Joanne Berger-Sweeney - US grants

This laboratory sequence integrates studies of the behavioral, electrophysiological, histological, and neurochemical effects of medial septal lesions in rats. The course engages students in experimental design, hypothesis testing, and analysis and interpretation of data. Grant related equipment includes the instrumentation, hardware and software necessary to conduct and analyze passive avoidance behavioral experiments (Reflex-16 instrumentation) and neurochemical analyses (HPLC). The project will significantly enhance research opportunities for a number of young women and provide them with motivation to pursue careers in the sciences.

The brain is especially vulnerable to damage in the neonatal and early fetal period. Early brain damage can lead to a bewildering variety of behavioral problems. Damage early in development does not necessarily cause the same effects as damage in adulthood. Dr. Berger Sweeney has developed a novel model system for studying the effects of early brain damage. She has found that lesions of an important nucleus in the forebrain the nucleus basalis of Meynert (nBM) cause unusual cellular formations in the sensori motor cortex in adulthood and have severe deficits in spatial navigation. She hypothesizes that the behavioral and morphological effects are due to transient depletion of cholinergic afferents to the cortex. She will now determine whether the affected behaviors are ones known to be dependent on cholinergic function or whether the deficits are due to some more nonspecific effect of the early lesion. She will also attempt to reverse the effects of the early lesions by augmenting the function of the depleted transmitter. The results will greatly strengthen our understanding of the mechanisms by which early brain damage affects behavior and may set the stage for developing effective therapies.***//

9458101 Berger-Sweeney The proposed studies will examine mechanisms that underlie sexual dimorphism of cerebral cortical structure and cognitive functions in mice. More specifically, the studies will focus on how cortically-projecting neurons in the basal forebrain (BF) influence the developing cortex and cognition in the two sexes. A BF lesion model will grow to adulthood. Previous studies show that a neonatal BF lesion leads to persistent alterations in cortical morphology and to cognitive deficits in adulthood. Recent studies show that lesion-induced structural and functional deficits are more pronounced in male than in female mice. For the proposed studies, a combination of neurochemical, anatomical and behavioral methods will be used to examine mechanisms that underlie these sex differences. Critical questions to be addressed include: Does the BF influence cortical maturation at different times in males and females? What neurotransmitters are responsible for morphological and behavioral differences between the sexes? Do gonadal hormones differentially interact with the developing BF system in the two sexes? Answers to these questions will provide exciting insights into how sex differences in cortical maturation may relate to sex-specific cognitive development.

A wealth of studies in adults suggests that acetylcholine (a chemical in the brain) plays an important role in cognitive processes such as spatial learning and memory. Considerably less is known about the role that acetylcholine plays in the developing mammal, and how this chemical may help to establish the complex neural circuitry that will underlie cognitive processes later in life. The proposed study will explore the role of acetylcholine in early postnatal development in rat by examining how cognitive processes develop in the absences of this chemical. Furthermore, the proposed study will examine how other neurochemical systems may compensate for the loss of acetylcholine. This neurochemical compensation is one form of neuroplasticity (remodeling/ dynamic changes) in the nervous system that is a hallmark of the developmental process. All of the proposed studies will be conducted in rats of both sexes to determine whether the two sexes respond similarly to developmental manipulations.
This study will provide new insights into the role of an important neurochemical in the maturation of the brain and behavior. The study should also provide insights into how a developing mammal responds behaviorally to changes in the neurochemical environment, as well as insights into the types of compensations that are made in response to these changes.

Acquisition of a Magnetic Resonance Imaging Accessory
for a 400 MHz NMR Spectrometer:
Interdisciplinary Research in MRI in an Undergraduate College Setting

ABSTRACT

A grant has been awarded to Dr. Nancy H. Kolodny and her colleagues at Wellesley College, an undergraduate liberal arts college for women, to establish a Magnetic Resonance Micro-Imaging Facility in Wellesley's Science Center. This facility will offer unique interdisciplinary research, teaching, and learning opportunities to Wellesley's faculty and students, with initial research projects in the emerging field of neuroscience.

With the establishment of the micro-imaging facility, two different types of Magnetic Resonance Imaging (MRI) techniques, functional MRI (fMRI) and contrast enhanced MRI will be developed. These techniques will be used to answer important neurobiological questions. Functional MRI will be utilized to examine the brains of crustaceans such as lobsters, and mice. Details of activity patterns in the olfactory pathway of the crustacean brain will be elucidated. In mice, the question of whether gender and age affect brain function will be investigated, focusing on the response of the brain to stimulation of the whisker barrels. Contrast enhancement techniques will be used to address questions related to the role of serotonin, an important brain biochemical, in olfactory neurons in newborn crustaceans. An MRI experiment will be introduced into Wellesley's undergraduate introductory developmental biology course. Students will use MRI to explore the pupal development of tobacco hawkmoth. Not only will this give students experience with MRI, it will also provide an opportunity for dynamic observation of living organisms during development.

The scientific problems to be examined in the new Magnetic Resonance Micro-Imaging Facility at Wellesley College are of importance in the developing basic understanding of brain and neuron function. Furthermore, training undergraduate students in the use of MRI will both inspire them to further study of science and enable them to pursue sophisticated research during their college years and beyond.