Christian Éthier,
Ph.D.

Assistant Professor
Department of Psychiatry and Neurosciences

Research Overview

Design of brain-computer interfaces to understand and stimulate neuronal activity leading to the formation of new neuronal connections.

Dr. Christian Éthier studies how neuronal activity, the passage of an electrochemical current between neurons, leads to the formation or strengthening of connections between these neurons. This phenomenon, known as neuronal plasticity, is essential to the process of learning or repairing neural circuits following injury or stroke damage.

Dr. Ethier's team aims to find ways to guide neural reorganization, through electrical or optical stimulation (with light), and help people who have suffered damage to the nervous system.

Neuroprostheses for the rehabilitation of paralyzed patients.

At the interface between engineering and neuroscience, Dr. Ethier's research has led to the development of neuroprosthetics, tested in monkeys, that read the activity of the brain's cortex and convert these readings into electrical signals transmitted to the hands to make them move. This type of neuroprosthesis may one day allow people paralyzed by a spinal cord injury to use their hands in a near-normal way.

Research Interests

Our primary objective is to study the rules governing activity-dependent plasticity in vivo. We evaluate how connections between neurons can be modulated at the structural level, by combining neural activity associated with voluntary effort to action potentials elicited by electrical or optical stimulation.

We design neuroelectronic and optogenetic interfaces to create an artificial bridge between neuronal structures, and promote associative plasticity in the cortical and spinal motor networks.

Ultimately, our research could lead to the design of new medical devices, with the potential to guide neural reorganization and promote motor recovery after neurological lesions, such as strokes and spinal cord injuries.

Key Publications

Ethier C, Acuna D, Solla SA, Miller LE. (2016) Adaptive neuron-to-EMG decoder training for FES neuroprostheses. J Neural Eng. 2016 Jun 1;13(4):046009.

MD Best, K Takahashi, AJ Suminski, C Ethier, LE Miller, NG Hatsopoulos. (2016) Comparing offline decoding performance in physiologically defined neuronal classes. Journal of neural engineering 13 (2), 026004

Ethier C, Gallego JA, Miller LE. (2015) Brain-controlled neuromuscular stimulation to drive neural plasticity and functional recovery. Curr. Opin. Neurobiol. Mar 28;95-102.

Ethier C, Miller LE (2014) Brain-controlled muscle stimulation for the restoration of motor function. Neurobiology of Disease. Oct 28. S0969-9961(14)00327-1.

Capaday C, Ethier C, Van Vreeswijk C, Darling WG. (2013) On the functional organization and operational principles of the motor cortex. Front Neural Circuits. Apr 18;7:66

Ledbetter NM, Ethier C, Oby ER, Hiatt S, Wilder AM, Ko J, Agnew S, Miller LE, Clark G (2013) Intrafascicular stimulation of monkey arm nerves evokes coordinated grasp and sensory responses. J Neurophysiol. 109(2):580-90

Oby ER, Ethier C, Miller LE. (2012) Movement representation in primary motor cortex and its contribution to generalizable EMG predictions. J Neurophysiol. 109(3):666-678

Ethier C, Oby ER, Bauman MJ, Miller LE (2012) Restoration of grasp following paralysis through brain-controlled stimulation of muscles. Nature; 485(7398):368-71.

Flint RD 3Rd, Ethier C, Oby ER, Miller LE, Slutzky MW (2012) Local field potentials allow accurate decoding of muscle activity. J Neurophysiol; 108(1), 18-24.

Nazarpour K, Ethier C, Paninski L, Rebesco JM, Miall RC, Miller LE (2012) EMG prediction from motor cortical recordings via a non-negative point process filter. IEEE Trans; 59(7):1829-38.

Capaday C, van Vreeswijk C, Ethier C, Ferkinghoff-Borg J, Weber DJ (2011) Neural mechanism of activity spread in the cat motor cortex and its relation to the intrinsic connectivity. J Physiol. 2011 May 15;589 (Pt 10):2515-28.

Ackermann D.M. Jr., Ethier C., Foldes E.L., Oby E.R., Tyler D., Bauman M., Bhadra N., Miller L.E., Kilgore K.L.(2011) Electrical conduction block in large nerves: high-frequency current delivery in the nonhuman primate. Muscle & Nerve; 43(6):897-9.

Capaday C, Ethier C, Brizzi L, Sik A, van Vreeswijk C, Gingras D (2009) On the nature of the intrinsic connectivity of the cat motor cortex: evidence for a recurrent neural network topology. J Neurophysiol; 102(4):2131-41.

Ethier C, Brizzi L, Giguère D, Capaday C (2007) Corticospinal control of antagonistic muscles in the cat. Eur J Neurosci; 26(6):1632-41.

Ethier C, Brizzi L, Darling WG, Capaday C (2006) Linear summation of cat motor cortex outputs. J. Neurosci; 26(20):5574-81.