Click on the faculty member’s name for more information about them.
Associate Professor, Pharmacology and Physiology
Office: Med-Dent SW401
Lab: Med-Dent SW402
Education: B.Sc. (Hons) 1990, LL. B. University of Canterbury NZ, 1991, Ph.D. Australian National University, 1996
Current Research: How do cells detect changes in the external or extracellular environment? We are interested in the fundamental mechanisms that allow cells to sense diverse chemical or physical stimuli. Our focus is a class of membrane ion channels called “Transient Receptor Potential” (TRP) channels. We also explore novel ligand signaling at G-protein coupled receptors both in neurons and immune cells. We use a combination of electrophysiological, cell imaging, genetic and biochemical techniques, and where possible, appropriate animal models.
Tinatin I Brelidze
Assistant Professor, Pharmacology & Physiology
Office: SE406 Med-Dent
Lab: SE406 Med-Dent
Education: Diploma in Physics (Hons), Tbilisi State University (Georgia), 1996; Ph.D. Physiology & Biophysics, University of Miami, 2003
Current Research: Ion channels are guardians of membrane potential and are essential for the physiological function of every living cell. Abnormalities in ion channel opening and closing (gating) or expression pattern are often linked to inherited or acquired diseases. Our research interests are focused on understanding the mechanisms of ion channel gating. To uncover the novel mechanisms of ion channel gating we use a combination of electrophysiology, X-ray crystallography and fluorescence based methods.
Mark P. Burns
Associate Professor, Neuroscience
Laboratory for Brain Injury and Dementia
Office: Research Building, WP22a
Lab: Research Building, WG03
Education: National University of Ireland, Galway: B.Sc. (Hons), Physiology, 1997; Ph.D. Pharmacology, 2000
Current Research: The Laboratory for Brain Injury and Dementia (LBID) at Georgetown University studies the acute activation of pathways involved in chronic neurodegenerative diseases such as Alzheimer’s disease after traumatic brain injury (TBI) Our aim is to understand if these pathways are playing a role in acute cell death after TBI, and to to understand if the activation of these pathways are involved in development of dementias, such as Alzheimer’s disease and chronic traumatic encephalopathy (CTE). We use contusion and concussive brain trauma models in the LBID, and the lab has capability to perform the surgical, behavioral and biochemical aspects of this research. We take advantage of the outstanding core imaging facilities available at Georgetown University, including a small animal imaging laboratory with a 7Tesla magnetic resonance imager, confocal microscopy, stereology, fluorescent and standard microscopy.
Casey Lab (new window)
Office: Regents Hall 408
Education: Ph.D. Stanford University, Biology, 1996
Current Research: Our goal is to define the gene network that controls the induction and differentiation of the central nervous system. The CNS is derived from the ectoderm which can develop into either epidermal or neural tissue. Neural tissue then differentiates into either neurons or glial cells. Many of the signal pathways and transcription facors involved in directing these fate choices are known, however, how their actions are coordinated is unknown. To elucidate this mechanism, our studies focus on the function of the SoxB proteins which encode highly conserved, HMG box transcription factors. By studying the regulation and function of the SoxB proteins, we can piece together the steps that drive ectoderm to develop into epidermis and neural tissue to form a neuron.
Thomas M. Coate
Assistant Professor, Biology
Coate Lab (new window)
Office: Reagents Hall 412
Education: B.S. University of Puget Sound; Ph.D. Oregon Health & Science University
Current Research: The long-term goal of the research in the Coate laboratory will be to define the signaling mechanisms underlying neural development within sensory systems and how synaptic connections can be reestablished in cases of damage or disease. In the field of developmental neuroscience, we are now at an exciting time where we can take multi-faceted approaches to understanding (with excellent temporal and spatial resolution) the mechanisms by which precise cell types coordinate appropriate axon guidance decisions and synapse formation. In our research, we aim to understand the mechanisms by which spiral ganglion neurons (SGNs) make functional connections with mechanosensory hair cells in the mouse cochlea. We are currently addressing how secreted Semaphorins, which activate Neuropilin/Plexin co-receptors, control SGN axon guidance decisions in the cochlear sensory epithelium. We are also investigating how the transcription factor Pou3f4 controls the expression of axon guidance factors in the developing cochlea (such as ephrins and Eph receptors) and how those factors control cochlear innervation. The cochlea provides an excellent model for discovering how circuits assemble within a complex organ system, as it is composed of an array of cell types and structures precisely arranged to detect a range of sound frequencies.
Associate Professor, Neuroscience
Office: NRB, EP-16
Lab: NRB, EP-16
Education: A.B. Cornell University, Biochemistry; M.D. Boston University
Current Research: Matrix metalloproteinases (MMPs) area family of zinc-dependent endopeptidases that are released in a neuronal activity dependent manner. MMP expression and activity can also be dramatically upregulated with injury. Many studies have therefore focused on their role in pathology. Less is known about the role of MMPs in normal CNS physiology, and whether critical physiological processes might be disrupted when MMP levels are pathologically elevated. While recent studies suggest that MMPs play a role in learning and memory, the mechanisms by which they do so are not well understood. Similarly, how excessive MMP activity might contribute to synaptic injury is not clear. Our work is focused on specific mechanisms by which MMPs can influence neuronal and synaptic structure and function. Our focus is on cleavage of synaptic adhesion molecules and thrombin type G protein coupled receptors.
Associate Professor, Physics and Pharmacology
Neural Dynamics Lab
Office: Med-Dent SE 407
Lab: Med-Dent SE 407
Education: Ph.D. University of Michigan, 2003
Current Research: We use arrays of extracellular multi-electrodes to record and stimulate electrical activity from cultured neural circuits as well as from acute neural slices. We modulate network rhythmicity by manipulating the balance between excitation and inhibition to investigate the principles by which neurons interact. What is the causal role of emergent coherent activity for neuronal communication?
Center for the Study of Learning
Office: Bldg D, Rm 143
Lab: Bldg D, Suite 150
Education: B.Sc. University College London, Physiology, 1989; D.Phil. Oxford University, Physiology, 1993.
Current Research: Dr. Eden’s research has focused on the application of functional neuroimaging techniques to study the neural basis of reading and how it may be altered in individuals with developmental disorders or altered early sensory experience. Further, she and her colleagues are researching how reading is impacted by instructions or mode of communication and are utilizing functional MRI to study the neurobiological correlates of reading remediation.
Patrick A. Forcelli
Assistant Professor, Pharmacology & Physiology
Laboratory of Molecules, Circuits and Behavior
Office: NRB W214
Lab: NRB W217
Education: Ph.D. Georgetown University, Neuroscience, 2011
Current Research: 1. Vulnerability of the developing brain to drug induced damage – Anti-seizure medications (also called anticonvulsant or antiepileptic drugs) are the mainstay of treatment for epilepsy. However, the use of these medications in special populations (e.g., pregnant women with epilepsy, neonates with seizures) poses a challenge due to the exquisite sensitivity of the developing brain to perturbations of neural activity. Many commonly utilized anti seizure drugs induce apoptosis in the neonatal rat brain, disrupt functional and morphological synaptic development, and alter behavioral function. We are continuing to examine this class of drugs to characterize effects on brain development, identify mechanisms of toxicity and search for therapeutic approaches to minimize long-term effects. We employ a combination of histological, biochemical, physiological, behavioral and imaging approaches to address these questions.
2. Hippocampal and basal ganglia circuits in seizure progression. The same neural circuits through which seizures propagate are vital participants in normal cognitive and emotional function. We are examining hippocampal and basal ganglia contributions to both normal behavior and to seizure propagation. To determine the role of these circuits we are using a combination of lesions, focal pharmacological (in rodents and primates), electrical, and state of the art pharmacogenetic and optogenetic methods. These techniques are used to perturb circuit function during behavioral tasks as well as in animal models of seizures/epilepsy. Finally, we are also assessing the ability of shRNA-mediated knockdown of select targets within these circuits to delay or prevent the development of epilepsy.
Rhonda B Friedman
Center for Aphasia Research and Rehabilitation
Office: Building D, Room 203B
Lab: Building D, Suite 207
Education: B.A. University of Pennsylvania, 1974; Ph.D. MIT, 1978
Current Research: Dr. Friedman’s research focuses on how language is processed in the normal brain; how language breaks down in a brain damaged by stroke, head injury, or dementia; how the brain recovers language function after injury; and how the recovery process can be aided by non-pharmaceutical therapies. Research focuses particularly on semantic memory, naming, and reading. Techniques employed include behavioral studies; treatment studies; ERP; eye-tracking; and imaging studies. Current studies focus on learning paradigms in rehabilitation, and prophylaxis of cognitive decline in dementia.
Associate Professor, Ophthalmology, Neurology, Biochemistry
Office: Med-Dent Bldg, Room NE 203
Lab: Med-Dent Bldh Room NE 212-218
Education: B.S. University of Paris VII, Jussieu; M.S., Ph.D., University of Paris VI, Pierre et Marie Curie, Paris, France
Current Research: Dr. Golestaneh’s lab is investigating how aging mechanisms affect the cells and induce diseases such as age-related macular degeneration (AMD). Using patient-specific induced pluripotent stem (iPS) cells Dr. Golestaneh is studying the cellular and molecular mechanisms that induce the AMD and is developing ways to stop this disease from occurring. Another focus of the lab is developing new methods of autologous cell-based therapy for AMD by generating patient-specific stem cell-derived neuroretinal cells.
Associate Professor, Psychology
Georgetown Laboratory for Relational Cognition
Office: 302C White Gravenor
Lab: 303 White Gravenor
Education: Ph.D. Dartmouth College, 2007.
Current Research: My motivating interest is in human creative intelligence and especially in understanding how neural processes constitute our best ideas. Adam’s work focuses on reasoning that reveals meaningful connections between seemingly distant concepts, often in the form of analogies.
Dean of the Graduate School
Professor, Neuroscience, Physics
Office: Car Barn 416
Education: Ph.D. Hebrew University of Jerusalem, Israel, 1984
Current Research:• Encoding and Decoding of Visual Information in Retinal Ganglion Cells • Cell-molecular Re-engineering of Retinas in Retinitis Pigmentosa • Plasticity of Retinal Receptive Fields • Optimal Processing Principles for Retinal Function • Optimal Processing Principles in Visual Perception • Computation and Psychophysics of Visual Perception
Brent T Harris
Director of Neuropathology and Associate Professor, Neurology and Pathology
Neuropathology Research Lab
Office: Bldg D, 202C
Lab: Bldg D, 335/7/9
Education: B.A. Colby, 1982; M.S. Hahnemann, 1988, Ph.D., M.D. Georgetown University, 1995
Current Research: Dr. Harris has dual appointments in Neurology and Pathology. As a neuropathologist and physician-scientist Dr. Harris has clinical, research, and teaching interests in neurological diseases. He has active collaborations and research programs in his own lab in the areas of neurodegeneration, CNS neoplasia, and traumatic brain injury. His primary interest is in understanding how mechanisms of neuroinflammation and glial-neuronal communication influence the pathophysiology of neurological diseases. In addition to investigating disease processes he also seeks to uncover targets for pharmacological intervention.
Haiyan He, Ph.D.
lab website: He-lab.org
Office: Regents Hall 412
Education: B.S. Shanghai Jiaotong University, China; M.S. Peking University, China; Ph.D. University of Maryland, College Park, MD
Current Research: The long-term goal of He lab is to unravel the molecular and cellular mechanisms underlying the intricate balance between plasticity and stability of neural circuits in both early embryonic development and adulthood, with a special focus on inhibitory neurons. We use the albino Xenopus laevis (tadpole) as our animal model. The central nervous system of the tadpole is amenable to a wide variety of manipulations from molecular to circuit level. It provides a unique in vivo vertebrate system to study the basic laws governing the organization and formation of nascent neural circuits, where plasticity and stability are both pivotal for the survival of the animal. We use a number of techniques in the lab, including time-lapse in vivo imaging of neuronal structure and function and using bio-orthogonal non-canonical amino acid (BONCAT) to tag activity-induced newly synthesized proteins, as well as behavioral evaluation of visual functions. Current projects include investigating how excitatory and inhibitory synaptic inputs are coordinated in response to experience changes and examining functional roles of the degradation of newly-synthesized protein in maintaining neuronal homeostasis.
Jeffrey K. Huang
Associate Professor, Biology
Office: Regents 406
Lab: Regents 411
Education: B.A. Washington University; Ph.D. Mount Sinai School of Medicine of NYU
Current Research: My lab is interested in the biology and pathology of glial cells. We focus on oligodendrocytes, a type of glia, whose cellular processes engage with and enwrap CNS axons, and form the lipid-rich myelin membranes required for rapid, saltatory conduction. Myelin destruction in diseases such as multiple sclerosis impairs axonal conduction and results in progressive axonal degeneration. We are currently investigating the mechanisms by which oligodendrocytes interact and communicate with axons, and how their interactions might promote axonal integrity and survival. We are also investigating the mechanism of myelin regeneration, with a focus on how oligodendrocytes regenerate from endogenous neural progenitor cells to replace myelin during homeostatic turnover or after demyelination. We use primary oligodendrocyte/neuron co-cultures, transgenic mice, and models of experimental CNS injury and demyelination, combined with molecular biology and imaging tools to address these questions.
Assistant Professor, Neuroscience
Cognitive Neuroimaging Laboratory
Website (new window)
Office: WP-24A, NRB
Lab: EP-12D, NRB
Education: Ph.D. The Catholic University of America, Experimental Psychology, 2005
Current Research: Magnetic resonance imaging (MRI) has a strong potential to serve as a non-invasive research and clinical tool of neurological disorders. Oru lab has been working to develop and validate novel and advanced MRI techniques that are sensitive to subtle neuronal injury at early stages of disease, with a focus on functional MRI (fMRI). The ultimate goal is to develop multimodal MRI biomarkers that can effectively detect and accurately quantify disease progression, even in the absence of behavioral symptoms, with the potential to guide and evaluate early interventional therapies.
Associate Professor, Neurology, Neuroscience, and Psychology
Complex Adaptive Systems Neuroscience
Office: NRB WP09A
Lab: NRB WP09
Education: Ph.D. LSU-Baton Rouge, Physiology and Zoology, 1986
Current Research: My lab is equipped to use sounds and computational models to probe neural circuits so that we can understand how the brain works, what its design features are, and how neurons compute. We tackle these questions using a multiplicity of techniques, organisms, and approaches to obtain neurometrics across a wide range of spatial, spectral, and temporal scales. Topics of interest: 1. Sensory coding and computational plasticity: how are species-specific sounds encoded/decoded within the cortex and amygdala? Solution of this nontrivial problem may inform us about the origins and mechanisms for speech and music perception and facilitate design of neuroprosthetic devices. 2. Cortico-cortical and cortico-limbic interactions: We study the role of functional connectivity, oscillations and single-unit responses. 3. Learning, Memory, and Distress: The brain exhibits multistate and multisite adaptive plasticity for decision-making. How do anxiety, traumatic stress, and autism spectrum disorders emerge?
Professor, Pharmacology and Physiology
Office: Medical Dental Bldg NE413
Lab: Medical Dental Bldg NE416-420
Education: Ph.D. Ohio State University, Pharmacology, 1974
Current Research: My laboratory studies the subunit composition, pharmacological properties and regulation of neuronal nicotinic receptors. We are particularly interested in understanding the importance of desensitization of these receptors and the mechanisms by which chronic exposure to nicotine increases these receptors in brain.
Office: NRB EG-09a
Lab: NRB EG-09
Education: Ph.D. University of Chicago, 1977
Current Research: My laboratory is involved studies determining whether ephrins and Eph receptors interact to generate signals that regulate the extent of axonal regeneration and synaptic plasticity after CNS trauma and during development.
Professor & Chair, Neuroscience
Maguire-Zeiss Lab (new window)
Office: NRB EP08
Lab: NRB EP08
Education: B.S. Albright College, 1981; Ph.D. Pennsylvania State University College of Medicine, 1987
Current Research: My laboratory is focused on understanding the mechanisms involved in age-related progressive neurodegenerative diseases. Specifically, we are investigating the role of increased oxidative stress, protein misfolding and inflammation using mouse transgenic and toxicant models as well as cell culture technologies. Our work includes studies with the Parkinson’s disease protein, α-synuclein, and how it increases oxidative stress and proinflammatory molecules, as well as, the role of inflammation in HIV-associated neurocognitive disorder. We hope our studies will help us to better understand how inflammation is involved early in PD and HAND.
Office: NRB, W209B
Education: B.A., M.A. Charles University Prague, Czech Republic; Ph.D. Czechoslovak Academy Sciences, Prague, Czech Republic, 1986
Current Research: Neural substrates of social and emotional behavior; the role of the amygdala and orbitofrontal cortex in processing reward; medial temporal lobe structures (hippocampus, perirhinal cortex) and cognitive functions (object recognition and spatial memory); amygdala and midbrain (superior colliculus) interactions; autism, PTSD; reversible pharmacological manipulations of discrete brain structures, systemic drug effects.
Associate Professor, Psychology
Laboratory on Social & Affective Neuroscience
Office: WGR 302B
Lab: WGR 302
Education: Ph.D. Harvard University, Social Psychology, 2004
Current Research: How do people understand what others think and feel? How does that relate to what they think and feel themselves? What causes people to want to help or harm others? These are the questions that underlie research on empathy and mentalizing. Research in the lab is aimed at understanding aspects of human social interactions, emotional functioning, and empathy using cognitive neuroscience methods. We focus in particular on emotion and on nonverbal communication. Our research includes studies with adolescents and adults, incorporating neuroimaging, cognitive and behavioral testing, and psychopharmacological techniques.
Associate Professor, Neurology
Office: Bldg D 202A
Education: Ph.D. Russian Academy of Sciences, Moscow, Neurophysiology, 1989
Current Research: Dr. Medvedev’s expertise includes systems electrophysiology, signal analysis and neural network modeling. His research interests focus on neural mechanisms of cognitive processes in normal and neurological pathology. His current research combines a new technology of noninvasive near-infrared (NIR) optical functional imaging of the brain with a more traditional electrophysiological analysis of on-going and event-related electrical activity (EEG, ERP, evoked and induced gamma-band oscillations).
Office: NRB, WP13
Lab: NRB, EG19
Education: Ph.D. University of Milan, Italy, 1982
Current Research: Neurotrophic factors influence axon and dendrite growth, synaptic plasticity and neurogenesis, and the interaction of neurons with glial cells. They play critical roles in preventing neurological diseases including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, stroke and epilepsy, but they can also promote neuronal apoptosis. Our laboratory has recently demonstrated that the neurotrophin brain-derived neurotrophic factor (BDNF) modulates the expression and function of chemokine receptors that contribute to AIDS dementia complex. We envision this research as catalyzing important new efforts to translate the basic science of the neurotrophins into effective new treatments for neurodegenerative diseases. In addition, we study the effect of opioids on the neuronal survival.
Associate Professor, Neurology
The Laboratory for Dementia and Parkinsonism (new window)
Office: Bldg D, 203C
Education: M.B. (M.D. equivalent), Ph.D. University of Sydney, Australia, 2002
Current Research: Our laboratory evaluates potential therapeutic drugs for neurodegenerative diseases in pre-clinical models and clinical trials. We investigate cellular, biochemical and pathological mechanisms that underlie neurodegenerative diseases with dementia and Parkinsonism, including Alzheimers disease (AD) and other dementias, and Parkinsons disease (PD) and related movement disorders. We also investigate the neuro-pathological and biochemical pathways involved in the spectrum of motor neuron disease (MND) with fronto-temporal dementia (FTD).
Elissa L. Newport
Professor of Neurology, Director of CBPR, Neurology
Center for Brain Plasticity and Recovery
Office: Bldg D, Suite 145, Rm 155
Lab: Bldg D, Suite 145
Education: Ph.D. University of Pennsylvania, 1975
Current Research: Dr. Newport’s research examines language acquisition and other types of implicit pattern learning. We focus on young children, asking how they acquire spoken or sign languages, even when they may have little consistent or complex linguistic input. Our studies include fieldwork on young, developing sign languages around the world, and also experiments in the lab, investigating how children and adults learn miniature artificial languages that reproduce specific properties of natural languages and their acquisition circumstances. We have shown that children expand languages as they learn them, making them more consistent and shifting them toward universal principles of language structure. We also study how children and adults acquire or recover language after left hemisphere strokes. This research investigates the mechanisms underlying language acquisition and language reorganization after brain injury, with a particular interest in developmental plasticity.
Associate Professor, Pediatrics
Office: Bldg D, 285
Lab: Bldg D, 272
Education: Ph.D. University of Montpellier I, France, Physiology
Current Research: Our long term goal is to understand how controlling voltage-gated calcium channels and related calcium signaling can be used to prevent and treat inherited seizures, acquired epileptogenesis, alcohol withdrawal seizures, and neonatal seizures following alcohol exopsure during gestation.
Professor, Pharmacology and Physiology
Molecular Neurobiology of Memory [mNeMe]
Office: Med-Dent C405
Lab: Med-Dent C405
Education: B.A. Harvard University, 1991; Ph.D. University of California at Berkeley, 1996
Current Research: My laboratory is interested in the molecular changes that occur at CNS synapses in response to experience. We utilize a combination of approaches ranging from molecular biology and biochemistry to cell biology, imaging, and mouse genetics to address three major questions: 1) how do neurons encode long-term storage of information? 2) how do neurons maintain stability of function by homeostatic synaptic plasticity mechanisms? and 3) how does failure of these mechanisms contribute to neurological and neurodegenerative disorders?
Josef P. Raushecker
Laboratory for Integrative Neuroscience and Cognition
Office: NRB WP19
Lab: NRB WP23
Education: Ph.D. Munich Institute of Technology, 1980; D.Sc. Tubingen University, Neurophysiology, 1985
Current Research: Dr. Rauschecker is interested in the functional organization and plasticity of the cerebral cortex. He is especially interested in how perception, memory, and language are implemented by the brain. His laboratory is one of only a handful in the country engaged in the neurophysiology of auditory cortex in nonhuman primates. In parallel studies, he is using functional magnetic resonance imaging (fMRI) in humans for the study of the neural basis of language, music and other higher auditory processing. His laboratory is also interested in the effects of sensory deprivation during brain development, relating to the question of how the brain of individuals with early blindness or deafness gets reorganized.
G. William Rebeck
Professor, Department of Neuroscience
Office: NRB WP-13
Lab: NRB WP-26, WP-27
Education: A.B. Cornell University, 1982; Ph.D. Harvard University, 1991
Current Research: I have been studying the effect of APOE on Alzheimer’s disease pathogenesis since 1993. The APOE4 allele is the strongest genetic risk factor for Alzheimer’s disease. We study the role of the APOE in neuronal signaling and glial activation, cell culture systems and APOE knock-in mice, which express the human APOE alleles under the endogenous mouse APOE promoter. We have found that the APOE4 isoform is altered in its post-translational modifications in the CNS compared to other APOE isoforms. We have also found that the APOE4 mice have reduced neuronal complexity and increased sensitivity to glial activation. These effects of APOE occur in the absence of Alzheimer’s disease pathological changes, suggesting that APOE modifies normal brain functions. We have found that APOE4 mice are also more susceptible to cognitive impairment after chemotherapy. Altering APOE regulation and modification in normal brains presents opportunities to prevent cognitive impairments due to Alzheimer’s disease and chemotherapy.
Laboratory for Computational Cognitive Neuroscience
Office: NRB WP-12
Lab: NRB WP-01
Education: Ph.D. MIT, 2000
Current Research: The lab investigates the computational mechanisms underlying human object recognition as a gateway to understanding the neural bases of intelligent behavior. We combine computational models with human behavioral, functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) data. This comprehensive approach addresses one of the major challenges in cognitive neuroscience today: the necessity to combine data from a range of experimental levels in order to develop a rigorous and predictive model of human brain function that quantitatively and mechanistically links neurons to behavior. This computational grounding of behavior in processing at the neuronal level is of key interest for the investigation of the neural bases of cognitive and behavioral impairments in complex mental disorders, to pave the way for neuroscience-based therapies. In addition, understanding the neural mechanisms underlying object recognition in the brain is of significant interest for Artificial Intelligence, as the capabilities of pattern recognition systems in engineering (e.g., in machine vision or speech recognition) still lag far behind that of their human counterparts in terms of robustness, flexibility, and the ability to learn from few exemplars.
Professor, Nephrology & Hypertension, Dept. of Medicine; Director, CSD
Center for the Study of Sex Differences
Office: Bldg D 232
Education: Ph.D. University of Maryland, Baltimore, Biochemistry, 1987
Current Research: Dr. Sandberg’s laboratory is investigating the structural analysis and regulation of G protein-coupled receptors in neuronal physiology and pathophysiology. In particular, her research focuses on the receptors for angiotensin II, corticotropin releasing hormone, gonadotropin releasing hormone, vasopressin and neuropeptide Y and their role in neuronal and cardiovascular physiology and pathophysiology. A second major aim of this laboratory is to study mechanisms of G protein-coupled receptor gene regulation. Dr. Sandberg is especially interested in understanding mechanisms of gene control at the posttransciptional level.
Ella.StriemAmit@georgetown.edu (new window) (new window)
SAMP Lab Website
Office: New Research Building, WP10
Education: PhD, 2014, The Hebrew University of Jerusalem
Current Research: Dr. Striem-Amit’s lab, the SAMP Lab (Sensory and motor plasticity), explores the extent to which brain organization depends on one’s own sensory or motor experience. The lab does this by studying models of early-onset sensory and motor deprivation using behavioral and functional magnetic resonance imaging (fMRI) techniques.
The lab examines the neural processing of action in several groups who experience early sensory and motor deprivation, including the main study group: people born without hands.
How do these people, who use other body parts such as their feet to perform everyday actions, represent and generate actions usually performed with the hands? For example, what parts of the motor system represent the actions that are typically performed with a hand but are now performed with a foot? How does the brain’s wiring enable such plasticity? And what regions cannot reorganize for another effector but are truly specific for the hands as a topographical body part?
Understanding the plasticity and organization of the motor system has the potential to inform rehabilitation following hand function loss due to stroke or amputation and advance the development of functional motor prostheses.
Other research lines explore brain plasticity in other models of sensory deprivation, such as people born blind or deaf. We will study the commonalities and differences between sensory and motor deprivation. Furthermore, we will characterize the neural differences between deprivation of a whole sensory channel (being born completely blind or deaf) as compared to part of it (e.g. missing only the hands).
Overall, studying brain development, plasticity and organization across models, the lab will aim to gain insight of the general principles of how our brains develop and adapt.
Interested in joining the lab? Email me!
Center for Brain Plasticity and Recovery
Office: Building D, Suite 165
Education: Ph.D. University of California, San Diego, Psychology, 1982
Current Research: Dr. Ted Supalla’s research centers on the structure and emergence of sign languages around the world. This has included studies of American Sign Language acquisition and processing, and the evolution and structure of homesign, international pidgin sign, and signed languages in other countries. Comparisons between early and modern ASL, and also between other young and well-developed sign languages, can provide an understanding of how languages form and change, and whether the processes of language change for sign languages are the same as those for spoken languages. Dr. Supalla is also interested in the on-line processing of ASL by native signers, including studies of sentence comprehension, sentence reproduction, and short-term memory in signed versus spoken languages, as well as fMRI studies asking what parts of the brain are activated during visual-gestural language and non-linguistic processing.
Associate Professor, Neurology
Cognitive Recovery Lab
Office: Bldg D 157
Education: M.D., Ph.D. Georgetown University, Neuroscience 2005
Current Research: Peter Turkeltaub is a cognitive neurologist and neuroscientist whose research investigates the brain’s organization for language and other cognitive faculties, how this organization changes in the context of developmental or acquired brain disorders, and how we might enhance recovery. The work is conducted using healthy volunteers and individuals with developmental and acquired language disorders. We use a variety of techniques, primarily TMS, tDCS, fMRI, neuroimaging meta-analysis, and neuropsychology. We aim to expand our methods to include voxel-based lesion analysis, combined tDCS/fMRI, and combined TMS/EEG. A key aim of the laboratory is to develop new treatments for language disorders and translate these treatments to the bedside.
Professor, Department of Neuroscience
Brain and Language Lab
Office: Building D, 237
Lab: Building D, 237
Education: Ph.D. MIT, 1993
Current Research: Dr. Ullman’s research investigates the neural and computational bases of both first and second language, how language and memory are affected in various disorders (e.g., autism, Tourette syndrome, Specific Language Impairment, Parkinson’s disease, Alzheimer’s disease), and how factors such as sex (male vs. female), handedness (left vs. right), genetic variability, and hormones (e.g., estrogen) affect the neurocognition of language and memory.
Professor, Department of Physics
Dynamics Imaging Laboratory
Office: Regents Hall 320
Lab: Regents Hall 333
Education: Ph.D Stanford, Physics, 1993
Current Research: Dr. Urbach has been actively involved in a broad range of interdisciplinary research and training activities. A physicist with a background in materials science and nonlinear dynamics, he began collaborative work in neuroscience over a decade ago. His recent research has focused on using advanced materials fabrication and live cell imaging technologies to elucidate the role of mechanical and structural cues in axon outgrowth and guidance, with the goal of developing novel strategies to engineer nerve regeneration after injury.
Professor, Psychology; Investigator at Children’s National Medical Center
Developmental Cognitive Neuroscience Laboratory
Office: White Gravenor, 401
Education: Ph.D. Syracuse University, Developmental Psychology
Current Research: Dr. Vaidya’s research program is focused upon characterizing the functional neural architecture of adaptive mechanisms during the life span. Her research focuses on two types of adaptive mechanisms – 1) Processes that require little effort such as learning from environmental regularities without intention or conscious awareness (termed implicit memory and learning); and 2) Processes that are effortful such as voluntary control over thoughts and actions (termed executive control). Further, her studies investigate how these adaptive mechanisms differ across individuals, particularly with respect to genetic functional polymorphisms of the dopamine system (e.g., DAT, COMT).
Director of CFMI; Associate Professor, Neurology
Center for Functional and Molecular Imaging
Office: Pre-Clin, Suite LM-14
Lab: Pre-Clin, Suite LM-14
Education: B.S. University of Oklahoma, 1987; M.S. Dartmouth College, 1991; Ph.D. Dartmouth College, 1993
Current Research: My research interests are varied but focus on the interaction of medial prefrontal cortex and the limbic system with regards to emotion regulation in disorders such autism and PTSD. My other area of focus is development and the effects of different environmental influences such as early alcohol initiation. As the Director of the neuroimaging center, I’m also involved in a number of other studies.
Professor, Pharmacology & Physiology
Vicini Lab (new window)
Lab of Cellular and Molecular Neurophysiology (new window)
Education: Ph.D., U Torino, Italy, 1979
Current Research: Using transgenic mice with the two major striatal output pathways labeled we are answering a fundamental question: What role tonic and phasic GABA and NMDA conductance plays in striatal disorders? We are studying the functional consequence of the activation of distinct dopamine receptors on NMDA and GABAa receptor subytpes.Our study has great potential to identify novel therapeutic targets for treating disorders associated with striatal dysfunction including Parkinson’s disease, Huntington’s disease, tardive dyskinesia, Tourette’s syndrome and drug addiction.
Office: BSB, 225
Lab: BSB, 228-230
Assistant Professor, Pharmacology and Physiology
Education: B.S., Biological Sciences, Tsinghua University, 2003; Ph.D., Neurobiology, Duke University, 2009
Current Research: The brain is incredibly complex and remarkably malleable in terms of developmental and learning-related plasticity. Homeostatic signaling systems act to stabilize the function of individual nerve cells and neural circuitry, thereby ensuring robust and reproducible brain function and behavior throughout life. My laboratory investigates the molecular mechanisms that underlie the homeostatic control of the nervous system. We are particularly interested in the intercellular signals that convey information between different types of cells during homeostatic plasticity. We use an array of electrophysiological, imaging, molecular and genetic tools in Drosophila melanogaster and mice to address:
- What is the signaling function of glia in synaptic homeostatic plasticity?
- How does dynamic regulation of extracellular matrix (ECM) and adhesion molecules modulate synaptic transmission?
- How do genetic mutations and failed homeostasis contribute to neurological and psychiatric diseases, such as epilepsy and autism spectrum disorders?
Professor, Oncology & Pharmacology
Office: Lombardi Cancer Center
Education: M.D. J.Gutenberg-University, Mainz, Germany, 1973; Ph.D. J.W. Goethe-University, Frankfurt, Germany, 1985
Current Research: My laboratory has been centered around angiogenesis factors released from tumor cells as molecularly defined therapeutic targets. We have purified a novel heparin-binding polypeptide growth factor (pleiotrophin, PTN) from supernatants of breast cancer cells and cloned the respective genomic and cDNA. The respective protein is secreted from different human tumor cells, is expressed in a number of primary human tumors (breast, prostate and lung cancer and melanoma), and can function as an angiogenesis factor. Since this gene is normally only expressed at appreciable levels during embryonal development, we have been interested in the mechanisms depression during the malignant process and have charactered different promoter and enhancer elements as regulators of the gene. In addition, we have generated different cell lines overexpressing the pleiotrophin gene to obtain defined targets for in vitro and in vivo studies of drugs that inhibit this gene product and have targeted the transcript with ribozymes. Finally, we have generated sufficient amounts of recombinant pleiotrophin protein to characterize signal transduction and clone a candidate receptor cDNA by expression screening.
The laboratory applies numerous different molecular techniques involving DNA, RNA as well as proteins in mammalian and other eukaryotic cells, including extensive cell biology, protein and RNA detection in cells and tissues, gene cloning, regulation and expression studies. Cellular or animal models of development/differentiation and diseases, human tissue or bodily fluid samples from patients are used. PhD students in the laboratory would be able to chose the appropriate technique to answer the question being asked in their research.
Laboratory of cortical dynamics
Office: Basic Science 207A
Lab: Med-Dent SE101-105
Education: M.A., Ph.D, Peking University, 1983, 1986
Current Research: We use voltage-sensitive dyes to visualize cortical neuronal activity and spatiotemporal dynamics of populational neuronal activity. Brain functions are carried out by the activation of large number of neurons. Spatiotemporal patterns such as oscillations and propagating waves are frequently seen during normal brain function such as sensory processing, motor planing, thinking, sleeping and a variety of pathological conditions such as epilepsy and Pakinsons. We study wether wave patterns ( such as spirals and wave compressions) contribute to normal and pathological processes in the cortex. Our ultimate goal is to understand how the functions of the cortex emerge from the organized activity of large number of neurons.
Robert P. Yasuda
Assistant Professor, Pharmacology & Physiology
Office: Med-Dent SW407
Lab: Med-Dent NE411
Education: Ph.D. University of Colorado, 1986
Current Research: My laboratory is involved in the study of the structure and function of neuronal nicotinic receptors in the brain that are composed of five protein subunits that act as ligand-gated ion channels. These receptors are thought to be involved in the ncotine addition seen in smokers. We utilize molecular biological, biochemical and electrophysiological methods to study these receptors. Specifically, we are interested in understanding the nature of the nicotine binding site and how the order of these nicotinic receptor subunits affects function. One approach we are currently using is the creation of concatamers of the nicotinic receptor subunits that allow us to make receptors composed of subunits of known order and composition.
Affiliate Faculty: available as co-mentors or thesis committee members
Office: 3-PHC 3004F
Lab: 3-PHC 3004F
Education: M.D. University of Manitoba, Canada, 1981
Current Research: Our mission is to improve the lives of our patients who suffer from Chronic Fatigue Syndrome, Gulf War Illness, and other idiopathic conditions. We aim to understand the underlying mechanisms that lead to the chronic nature of pain and fatigue through: Non-invasive functional magnetic resonance imaging (fMRI) brain scans, Serial changes in bodily fluids following a physiological stressor, Alterations in autonomic control.
Georgetown Early Learning Project
Office: 301A WGR
Lab: 413 WGR
Education: Ph.D. Otago, Psychology, 1999
Current Research: Learning in context. I study the transfer of learning as a function of environmental conditions. I have a line of research examining learning from television, books and touchscreens during infancy and early childhood. I also study how bilingual exposure influences transfer of learning.
Office: NRB EP-04B
Education: Ph.D. Ohio State University, Pharmacology, 1977,
Current Research: Dr. Bayer’s research is focused on cellular and molecular mechanisms by which the brain communicates with circulating cells of the immune system. Current studies are focused on identifying specific cellular markers in circulating immune cells which predict the overall vulnerability of the immune system to a repeat exposure to stress and centrally acting drugs. These studies utilize a variety of multidisciplinary approaches including molecular and cellular based assays, genomics, pharmacological strategies, neurological imaging and quantitative histological methods.
Chief, Human Cortical Physiology and Stroke Neurorehabilitation Section, NINDS, NIH
Education: M.D. University of BsAs, Argentina
Current Research: The goal of our research is to understand the mechanisms underlying plastic changes in the human central nervous system and to develop novel therapeutic approaches for recovery of function after stroke and traumatic brain injury based on these advances. Our work focuses on the human motor system and on motor learning in health and disease. Our research protocols in healthy volunteers intend to gain insight into mechanisms of human neuroplasticity and motor learning, particularly the ability to retain newly learned skills over time. Advances in this understanding in healthy volunteers are subsequently applied to patients with neurological conditions like stroke and traumatic brain injury to facilitate neurorehabilitative processes. We are engaged in translational efforts to develop rational rehabilitative interventions to improve motor disability after stroke and traumatic brain injury using peripheral nerve stimulation, TMS and tDCS and brain computer interface to control grasping motions of orthosis attached to paretic hands, leading to modulation of neural activity in relevant neural networks.
Associate Professor, Center for Neuroscience Research
Joshua Corbin Laboratory
202 476 6281
Office: Children’s National Medical Center
Lab: 6th Floor, Children’s National Medical Center
Education: B.A. Rutgers University; Ph.D. University of North Carolina-Chapel Hill
Current Research: The Corbin lab studies the genetic and cellular basis of the normal and abnormal development of the mammalian amygdala. Despite an extensive understanding of amygdala function and anatomy, currently little is known regarding the development of this complex structure, and how altered development of the amygdala contributes to the phenotypes observed in developmental disorders such as Autism Spectrum Disorders and Fragile X Syndrome. To address these questions, we use the mouse as an experimental model, employing both standard and cutting edge embryological, transgenic, electrophysiological and optogentic approaches. The ultimate goal of the studies in our lab is to understand the link between developmental events and the assembly of the mature amygdala at a genetic, cellular, structural and functional level.
Alexander W. Dromerick
Professor, Vice Chair, Rehabilitation Medicine (primary),
NRH Neuroscience Research Center
Office: National Rehabilitation Hospital
Lab: Research Division
Education: M.D. University of Maryland, 1986
Current Research: My research focuses on human subjects research in people with stroke and arm amputation. I use clinical populations to ask questions about the nature of motor recovery or acquisition of prosthesis skill, changes in brain physiology, and alterations in health-related behaiviors. Techniques used include clinical trials, neuroimaging, upper extremity biomechanics, transcranial magnetic stimulation, and measurement methodology. I collaborate with colleagues at National Rehabilitation Hospital, Georgetown University, Catholic University, and nationally.
Investigator, Advanced MRI Section, LFMI, NINDS, NIH
Office: Building 10, Room B1D-724, NIH
Lab:Building 10, Room B1D-728, NIH
Education: Ph.D. University of Delft, Holland, Physics
Current Research: In addition to providing structural information, MRI has the potential to non-invasively map physiologic parameters and function. Our research focuses on optimally exploiting this potential by investigating the mechanisms behind MRI contrast, exploring avenues to manipulate the contrast, and optimizing MRI data acquisition and analysis to achieve optimum sensitivity, resolution, reliability, and accuracy. Specific aims are the development of MRI techniques for the measurements of structural anatomy, tissue metabolism, tissue perfusion, and the spatial distribution of brain activity. Recent work has focused on high field MRI technology, the magnetic properties of brain tissue, and the study of spontaneous brain activity.
Senior Investigator, Developmental Neurobiology Section, NIH
Office: Building 10, Room 7N218, NIH
Education: Ph.D. Case Western Reserve University, 1970
Current Research: Research in the Geller laboratory focuses on understanding the mechanisms that control axonal growth and pathfinding, both during neural development and to stimulate regeneration after injury to the brain or spinal cord. Dr. Geller’s laboratory is evaluating the mechanisms by which astrocytes provide directional cues for neuronal processes, focusing on the behavior of the growth cones at their tips as they encounter molecular boundaries. Molecules secreted into the extracellular matrix by astrocytes may be permissive or inhibitory for growth and guidance. Collaborative studies are focused at understanding how neuronal guidance is affected by physical rather than chemical cues. Together they have demonstrated that neurite outgrowth can be controlled by the stiffness of the substrate, with different neuronal populations responding to different stiffness. Whether stiffness can be used to control directional outgrowth is an area of current investigation. In addition, the laboratory is investigating how physical cues (stiffness and structural confinement of growth) can affect the response of the neurons to CSPGs.
Chief, Neuroethics Studies Program, Pellegrino Center for Clinical Bioethics
Office: Bldg D, Rm 238
Education: Ph.D. City University of NY, Biopsychology, 1986
Current Research: Studies of neural bases of human ecology and moral decisions and action; studies of ethical issues arisisng in and from neuroscientific and neurotechnological research and applications in medicine, public life and national security and defense. Neuroscience of chronic pain, analgesia and pain care (specifically, role of serotonin 5-HT3 receptor system in inflammatory pain).
Professor, Oncology, Biochemistry and Molecular & Celluar Biology
Office: NRB E207
Lab: NRB E207
Education: Ph.D. Univ. of Pittsburgh, Toxicology, 1996
Current Research: Neurotrophins in neurodegeneration and cancer, ABC transporters and lipoproteins
Research Assistant Professor
Center for Brain Plasticity and Recovery
Office: Bldg D, Suite 145, Room F
Education: Ph.D. University of Giessen, Germany, Psychology, 2009
Current Research: Dr. Greenwald’s research employs behavioral and magnetic resonance imaging (MRI) methods to investigate specific cognitive functions (e.g., visuo-spatial cognition, language, attention) and their functional neuroanatomy. She works with patients who have acquired brain injury at different points in life (e.g., stroke during the perinatal period, during childhood, or in adulthood) as well as neurologically healthy controls. Her long-term goal is to improve assessment tools and rehabilitation options for patients with cognitive impairments.
Research Assistant Professor, Neuroscience
Laboratory of Integrative Neuroscience and Cognition
Office: NRB WP15
Lab: NRB WP23, RRF G33/34, G32, G22
Education: Ph.D., Nencki Institute Warsaw, Poland, Neuroscience, 2004
Current Research: Organization of cortical processing of auditory stimuli, studied with fMRI and single-unit recordings in non-human primates. Processing stimulus identity and meaning in auditory ventral stream. Auditory-motor integration in the dorsal stream. Gating and control of auditory input.
Professor, Psychiatry, Howard University College of Medicine
NAAG Peptidase Inhibitors as Therapeutic Drugs
Office: 520 W St. NW, Ste 533
Education: M.D. Case Western Reserve School of Medicine, 1982
Current Research: Much of his research and publications have addressed the role of sleep disturbance in the pathogenesis and treatment of PTSD. His current RO-1 research studies patients who are being treated for traumatic injuries and includes early sleep recordings and longitudinal assessment of PTSD. This work has led to several recent publications of sleep-related and other predictors of the early development of PTSD.
Office: Georgetown University Hospital, PHC 7
Education: M.D. Tehran University of Medical Sciences, 1987; Internship, Yale, 1994; Residency, Baylor, 1998; Fellowship, Johns Hopkins, 2001
Current Research: In drug-resistant (refractory) epilepsy the alternative option is limited to surgery however, this is not always a viable option. We explore the potential therapeutic effects of novel modalities in particular hypothermia and cortical stimulation for these patients. We study the effects of hypothermia (cooling) in slice models of epilepsy in Dr. Stefano Vicini’s laboratory. We have shown that cooling can terminate epileptiform discharges in these models with no discernible tissue damage. We have explored the cellular mechanisms of action of hypothermia in particular a possible differential effect on interneurons vs. pyramidal cells. We are also studying the role of high frequency oscillations (HFOs) in epilepsy and cognitive processing. We plan to investigate the potential disease modifying (antiepileptogenic) effects of hypothermia with the goal of establishing a Georgetown Center for Advanced Epilepsy Research in collaboration with Drs. in Drs. Jian Yong Wu, Andrei Medvedev, Patrick Forcelli, and outside investigators. We are also exploring the characteristics of seizure onset focus and epileptogenesis as well as the possibility of using cortical stimulation for treatment of insomnia.
Distinguished Professor, Biology
NAAG Peptidase Inhibitors as Therapeutic Drugs
Office: Reiss, Main Campus, 407
Lab: Reiss, Main Campus, 425
Education: B.S. Georgetown University, 1966; Ph.D. Georgetown University, 1970
Current Research: Our lab has pioneered the characterization of NAAG as the 3rd most prevalent transmitter in the mammalian nervous system.We identified the receptor that NAAG activates (mGluR3) and cloned the peptidase enzymes that inactivate it following synaptic release. In collaboration with colleagues in the medical center at Georgetown, we developed potent inhibitors of these enzymes and have applied these inhibitors in animal models of significant clinical conditions including schizophrenia, inflammatory and neuropathic pain and traumatic brain injury. We continue to study the neurobiology of NAAG n cell and molecular studies and using mice that are null mutant for the enzymes and this receptor and to characterize additional NAAG peptidase inhibitors aiming at providing proof of concept of the clinical importance of these drugs. We have actively collaborated with colleagues in the medical center over the past 20 years.
Education: M.D. University of Wisconsin Medical School, 2005; Ph.D. University of Wisconsin, 2005; Internship, New York Presbyterian Hospital – Cornell, 2006; Pediatric Neurology Residency, New York Presbyterian Hospital – Cornell, 2010; Sleep Fellowship, Northwestern Memorial Hospital, 2011
Current Research: I currently have two lines of research. My primary research interest involves investigating frontal lobe abnormalities in children with temporal lobe epilepsy. Specifically using neuropsychological testing to characterize these abnormalities as well as fMRI to understand the functional network abnormalities that underlie this frontal lobe dysfunction. My secondary research interest involves examining the effect of sleep on concussion and associated cognitive dysfunction.
Associate Professor, Pharmacology
Office: BSB 235
Lab: BSB 230
Education: B.S. Xavier, 1993; Ph.D. Vanderbilt, 2000
Current Research: My varied research interests include determining the mechanisms governing synaptic transmission in the dorsal striatum using electrophysiological, genetic and biochemical methods. The striatum is a crucially important brain region involved in the smooth execution of motor control and other various functions. Disruptions in striatal physiology result in debilitating motor problems exemplified by Parkinson’s disease and Huntington’s disease. My research goals are to more fully understand the complex interactions of small molecule neurotransmitters in the striatum. These include investigating the relationships and crosstalk among glutamate, dopamine, acetylcholine and endocannabinoids governing normal and pathological states which dictate striatal output.
Associate Professor, Pharmacology
Office: MedDent 410NW
Lab: MedDent 412NW
Education: Ph.D. University of Sheffield, England, Neuroscience, 1990
Current Research: The emphasis of research in my laboratory is on understanding the brain neurocircuits that regulate the function of the upper gastrointestinal tract such as those that control gastric tone and motility. To this end, we employ varied approaches that include microinjection of chemical substances in the brain, recordings of end organ function, patch-clamp electrophysiology in brain slices and neuroanatomical tract tracing.
Raymond Scott Turner
Memory Disorders Program
Office: 202B Bldg. D
Lab: 268 Bldg. D
Education: M.D., Ph.D. Emory Univ., 1988
Current Research: Active and passive immunization strategies for transgenic Alzheimer’s disease (AD) mouse models. Molecular mechanisms, therapeutic effects on memory/behavior and on CNS neuropathologies, and neuroinflammatory effects. Role of ApoE genotype on immunotherapies by using hApoE knock-in AD transgenic mice.
Barry B. Wolfe
Office: SW407 Med-Dent
Lab: NE411 Med-Dent
Education: B.S. UCLA, 1967; M.S. CSUN, 1969; Ph.D. U.C. Santa Barbara, 1973
Current Research: Recent projects have focused on the metabotropic glutamate receptor 1 (mGlu1 R). mGlu1 R are normally expressed in neurons, most highly in the cerebellum. However, in collaboration with other researchers in our Department, we have found that the mGlu1 R is an oncogene and is ectopically expressed in many cancers. The cancer cells, when they over-express the mGlu1 R, become dependent or ‘addicted’ to the stimulation via this receptor. Recent graduate students have shown that blocking this receptor, or silencing its gene, results in dramatic decreases in the rate of growth of tumors. Current and future experiments will focus on discovering the mechanism(s) by which this receptor stimulates cancer cell growth as well as the development of high-throughput assays to screen for drugs that negatively regulate this receptor.
Principal Investigator, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, NIH
Functional and Restorative Neurosurgery Section, NIH
Office: National Institutes of Health: Bldg 10 – Room 3D20
Education: M.D., Ph.D. University of Pennsylvania, 2003
Current Research: Our lab exploites the unique investigative opportunities provided by intracranial recordings during neurosurgical procedures. Using electrodes captured from epilepsy patients implanted with subdural and depth electrodes, we investigate the activation of cortical networks during memory encoding and recall. And using recordings captured during the implantation of deep brain stimulators, we investigate the role of the basal ganglia in learning and decision-making.