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Mitra J. Z. HartmannProfessor of Biomedical EngineeringProfessor of Mechanical EngineeringDirector of Graduate Studies for Biomedical Engineering

Dr. Hartmann's research focuses on the neurobiology and biomechanics of active sensing behaviors, and on the development of bio-inspired computational models and hardware to test candidate neurobiological algorithms. Our lab is particularly interested in how sensory feedback is used in real time to guide motor activity, and how movement enables sensory acquisition and perception. The main scientific interests of the lab are:

  • How animal biomechanics enables efficient movement and active sensing
  • How animals represent 3-dimensional spatial information using spatiotemporal variations in activity across 2-dimensional receptor sheets
  • How the construction of hardware and computer models of animal movement and sensing can provide insights into the underlying organization of the nervous system

Current research in the laboratory concentrates specifically on the sensory modulation of behaviors involving rhythmic movement, because rhythmic movement, and perturbations to it, is relatively easy to observe, measure, and quantify. We work with two model systems that use sensory feedback to modulate fundamentally periodic activity: rat whisking behavior, and bipedal locomotion. By studying how sensory feedback affects periodic motion, we hope to gain insight into the continuous, recursive interplay between sensory and motor signals during active behaviors.

The Sensory and Neural Engineering (SeNSE) Group

Whiskers and the sense of touch

The SeNSE group is part of the Center for Robotics and Biosystems, whose research focuses on robotics, neuroscience, and bio-inspired robotics.

Our sense of touch is mysterious. It is easy for you to reach into your pocket or purse and — without looking — identify your cellphone, keys, or a coin. Somehow, your brain combines information about your hand movements and the contacts that you make, to enable you to perceive a particular object.

The long term goal of our laboratory is to better understand how movement and touch are combined in the brain to enable perception.This type of research could ultimately help people disabled by stroke or brain injury.

We use rats as a model to study the sense of touch. Rats, however, don't use their "hands" (paws) very much to explore objects. Sometimes they do, but mostly they use their whiskers. If you've ever watched a rat run around, you'll notice that they're constantly touching their noses to objects. If you were able to use a slow-motion video camera to watch the rat, as our laboratory does, what you would see is that the rat is continuously brushing its whiskers against objects very rapidly, between 5 and 25 times a second. This behavior is called "whisking." The rat is touching different objects to figure out their location, size, shape, and texture. 

In broad terms, our work may be divided into three main research areas:

  • Quantifying and simulating whisking behavior: We use high-speed video to quantify rat whisking behavior, and we use computational models to quantify the contact patterns that whiskers make with different objects.
  • Understanding the mechanics of whiskers: We study the mechanics of whiskers in order to gain insight into how the rat's brain is able to interpret mechanical signals to determine object properties such as size, shape, and texture.
  • Constructing robotic models of the whisker system: We construct small robots with whiskers. These robots may find application in several different industries, and are an important investigative tool in neuroscience research.

Sensory data and the control of locomotion

We have become interested in how the nervous system might use sensory data from the feet, knees, and hips to help control walking. We have performed simulations of bipedal walking over rough terrain to demonstrate that actuation based on simple combinations of sensory inputs from the joints can lead to stable walking.

The Digital Rat: A 3D model of the rat head and vibrissal array

The Digital Rat represents our laboratory's efforts towards the development of a morphologically and mechanically accurate model of the rat head and vibrissal (whisker) array. The long-term goal is to develop a simulation environment that can be used to model the spatiotemporal patterns of mechanical input to vibrissae during the rat's tactile exploratory behaviors. Read more about the software here. 

Postdoctoral Scholar, Bio-Inspired Technology and Systems Laboratory
Jet Propulsion Laboratory, Pasadena, CA

Postdoctoral Scholar, Computational Neurobiology
California Institute of Technology, Pasadena, CA

Ph.D., Integrative Neuroscience
California Institute of Technology, Pasadena, CA

B.S., Applied and Engineering Physics
Cornell University, Ithaca, NY

Science Bytes 

An overview of whisking and whisker mechanics is shown in this video from Science Bytes. The video explains some basic mechanical principles, such as how stiffness and distance affect how much the whisker bends. The video also describes how the bending of the whisker underlies the rat's extraordinary sensing capabilities and explains some connections to future developments in robotics.

Science Friday 

This interview and video from National Public Radio's program Science Friday explains some ways our laboratory is investigating the sense of touch and sensorimotor integration. When a whisker bends against an object, forces and torques are generated at the whisker base. By quantifying these mechanical signals we are able to begin to understand what information the brain is receiving.

General Public

Media, Tours, Public Talks

Work from our lab has been featured in several media outlets 

We also give tours to elementary, middle and high schools students. Each academic year, we reached out to a couple hundreds of students from different parts of the country, including high school students attending the National Student Leadership Conference, high school students from North Lawndale College Prep in Chicago, and incoming freshmen in Northwestern's EXCEL program.

Northwestern University Brain Awareness Outreach

NUIN PhD students Chris Bresee, Nick Bush, and Admir Resulaj all actively volunteer for Northwestern University Brain Awareness Outreach (NUBAO). NUBAO is an organization led by graduate students that puts on numerous events every year designed to engage and excite the public about the brain and neurosience research. NUBAO events include: the annual Brain Fair which usually attracts over 500 guests and involved over 80 volunteers, the annual Teachers Workshop where graduate students help Chicago Public School teachers bring neuroscience into their classrooms, and a seminar series at Walter Payton High School where graduate students give bi-monthly lectures about a neuroscience topic related to their own research. 

Robot Revolution at the Museum of Science and Industry, Chicago

PhD Students Lucie Huet and Anne Yang are featured in one of the “Into the labs” video clips at Robot Revolution , on exhibit at the Museum of Science and Industry in Chicago from May 21, 2015 to January 3, 2016. In the video, Lucie gives a brief introduction of our sensing robot inspired by rat whiskers.

National Robotics Week at the Museum of Science and Industry, Chicago

Mitra Hartmann gave a public talk titled "Rodents and Robots and Whiskers, Oh My!" during National Robotics week at Chicago's Museum of Science and Industry


Take Our Sons and Daughters to Work

Members in the Hartmann Lab volunteered in the 22nd annual Take Our Daughters and Sons to Work Day, which was open to friends and relatives ages 8 through 16 of Northwestern University faculty and staff members. Our lab presented the topic, "Touch & Movement: It’s electric!". We showed students how our nervous system communicates with electrical signals and how electrical stimulation relates to our sense of touch and ability to move about. The interactive setup ranged from sensing technologies to prosthetics to music.

Downers Grove North Lectures

On Mar 6 2015 and Mar 11 2016, PhD student Nick Bush was invited out to Downers Grove North High School to give talks to advanced high school biology students. This year he gave his lecture to 6 high school classes. The talk focused on the fundamentals of neural encoding and sensorimotor systems. The talk also describes the day to day responsibilities of researchers, and how to pursue a scientific career, with the hopes of inspiring incoming college students to get involved in research.

Mentorship Opportunities for Research Engagement

Graduate student Pravin Kumarappan is the communications coordinator for Mentorship Opportunities for Research Engagement (MORE) , an organization that provides graduate students and post-docs opportunities to mentor high school students in science, technology, engineering, and math (STEM). This organization grew out of the partnership with Niles West High School where students participate in high level STEM research under the mentorship of NU graduate students.

Career Day for Girls

PhD Students Chris Bresee, Lucie Huet, and Anne Yang gave laboratory tours during Career Day for Girls on February 28th, 2015 and February 27th, 2016. Students were shown rat whisking behaviors and simulations, robotic whisker controllers, and were able to look through a microscope to observe whisker follicles and muscles at high resolution. Career Day for Girls is held annually by McCormick and Society for Women Engineers. Each year about 300 middle school and high school students attended from the greater Chicago area.


Northwestern Robotics Club

Prof. Mitra Hartmann is the faculty advisor to the Northwestern Robotics Club. The club has ~50 active members who work on a variety of projects that range from constructing a robotic lacrosse goalie to participating in the University Rover Challenge. The club also holds workshops and classes for beginning students, for example, in 2014-15 the club held tutorials on 3D printing, basic electronic circuits, and ROS programming. Visit us on FacebookTwitter

Excel Leadership Program

PhD Students Lucie Huet and Hayley Belli were mentors for Northwestern's Excel Leadership Program. The Northwestern EXCEL program, run in conjunction with BioEXCEL and ChemEXCEL, invites incoming mechanical engineering freshmen from underrepresented populations to experience Northwestern for a summer, where they live in the dorms and take versions of the courses they will take in the fall. Lucie and Hayley designed and co-taught the Engineering Analysis I (EA1) course.PhD student Nick Bush co-presents with Stephanie Naufel from BME for the bioEXCEL group. This presentation focuses on the fundamentals of how the brain and nervous system take in information from its surrounding – specifically through touch—and subsequently creates motor commands to elicit movements. The talk focuses on the electrical properties of the nervous system.

Undergraduate Mentoring and Advising

PhD Student Lucie Huet mentored an undergraduate mechanical engineering student from the student’s sophomore year through her senior year at Northwestern. They were paired through the Northwestern University chapter of the Society for Women Engineers, and they met regularly to discuss all aspects of undergraduate and graduate student engineering life and academics.PhD Student Hayley Belli serves as the Assistant Master at Slivka Residential College for Science and Engineering. In this role, Hayley plans STEM-related academic and social programming for current Northwestern University undergraduate students.


McCormick Graduate Leadership Council

PhD Student Hayley Belli volunteers with the McCormick Graduate Leadership Council (MGLC), which organizes social, academic, and professional development opportunities for Master’s and PhD students in the McCormick School of Engineering and Applied Sciences.

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