Martha Streng

Ph.D. 2017

E-MAIL: stren021@umn.edu

Thesis Title:

Encoding and control of motor prediction and feedback in the cerebellar cortex

Current Position:

Postdoctoral Associate with Dr. Esther Krook-Magnusen, University of Minnesota.

UNDERGRAD INSTITUTION AND MAJOR:
Mount Holyoke College, B.A. in Neuroscience and Behavior, 2012

GRADUATE ADVISOR
Timothy Ebner, M.D., Ph.D., Department of Neuroscience

THESIS COMMITTEE MEMBERS

DESCRIPTION OF GRADUATE RESEARCH

Extensive research implicates the cerebellum as a forward internal model that predicts the sensory consequences of motor commands and compares them to their actual feedback, generating prediction errors that guide motor learning. However, lacking is a characterization of how information relevant to motor control and sensory prediction error is processed by cerebellar neurons. Of major interest is the contribution of Purkinje cells, the primary output neurons of the cerebellar cortex, and their two activity modalities: simple and complex spike discharges. The dominant hypothesis is that complex spikes serve as the sole error signal in the cerebellar cortex. However, no current hypotheses fully explain or are completely consistent with the spectrum of previous experimental observations.

To address these major issues, I recorded Purkinje cell simple and complex spike activity during a pseudo-random manual tracking task requiring the continuous monitoring and correction for errors. During tracking, complex spikes trigger robust and rapid changes in the simple spike modulation with limb kinematics and performance errors. Additionally, complex spikes are not evoked as a result of a specific ‘event’ as has been previously suggested. Instead, complex spikes are modulated predictively with behavior. Together, this suggests a novel function of complex spikes, in which climbing fibers continuously optimize the information in the simple spike firing in advance of changes in behavior.

I also implemented two manipulations of visual feedback during pseudo-random tracking were implemented to assess whether disrupting sensory information pertinent to motor error prediction and feedback modulates simple spike activity. During these manipulations, the simple spike modulation with behavior is consistent with the predictive and feedback components of sensory prediction error. Together, this thesis addresses a major outstanding question in the field of cerebellar physiology and develops a novel hypothesis about the interaction between the two activity modalities of Purkinje cells.

RESEARCH CATEGORIES

  • Behavior and Cognitive Neuroscience
  • Computational Neuroscience
  • Motor Control
  • Synaptic Plasticity and Learning

GRADUATE LEVEL AWARDS AND HONORS

  • MnDRIVE Brain Conditions Postdoctoral Fellowship in Neuromodulation, 2017
  • Beatrice Z. Milne and Theordore Brandenburg Award, 2017
  • F31 Ruth R. Kirschtein National Research Service Award, 2015
  • IGERT Innovation Grant, 2015 (Co-PI: Abbey Holt Becker)
  • Sping and Ying Ngoh Lin Award, 2015
  • NSF IGERT Systems Neuroengineering Trainee, 2013-2015
  • Stark Award for Advanced Scholarship, 2014

GRADUATE LEVEL PUBLICATIONS

  • Streng ML, Popa LS, Ebner TJ. Modulation of sensory prediction error in Purkinje cells during visual feedback manipulations. In revision.
  • Streng ML, Popa LS, Ebner TJ. Climbing fibers predict movement kinematics and performance errors. Journal of Neurophysiology, 2017; 118(3):1888-1902.
  • Streng ML, Popa LS, Ebner TJ. Climbing Fibers Control Purkinje Cell Representations of Behavior. J Neurosci. 2017 Feb 22;37(8):1997-2009.
  • Popa LS, Streng ML, Ebner TJ. Long-term predictive and feedback encoding of motor signals in the simple spike discharge of Purkinje cells. eNeuro, 2017; 4(2) e0036-17.2017 1–22
  • Popa LS, Streng ML, Ebner TJ. (2016).The errors of our ways: Understanding error representations in cerebellar-dependent motor learning. Cerebellum 15(2); 93-103
  • Popa  LS*, Streng ML*, Ebner TJ. Signaling of Predictive and Feedback Information in Purkinje Cell Simple Spike Activity.  In: The Neuronal Codes of the Cerebellum.  Heck, D., Editor, Elsevier, New York, NY. pp. 1-25. 2015. 10.1016/B978-0-12-801386-1.00001-0
    * denotes co-equal first authors

GRADUATE LEVEL ABSTRACTS

  • Streng ML, Popa LS, Ebner TJ. “Climbing fibers control Purkinje cell representations of behavior.” Society for Neuroscience annual meeting, San Diego, CA, November 2016.
  • Streng ML, Popa LS, Ebner TJ.  “The ghost in the machine: long range cerebellar signals. Society for Neuroscience annual meeting, San Diego, CA, November 2016.
  • Streng ML, Popa LS, Ebner TJ. “Predictive and feedback motor signals in the output of cerebellar Purkinje cells.” Minnesota Neuromodulation Symposium, Minneapolis, MN, April 2016.
  • Streng ML, Popa LS, Ebner TJ. (2015). Neural correlates of sensory prediction error in purkinje cell simple spike discharge. Poster presented at the Gordon Research Conference: Cerebellum; Lewiston, ME. August 2015
  • Streng ML, Popa LS, Ebner TJ. (2015). Manipulations of visual feedback modulate purkinje cell encoding of tasks consistent with a forward internal model. Poster presented at the Society for the Neural Control of Movement annual conference; Charleston, SC. April 2015
  • Streng ML, Popa LS, Ebner TJ. (2014). Manipulations of visual feedback modulate purkinje cell simple spike encoding of error signals during a manual random tracking task. Poster presented at the Society for Neuroscience annual conference; Washington, D.C. November 2014.
  • Streng ML, Popa LS, Ebner TJ. (2014). Manipulations of visual feedback modulate purkinje cell simple spike encoding of error signals during a manual random tracking task. Poster presented at the IEEE Engineering in Medicine and Biology annual conference; Chicago, IL. August 2014.
  • Streng ML, Popa LS, Ebner TJ. (2014). Manipulations of visual feedback modulate purkinje cell simple spike encoding of error signals during a manual random tracking task.  Poster presented at the Society for Research on the Cerebellum annual conference; Rome, Italy. July 2014.

PROFESSIONAL PRESENTATIONS

  • Streng ML, Popa LS, Ebner TJ. “Climbing fibers predict movement kinematics and performance errors.” Oral presentation at the Society for Neuroscience annual meeting, November 2017.
  • Streng ML, Popa LS, Ebner TJ. (2016) Do as I say, not as I do: Climbing fibers direct Purkinje cell representations of behavior. Oral Presentation at the Graduate Program in Neuroscience annual retreat, February 2016.
  • Streng ML, Popa LS, Ebner TJ. (2015). Manipulations of visual feedback modulate purkinje cell encoding of task performance consistent with a forward internal model. Oral presentation at Department of Neuroscience Colloquium Series, University of Minnesota, Minneapolis, MN, February, 2015.

ROTATIONS

GPN COMMITTEES

  • Steering Committee 2016-2017
  • Admissions Committee, 2014-2016
  • Awards Committee, 2013-2015

PROFESSIONAL OUTREACH

  • Guest lecturer, Saint Paul Ballet’s “Take Back the Tutu” lecture series, 2015-2016

INTERSHIPS

PROFESSIONAL MEMBERSHIPS

  • Society for Neuroscience
  • IEEE Engineering in Medicine and Biology Society
  • Society for the Neural Control of Movement

WHY DID YOU CHOOSE UMN?
I chose the Graduate Program in Neuroscience for the diversity and caliber of faculty research, the strength of the core coursework, and the highly collaborative atmosphere.

WHAT ADVICE WOULD YOU GIVE A FIRST YEAR GRADUATE STUDENT?
Pursue at least one research rotation that is completely outside of your comfort zone.

Martha Streng