1. Barreto Estrado, Jennifer L., Ph.D. (Assistant Professor)
   e-mail:jbarreto@rcm.upr.edu

   Actions of sex steroids in the brain regulate reproductive behaviors. However, it has become increasingly clear that sex steroids have regulatory functions beyond the influence on reproduction. For instance, natural and synthetic androgens can induce increases in body muscle, but also psychiatric disorders such as anxiety, depressive episodes and aggression. Androgens modulate specific cellular substrates such as neuropeptides and growth factors, suggesting their involvement in the cellular mechanisms underlying behavior. Neuropeptides have been associated with reproductive behavior as well as with anxiety-related behaviors. Opioids and NPY are highly expressed in brain regions that control reproduction and anxiety, such as the medial pre-optic area (mPOA) and the amygdala complex (AMY). However, the cellular and molecular events underlying these behaviors after androgen exposure are poorly understood and have been addressed mainly using in vivo studies systems. Often, the data of in vivo studies is contradictory, reflecting the complex interactions that the in vivo systems have.

2. Blanco, Rosa E., Ph.D. (Professor)
   e-mail:rblanco@neurobio.upr.clu.edu

   My research interests are concerned with the interactions between neurons and glial Cells that determine the survival of injured retinal ganglion cells, and understanding the role that growth factors play on the recovery and plasticity of the visual system. I am also interested in the specificity of the synaptic connections between neurons during development and regeneration.

3. Cant, John G. H., Ph.D. (Professor)
   e-mail:jcant@rcm.upr.edu
   
   Two separate research interests are:

1. Adaptive analysis of the postcranial morphology of primates, focusing on locomotor and postural behavior in relation to forest canopy structure.
2. Comparison of relations among body weight, locomotro behavior, and use of canopy between primates and other taxa of arboreal mammals.

3. Díaz-Ríos, Manuel, Ph.D. (Assistant Profesor)
   e-mail:mdiaz@neuro.upr.edu

   The basic motor patterns driving rhythmic limb movements during locomotion, such as in normal walking, are generated by neuronal networks located within the spinal cord. This relatively simple locomotor behavior is generated by the rhythmic activity of motor neurons under the control of spinal networks known as central pattern generators (CPGs) that are composed of multiple interneuron cells types. The identity and contribution of defined interneuronal populations to mammalian locomotor behaviors is poorly understood. His research will aim to initially study one of these populations of internerurons, the commissural interneurons (CINs).

4. Dunbar, Donald C., Ph.D. (Professor)
   e-mail:ddunbar@rcm.upr.edu
   
   My research is in mammalian motor systems, with particular emphasis on locomotion (i.e., gait) and posture. Locomotor and postural behaviors result from the interaction of neural, biomechanical, and morphological components. My overall research goal is to reveal the relative contributions of these components to a given movement pattern (e.g., walking, postural maintenance), to understand how and why this pattern changes with age, and to determine how a normal pattern is altered (e.g., limping, spatial disorientation). How these components interact can be revealed by analyzing the natural movement patterns of body segments, the orientation and trajectory of the whole body as it moves through its surroundings, the forces generated by these movements, the associated electrical activity of muscles (EMG), and anatomical design.
   Current research projects include:

1. Natural locomotor and postural development in free-ranging (Cayo Santiago) and captive (Sabana Seca) rhesus monkeys at the Caribbean Primate Research Center;
2. natural locomotion and posture of wild hanuman langur and bonnet macaque monkeys in India;
3. the role of primate head and trunk stabilization in vestibular perception of whole-body orientation relative to space (i.e., gravity-vertical, earth-horizontal) during natural posture and locomotion;
4. sensorimotor control of human spatial orientation and navigation when performing multiple jumps, and the potential role of cognitive maps.

4. Jorge, Juan Carlos, Ph.D. (Assistant Professor)
   e-mail:jcjorge@neurobio.upr.clu.edu
   
   The central goal of my research program is to understand how gonadal steroids, also known as sex hormones, mediate sex-specific neuroendocrine function and behaviors in health and disease. Sex hormones impact brain function not only via their classical nuclear hormone receptor pathway but also via allosteric modulation of a number of neurotransmitter systems. The g-aminobutyric acid type A receptor (GABAA-R), which is the most important inhibitory neurotransmitter system of the brain, has been shown to play a pivotal role in sex-, parental-, aggressive-, and anxiety-related behaviors. Given that both the molecular identity and the neurophysiological properties of the GABAA-R is under sex hormones control, the working hypothesis of my research laboratory is that GABAA-R facilitate neuroendocrine function in a hormone-dependent and sex-specific manner. We use the brain slice preparation to determine the biophysical properties and pharmacological profile of GABAA-R within key sexually dimorphic neural networks of mice and rats during critical developmental periods.
   
   Neuroanatomical techniques are employed to determine sex hormones effects on neuronal structure at critical neuroendocrine junctures. Systemic and intracranial perfusion of steroids and neuromodulators are also employed to assess quantitatively relevant behaviors in rodents. These studies will provide critical information to better design therapeutic strategies to treat premenstrual syndrome (PMS), postpartum depression (PPD), catamenial epilepsy, affective disorders (anxiety and depression), and management of drug and alcohol abuse, where pathological hormonal environments disrupt appropriate GABAA-R function.
5. Kensler, Robert W., Ph.D. (Professor)
   e-mail:rkensler@rcm.upr.edu
   
   In my laboratory, the primary research objective is to elucidate the structure of the myosin-containing thick filaments found in striated muscles. The goal of the work is to understand how differences in the packing of myosin and accessory proteins in thick filaments from different muscles may relate to differences in the physiological properties of the muscles and to understand the mechanism of force production at the molecular level. The key principle guiding much of the work is the observation from X-ray diffraction studies that the heads of the myosin molecules on the filament in living muscle are helically arranged. We have been one of the pioneering laboratories in the development of procedures which allow the filaments from some muscles to be biochemically isolated with the helical arrangement of the heads largely preserved, thus making the structure of the filaments amenable to analysis by a combination of electron microscopy with computer image analysis of the electron micrographs. This approach utilizes the principles of helical diffraction and computer image analysis of helical structures to determine the helical parameters and to compute a three-dimensional reconstruction of the electron density of the proteins in the thick filament.
   
   Using this approach we have computed three-dimensional reconstructions both of several invertebrate (horseshoe crab and scorpion) and vertebrate (frog and fish) skeletal muscle thick filaments. The primary goal of the current research is to elucidate the structure of the mammalian cardiac muscle thick filament; and to study the effects of phosphorylation of myosin light chain and other thick filament accessory proteins on the structure of the thick filaments and their interactions with actin to produce contraction. Determination of the structure of the cardiac thick filament as compared to the skeletal muscle thick filament is important for understanding the differences in physiological properties of cardiac muscle and skeletal muscle.
   
   The techniques employed in the laboratory include electron microscopy (negative staining and platinum shadowing), computer image analysis using both Fourier analysis and single particle analysis, cell fractionation, centrifugation, and SDS gel electrophoresis. Training opportunities are available for graduate students, undergraduates, and medical students.
6. Kicliter, Earl, Ph.D. (Professor)
   e-mail:ekiclite@neurobio.upr.clu.edu
   
   The research in my laboratory is directed to understanding the structure and function of vertebrate visual systems; structural correlates of aging in visual systems.
7. Luckett, W. Patrick, Ph.D. (Professor)
   e-mail:pluckett@rcm.upr.edu
   At present, my research focuses on two major areas:

1. Comparative morphogenesis of the fetal membranes and placenta in mammals, with emphasis on the use of such data for analyzing evolutionary relationships among mammals. These analyses are done in conjunction with a consideration of other types of biological data (comparative anatomical, paleontological, molecular) for assessing evolutionary relationships. This also entails a consideration of the theoretical framework for analyzing phylogenetic relationships, and assessing problems of homology and convergence during evolution;
2. Comparative development of the deciduous and successional dentitions of mammals. This research is also focused on analyzing the ontogenetic basis for evolutionary change in the mammalian dentition, and in detecting homologies of tooth change, tooth reduction, and tooth loss during mammalian dentition.
   Both areas of research entail examination of numerous developmental stages of fetal and juvenile mammals by serial histological sections, and this research is commonly carried out at large embryological collections in the United States, Europe and Australia.

8. Lugo, Nidza, Ph.D. (Professor)
   e-mail:nlugo@neurobio.upr.clu.edu
   
   The main area of research in our laboratory is comparative neuroanatomy of the mammalian visual system and circadian visual system We conduct studies to determine:

1. the morphology, connections and neurochemical properties of visual system neuronal populations, with emphasis on retinal ganglion cell
2. changes in the expression of NPY and GABA during the process of aging in the circadian visual system of a diurnal animal model.
   Methods used include neuroanatomical and tract-tracing techniques, immunohistochemistry and basic Molecular Biology techniques.

9. Miller, Mark W., Ph.D. (Professor)
   e-mail:mmiller@neurobio.upr.clu.edu
   
   Our research focuses on the neuronal circuits that govern behavior. We use several marine invertebrate animal models, due to the advantageous properties of their simple nervous systems. In then blue crab, Callinectes sapidus, we are investigating how the central nervous system regulates the heartbeat, and specifically how neuromodulators achieve such modulation via corrodinated cental and peripheral actions (see T.J. Fort et al., 2004). In the marine mollusk, Aplysia californica, we have identified key interneurons that regulate feeding behavior using two classical neurotransmitters, GABA and dopamine (see Díaz-Ríos et al., 2002). These studies increase our understanding of the neural control of behavior in all animals, including humans. They should also provide insight into fundamental neuronal mechanisms that underlie maladaptive brain activities.
10. Pérez-Acevedo, Nivia L., Ph.D. (Assistant Professor)
    e-mail:niperez@rcm.upr.edu

    One of the goals of Dr. Pérez-Acevedo is to determine the role of metabotropic glutamate receptors (mGluRs) in anxiety-related behaviors at the cellular and behavioral level. mGluRs might be an alternative approach for the discovery of a new generation of anxiolytics to treat anxiety. It can be expected that selective modulators of glutamate activity will be of great clinical significance for pharmacotherapeutic intervention in syndromes such as depression and Posttraumatic Stress Disorders.

11. Singh, Dave, Ph.D. (Associate Professor)
    e-mail:gdsingh@rcm.upr.edu
    
    Birth defects cause major concerns to parents and offspring. In my program of research, the clinical nature, etiology, prevention and management of congenital malformations will be studied using geometric morphometric techniques. These modern techniques include 3-D digital surface photogrammetry, Procrustes superimposition, finite element scaling analysis, thin-plate spline transformations, Euclidean distance matrix analysis, as well as 3-D pseudo-animation. Other studies will be carried out, using immunocytochemical and molecular genetic techniques. Specific areas of focus include:

1. Craniofacial dysmorphology, particularly computerized mathematical modeling of malformations such as craniofacial microsomia, orofacial clefting, malocclusions etc.
2. Craniofacial development in relation to surgical management as well as dentofacial orthopedic therapy of craniofacial deformities, particularly algorithm development and mathematical analyses to model predictive growth during normal and dysmorphic development, as well as long-term post-treatment stability
3. Growth guidance, particularly dentofacial asymmetry and antero-posterior distraction osteogenesis of the craniofacial complex.
4. Genetic determination of craniofacial birth defects, including analysis of the human genome of normal and dysmorphic subjects, particularly in relation to craniofacial deformities (including ethnically diverse populations).
5. Drug-induced facies, particularly the characterization of craniofacial features associated with cocaine and other drug abuse during pregnancy.

11. Sosa Lloréns, María A., Ph.D. (Asociate Professor)
    e-mail:masosa@neurobio.upr.clu.edu
    
    My research work is at present concerned with understanding the mechanisms underlying the phenomenon of synaptic competition. Neurons sharing a common target influence one another in such a way that their synaptic efficacy is reduced. In some instances, as is the case for the developing neuromuscular junction, polyinnervation of target cells is a transient stage. In such systems, synaptic competition plays a role in determining which connection is to be maintained and which are to be retracted. However, in what may very well be the majority of cases in the central nervous system, target neurons can remain multiply innervated during postnatal development and adulthood. I study synaptic competition in such a situation in an invertebrate anumal model. The cercal sensory system of the common cockroach Periplaneta Americana, using techniques of electrophysiology, intracellular dye injection, as well as light, electron and confocal microscopy. I am also interested in developing a tissue culture system in which synaptic competition between neurons can be studied in more detail, using techniques of electrophysiology and molecular biology
12. Turnquist, Jean E., Ph.D. (Professor)
    e-mail:jturnquist@rcm.upr.edu
    
    Research interest in functional morphology of non-human primates with emphasis on the musculoskeletal system. Current research includes kinematic analysis of locomotion of various New World monkeys; radiographic analysis of interspecific joint configuration; and osseous changes associated with aging, e.g., osteoarthritis, spondyloarthropathies, and osteoporosis. Analysis of the correlation of function and pathology with gross and microscopic osseous structure is an important aspect of these studies.

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Emma Fernández-Repollet,Ph.D.

Program Director

RCMI Program

Room 621-A, 6th. floor

Main Building, Medical Sciences Campus

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Email: efernandez@rcm.upr.edu

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