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Motherhood, Memory And Aging : Object Recognition Performance, Julia Margaret Friedenberg

Master's Theses

Reproductively experienced female rats have been shown to have attenuated stress responses, improved visual systems, and better memory and learning. This study sought to extend those findings by comparing aged reproductively experienced and aged virgin female rats on an object recognition task, as well as comparing levels of corticosterone and 17p-estradiol and neural activation. Multiparous (MP, 2 reproductive experiences) females performed better on the task and demonstrated quicker habituation to the task than nulliparous (NP, no reproductive experiences) females. No hormonal or neural activation differences were found. The present study contributes to the growing research areas of reproductive experience and …

Intricacies Of Development : The Impact Of Maternal Experience And Isolation On The Social Development Of Juvenile Male Rats, Lillian Maria Christon

Master's Theses

Reproductive experience induces changes in females. Parity-related differences in maternal treatment of offspring can induce enduring changes in offspring. The relationships between maternal experience, early social isolation, and development were explored in rodents in this experiment. Male rats were weaned from multiparous (MP) and primiparous (PP) mothers and placed into isolation or social housing for four weeks. They were then observed in a social-interaction test. Social behavior and neural oxytocin and vasopressin were assessed post-testing, while corticosterone levels were measured across the four weeks. Weaning was extremely stressful for all offspring. PP- and MP-raised pups exhibited differences in social behavior, …

A Role For Vasopressin And Oxytocin In Parental Behavior Of The Male Sprague-Dawley Rat, Ekaterina V. Karelina

Master's Theses

Paternal behavior, though infrequent in many mammalian species, can be induced under laboratory conditions through manipulation of either hormonal or environmental states. Rodent studies of parental behavior have implicated similarities for males and females in not only the actual behavioral repertoire, but also the brain mechanisms governing the set of behaviors in both sexes. The current project investigated changes in oxytocin and vasopressin in the hypothalamus of paternal male rats. We found that paternal behavior, which was readily induced through sensitization (chronic pup exposure), was significantly correlated with increasing oxytocin and vasopressin immunoreactivity within the paraventricular nucleus. Further, corticosterone levels …

Learned Fear And Reaction To Novel Stimuli: Behavioral And Hormonal Stress Responses In The Maternal Rat, Brandi Nicole Rima

Master's Theses

The present thesis examines the relationship between reproductive experience and the behavioral, neural, and hormonal processes of learned fear in the female rat. Multiple research models indicate that reproductive experience functions to decrease the female's stress response in potentially harmful environments, thus providing her with numerous survival benefits, including decreased fearfulness, increased aggression, and refined hunting skills. Based on existing understandings of maternal experience and unconditioned fear, this study was designed to determine how nulliparous (no reproductive experience, NP), primiparous (one reproductive experience, PP) and multiparous (more than one reproductive experience, MP) rats comparatively respond to a Pavlovian paradigm of …

The Presence Of Pups After Birth : Effects On Spatial Memory And The Pre-Synaptic Protein Synaptophysin, Abbe Hoffman Macbeth

Master's Theses

A newly maternal rat goes through many changes when she gives birth, mostly due to prolonged elevation of hormones, particularly estrogen. Estrogen has been shown to increase memory capabilities by increasing synaptic activity in the CA1 hippocampus, but exactly how is still unknown. The current project uses reproductive experience to determine whether high hormone levels experienced during pregnancy and lactation affect spatial memory and synaptophysin, a pre-synaptic protein that controls vesicle exocytosis and thus may be responsible for enhanced synaptic connectivity. We found that reproduction itself does not affect memory of a spatial task, but the presence of pups has …

Brain-Derived Neurotrophic Factor And Maternal Behavior : Neuronal Alterations In The Medial Preoptic Area And Suppression Of Pup Attacks, Lillian Flores Stevens

Master's Theses

Brain-derived neurotrophic factor (BDNF), by virtue of its relationship to various neurotransmitter systems, hormones, and to estrogen in particular, may play a role in maternal behavior. To explore this possible role, female virgin Sprague Dawley rats received continuous intracerebroventricular infusions ofBDNF sense oligonucleotide and were exposed to pups for maternal behavior testing. Behaviorally, BDNF sense had no effect on maternal behavior but did significantly suppress pup attacks during the first 24 hours of exposure. BDNF had a significant effect on neuronal morphology in the medial preoptic area (mPOA) as well, such that neurons in this region exposed to BDNF had …

Reproductive Experience And Aging : Possible Neuroprotective Effects Of Motherhood, Jessica Dawn Gatewood

Master's Theses

Hormonal fluctuations associated with pregnancy and post partum periods create significant changes in the brain and behavior in female rats. Animals were tested in a land version of the Morris Water maze for three days at 6, 12, 18 and 24 months. At the ages of 12, 18, and 24 months animals were also tested in the same maze using a reversal task. At the conclusion of the study brains were analyzed for Amyloid Precursor Protein (APP) to determine the amount of neurodegeneration among the groups. Multiparous animals showed significantly superior performance , followed by primiparous animals, and nulliparous animals …

Glial Cell Alterations In The Rat Medial Preoptic Area And Hippocampus As A Function Of Reproductive State, Gordon Wentworth Gifford

Master's Theses

Changes in reproductive state are accompanied by fluctuating levels of female gonadal hormones at higher levels and for longer periods of time than the normal estrus cycle. These hormones have been noted, in cell culture and over the regular estrus cycle, to influence structural changes in neurons and glial cells in areas of the brain associated with the conduct of maternal behavior. The purpose of this project was to characterize changes in GFAP immunoreactivity and astrocyte morphology in the mPOA and hippocampus as a function of reproductive state and female steroid hormone treatment. Results of this investigation noted an increases …

Modifications Of Nitric Oxide And Sexual Behavior In Prenatally Stressed Male Rats, Stephen D. Miller

Master's Theses

Normal male sexual differentiation is the culmination of perfectly timed, prenatal gonadal hormone release. Prenatal stress (PS) has a detrimental effect upon this process, obstructing the natural development of brain structures and sexual behavior. Prenatally-stressed male rats exhibit many physiological and neuroendocrinological differences when compared to control males. PS has a particularly harmful effect upon male sexual behavior, to which the neurotransmitter nitric oxide (NO) has been shown to be intimately involved. The present experiment examined whether PS reduces nNOS, the rate limiting enzyme of NO, in the medial preoptic area (rnPOA) of male rats, and whether administration of the …

Changes In Spatial Learning Ability In Female Rats Due To Neonatal Transplantation Of Male Hippocampal Tissue, David B. Carr

Honors Theses

It has long been acknowledged that sex differences occur in the performance of learning tasks. Specifically, it has been found that males typically outperform females in spatial learning tasks such as maze tasks. Recently, evidence has emerged which directly links sex differences in behavior to specific regions of the central nervous system (CNS). This evidence indicates that sexually dimorphic behaviors may be altered by the neonatal transplantation of opposite sex brain tissue. This research sought to extend these findings by examining the effects of neonatal transplantation of male hippocampal tissue on the spatial learning ability of adult females in three …

The Effects Of Litter Size On Behavioral Development And Adult Emotinoality In The Rat, Elizabeth N. Pully

Master's Theses

The effects of the early experience variable of litter size is examined at two developmental time periods (infancy and adulthood) in the rat. The study departs from the majority of the early experience experimentation in its use of a naturally occurring independent variable in place of the typical handling and shocking procedures. Large (n = 9), medium (n = 5), small litters (n = 3) were developed by pooling rat pups at birth and then distributing them to randomly selected, lactating females. Observations of behaviors (including maternal grooming) during the preweaning stage of development disclosed substantial differences in response activity …

Timidity, Emotionality, And Activity In Rats Deprived Of Grooming, Josiah B. Henneberger

Master's Theses

The purpose of this current study was to investigate the effect of restriction of grooming, by means of collars, on activity, emotionality, and timidity. On the basis of the common occurrence of grooming when under stress some relationship between licking and emotionality was assumed to exist by the author. it was therefore expected that differences would be found among the treatment group.

The current study made use of a three factor design. One factor was the treatment factor, another factor was the replications factor, and the third was the days factor. The days factor has repeated measures and the replications …

Classically Conditioned Licking And Acquired Orienting As A Function Of Qualitatively Different Ucs Values : Acquisition, Shifting And Extinction, Jerry Weeks Rudy

Master's Theses

The purpose of the present study was twofold: (A) to study classically conditioned licking in rats as a function of a qualitative UCS difference, defined as 15% sucrose concentration and 0% concentration (plain tap water); (B) to study acquired orienting as a function of these UCS values. Several aspects of conditioned performance were investigated: (1) the effect of UCS intensity on level of responding during acquisition; (2) the effect of UCS intensity on rate of approach to terminal level of responding; (3) a possible learning performance distinction in appetitive classical conditioning; (4) rate of extinction as a function of the …

A Comparison Of The Effects Of 23 Hour Food Deprivation And 23 Hour Water Deprivation On The Weight And Intake Of The Albino Rat, Otis Byron Ward

Master's Theses

The present study is designed to make a direct comparison of food and water deprivation schedules both in terms of the animals' adjustment to the schedules and the relative effects of the two schedules on several weight and intake measures. The three groups used are: a control group, a 2) hour food deprivation schedule group, and a 23 hour water deprivation schedule group. The groups will be compared over a period of 50 days in terms of body weight, weight loss and gain, and food and water intake.

The Effects Of Water Deprivation On The Body Weight, Food Intake And Water Intake Of The Albino Rat, Kenneth A. Blick

Master's Theses

A survey of the literature reveals a substantial body of research concerned with the effects of food and/or water deprivation on body weight, food and water intake, and activity of the albino rat. This research is important because many psychological experiments, particularly those studies in the field of animal learning in which motivation is induced by the use of a nutritional maintenance schedule, require some measurement of performance on consecutive days during which the rats are in a motivational state.