“Those of us who do electrophysiological recording routinely will argue that there are few events as wondrous and exciting as listening to the sound of a live neuron speaking its own particular language and seeing this language as bursting electrical patterns flickering across the oscilloscope screen.”
–Rodolfo Llinas in `I of the Vortex: From Neurons to Self`
I started my neuroscience career by studying ion channels on retinal ganglion cells and also did circuit mapping on cortical slices. However, I am most interested in deciphering how single neurons integrate (or compute) synaptic inputs under in vivo condition. Through studying synaptic potentials in vivo, I hope to understand the transduction and transformation of neural signals in the neural circuits. For my Ph.D., I developed dual whole-cell patch-clamp recordings in cat visual cortex, which allowed me to observe synchronous high-frequency membrane-potential fluctuations in pairs of neurons in vivo. I also came up with an in vivo configuration where I stimulated a single simple cell while recording the membrane potential of a complex cell to test their connectivity. During my postdoc, I applied in vivo whole-cell recordings in head-fixed, task-performing mice, which led me to discovered reafference-driven inhibition in the barrel cortex during active tactile sensing and a feedforward mechanism for sensory gating. To understand the roles of diverse types of GABAergic inhibitory interneurons, I went on to record three major types of interneurons across layers of barrel cortex in behaving mice and revealed their specific temporal dynamics in behavior. In 2019, I joined the School of Life Sciences, IDG/McGovern Institute of Brain Research, and Center for Life Sciences at Peking University. My research now focuses on understanding how animals predict the sensory consequences of actions.
2006 - 2011, Ph.D., Neuroscience, Northwestern University
2004 - 2006, MSc, Anatomy and Neurobiology, Dalhousie University
1999 - 2003, BS, Fundamental Science, Tsinghua University
2012 - 2019, Postdoc, Janelia Research Campus
Books and Book Chapter
Svoboda K and Yu J. (2018) Barrel Cortex. Handbook of Brain Microcircuits, pp. 59-66. Oxford University Press
The brain produces efference copy signals to predict the sensory consequences of actions, which underlies motor learning, motor control, and active sensing. This explains the observation that one cannot tickle themselves because self-produced tactile signals are thought to be attenuated in the brain by motor-related efference copy signals. However, in many cases, we still do not know the neural basis of efference copy signals, how they are linked to movement command, and how they interact with the sensory systems.
Our lab uses self-touch as a model to understand the neural basis of efference copy. Self-touch has been studied extensively in human subject, where functional brain mapping and MEG recordings were applied to reveal the differential representations of self- versus external-touch in various brain regions. To understand at the circuit level how sensory signals from self-touch are processed, our group uses novel tactile behavior in head-fixed mice and employs single-cell and population recordings to reveal differential representations of self-touch and external touch in distributed neural circuits, including the thalamus, cortex, and the cerebellum. Together, we are interested in elucidating how animals track their own actions, as well as understanding multiple neurological diseases (including schizophrenia) that disrupt this basic function of the brain.
Representative Peer-Reviewed Publications
Yu J, Hu H, Agmon A, Svoboda K. (2019) Principles Governing the Dynamics of GABAergic Interneurons in the Barrel Cortex. bioRix. doi.org/10.1101/554949 (under review)
Gutnisky D, Yu J, Hires SA, To MS, Bale MR, Svoboda K, Golomb D. (2017) Mechanisms underlying a thalamocortical transformation during active tactile sensation. PLoS Comput Biol. 7;13(6):e1005576.
Yu J*, Gutnisky D*, Hires SA, Svoboda K. (2016) Layer 4 fast-spiking interneurons filter thalamocortical signals during active somatosensation. Nature Neuroscience 19(12):1647-1657. (* equal contribution)
Hires SA, Gutnisky DA, Yu J, O`Connor DH, Svoboda K. (2015) Low-noise encoding of active touch by layer 4 in the somatosensory cortex. Elife 4:e06619.
Yu J, Ferster D. (2013) Functional coupling from simple to complex cells in the visually driven cortical circuits. Journal of Neuroscience 33(48):18855-66.
O`Connor DH, Hires SA, Guo ZV, Li N, Yu J, Sun QQ, Huber D, Svoboda K (2013) Neural coding during active somatosensation revealed using illusory touch. Nature Neuroscience 16(7):958-65.
Yu J, Ferster D (2010) Membrane potential synchrony in primary visual cortex during sensory stimulation. Neuron 68(6):1187-201.
Yu J, Daniels BA, Baldridge WH. (2009) Slow excitation of cultured rat retinal ganglion cells by activating group I metabotropic glutamate receptors. Journal of Neurophysiology 102(6):3728-39.
Yu J, Anderson CT, Kiritani T, Sheets PL, Wokosin DL, Wood L, Shepherd GM. (2008) Local-Circuit Phenotypes of Layer 5 Neurons in Motor-Frontal Cortex of YFP-H Mice. Frontiers in Neural Circuits 2008;2:6.
Weiler N, Wood L, Yu J, Solla SA, Shepherd GM. (2008) Top-down laminar organization of the excitatory network in motor cortex. Nature Neuroscience 11(3):360-6.
Hartwick AT, Bramley JR, Yu J, Stevens KT, Allen CN, Baldridge WH, Sollars PJ, Pickard GE. (2007) Light-evoked calcium responses of isolated melanopsin-expressing retinal ganglion cells. Journal of Neuroscience 27(49):13468-80.
2019 PTN Neural Circuits and Behavior
Currently, we focus on the somatosensory systems in the thalamus, cerebral cortex, and cerebellum. Our research follows the central goals of systems neuroscience: to understand how circuit connectivity gives rise to the firing properties of neurons and to understand how the spikes of neurons produce animals’ behavior. To achieve these goals, we combine a wide range of techniques, including in vivo whole-cell recordings, brain slice electrophysiology, multi-channel single-unit recordings (e.g., Mini Matrix), intrinsic signal imaging, voltage and calcium imaging, optogenetics, chemogenetic and pharmacological manipulations. For behavior, we are developing novel head-fixed behaviors in mice and make quantitative measurements to probe the relationship between neural activity and behavior. We also perform psychophysical experiments on human subjects to learn how humans perceive expected versus unexpected tactile stimuli, which will guide the design and interpretation of animal experiments.
In addition, we are keenly interested in applying robotics and virtual reality techniques to animal behaviors to explore how animals interpret the environment and their own actions within it.