Chiye Aoki - US grants

Norepinephrine (NE) exerts diverse actions in visual and other neocortical areas. The collective actions of NE are important for coordinating peripheral sympathetic activities and goal-directed behaviors evoked by external stimuli. Three broadly based light and electron microscopic immunocytochemical studies are proposed to determine possible cellular substrates for the diversity of noradrenergic actions in the visual cortex. Specifically, the laminar distribution and subcellular sites of termination of catecholaminergic (CA) afferents and their relation to the B- adrenergic receptor (BAR) or one of four other putative transmitters, acetylcholine (Ach), GABA, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) will be examined. Peroxidase- antiperoxidase and/or immunoautoradiographic labeling methods will be used to localize antigenic sites for antisera against the catecholamine- and acetylcholine-synthesizing enzymes, BAR and the latter three transmitters. Cat will be the primary experimental animal, because the vast majority of the literature on visual physiology and developmental plasticity has been established in this species. The specific goals are to determine: (1) whether the CA terminals exhibit heterogeneity in their relations to (a) the target sites (i.e. perikaryal vs dendritic vs axonal) or (b) the localization of BAR, (i.e. neuronal vs glial, presynaptic vs postsynaptic vs extrajunctional); (2) whether cholinergic terminals have specific cellular relations to CA terminals; and (3) whether neurons containing GABA, NPY or VIP show laminar variations in their cellular associations with CA terminals or other unlabeled neurons. By correlating the ultrastructurally identified sites of cellular associations and their relative frequencies with light microscopically identified laminar positions, the functional and cytoarchitectonic interrelationship of these transmitters should begin to emerge. This information is important for understanding the mechanism of vision and other modalities of sensory perception and may be of clinical relevance in understanding the consequences of sensory deprivation during development.

This is a Shannon Award providing partial support for research projects that fall short of the assigned institute's funding range but are in the margin of excellence. The Shannon award is intended to provide support to test the feasibility of the approach; develop further tests and refine research techniques; perform secondary analysis of available data sets; or conduct discrete projects that can demonstrate the PI's research capabilities or lend additional weight to an already meritorious application. Further scientific data for the CRISP System are unavailable at this time.

Dr. Aoki has been selected to receive one of 30 prestigious NSF Presidential Faculty Fellowship awards based upon her outstanding research accomplishments. During the period of this award, Dr. Aoki will be using electron microscopic immunocytochemistry to identify chemically specified axons or growth cones in relation to transmitter receptors within intact cortical tissue. At birth, the density of synapses in the cerebral cortex is no more than 10% of the adult level, and nothing is presently known about the development of chemically specified synapses within cortex. The maturation of noradrenergic and excitatory synapses during early life is particularly important for understanding the mechanisms that underlie cortical plasticity. The importance of noradrenaline in cortical plasticity is reflected in a new working hypothesis supported by results that cortical plasticity is dictated by the dual modulation of excitatory synapses utilizing both catecholamines and acetylcholine.

Norepinephrine (NE) exerts diverse actions in visual and other neocortical areas. The collective actions of NE are important for coordinating peripheral sympathetic activities and goal-directed behaviors evoked by external stimuli. Three broadly based light and electron microscopic immunocytochemical studies are proposed to determine possible cellular substrates for the diversity of noradrenergic actions in the visual cortex. Specifically, the laminar distribution and subcellular sites of termination of catecholaminergic (CA) afferents and their relation to the B- adrenergic receptor (BAR) or one of four other putative transmitters, acetylcholine (Ach), GABA, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) will be examined. Peroxidase- antiperoxidase and/or immunoautoradiographic labeling methods will be used to localize antigenic sites for antisera against the catecholamine- and acetylcholine-synthesizing enzymes, BAR and the latter three transmitters. Cat will be the primary experimental animal, because the vast majority of the literature on visual physiology and developmental plasticity has been established in this species. The specific goals are to determine: (1) whether the CA terminals exhibit heterogeneity in their relations to (a) the target sites (i.e. perikaryal vs dendritic vs axonal) or (b) the localization of BAR, (i.e. neuronal vs glial, presynaptic vs postsynaptic vs extrajunctional); (2) whether cholinergic terminals have specific cellular relations to CA terminals; and (3) whether neurons containing GABA, NPY or VIP show laminar variations in their cellular associations with CA terminals or other unlabeled neurons. By correlating the ultrastructurally identified sites of cellular associations and their relative frequencies with light microscopically identified laminar positions, the functional and cytoarchitectonic interrelationship of these transmitters should begin to emerge. This information is important for understanding the mechanism of vision and other modalities of sensory perception and may be of clinical relevance in understanding the consequences of sensory deprivation during development.

DESCRIPTION(Verbatim from the Applicant's Abstract): The long-term goal is to understand the cellular and molecular mechanisms linking sensory experience during early life to maturation of excitatory synapses in the somatosensory cortex. The maturation of cortical synapses can be detected biophysically by a switch from EPSP depression following repetitive presynaptic action potentials (immature) to EPSP facilitation (more mature). The general working hypothesis is that the molecular composition of postsynaptic structures correlates with and confers the degree of maturity upon the presynaptic axons. We will test this hypothesis by combining patch-recording of multiple, synaptically connected neurons within rat somatosensory cortical slices with electron microscopic (EM)- immuno-cytochemical (ICC) analysis of the recorded neurons to determine whether: (1) the more mature, facilitating synapses exhibit the NMDA receptor (NMDAR) subunits-NR1, NR2A, as well as the AMPA receptors and neuronal nitric oxide synthase (nNOS) at postsynaptic densities; (2) the immature, depressing synapses are characterized by 'pioneer' NMDARs that arrive to the plasma membrane first, along with neuronal nNOS via PSD-95; (3) activation of these pioneer NMDARs regulate recruitment of cytoplasmic NMDAR and AMPA receptor subunits to nascent postsynaptic sites; (4) pharmacological blockage of NMDAR will prevent the insertion of NR1/NR2A heteromers of NMDAR and AMPA receptors and also delay or abolish the switch at synapses from the depressing to the facilitating phenotype. The works of Aoki and Reyes indicate that synapse maturity can vary widely within single layers and even within single neurons. Thus, the combined EM, ICC and biophysical analysis of single synapses and single postsynaptic densities should be particularly helpful in elucidating functional links between ultrastructure, molecular composition, and physiological properties of excitatory synapses that form during early postnatal life in the somatosensory cortex and dictate life-long capacities of cortical neural function. The knowledge gained from such a study is required in designing molecular remedies for deficits caused by sensory deprivation during early life.

DESCRIPTION (adapted from applicant's abstract): The long-term goal is to understand the cellular and molecular mechanisms linking visual experience during early life to maturation of excitatory synapses in the visual cortex. The maturation of cortical synapses can be detected biophysically by a switch from EPSP depression following repetitive presynaptic action potentials (immature) to EPSP facilitation (more mature). The general working hypothesis is that the molecular composition of postsynaptic structures correlates with and confers the degree of maturity upon the presynaptic axons. We will test this hypothesis by combining patch-recording of multiple, synaptically connected neurons within neonatal rat visual cortical slices with electron microscopic (EM) - immuno- cytochemical (ICC) analysis of the recorded neurons to DETERMINE WHETHER: (1) the more mature, facilitating synapses exhibit the NMDA receptor (NMDAR) subunits - NR1, NR2A - at postsynaptic densities, as well as the muscarinic acetylcholinergic receptors (mAChR) pen-synaptically; (2) the immature, depressing synapses are characterized by pioneer NMDARs that arrive to the plasma membrane first, along with alpha7 nicotinic AChR; (3) activation of these 'pioneer' NMDARs regulate recruitment of cytoplasmic NMDAR subunits and mAChRs to nascent postsynaptic sites; (4) pharmacological blockade of NMDAR will prevent the insertion of NR1/NR2A heteromers of NMDAR and AChR and also delay or abolish the switch at synapses from the depressing to the facilitating phenotype. The works of Aoki and Reyes indicate that synapse maturity can vary widely within single layers and even within single neurons. Thus, the combined EM, ICC and biophysical analysis of single synapses and single postsynaptic densities should be particularly helpful in elucidating functional links between ultrastructure, molecular composition, and physiological properties of excitatory synapses that form during early postnatal life in the visual cortex and dictate life-long capacities of cortical neural function. The knowledge gained from such a study is required in designing molecular remedies for deficits caused by sensory deprivation during early life.

Support from the NSF REU Site Grant will enable the Center for Neural Science at New York University to support an established, successful summer undergraduate research program (SURP). SURP was founded as a model program in 1990 and has continued ever since at a reduced level through funds derived from individual grants and institutional funds. Support from the NSF REU Site Grant will make it possible to regularize and expand the program, reach out to students beyond NYU, thereby impact a broader student population. Under-represented minorities, women and undergraduates from small colleges that are limited in resources for equipment and research opportunities will be pursued actively, through collaboration with NYU's Faculty Resource Network., a consortium of 13 historically black colleges and universities in the South and 15 regional liberal arts colleges, together representing over 100,000 undergraduates and over 8,300 faculty members. Eight to ten undergraduates, mostly between their sophomore and junior years, who have demonstrated keen interest in basic neural science research and with a GPA minimum of 3.0 will be chosen every summer from a pool of approximately 100 applicants.
First-hand research experience will be made available to these students by placing them in one of the CNS labs, ranging in subfields from theoretical neurobiology, sensory physiology, behavioral and molecular investigation of emotional memory, to cellular and molecular basis of brain development and recovery from injuries. Their education, training, and progress will be fostered and monitored using a three-tiered system, consisting of the following: (1) one-to-one, daily interactions with a mentor and affiliated members of the host lab; (2) weekly and bi-weekly group luncheons, overseen by the director, during which self-assessments are made and a lecture series is scheduled; and (3) close, week-by-week coaching of each student's skills in oral and written presentations, leading up to a Symposium and preparation of a written report during the last week of the program that describe the rationale, hypothesis, outcome and interpretation of data generated from the summer research activity.
As in the past, the CNS SURP's seminar series and social functions will run conjointly with those of the NYU Washington Square Campus's Leadership Alliance program in Social Studies and NYU Medical School's Sacklar Institute Minority Undergraduate Summer Research Program in Biomedical Sciences. These joint functions, together with a variety of social and cultural activities that will be planned over lunches, dinners, after-hours and week-ends for the CNS SURP group, will provide students with opportunities to be part of a large group of undergraduate and graduate students, post-docs, and faculty. This program will ensure that the CNS SURP students obtain a realistic view about diversity in scientific inquiries, style, and gain opportunities to chat casually about practical issues of becoming a scientist, such as family planning, balance between personal life and work environment, opportunities and options for PhDs and MD-PhDs, etc. while also enjoying York City's rich collection of culture and research institutions.

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ABSTRACT


The NSF-funded REU Site at New York University offers opportunities for basic research in the field of neural science. The objective of this field of science is to understand the biological basis of brain functions involving sensory perception, cognition, memory, learning, planning and emotion. At the Center for Neural Science (CNS), in particular, undergraduates are mentored to in several areas: cellular biology of learning and memory, neuro-economics dealing with mechanisms that underlie decision-making, visual neuroscience, etc. The neuroscientists at the Center form a friendly, cohesive group, yet their scope of activities ranges from genetics to molecular and cellular neurobiology to mathematical modeling of neural networks. By keeping the REU group small (10 students are admitted yearly), each student will be able to benefit from the intense, personalized mentorship he or she receives, while also gaining knowledge about research activities of all other participants through activities in the form of lunches, visitation of other students' labs, and group meetings with all of the faculty members serving as REU mentors. The program will seek to recruit under-represented minorities from small liberal arts colleges and/or historically black colleges. Rather than using SAT or GPA scores, the key requirement for selection will be that students have demonstrated keen interest in neural science research and are self-driven and inquisitive. More information is available at http://www.cns.nyu.edu/undergrad/surp/ or by contacting Dr. Chiye Aoki (tel 212-998-3929; email chiye@cns.nyu.edu).

DESCRIPTION (provided by applicant): Anorexia nervosa (AN) is a psychiatric illness with no accepted pharmacological treatment [1] and with one of the highest mortality rates among the mental illnesses (10-20%) [2-4]. Even if not fatal, AN can cause life-long damages to multiple organ systems, creating an increased burden on the health care system. AN has a stereotypical age of onset at puberty, with 90-95% of cases occurring in females [5]. This developmental pattern suggests that hormonal changes in females associated with puberty may trigger changes in brain connections that increase an individual's vulnerability to stress, anxiety and AN. AN is also associated with frequent relapses[6], suggesting that anorectic behavior during this pivotal, final stage of brain development may cause long-lasting changes in brain connections. The long-term goal of this project is to identify developmental changes at central synapses that are linked to AN vulnerability among females entering puberty and to characterize changes that are induced further by this illness and following recovery. We will test a novel hypothesis - namely, that pubertal females are more vulnerable to AN due to fluctuation in the release of a neurosteroid, THP, that triggers an increased expression of a4b2d GABAA receptors at the plasma membrane of hippocampal pyramidal neurons which, in turn, renders the hippocampus hyper-excitable during stressful events. This THP-GABA hypothesis will be tested by using an animal model of AN, activity-based anorexia (ABA), which captures multiple key features of AN but for which the sex- and age-dependence have not been fully explored. We will first run behavioral tests to determine whether the two key factors that influence the human population - age and sex - also influence ABA vulnerability of rodents. This will be achieved by comparing the behavioral factors related to the development of ABA, recovery from ABA and ABA relapse across 3 developmental stages (prepubertal, pubertal, and adulthood) and 2 sexes (male and female). We will then use biochemical and electron microscopic immunocytochemical approaches to determine whether a4b2d GABAA receptor expressions in certain brain regions (biochemical data) and at synapses (EM data) correlate with ABA vulnerability, development, recovery and relapse. To further test the THP-GABA hypothesis, we will also determine whether ABA vulnerability and EM/Biochemical changes associated with the onset of puberty among females are reduced by pre-treatments that target the THP-GABA system. PUBLIC HEALTH RELEVANCE: Anorexia nervosa (AN) is a psychiatric illness occurring predominately among females entering puberty, with one of the highest mortality rates among mental illnesses (10-20%) and no accepted pharmacological treatment. The aim of this proposal is to test a novel hypothesis - namely, that females entering puberty are more vulnerable to AN because the limbic system of female brains at this stage in development express more of a particular type of neurotransmitter receptor that is sensitive to both GABA (an inhibitory neurotransmitter) and a stress-related hormone, THP (also called allopregnanolone). The results obtained from this study will provide the rationale for exploring a new pharmacologic treatment that targets the site of action of THP upon the GABAergic system within limbic pathways.

DESCRIPTION (provided by applicant): Our aim is to understand the neural circuit underlying the cognitive control over the mal-adaptive behaviors that stem from stress-induced anxiety, especially among female adolescents. We also aim to understand why adolescent females are more vulnerable than males, adults and children to mental illnesses that are co-morbid with anxiety disorders. We have shown that adolescent female rodents that are exposed to the stress of food restriction (FR) exhibit individual differences in vulnerability to an anxiety disorer-like behavior, consisting of abnormality on the elevated plus maze, voluntary food restriction and excessive exercise, the latter of which contribute to severe weight loss and for some, death. This compilation of FR-evoked abnormalities, called activity-based anorexia (ABA) differs widely among individuals and correlate strongly with changes in the GABAergic inhibitory system (axons and alpha4betadelta-GABA receptors) in the prefrontal cortex and hippocampus. What remains unknown is whether the behavioral and anatomical changes are causally linked and if so, the mechanism for the stress (in this study, FR)-evoked up-regulation of the GABAergic system that protects animals from the mal-adaptive behavior. We hypothesize that (1) up-regulation to the GABAergic system of the prefrontal cortex and hippocampus is causal to the animal's ability to make decisions regarding responses to stressful environments (e.g., to eat or to run) that are more adaptive and to regulate the stress-evoked anxiety; and (2) individual differences in the GABAergic system of the prefrontal cortex and hippocampus arise from gonadal hormone fluctuations at puberty and the activity-dependent BDNF release. We will test these hypotheses by (1) determining the extent to which experimentally boosting the GABA system in the hippocampus and prefrontal cortex reduces ABA vulnerability and trait anxiety; and (2) determining whether systemic progesterone or the systemic or local alterations of BDNF level increase the strength of the GABA system and with it, reductions in the mal-adaptive behavior of voluntary FR, excessive exercise, and anxiety measures on the elevated plus maze. These goals will be achieved by quantifying the mal-adaptive behaviors of mice that are globally or locally knocked down of or boosted of the expression of GABAR subunits or of the GABA synthesizing enzyme or of BDNF and verifying the ultrastructure of GABAergic synapses by electron microscopy.

This REU site award to New York University, located in New York City, NY, will support the training of 10 students for 10 weeks during the summers of 2015-2019. Students will conduct research in neural science -- the study of the biological basis of human nature -- and use their basic knowledge in biology, mathematics, physics and chemistry to solve research problems needing a multidisciplinary approach. A wide variety of projects are available, ranging in scale from the molecular to cellular, and from neuronal network to behavior. Examples of questions students can investigate include: how individuals learn and memorize; what parts of the brain are activated when risky versus carefully calculated decisions are made; how attention modifies perception; how neonatal sensory experience affect mental capacities in adulthood, etc. Students are selected based on their desire to partake in basic research, as well as a match between their expressed topic of interest and those of mentors. The program aims to diversify the workforce in the field of neuroscience by attracting highly motivated individuals interested in pursuing a graduate degree in neuroscience. Students who are underrepresented in the field of neuroscience and have limited research opportunity at their home college/university will be given high priority for the program. For the application process, students will submit a CV and a personal statement describing their research interest in the field of neural science, and obtain two letters of recommendations.

It is anticipated that approximately 50 students, primarily from schools with limited research opportunities, will be trained in the program. Students will learn how research is conducted, and students will be required to present their results through a poster and oral presentation at the SURP symposium. Student will also be required to write a scientific paper describing the results of their summer research.

Students are required to be tracked after the program and must respond to an automatic email sent via the NSF reporting system (SALG URSSA). More information is available by visiting http://www.cns.nyu.edu/undergrad/surp/, or by contacting the PI (Dr. Chiye Aoki at ca3@nyu.edu) or the co-Director (Dr. Margarita Kaplow at mkaplow@nyu.edu).