Kristina Nielsen, Ph.D.

  • Associate Professor of Neuroscience

Research Interests

Neural circuits underlying object recognition


Dr. Kristina Nielsen is an assistant professor of neuroscience at the Johns Hopkins University School of Medicine. Her research focuses on the neural circuits underlying object recognition. Dr. Nielsen is a researcher at the Zanvyl Krieger Mind/Brain Institute at Johns Hopkins.

Dr. Nielsen’s team is currently using two-photon microscopy to perform high-resolution functional imaging of visual areas in the non-human primate. The goal of their research is to reveal the fine scale organization of these circuits, with an emphasis on higher level visual areas.

Dr. Nielsen earned her Ph.D. from the Max Planck Institute for Biological Cybernetics in Tübingen, Germany. There, she conducted research in the lab of Nikos Logothetis, investigating the encoding of objects and object parts in the inferotemporal cortex. In 2006, she joined the labs of Ed Callaway and Rich Krauzlis at the Salk Institute in La Jolla, California, as a post-doctoral fellow. Her post-doctoral work focused on two techniques that allow the study of the function of neural circuits in vivo with a high degree of specificity: viral vector-based approaches and two-photon microscopy. more


  • Associate Professor of Neuroscience

Departments / Divisions

Centers & Institutes



  • Ph.D.; Eberhard Karls University of Tubingen (West Germany) (2005)
  • B.S.; Philipps Universitat Marburg (Germany) (2000)

Research & Publications

Research Summary

Dr. Nielsen's laboratory investigates the neural circuits in the visual cortex that are responsible for encoding objects. In the primate brain, a series of visual areas are involved in object recognition, with different areas extracting different features from the objects in a visual scene. These areas are organized in a hierarchical manner: While lower level areas encode simpler object features such as the orientation of edges, higher level areas respond to more complex features such as parts of objects or even entire objects such as faces.

To a large extent, researchers know which features are represented where, but to understand how object features are encoded, they need to understand the organization of the neural circuits that comprise and connect these areas. Dr. Nielson's lab aims to reveal the fine-scale organization of these circuits, with an emphasis on higher-level visual areas. They use two-photon microscopy to perform high-resolution functional imaging of visual areas in the non-human primate. They also investigate how the function of higher visual areas changes over the course of brain development in ferrets, by measuring the activity of single neurons in these areas, as well as determining the animal’s visual capabilities at various developmental stages.


Lab Website: Kristina Nielsen Laboratory

Selected Publications

Nauhaus I, Nielsen KJ, Disney AA, Callaway EM. "Orthogonal micro-organization of orientation and spatial frequency in primate primary visual cortex." Nat Neurosci. 2012 Dec;15(12):1683-90. doi: 10.1038/nn.3255. Epub 2012 Nov 11. Erratum in: Nat Neurosci. 2013 Dec;16(12):1907.

Nielsen KJ, Callaway EM, Krauzlis RJ. "Viral vector-based reversible neuronal inactivation and behavioral manipulation in the macaque monkey." Front Syst Neurosci. 2012 Jun 19;6:48. doi: 10.3389/fnsys.2012.00048. eCollection 2012.

Nauhaus I, Nielsen KJ, Callaway EM. "Nonlinearity of two-photon Ca2+ imaging yields distorted measurements of tuning for V1 neuronal populations." J Neurophysiol. 2012 Feb;107(3):923-36. doi: 10.1152/jn.00725.2011. Epub 2011 Nov 23.

Marshel JH, Mori T, Nielsen KJ, Callaway EM. "Targeting single neuronal networks for gene expression and cell labeling in vivo." Neuron. 2010 Aug 26;67(4):562-74. doi: 10.1016/j.neuron.2010.08.001.

Nielsen KJ, Logothetis NK, Rainer G. "Object features used by humans and monkeys to identify rotated shapes." J Vis. 2008 Feb 22;8(2):9.1-15. doi: 10.1167/8.2.9.

Academic Affiliations & Courses

Graduate Program Affiliation


Activities & Honors


  • Synergy Award, The Johns Hopkins University School of Medicine, 2017
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