Voluntary, purposive behavior requires that we extract information about the world, formulate plans for action, and then execute the movements required to bring about desired outcomes. Our lab studies a critical nexus in the mammalian brain where sensory information and motor planning come together to subserve volition - the basal ganglia.
10/17/16 | New paper describing a reagent born from a collaborative (Karpova, Looger, Hantman, Ritola) + visitor project (Schaffer @ Berkeley): directed evolution of a retrograde AAV
News
08/31/16 | A thoughtful commentary on the clinical implications of Yttri & Dudman 2016 appeared in Movement Disorders
Publication
06/01/16 | Eric Yttri's new paper describing flexible, learned control of movement in the basal ganglia is published in Nature
Publication
03/28/16 | Our new collaborative review with BLAM lab is now available at Current Opinion.
Publication
09/10/15 | Our first paper studying the role of dopamine in movement using a mouse model of Parkinson¡¯s disease is online now at Cell.
Publication
07/23/15 | Wei-Xing's paper about inferring dopamine neuron activity from evoked potentials is online with an informative commentary in F1000.
Event
03/28/16 | Please consider applying to our meeting on Action Selection at Janelia this Fall.
Publication
01/01/15 | A faithful, but changing, code for space along the dorsoventral axis of the hippocampus. Paper with our collaborator Isabel Muzzio is now out online.
Publication
04/15/15 | The fourth edition of The Rat Nervous System with a chapter on the Basal Ganglia by Chip Gerfen and Joshua Dudman is now available.
Tools
04/01/15 | Scientifica has now licensed RIVETS; expect improved hardware integration with some of the best equipment out there.
News
02/10/15 | Learn about our lab's connections to the local science magnet school - the Loudoun Academy of Science.
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quantitative behavior
05/01/14Waiting games
Our recent paper described a behavioral task in which mice learn to maximize reward by adopting optimal waiting times in the presence of highly variable reward delays.
We have developed a system for rapidly configurable and switchable mechanical system for in vivo and in vitro electrophysiology and imaging.
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About the lab
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The work in our lab aims to elucidate the neurobiology of purposive behavior, as well as its pathological disruption in Parkinson's disease and addiction. See all the updates from the lab.
Our lab spans a wide range of technical approaches from electrophysiology during behavior to two-photon imaging. For our work we seek talented people with skills in physiology, behavior, imaging, or, computation, and a strong desire to combine multiple technical approaches. Inquiries can be sent directly to the lab by contacting us.
For interested students, we have a small number of slots for exceptional graduate students through the Janelia Graduate Program or the Graduate Research Fellowship program. For undergraduates, our lab is a regular participant in the Janelia Undergraduate Scholars program.
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Published work
Over the past few years we have focused on studying the circuits of the basal ganglia in the context of reward seeking behaviors in mice. Previous work has spanned a range of techniques and questions from behavioral measures of disease progression in human patients to the atomic structure of glutamate receptors.
Data derived from: Google Scholar.
Title
~100 year-1
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"...The problem of actions, in other words the effect which the organism is striving to achieve, is something which is not yet, but which is due to be brought about. The problem of action, thus, is the reflection or model of future requirements (somehow coded in the brain); and a vitally useful or significant action cannot be either programmed or accomplished if the brain has not created a prerequisite directive in the form of future requirements that we have just mentioned."
The major input nucleus of the basal ganglia - the striatum - is composed largely (>90%) of a class of projection neurons called 'medium spiny neurons'. This image is one such neuron filled with fluorescent dye through a small glass pipette and imaged on a two-photon microscope.
Classes of cortical input
Multiple classes of neocortical neurons provide input to the dorsal striatum. Using reagents developed at Janelia we can label multiple classes (green vs. red) selectively.
Basal ganglia anatomy
A rendering of the anatomy of the basal ganglia in the mouse brain. The major input nucleus, the striatum, is shown in pink. Cortical and thalamic regions that provide input are shown in blue and major output targets are shown in green.
Basal ganglia loops
Retrogradely labeled dopamine neurons (green) and anterogradely labeled axonal projections (red) from the dorsal striatum.
The perithreshold regime
All proteins are subject to brownian motion, including ion channels in the membranes of neurons. Thermal fluctuations in protein confirmation lead to stochastic opening and closing of the conducting pore of the ion channel. Although these fluctuations are assumed to be small we used computational modeling to show that in a very specific aspect of neuron function - the time when the membrane is very close to the threshold for firing an action potential - these fluctuations can dominate the spiking behavior of the neuron. As a consequence complicated patterns of spiking can emerge exclusively in stochastic models (but not in deterministic models which are generally used). This image graphically illustrated the unstable, but balanced state of the membrane around spiking threshold.
Correlation structure of striatal afferents
We used a series of retrograde tracing experiments to attempt to estimate the covariance of inputs to the dorsal striatum. The structure revealed a surprisingly important contribution of convergent targeting (~40% of variance) superimposed on a topographic organization (~60% of variance). This is similar to the estimate produced by a large anterograde tracing dataset by the Allen Brain Institute.
The road wound among the fields where the rice was growing luxuriantly, and where now and then they found beans and millet, and other[Pg 165] products of Japanese agriculture. The cultivation was evidently of the most careful character, as the fields were cut here and there with little channels for irrigation; and there were frequent deposits of fertilizing materials, whose character was apparent to the nose before it was to the eye. In some places, where the laborers were stooping to weed the plants, there was little more of them visible than their broad sun-hats; and it did not require a great stretch of the imagination to believe they were a new kind of mushroom from Brobdingnagian gardens. Hills like sharply rounded cones rose from each side of the narrow valley they were descending; and the dense growth of wood with which the most of them were covered made a marked contrast to the thoroughly cleared fields. The boys saw over, and over, and over again the pictures they had often seen on Japanese fans and boxes and wondered if they were realities. They had already learned that the apparently impossible pictures we find in Japanese art are not only possible, but actual; but they had not yet seen so thorough a confirmation of it as on this day's ride. "It wants some time of two o'clock yet," he said. "My friend, Dr. Bruce, does not go to bed early, so I shall go round and look him up. We'll go into the other letters carefully when we have time, Prout, but for the present I should like to borrow this one if you have no objection. What do you say?" "We have plenty of them; but many of us fall by the treacherous shooting of the civilians; they are swine, swine! And these Belgian women ... they are the dirtiest bitches ... beastly swine...." But he did not take any notice of all my exhortations and was entirely impervious to them in his grief. So I went to the station side by side with the weeping man, and surrounded by the six soldiers. The crackle of the flames, the sound of collapsing houses seemed more terrifying in the night than in day-time, and now and again I got a shock when suddenly, by the uncertain light of the flames, I saw the corpse of a civilian lying in the dark shade of the tall trees on the Boulevard. V. When we left he was in a coppersmith's shop, singing with wide open, staring eyes; his face had a strangely sad expression while he sang a gay, jigging tune to foolish words that made the people laugh. In Mme. Tallien we have a woman exactly opposite to the other two in character, principles, and conduct. Differing from both of them in birth and circumstances¡ªfor she was the daughter of a Spanish banker of large fortune¡ªwith extraordinary beauty, the hot, passionate blood of the south, a nature, habits, and principles undisciplined by authority and unrestrained by religion, she was early imbued with the creed of the revolutionists, and carried their theories of atheism and licence to the logical consequences. The helmsman had switched on its searchlight. ¡°Thank you, sir. Well, if that was true¡ªand if it wasn¡¯t¡ªwhy is the ghost walking again in the very hangar that the seaplane wreckage is in?¡± 275 "Have you bit it off, or did some girl, that you bolted off in such a hurry to see, drain you so dry o' talk that you haint got a word left? Who is she? What does she look like? What made you in sich a dreadful hurry to see her? You didn't go clear up to Bad Ax, did you, and kill that old widower?" HoMEÅ·ÃÀÒ»¼¶ÈË°®°®
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