Sensorimotor Neurophysiology

Current research is being pursued through collaborations at USC with Profs. Valero-Cuevas and Schweighofer and at Lund University, Sweden, with Prof. Henrik Jorntell and University of Queensland, Australia, with Prof. Tim Carroll.

Publications

Contemori, S., Loeb, G. E., Corneil, B. D., Wallis, G., & Carroll, T. J. (2023). Express Visuomotor Responses Reflect Knowledge of Both Target Locations and Contextual Rules during Reaches of Different Amplitudes. The Journal of Neuroscience, 43(42), 7041-7055. doi:10.1523/jneurosci.2069-22.2023

Loeb, G.E. “Remembrance of things perceived: Adding thalamocortical function to artificial neural networks,” Front. Integrative Neurosci. 17:1108271, doi.org/10.3389/fnint.2023.1108271, 2023. 

 Contemori, S., Loeb, G.E., Corneil, B.D., Wallis, G. and Carroll, T.J. The influence of temporal predictability on express visuomotor responses, J. Neurophysiol. 125(3):731-747, 2021.

Contemori, S., Loeb, G.E., Corneil, B.D., Wallis, G. and Carroll, T.J. Express visuomotor responses reflect knowledge of both target locations and contextual rules during reaches of different amplitudes, J Neurosci. (early release https://www.jneurosci.org/content/43/42/7041), 2023. 

Contemori, S., Loeb, G.E., Corneil, B.D., Wallis, G. and Carroll, T.J. Symbolic cues enhance express visuomotor responses in human arm muscles at the motor planning rather than the visuospatial processing stage, J. Neurophysiol.  128(3):494-510, doi.org/10.1152/jn.00136.2022, 2022. 

Contemori, S., Loeb, G.E., Corneil, B.D., Wallis, G. and Carroll, T.J. Trial-by-trial modulation of express visuomotor responses induced by symbolic or barely detectable cues. J Neurophysiol 126:1507–1523, 2021. 

Enander, J., Jones, A.M., Kirkland, M., Hurless, J., Jorntell, H. and Loeb, G.E A model for self-organization of sensorimotor function:  the spinal monosynaptic loop, J. Neurophysiol. 127(6):1460-1477, https://doi.org/10.1152/jn.00242.2021, 2022.

Enander, J., Loeb, G.E. and Jorntell, H. A model for self-organization of sensorimotor function: spinal interneuronal integration, J. Neurophysiol. 127(6):1478-1495, https://doi.org/10.1152/jn.00054.2022, 2022.

Loeb, G.E. Why do we have muscle spindles? Crosstalk50 commentary, J. Physiol., 2021.

Loeb GE. Learning to use Muscles. Journal of Human Kinetics. 2021;76:9.

Rongala, U.B., Enander, J.M.D., Kohler, M., Loeb, G.E. and Jorntell, H. A non-spiking neuron model with dynamic leak to avoid instability in recurrent networks. Frontiers Comp. Neurosci. 15:1-15, doi:10.3389/fncom.2021.656401, 2021.

Hagen DA, Marjaninejad A, Loeb GE, Valero-Cuevas FJ. insideOut: A Bio-Inspired Machine Learning Approach to Estimating Posture in Robots Driven by Compliant Tendons. Frontiers in Neurorobotics. 2021;15(130).

Shida-Tokeshi J, Lane CJ, Trujillo-Priego IA, Deng, W, Vanderbilt, DL, Loeb, GE, Smith, BA. Relationships between full-day arm movement characteristics and developmental status in infants with typical development as they learn to reach: An observational study, Gates Open Res 2:17, doi: 10.12688/gatesopenres.12813.2, 2018.

Trujillo-Priego, I.A., Lane C.J., Vanderbilt, D.L., Deng, W, Loeb, G.E., Shida, J, Smith, B.A. Development of a wearable sensor algorithm to detect the quantity and kinematic characteristics of infant arm movement bouts produced across a full day in the natural environment, Technologies. 2017, 5, 39, doi: 10.3390/technologies5030039, 2017.

Jalaleddini, K., Niu, C., Chakravarthi Raja, S., Sohn, W.J., Loeb, G.E., Sanger, T., and Valero-Cuevas, F. Neuromorphic meets neuromechanics, Part II: The role of fusimotor drive J. Neural Eng., 14, 025002, doi.org/10.1088/1741-2552/aa59bd, 2017.

Loeb, G.E. and Tsianos, G.A. Major remaining gaps in models of sensorimotor systems Front. Comput. Neurosci. 9, 70, doi.org/10.3389/fncom.2015.00070, 2015.

Loeb, G.E. and Mileusnic, M. Proprioceptors and models of transduction Scholarpedia 10(5):12390, 2015.

Loeb, G.E. and Davoodi, R. Musculoskeletal mechanics and modeling Scholarpedia, 2015.

Loeb, G.E. and Fishel, J.A. Bayesian Action & Perception: Representing the World in the Brain Frontiers in Neuroscience 8:341, doi: 10.3389/fnins.2014.00341, 2014.

Tsianos, G.A., Goodner, J. and Loeb, G.E. Useful properties of spinal circuits for learning and performing planar reaches J. Neural Eng. 11, 056006, doi: 10.1088/1741-2560/11/5/056006, 2014.

Loeb, G.E. Spinal Cord, Integrated (Non CPG) Models of Encyc Comp Neurosci DOI: 10.1007/978-1-4614-7320-6_648-1, 2014.

Tsianos, G.A. and Loeb, G.E. Muscle physiology and modeling Scholarpedia 8(10):12388, 2013

De Rugy, A., Loeb, G.E. and Carroll, T.J. Are muscle synergies useful for neural control? Front. Comput. Neurosci., 7, 19, doi: 10.3389/fncom.2013,00019.

Hauschild, M., Mulliken, G.H., Fineman, I., Loeb, G.E. and Anderson, R.A. Cognitive signals for brain-machine interfaces in posterior parietal cortex include continuous 3D trajectory commands. Proceedings of the National Academy of Sciences 109(42): 17075-17080, 2012.

Loeb, G.E., Optimal isn’t good enough. Biological Cybernetics, 106(11):757-765, doi: 10.1007/s00422-012-0514-6, 2012.

De Rugy, A., Loeb, G.E., and Carroll, T.J. Muscle coordination is habitual rather than optimal. J. Neuroscience 32:7384-7391, 2012.

Tsianos, G.A., Raphael, G. and Loeb, G.E. Modeling the potentiality of spinal-like circuitry for stabilization of a planar arm system. Prog. Brain Res. 194:203-213, 2011.

Brown, I.E. and Loeb, G.E. A reductionist approach to creating and using neuromusculoskeletal models. Chapter in: Neuro-Control of Posture and Movement, (Eds.) J. Winters and P. Crago, Springer-Verlag, New York, pp 148-163, 2000.

Raphael, G., Tsianos, G.A., and Loeb, G.E. Spinal-Like Regulator Facilitates Control of a Two-Degree-of-Freedom Wrist The Journal of Neuroscience 30(28):9431-9444 2010.

Cheng, E.J. and Loeb, G.E. On the Use of Musculoskeletal Models to Interpret Motor Control Strategies from Performance Data. Journal Neural Engineering 5:232-253, 2008.

Kaliki, R.R., Davoodi, R. and Loeb, G.E. Prediction of Distal Arm Posture in 3-D Space from Shoulder Movements for Control of Upper Limb Prostheses. Proceedings of the IEEE, 96(7):1217-1225, 2008.

Song, D., Lan, N., Loeb, G.E. and Gordon, J. Model-Based Sensorimotor Integration for Multi-Joint Control: Development of a Virtual Arm Model, Annals of Biomedical Engineering, 36(6):1033-1048, 2008.

Hauschild, M., Davoodi, R., and Loeb, G.E. A Virtual Reality Environment for Designing and Fitting Neural Prosthetic Limbs. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 15(1):9-15, 2007.

Davoodi, R., Urata, C., Hauschild, M., Khachani, M. Loeb, G.E. Model-Based Development of Neural prostheses for Movement. IEEE Transactions on Biomedical Engineering, 54(11): 1909-1918, 2007.

Wolpaw,J.R., Loeb,G.E., Allison,B.Z., Donchin,E., do Nascimento,O.F., Heetderks,W.J., Nijboer,F., Shain,W.G. and Turner,J.N. BCI Meeting 2005–Workshop on signals and recording methods. IEEE Trans Neural Syst Rehabil Eng, 14(2):138-41, 2006.

Mileusnic, M.P., Brown, I.E., Lan, N. and Loeb, G.E. Mathematical Models of Proprioceptors: I. Control and Transduction in the Muscle Spindle. J. Neurophysiol. 96:1772-1788, 2006.

Mileusnic, M.P. and Loeb, G.E. Mathematical models of proprioceptors: II. Structure and function of the Golgi tendon organ. J. Neurophysiol. 96:1789-1802, 2006.

Corneil, B.D., Olivier, E., Richmond, F.J.R., Loeb, G.E. and Munoz, D.P. Neck muscles in the rhesus monkey. II. Electromyographic patterns of activation underlying postures and movements. J. Neurophysiol, 86:1729-1749, 2001.

Loeb, G.E. Learning From the Spinal Cord. J. Physiol. (London) 533:111-117, 2001.

Loeb, G.E., Overcomplete Musculature or Underspecified Tasks? Motor Control, 4:81-83, 2000.

Prochazka, A., Wolpaw, J.R., Clarac, F., Loeb, G.E. and Rothwell, J.C. What do reflex and voluntary mean? Modern views on an ancient debate. Exp. Brain Res. 130:417-432, 2000.

Loeb, G.E. Asymmetry of hindlimb muscle activity and cutaneous reflexes after tendon transfers in kittens. J. Neurophysiol.82:3392-3405, 1999.

Loeb, G.E., Brown, I.E. and Cheng, E. A hierarchical foundation for models of sensorimotor control. Exp. Brain Res., 126:1-18, 1999.

Loeb, G.E., Brown, I.E. and Scott, S.H. Directional Motor Control. Trends in Neurosci. 19:137-138, 1996.

Thomson, D.B., Loeb, G.E. and Richmond, F.J.R. Effect of neck posture on patterns of feline neck muscles: Compensatory head movements during horizontal whole-body rotation. Exp. Brain Res.10:392-400, 1996.

Loeb, G.E. What can we expect from models of motor control? Behav. & Brain Sci., 18(4):767-768, 1995.

Scott, S.H. and Loeb, G.E. The computation of position sense from spindles in mono-and multiarticular muscles. J. Neurosci. 14:7529-7540, 1994.

Thomson, D.B., Loeb, G.E. and Richmond, F.J.R. Effect of neck posture on the activation of feline neck muscles during voluntary head turns. J. Neurophysiol. 72:2004-2014, 1994.

Abrahams, V.C., Kori, A., Loeb, G.E., Richmond, F.J.R., Rose, P.K. and Kierstead, S.A. Facial input to neck motoneurons: Trigemino-cervical reflexes in the conscious and anaesthetised cat. Exp. Brain Res. 97:23-30, 1993.

Blaszczyk, J. and Loeb, G.E. Why cats pace on the treadmill. Physiol. & Behav. 53:501-507, 1993.

Loeb, G.E. The distal hindlimb musculature of the cat: Interanimal variability of locomotor activity and cutaneous reflexes. Exp. Brain Res. 96:125-140, 1993.

Levine, W.S. and Loeb, G.E. Neural control of limb movement. IEEE Control Systems Magazine, 12:38-46, 1992.

Richmond, F.J.R., Thomson, D.B. and Loeb, G.E. Electromyographic studies of neck muscles in the intact cat: I. Patterns of recruitment underlying posture and movement during natural behaviors. Exp. Brain Res. 88:41-58, 1992.

Richmond F.J.R. and Loeb, G.E. Electromyographic studies of neck muscles in the intact cat: II. Reflexes evoked by muscle-nerve stimulation. Exp. Brain Res. 88:59-66, 1992.

Loeb, G.E. Past the equilibrium point. Behav. & Brain Sci., 15:774-775, 1992.

Pratt, C.A., and Loeb, G.E. Functionally complex muscles of the cat hindlimb. I. Patterns of activation across sartorius. Experimental Brain Research, 85:243-256, 1991.

Chanaud, C.M., Pratt, C.A. and Loeb, G.E. Functionally complex muscles of the cat hindlimb. II. Mechanical and architectural heterogeneity within the biceps femoris. Experimental Brain Research, 85:257-270, 1991.

Pratt, C.A., Chanaud, C.M. and Loeb, G.E. Functionally complex muscles of the cat hindlimb. IV. Intramuscular distribution of movement command signals and cutaneous reflexes in broad bifunctional thigh muscles. Experimental Brain Research, 85:281-299, 1991.

Chanaud, C.M., Pratt, C.A. and Loeb, G.E. Functionally complex muscles of the cat hindlimb. V. The roles of histochemical fiber-type regionalization and mechanical heterogeneity in differential muscle activation. Experimental Brain Research, 85:300-313, 1991.

Gordon, D.C., Loeb, G.E. and Richmond, F.J.R. Distribution of motoneurons supplying cat sartorius and tensor fasciae latae, demonstrated by retrograde multiple-labelling methods. J. Comp. Neurol. 304:357-373, 1991.

He, J., Levine, W.S. and Loeb, G.E. Feedback gains for correcting small perturbations to standing posture. IEEE Trans on Automatic Cointrol, 36:322-332, 1991.

Duenas, S.H., Loeb, G.E. and Marks, W.B. Monosynaptic and dorsal root reflexes during locomotion in normal and thalamic cats. J. Neurophysiol., 63:1467-1476, 1990.

Loeb, G.E., Levine, W.S. and He, J. Understanding sensorimotor feedback through optimal control. Cold Spring Harbor Symp. Quant. Biol. 55: 791-803, 1990.

Loeb, G.E., He, Jiping and Levine, W.S. Spinal cord circuits: Are they mirrors of musculoskeletal mechanics? J. Motor Behavior, 21:473- 491, 1989.

Loeb, G.E. Strategies for the control of studies of voluntary movement with one degree of freedom. Behav. & Brain Sci. , 12:227, 1989.

Loeb, G.E. Neural control of locomotion. BioScience, 39(11):800-804, 1989.

Loeb, G.E. and Richmond, F.J.R. Motor partitioning: Epiphenomena masquerading as control theory. Behav. & Brain Sci., 12:660-661, 1989.

Krarup, C., Loeb, G.E. and pezeshkpour, G.H. Conduction studies in peripheral cat nerve using implanted electrodes: III. The effects of prolonged constriction on the distal erve segment. Muscle and Nerve, 12:915-928, 1989.

Krarup, C. and Loeb, G.E. Conduction studies in peripheral cat nerve using implanted electrodes: I. Methods and findings in controls. Muscle & Nerve, 11:922-932, 1988.

Krarup, C., Loeb, G.E., and Pezeshkpour, G.H. Conduction studies in peripheral cat nerve using implanted electrodes: II. The effects of prolonged constriction on regeneration of crused nerve fibers. Muscle & Nerve, 11:933-944, 1988.

Loeb, G.E. Hard lessons in motor control from the mammalian spinal cord. Trends Neurosci. 10:108-113, 1987.

Hoffer, J.A., Loeb, G.E., Marks, W.B., O’Donovan, M.J., Pratt, C.A. and Sugano, N. Cat hindlimb motoneurons during locomotion: I. Destination, axonal conduction velocity, and recruitment threshold. J. Neurophysiol. 57:510-529, 1987.

Hoffer, J.A., Sugano, N., Loeb, G.E., Marks, W.B., O’Donovan, M.J. and Pratt, C.A. Cat hindlimb motoneurons during locomotion: II. Normal activity patterns. J. Neurophysiol. 57:530-553, 1987.

Hoffer, J.A., Loeb, G.E., Sugano, N., Marks, W.B., O’Donovan, M.J. and Pratt, C.A. Cat hindlimb motoneurons during locomotion: III. Functional segregation in sartorius. J. Neurophysiol. 57:554-562, 1987.

Loeb, G.E., Marks, W.B. and Hoffer, J.A. Cat hindlimb motoneurons during locomotion: IV. Participation in cutaneous reflexes. J. Neurophysiol. 57:563-573, 1987.

Loeb, G.E., Hoffer, J.A., Sugano, N., Marks, W.B., O’Donovan, M.J. and Pratt, C.A. Activity patterns of identified alpha motoneurons to cat anterior thigh muscles during normal walking and flexor reflexes. In: Motor Control (Eds.) G.N. Gantchev, B. Dimitrov and P. Gatev, Plenum, New York, 1987, pp. 159-164.

Loeb, G.E., Yee, W.J., Pratt, C.A., Chanaud, C.M. and Richmond, F.J.R. Cross-correlation of EMG reveals widespread synchronization of motor units during some slow movements in intact cats. J. Neurosci. Meth. 21:239-249, 1987.

Loeb, G.E. Motor Control. In: Encyclopedia of Neuroscience, G. Adelman, Ed., Birkhauser Boston, Inc., Cambridge, Mass., 1987, pp. 690-692.

Howell, J.N., Binder, M.D., Nichols, T.R. and Loeb, G.E. Muscle spindles, Golgi tendon organs and the neural control of skeletal muscle. J. Am. Osteopathic Assoc. 86:599-602, 1986.

Loeb, G.E. Spinal programs for locomotion. Prog. Brain Res. 64:273-287, 1986.

Abraham, L.D. and Loeb, G.E. The distal hindlimb musculature of the cat: Patterns of normal use. Exp. Brain Res. 58:580-593, 1985.

Abraham, L.D., Marks, W.B. and Loeb, G.E. The distal hindlimb musculature of the cat: Cutaneous reflexes during locomotion. Exp. Brain Res. 58:594-603, 1985.

Loeb, G.E., Hoffer, J.A. and Pratt, C.A. Activity of spindle afferents from cat anterior thigh muscles. I. Identification and patterns during normal locomotion. J. Neurophysiol. 54:549-564, 1985.

Loeb, G.E., and Hoffer, J.A. The activity of spindle afferents from cat anterior thigh muscles. II. Effects of fusimotor blockade. J. Neurophysiol. 54:565-577, 1985.

Loeb, G.E., Hoffer, J.A. and Marks, W.B. Activity of spindle afferents from cat anterior thigh muscles. III. Effects of external stimuli. J. Neurophysiol. 54:578-591, 1985.

Loeb, G.E. Motoneurone task groups – coping with kinematic heterogeneity. J. Exp. Biol. 115:137-146, 1985.

Loeb, G.E. and Marks, W.B. Optimal control principles for sensory transducers. In: Proc. Internat. Sympos.: The Muscle Spindle. (Eds.) I.A. Boyd and M.H. Gladden. MacMillan Ltd., London, 1985, pp. 409-415

Loeb, G.E. The Control and Responses of Mammalian Muscle Spindles During Normally Executed Motor Tasks. Exercise and Sport Sciences Reviews, 12:157-205, 1984.

Rindos, A.J., Loeb, G.E. and Levitan, H. Conduction velocity changes along lumbar primary afferents in cats. Exp. Neurol. 86:208-226, 1984.

Hoffer, J.A. and Loeb, G.E. A technique for reversible fusimotor blockade during chronic recording from spindle afferents in walking cats. Exp. Brain Res. Suppl. 7:272-279, 1983.

Loeb, G.E. Finding common ground between robotics and physiology. Trends Neurosci. 6:203-204, 1983.

O’Donovan, M.J., Hoffer, J.A. and Loeb, G.E. Physiological characterization of motor unit properties in intact cats. J. Neurosci. Meth. 7:137-149, 1983.

Hoffer, J.A., O’Donovan, M.J., Pratt, C.A. and Loeb, G.E. Discharge patterns in hindlimb motoneurons during normal cat locomotion. Science 213:466-468, 1981.

Loeb, G.E. and Hoffer, J.A. Muscle spindle function during normal and perturbed locomotion in cats. In: Muscle Receptors and Movement, (Ed.) A. Taylor and A. Prochazka, MacMillan, London, 1981, pp 219-228.

Loeb, G.E. Somatosensory unit input to the spinal cord during normal walking. Can. J. Physiol & Pharm. 59:627-635, 1981.

Hoffer, J.A., Loeb, G.E. and Pratt, C.A. Single unit conductioon velocities from averaged nerve cuff electrode records in freeely moving cats. J. Neurosci., Meth. 4:211-225, 1981.

Duysens, J., Loeb, G.E. and Weston, B.J. Crossed flexor reflex responses and their reversal in freely walking cats. Brain Res. 197:538-542, 1980.

Duysens, J. and Loeb, G.E. Modulation of ipsi- and contralateral reflex responses in unrestrained walking cats. J. Neurophysiol. 44:1024-1037, 1980.

Loeb, G.E. and Marks, W.B. Epistemology and heuristics in neural network research. Behav. & Brain Sci. 3:556-557, 1980.

Loeb, G.E. and Duysens, J. Activity patterns in individual hindlimb primary and secondary muscle spindle afferents during normal movements in unrestrained cats. J. Neurophysiol. 42:420-440, 1979.

Loeb, G.E., Bak, M.J. and Duysens, J. Long-term unit recording from somatosensory neurons in the spinal ganglia of the freely walking cat. Science 197:1192-1194, 1977.

Loeb, G.E. Decreased conduction velocity in the proximal projections of myelinated dorsal root ganglion cells in the cat. Brain Res. 103:381-385, 1976.

Loeb, G.E. Ventral root projections of myelinated dorsal root ganglion cells in the cat. Brain Res. 106:159-165, 1976.

Marks, W.B. and Loeb, G.A. Action currents, internodal potentials, and extracellular records of myelinated mammalian nerve fibers derived from node potentials. Biophys. J., 16:655-668, 1976.