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07.03.2017

Work on how sensations pilot movement lands Searle Award

John Tuthill’s insect research illuminates guidance systems for navigating and maneuvering

By Leila Gray  |  HSNewsBeat  |  Updated 6:00 PM, 07.03.2017

Posted in: Research

  • How fruit flies process physical sensations to direct their flight and other movement is the topic of John Tuthill's reserach. NASA

To buzz around, land, taxi and take off again, fruit flies use positioning and guidance systems that might rival sophisticated aircraft. The operational details of these controls are the subject of John Tuthill’s research at UW Medicine and have led to a Searle Scholar Award.   Tuthill is an assistant professor of physiology and biophysics at the UW School of Medicine.

Watch a short, animated movie by Sophia Tintori on the neuroscience research on fly walking in his lab.

The Searle program selectively provides three-year grants, each totaling $300,000, to academic and research institutions to support the independent science of newly hired, outstanding  early-career  faculty.

Like many animals and people, flies receive signals that keep them posted on the location and movement of their external body parts,

Tuthill fly walking still image
Sophia Tintori
A still image from an animated movie by Sophia Tintori on John Tuthill's fly walking research
Fly walking research

like their legs or head.  These sensations are called proprioception.  People can usually tell, for example, if their hand is waving without looking at it.  

As they maneuver, most animals continuously take in tactile and other data from their surroundings and placement  clues from their own bodies.  At present, the Tuthhill lab is concentrating on the sensory circuits in fruit flies that process this information.

Proprioception sensations, as well as the feelings of warmth, cold or pressure, are described as somatosensory – signals that the body picks up, but not necessarily through a sense organ like the eye or taste buds.

The somatosensory system is a complex of neurons and neural circuits that act as detectors.  The signals that it detects are processed by the nervous system in ways that can influence behaviors.  In particular, Tuthill’s group is now looking at the motor circuits that control the fly’s leg muscles

 What makes the fruit fly a good model for laboratory studies of somatosensory functions at a cellular and circuitry level, Tuthill explained, is the existence of genetic methods for labeling neurons  and making targeted recordings. 

 Neurons are the nerve cells that receive and transmit impulses. The genetic toolkit allows researchers to  pinpoint and manipulate specific , identifiable classes neurons.   Tuthhill’s lab combines these genetic tools with measurements of  biological electrical activity and fluorescent microscopy of living tissue with two-photon imaging.

Many of their techniques enable them to make neural  observations as the flies go about their routines.

“As a fly cruises through the world, her brain gathers sensory information from the external environment, which is transformed in the central nervous system, and subsequently used to guide movements and behavior,” Tuthill wrote.  His lab is trying to understand how neural circuits implement each stage:  sensory coding, central integration, and motor control.

The targeted recordings, for example, made in Tuthill’s lab, are comprehensively mapping the junctions and connections between neurons, and documenting their response to stimuli. The lab is also studying how somatosensory feedback fine-tunes locomotor rhythms, such as running and flight, in what Tuthill calls the “nimble fruit fly.”

Their overarching goal is to gain a clearer understanding of the fundamental neural computations that underlie how the senses help control motor activity and other behaviors.

Tuthill noted, that, despite the apparent differences between flies and humans, the basic building blocks of their nervous systems are similar. 

John Tuthill
John Tuthill
John Tuthill

His hope is that, by identifying fundamental sensory and motor principles, progress can be made in understanding mechanisms behind some neurological and movement  disorders in people.  

Earlier this year,  Tuthill was also named a 2017 Sloan Fellow in recognition of his achievements that mark him as a leader among the newest generation of scientists.

Tuthill joins the ranks of other noted UW Medicine and UW scientists who are past Searles Scholars: Charles L. Asbury, Trisha N. Davis, Paul B. Hopkins, David Kimelman, John A. Leigh, James H. Thomas, Wesley Van Voorhis, and Barbara Wakimoto.

While he was a doctoral student at the Howard Hughes Medical Institute Janelia campus. Tuthill studied how the fly brain detects visual motion. Later, as a Harvard Medical School postdoctoral fellow, he pioneered studies of how the fly processes touch sensations. He joined the UW School of Medicine faculty in 2016.

Tagged with: neurosciences, behavior, motor control, neurons, Honors and Awards
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