Education & Training
- 2020-2022 Senior researcher (lab of Pieter Roelfsema), Netherlands Institute for Neuroscience
- 2014-2020 Postdoctoral researcher (lab of Pieter Roelfsema), Netherlands Institute for Neuroscience
- 2008-2014 Ph.D. in Visual Neuroscience (lab of Alexander Thiele), Newcastle University
Representative Publications
Demonstrated the creation of artificial percepts via electrical stimulation of the visual cortex, laying the foundations for future restoration of low vision in the blind:
Chen X, Wang F, Kooijmans R, Klink PC, Boehler C, Asplund M and Roelfsema PR. Chronic stability of a neuroprosthesis comprising multiple adjacent Utah arrays in monkeys. Journal of Neural Engineering 2023, 20(3).
Chen X, Wang F, Fernandez E, and Roelfsema P. Shape perception via a high-channel-count neuroprosthesis in monkey visual cortex. Science 2020, 370, 1191-1196.
Fernández E, Alfaro A, Soto C, Gonzalez-Lopez P, Lozano A, Peña S, Grima MD, Rodil A, Gómez B, Chen X, Roelfsema PR, Rolston JD, Davis T, Normann RA. Visual percepts evoked with an intracortical 96-channel microelectrode array inserted in human occipital cortex. Journal of Clinical Investigation 2021; 131(23):e151331.
van Velthoven EAM, Bredenoord AL, Haselager D, Broekman M, Chen X, Roelfsema PR, Jongsma KR. Ethical implications of visual neuroprostheses – a systematic review. Journal of Neural Engineering 2022; 19:026055.
Developed 3D modeling and printing pipeline to create customized implants, boosting longevity, efficacy, and ease of implantation, and enabling large-scale interfacing with the visual system:
Chen X, Possel J, Wacongne C, Klink P, Roelfsema P. 3D printing and modelling of customized implants and surgical guides for non-human primates. Journal of Neuroscience Methods 2017, 286, 38-55.
Chen X, Morales-Gregorio A, Sridhar S, Sprenger J, van Albada SJ, Grün S, Roelfsema PR. 1024-channel electrophysiological recordings in macaque V1 and V4 during resting state. Scientific Data 2022, 9(77).
Klink PC, Chen X, Vanduffel W & Roelfsema PR. Population receptive fields in non-human primates from whole-brain fMRI and large-scale neurophysiology in visual cortex. eLife 2021;10:e67304.
Established link between long-term perceptual improvements at a behavioural level and changes in cortical activity at the neuronal level:
Sanayei M, Chen X, Chicharro D, Distler C, Panzeri S, Thiele A. Perceptual learning of fine contrast discrimination changes neuronal tuning and population coding in macaque V4. Nature Communications 2018, 9, 4238.
Chen X, Sanayei M, Thiele A. Stimulus roving and flankers affect perceptual learning of contrast discrimination in macaca mulatta. PLoS ONE 2014, 9(10): e109604.
Chen X, Sanayei M, Thiele A. Perceptual learning of contrast discrimination in macaca mulatta. Journal of Vision 2013, 13(13), 22.
Chen X, Hoffmann KP, Albright TD, Thiele A. Effect of feature-selective attention on neuronal responses in macaque area MT. Journal of Neurophysiology 2012, 107(5), 1530-1543.
Research Interest Summary
Research Interests
The Chen lab develops high-channel-count, chronically implantable devices to record from and stimulate the brain. We harness cutting-edge developments in electrode fabrication and microelectronics to improve probe durability and biocompatibility, generating fundamental neuroscientific knowledge and translating results from the lab to the clinic.
Our applications include the restoration of life-enhancing vision in the blind. Blindness affects 40 million people worldwide, with a wide variety of causes, including injury to or degeneration of the retina and optic nerve. Brain implants interface directly with visual regions in the brain, bypassing the retina and optic nerve to produce artificially generated percepts without input from the eye.
We use devices with >1000 channels to interface with large areas of the visual cortex, delivering tiny electrical currents to elicit the perception of dots of light (known as ‘phosphenes’). We deliver stimulation across multiple electrodes simultaneously, inducing percepts composed of multiple phosphenes, and causing our subjects to see movement, and simple shapes such as letters.
Our work has been featured in numerous international and national newspapers, radio and television, including CNN, Science Magazine, Science Podcasts, Scientific American, Het Parool, De Volkskrant, El País, NOS, NPO Radio, and RTL News.
Selected Patents/ Patent Applications
Roelfsema, P. R., & Chen, X. A neuroprosthetic system and method for substituting a sensory modality of a mammal by high-density electrical stimulation of a region of the cerebral cortex. EP3632503A1, filed Nov 1, 2018 (granted).
Roelfsema, P. R., Chen, X., Li, B., Lozano, A. M. O., Wang, F., La Grouw, M. A computer-implemented method of mapping electrodes of a brain prosthesis. EP22206219.2, filed Nov 8, 2022 (pending).
We are hiring: Lab technician/ Lab manager/ Postdoc/ PhD student.
Contact Dr Chen at x.chen@pitt.edu for more information.