People

faculty

James Knierim

James Knierim

Professor of Neuroscience

337 Krieger Hall
Office: 410-516-5170 | Lab: 410-516-5292
jknierim@jhu.edu

Research Interests: Behavioral Neurophysiology of the Hippocampal Formation

assistant research scientists

Heekyung Lee

Heekyung Lee

Heekyung@jhu.edu

Research Interests: The hippocampus plays an important role in memory formation, storage, and retrieval. In particular, the CA3 subregion of the hippocampus has received attention for its potential role in associative memory because of its strong recurrent circuitry. Using electrophysiological approaches, my current research is focused on understanding the neural computation in the CA3 subregion, in both young and aged animals.

postdoctoral fellows

Teruko Danjo

Teruko Danjo

teruko@jhu.edu

Research Interests: Roles of interregional communications within the hippocampal network

William Hockeimer

William Hockeimer

whockei1@jhmi.edu

Research Interests: Electrophysiological data from the hippocampus has revealed that individual neurons called place cells are active in certain spatial locations and that this activity can be modulated by the the non-spatial, sensory cues present. This has led to a theory called the Cognitive Map Theory which proposes that memories about our experiences are encoded in terms of the locations in which they took place. My project seeks to provide a direct test of an idea regarding how the Cognitive Map could be constructed at the neural level. A hypothesis termed the

Yueqing Zhou

Yueqing Zhou

zhouyq@jhu.edu

Research Interests: Exploratory-related head-scanning predicts the generation of new place fields or the potentiation of existing place fields in hippocampus. Combing MFB stimulation and in-vivo one-photon calcium imaging techniques, my project focus on understanding how reward contributes to the head-scanning behavior and formation or potentiation of place fields in rats. Ring attractors are a class mechanistic model of internal dynamics underlying the head-direction (HD) system. By recording retrosplenial cortex in Dome which developed by Knierim Lab, my work also focus on providing evidence to understand whether the ring attractor models are compatible with brain anatomy and physiology in the ability of these allothetic inputs to control the activity hill in cases where the animal is disoriented or when there is a conflict between different sources of allothetic directional information.

graduate students

Yuxi Chen

Yuxi Chen

ychen315@jhmi.edu

Research Interests: Yuxi Chen is a neuroscience PhD student. She worked on the neural basis of sensorimotor sequence generation as an undergrad and now looks forward to a hippocampal adventure in the Knierim lab.

Bharath Krishnan

Bharath Krishnan

bharath@jhmi.edu

Research Interests: The medial Entorhinal Cortex (MEC) is a region in the temporal lobe of the brain that is perhaps most well-known as the place where grid cells were first discovered. Apart from being home to grid cells, this region contains a plethora of other cell types with very interesting properties such as border cells, speed cells, object-vector cells etc. As one the primary inputs to the hippocampus, the MEC is thought to provide an allocentric representation of space and comprise the neural substrate for path-integration. The goal of my project is to understand the specific computations performed in the MEC with the help of electrophysiological recordings performed in the Dome apparatus. Learning more about how MEC cells respond to 'recalibration' of the path integrator could shed more light on how this vital region contributes to the formation of our perception of the world around us.

Pel Ozel

Pel Ozel

pozel1@jhu.edu

Research Interests: Pelin Ozel is a grad student in the neuroscience department. Prior to joining the Knierim lab, she studied head direction cells during 3D navigational tasks. Now, she is working with silicon probes and Neuropixels to study place field formation and potentiation in the hippocampus. Broadly, she is interested in how non-spatial stimuli (such as rewards and visual information) can be integrated into the cognitive map model.

Vyash Puliyadi

Vyash Puliyadi

vyash.puliyadi@jhu.edu

Research Interests: The lateral entorhinal cortex is one of the major inputs into the hippocampus and appears to particularly vulnerable in both aging and Alzheimer’s disease. In Alzheimer’s disease, there is significant neuronal loss and synaptic loss observed, early in disease progression. Similar findings have been observed in naturally aged Long Evans rat model of aging. In a collaboration with Michela Gallagher, my work in this area focuses on examining the single-unit activity of neurons in the lateral entorhinal cortex to unveil what kinds of information the lateral entorhinal cortex may conveys to the hippocampus and how it may be altered by the structural and molecular changes that occur during aging.

undergraduate students

lab staff

Geeta Rao

Geeta Rao

Lab Manager

geetarao@mail.mb.jhu.edu

Research Interests: Intermittent locomotion, exploration consisting of alternating bouts of forward progression and pauses, is a ubiquitously observed behavior. During the pauses in locomotion, rats engage in scanning behavior, consisting of lateral or vertical head movements, presumably to investigate environmental features. We have previously shown that increased neural activity during head scanning predicted the formation and potentiation of place fields on the next pass through that location (Monaco et. al, 2014.) This phenomenon may reflect single-trial encoding of non-spatial information onto a spatial framework, a hallmark of episodic memory. We plan to further characterize scan-related hippocampal place cell firing and field potentiation in hippocampal CA1 and CA3 subfields. We are also currently examining whether changes in scanning behavior and scan-related hippocampal cell firing may contribute to cognitive spatial deficits observed in old animals. Whether scan potentiation of place fields in old animals occurs is a particularly intriguing question that we will be addressing in the near future with further data acquisition. Whether firing during scanning behavior signals particularly salient locations in the environment, such as reward encounters, is a further avenue of investigation.

collaborators

Noah Cowan

Associate Professor, Department of Mechanical Engineering, Johns Hopkins University

Kathleen Cullen

Professor, Department of Biomedical Engineering, Whiting School of Engineering

Shahin Gharakozlou Lashkari

Graduate Student, Department of Mechanical Engineering, Johns Hopkins University

Katie Hedrick

Assistant Professor, Dedman College of Humanities & Sciences, Southern Methodist University

Ravikrishnan Jayakumar

Postdoctoral Fellow, Department of Mechanical Engineering, Johns Hopkins University

rperurj1@jhu.edu

Sang Hoon Kim

Postdoctoral Research Fellow, University of Pennsylvania

Gorkem Secer

Postdoctoral Fellow, Engineering Research Center, Johns Hopkins University

gsecer1@jhu.edu

Hongjun Song

Professor, Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania

Kechen Zhang

Associate Professor of Biomedical Engineering and Neuroscience, Johns Hopkins University School of Medicine

former lab members

Xiaojing Chen

Assistant Professor, South University of Science and Technology, Shenzhen, China

Sachin Deshmukh

Assistant Professor, Center for Neuroscience, Indian Institute of Science, Bangalore, India

Yoganarasimha Doreswamy

Associate Professor, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka

Marissa Ferreyros

Doug Goodsmith

Postdoctoral Research Fellow, University of Pennsylvania

Eric Hargreaves

Deep Brain Stimulation Clinical Neurologist, Deep Brain Stimulation Program, Robert Wood Johnson University Hospital

Jeremy Johnson

Medical Student, Emory University

Inah Lee

Associate Professor, Laboratory for Behavioral Neurophysiology of Learning and Memory, Seoul National University

Leo Lee

Graduate Student, Johns Hopkins University

Nick Lukish

Research Technologist

Manu Madhav

Assistant Professor, School of Biomedical Engineering, Djavad Mowafaghian Centre for Brain Health, University of British Columbia

Joshua Neunuebel

Assistant Professor, Department of Psychological and Brain Sciences, University of Delaware

Eric Roth

Assistant Professor, Department of Psychology and Brain Sciences, University of Delaware

Francesco Savelli

Assistant Professor, Department of Biology, University of Texas at San Antonio

Jennifer Siegel

Postdoctoral Associate, Center for Learning and Memory, University of Texas-Austin

Arjuna Tillekeratne

Research Technologist

Horatiu Voicu

Scientific Programmer, Genomics and Proteomics Core Laboratory, Baylor College of Medicine

Cheng Wang

Principal Investigator, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China

Chia-Hsuan Wang

Xintian Yu

Scientific Programmer, Dept. of Neonatology, University of Texas-Houston