1988 — 1990 |
Sullivan, Regina Marie |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Olfactory Based Filial Responses @ University of Oklahoma Norman
Newborns of many altricial mammalian species must identify their mother through the use of learned olfactory cues in order to survive. This early olfactory learning is associated with large functional and structural changes within the olfactory bulb in infant rats. Based on recently completed work, it appears that centrifugal projections from the brainstem to the olfactory bulb may be involved in both the behavioral and neural changes associated with olfactory learning. These projections contain norepinephrine (NE) and serotonin (5-HT). Extensive evidence has already linked both NE and 5-HT activity with sensory processing and arousal, and NE is known to play a modulatory role in neural development and memory formation. The goal of the proposed research is to understand the mechanisms underlying the acquisition of the behavioral and neural responses following olfactory classical conditioning in infant rats. Specifically, the role of olfactory bulb NE and 5-HT in neonatal olfactory learning will be assessed.
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0.901 |
1995 — 1999 |
Sullivan, Regina Marie |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Locus Coeruleus in Cognitive Functioning in Infancy @ University of Oklahoma Norman
DESCRIPTION (Adapted from applicant's abstract): The goal of the PI's research is to understand the development of simple cognitive function in neonates. Throughout an organism's life span, there are periods of time when learning is potentiated. This facilitated learning is presumably due to changes in an underlying neural structure. The goal of the present proposal is to document the changing characteristics of a specific brain area and its functional significance in potentiated learning in infancy. The PI's previous research has characterized a developmental epoch in infant rats in which the ability of pups to learn is greatly enhanced. However, this potentiated learning is not expressed through more rapid learning, attenuated extinction or longer retention. Instead, the significant factor for this potentiated learning appears to be based on the broad spectrum of stimuli which can function as reward for infants. For example, pairing an odor with either tactile stimulation, tailpinch or intra-oral milk infusions results in a subsequent odor preference. This "sensitive period" for learning takes place during the first two weeks of the rat pup's life. Through her previous work, the PI has demonstrated that norepinephrine is critical for learning during this "sensitive period". Blocking norepinephrine prevents olfactory learning. Furthermore, pairing an odor with norepinephrine is sufficient to produce an odor preference. Additionally, manipulation of the noradrenergic locus coeruleus also influences learning: stimulating the locus coeruleus during an odor presentation is sufficient to produce an odor preference and lesioning this brain area prevents learning. Work from other laboratories has demonstrated that the noradrenergic locus coeruleus has unique characteristics during the olfactory learning "sensitive period" which greatly increases its response to stimulation. Indeed, the locus coeruleus is activated by the same unique broad spectrum of stimuli which can function as reward in infants. For example, in contrast to the adult locus coeruleus, the neonatal locus coeruleus exhibits a robust response to tactile stimulation and tailpinch. Qualitative and quantitative properties of receptors, as well as biophysical properties of locus coeruleus neurons appear to be responsible for the unique response characteristics of the neonatal locus coeruleus. The specific goal of the present proposal is to explore the relationship between the "sensitive period" for learning and the immature locus coeruleus. To this end, the unique characteristics of the locus coeruleus will be manipulated to assess its effects during learning. Additionally, the locus coeruleus's role in learning in other sensory systems will be assessed to determine whether the locus coeruleus has a more general role in neonatal learning.
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0.901 |
2002 — 2006 |
Sullivan, Regina Marie |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Neurobiology of Cognitive Functioning in Infancy @ University of Oklahoma Norman
DESCRIPTION (provided by applicant): The goal of this research program is to understand the development of simple cognitive function in neonates. Throughout an organism's life span, there are periods of time when learning is facilitated. This facilitated learning is presumably due to changes in underlying neural structures. The goal of the present proposal is to document the changing characteristics of specific brain areas and their functional significance in learning during infancy. This will extend my previous work using learned infant rat attraction to caregivers as a model system. Normal mother-infant interactions are critical for development and survival of altricial infants. The central nervous system of altricial infants is specialized for optimizing attachments to their caregiver. Work during the previous funding period has demonstrated that this optimization includes at least two modulatory systems. First, the noradrenergic locus coeruleus demonstrates unique properties during the first 10 postnatal days of life in the rat that are necessary and sufficient for pups to learn relative odor preferences. Second, the amygdala, a structure involved in fear conditioning in adults, is not activated by aversive stimuli (e.g., odorshock association) until after postnatal day 10, effectively preventing pups from learning relative odor aversions, potentially even to an abusive caregiver. Based on these findings and new preliminary data, it is proposed here that the locus coeruleus and amygdala, combined with the corticosterone stress system function in a unique way during early development to create a sensitive period for infant attachment learning and suppression of learned avoidance behavior that ends during the second postnatal week. The specific aims include: 1) further characterize the role of the amygdala during the sensitive period, including identification of specific nuclei involved in ontogeny of learned (odor-shock) and innate fear, and the ability to extend the sensitive period with amygdala lesions. 2) Characterize the relationship between the locus coeruleus, amygdala and corticosterone during the sensitive period. Pilot data suggest that corticosterone injections can accelerate the ontogeny of learned odor aversions. Finally, 3) determine the role of the locus coeruleus, amygdala and corticosterone in the effects of long-term odor-shock conditioning. Pilot data suggest that odor-shock conditioning beginning during the sensitive period and extending for several days after its normal termination date effectively extends the sensitive period and delays emergence of fear conditioning and amygdala involvement. The results of these studies will be important for our understanding of normal neurobehavioral development and infant attachment behaviors to caregivers.
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0.901 |