 21d post-stress recovery period (Str-Rec). In addition, BDNF downregulation targeting the CA3 region prevents enhancement in dendritic complexity following recovery in chronically stressed rats, providing robust conditions to investigate the CA3-CA1 relationship. Consequently, rats were infused into the CA3 area with either an AAV vector with a coding sequence against BDNF (shRNA) or a sequence with no known mRNA complements (Scr). Apical and basal dendritic complexity of CA3 and CA1 was quantified by counting total dendritic bifurcations and dendritic intersections using the Sholl analysis (20 µm distances from soma). Please note that the quantification of the CA3 dendritic arbors was not part of this thesis project. The outcome of that investigation revealed that apical CA3 dendritic retraction was found in Str-Imm-Scr and Str-Rec-shRNA. For the CA1 apical area, gross dendritic bifurcation differences were not detected, but the Sholl quantification revealed regionally-enhanced dendritic complexity that varied by distance from the soma at the distal apical dendrites (Str-Imm-Scr) and proximal basal dendrites (Str-Rec-shRNA). For the latter, significant increases in basal branch points were detected with total branch point quantification method. Moreover, a correlation using all groups revealed a significant inverse relationship between CA3 apical dendritic complexity and CA1 basal dendritic complexity. The results demonstrate that chronic stress-induced CA3 apical dendritic retraction may relate to region-specific changes in CA1 dendritic complexity. The inability of past studies to detect changes in CA1 dendritic complexity may be due to the shortcoming of gross dendritic arbor measures in accounting for subtle region-specific alterations. To address this, the current study included a cohort with BDNF downregulated in the CA3 region. Overall, this suggests that decreased levels of BDNF in the hippocampus provide robust conditions in which changes to CA1 dendritic complexity can be detected.
ContributorsDaas, Eshaan Jatin (Author) / Conrad, Cheryl (Thesis director) / Orchinik, Miles (Committee member) / Ortiz, J. Bryce (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Description
Estradiol (E2) and Levonorgestrel (Levo) are two hormones commonly used in hormone therapy (HT) to decrease symptoms associated with menopause. Both of these hormones have been shown to have beneficial effects on cognition when given alone in a rodent model of menopause. However, it is unknown whether these hormones, when

Estradiol (E2) and Levonorgestrel (Levo) are two hormones commonly used in hormone therapy (HT) to decrease symptoms associated with menopause. Both of these hormones have been shown to have beneficial effects on cognition when given alone in a rodent model of menopause. However, it is unknown whether these hormones, when taken in combination, are beneficial or harmful to cognition. This is a critically important question given that these hormones are most often given in combination versus separately. This thesis is composed of two studies examining the cognitive effects of E2 and Levo using a rat model of surgical menopause. Study 1 assessed how the dose of E2 treatment in rats impacted cognitive performance, and found that low dose E2 enhanced working memory performance. Next, based on the results from Study 1, Study 2 used low dose E2 in combination with different doses of Levo to examine the cognitive effects of several E2 to Levo ratio combinations. The results from Study 2 demonstrated that the combination of low dose E2 with a high dose of Levo at a 1:2 ratio impaired cognition, and that the ratio currently used in HT, 3:1, may also negatively impact cognition. Indeed, there was a dose response effect indicating that working and reference memory performance was incrementally impaired as Levo dose increased. The findings in this thesis suggest that the E2 plus Levo combination is likely not neutral for cognitive function, and prompts further evaluation in menopausal women, as well as drug discovery research to optimize HT using highly controlled preclinical models.
ContributorsBerns-Leone, Claire Elizabeth (Co-author) / Prakapenka, Alesia (Co-author) / Pena, Veronica (Co-author) / Northup-Smith, Steven (Co-author) / Melikian, Ryan (Co-author) / Ladwig, Ducileia (Co-author) / Patel, Shruti (Co-author) / Croft, Corissa (Co-author) / Bimonte-Nelson, Heather (Thesis director) / Glenberg, Arthur (Committee member) / Conrad, Cheryl (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description

This paper provides a multidisciplinary analysis of the relationship between beauty and addiction, with a focus on the emerging field of neuroaesthetics. Neuroaesthetics investigates the neural mechanisms that underlie aesthetic experiences and how the brain cognitively processes beauty. Since there is a biological foundation of this report, I will predominantly

This paper provides a multidisciplinary analysis of the relationship between beauty and addiction, with a focus on the emerging field of neuroaesthetics. Neuroaesthetics investigates the neural mechanisms that underlie aesthetic experiences and how the brain cognitively processes beauty. Since there is a biological foundation of this report, I will predominantly discuss neuroanatomy, neurological studies, and the overlap in neural circuitry between beauty and addiction. In addition, I will discuss the philosophical roots of beauty, as well as the environmental elements involved. Chapter 1 begins by explaining the history of beauty and its importance. I discuss the main constituents of beauty and differentiate between key terms involved in the beauty experience. In order to understand the link between beauty and addiction, it is essential to have a knowledgeable background on what beauty is. Next, I discuss the neurobiology of addiction. The main component of this chapter involves the mesolimbic and mesocortical reward pathways. I also describe neuroanatomical terms involved in addiction. The last chapter considers the implications of neuroaesthetics in various studies, which primarily involve the use of fMRIs. I discuss the sensory evaluations of beauty and the brain regions involved in the beauty experience. From this, I found that the experience of beauty activates these main brain regions: PFC, amygdala, striatum, NAcc, cingulate, VTA, and most remarkably, field A1 of the mOFC. By combining the neurological studies with studies of aesthetics, I reached the conclusion that there is an overlap in the neural pathways during the experience of beauty and during addiction. Although it is necessary for further research to be conducted to properly declare this, I discovered that the pursuit of beauty can lead to addictive behaviors, as the reward centers of the brain are activated by aesthetic experiences.

ContributorsFarrell, Natalie (Author) / de Alcantara, Christiane Fontinha (Thesis director) / Conrad, Cheryl (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of Marketing (Contributor)
Created2023-05
Description

Alzheimer’s disease (AD) is an irreversible brain disorder that plagues millions of people with no current cure. Current clinical research is slowly advancing to more definitive treatments in hopes of reducing the effects of progressive cognitive and behavioral decline, but none so far can slow AD’s onset. A brain area

Alzheimer’s disease (AD) is an irreversible brain disorder that plagues millions of people with no current cure. Current clinical research is slowly advancing to more definitive treatments in hopes of reducing the effects of progressive cognitive and behavioral decline, but none so far can slow AD’s onset. A brain area known as the nucleus incertus (NI) was recently discovered to potentially impact AD because of its connections to brain targets that degenerate; however, the NI’s role is unknown. This goal of this experiment was to use a transgenic mouse model (APP/PS1) that expresses AD pathology slowly as found in humans, and to test the mice in a variety of cognitive and anxiety assessments. Mice of both sexes and two different ages were used, with the first being young adult before AD pathology manifests (around 3-4 months old), and the second being around the cusp of when AD pathology manifests (late adult, 8-10 months old). The mice were tested in a variety of cognitive tasks that included the novel object recognition (NOR), Morris water maze (MWM), and the object placement (OP), with the latter being the focus of my thesis. Anxiety measures were taken from the open field (OF) and elevated plus maze (EPM) with the visible platform (VP) used to ensure mice could perform on the rigorous MWM task. In the OP, we found an age effect, where the older mice were less likely to explore the moved object during the OP compared to the younger mice; motor ability was unlikely to explain this effect. We did not find any significant age by genotype effects. These findings indicate that cognitive impairment only just started to affect the older cohort, since OP impairment was found on one measure and not another. Other measures currently being quantified will be helpful in understanding this data, and to see whether learning, memory, and anxiety are affected.

ContributorsDapon, Bianca (Author) / Conrad, Cheryl (Thesis director) / Bimonte-Nelson, Heather (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2023-05