So far, the work has been focused towards the following objectives:
i) Develop electronic technologies for brain mapping to record from large number of active sites over large areas of the cortex. We have been developing the technology roadmap. The g-SGFET technology has reached high maturity, reaching very yields over 80% and high homogeneity, and reducing the 1/f electronic noise; we have validated in vitro and in vivo the recording capabilities of g-SGFETs; we have performed an in vitro assessment of g-SGFETs devices (8×8 arrays) for multiplexing strategies. We have successfully validated: (a) 2 different multiplexing strategies with arrays of 8×8 g-SGFET in acute in vivo experiments using discrete electronics, and (b) the g-SGFETs in an in vivo chronic setting using a wireless headstage.
A first ASIC has been full-custom designed for a novel switch-less multiplexing strategy of g-SGFET arrays. The design of a 1024-channel ASIC with digital output for the switch-less multiplexing of 32×32-arrays of GFET sensors has been completed and is currently being fabricated.
ii) Advance the fundamental understanding of the link between surface and intracortical signals and dynamics in cortical circuits. We have developed flexible cranial interface and performed first of a kind distributed recordings together with 3D behaviour, and a Green-function-based frequency domain procedure for LFP decomposition, and we have identified sparse and distributed anatomical basis for decoding of spatial representation from hippocampal LFP in theta frequency band. We have established joined depth and ECoG recordings in motor cortex combined with 3D limb analysis in locomoting head-fixed mice and identified contribution of theta dynamics to motor cortex activity; we have performed first recordings in minipigs with 256 channel wireless recording system combined with vocalization analysis.
iii) Gain new fundamental understanding of the distributed brain circuits of speech and their plastic flexibility before and after lesions. We have started to characterize the brain dynamics underlying overt and inner speech production in humans, both at the whole brain level using non-invasive, and more locally using invasive large-scale electrophysiology. We have collected several datasets in patients with ECoG electrodes for word level speech production, characterizing the covert speech network. We have also developed original decoding methods, and characterization of best neural signals to be decoded (high and low frequency signals, inter-site correlations).
iv) Development of speech BCI proof of concept. We have developed a versatile software framework to allow customizable real-time processing of any type of data streams (including neural recordings from different recording systems), incorporating real-time DNN-based speech synthesis for closed-loop BCI applications. A first closed-loop speech BCI paradigm was tested in a new epileptic patient. We developed a neuromorphic approach to perform online spike sorting that anticipates the advent of very large scale neural recordings with BrainCom implants that will need to be processed at very low-power for a wireless usage.
v) Develop a solid ethics framework to identify and explore issues linked to the use of brain implants. Collaborative research has continued on questions generated by neural decoding techniques, including the prospect for involuntary speech and inadvertent ‘mind reading’. Further work has addressed questions concerning user responsibility, control of devices, and the status of brain data.
- D1.1 Report on Novel Cortical µECoG and Intracortical Technologies read D1.1
- D1.3 Multiplexed Surface Conformal μECoG read D1.3
- D1.4 Noise Assessment read D1.4
- D2.1 System Integration of First Multiplexed Neural Interfaces with Digital Output read D2.1
- D3.1 Initial Evaluation of the Newly Developed Technology read D3.1
- D7.1 Communication Tools (Project Identity Set, Website, Logo) read D7.1
- RM Santos & A. Sirota. Phasic oxygen dynamics confounds fast choline-sensitive biosensor signals in the brain of behaving rodents, eLife (2021). read
- E Masvidal-Codina, TM Smith, D Rathore, Y Gao, X Illa, E Prats-Alfonso, E Del Corro, A Bonaccini Calia, G Rius, I Martin-Fernandez. Characterization of optogenetically-induced cortical spreading depression in awake mice using graphene micro-transistor arrays, Journal of Neural Engineering, 18(5), 055002 (2021). read
- R. Garcia-Cortadella, G. Schwesig, C. Jeschke, X. Illa, A.L. Gray, S. Savage, E. Stamatidou, I. Schiessl, E. Masvidal-Codina, K. Kostarelos, A. Guimerà-Brunet, A. Sirota, & J.A. Garrido. Graphene active sensor arrays for long-term and wireless mapping of wide frequency band epicortical brain activity, Nat. Commun., 12:211 (2021). read
- P. Roussel, G. Le Godais, F. Bocquelet, M. Palma, J. Hongjie, S. Zhang, A.L. Giraud, P. Mégevand, K. Miller, J. Gehrig, C. Kell, P. Kahane, S. Chabardés, & B. Yvert Observation and assessment of acoustic contamination of electrophysiological brain signals during speech production and sound perception, J. Neural Eng., 17, 056028 (2020). read
- A.G. Polyravas, N. Schaefer, V.F. Curto, A.B. Calia, A. Guimera-Brunet, J.A. Garrido, & G.G. Malliaras. Effect of channel thickness on noise in organic electrochemical transistors, Appl. Phys. Lett., 117, 073302 (2020). read
- E. Fourneret & B. Yvert. Digital Normativity: A Challenge for Human Subjectivation, Opinion, Front. Artif. Intell., 3, 27 (2020). read
- J. Delgado Saa, A. Christen, S. Martin, B.N. Pasley, R.T. Knight, & A.L. Giraud. Using Coherence-based spectro-spatial filters for stimulus features prediction from electro-corticographic recordings, Sci Rep, 10, 7637 (2020). read
- S. Rainey, K. McGivrillay, S. Akintoye, T. Fothergill, C. Bublitz, & B. Stahl. Is European Data Protection Regulation sufficient to deal with emerging data concerns relating to neurotechnology?, J. Law Biosci. (2020). read
- A. Astobiza, T. Ausin, R. Ferrer., S. Rainey., Chapter 15: The Ethics of Brain-Computer Interfaces, in S. Gouveia, (Ed.) The Age of Artificial Intelligence: An Exploration, Vernon Press (2020), ISBN: 978-1-62273-872-4.
- S. Rainey & Y.J. Erden. Correcting the Brain? The Convergence of Neuroscience, Neurotechnology, Psychiatry, and Artificial Intelligence, Sci Eng Ethics (2020). read
- S. Rainey, S. Martin, A. Christen, P. Mégevand, & E. Fourneret. Brain Recording, Mind‑Reading, and Neurotechnology: Ethical Issues from Consumer Devices to Brain‑Based Speech Decoding, Sci Eng Ethics (2020). read
- R. Garcia-Cortadella, N. Schäfer, J. Cisneros-Fernandez, L. Re, X. Illa, G. Schwesig, A. Moya, S. Santiago, G. Guirado, R. Villa, A. Sirota, F. Serra-Graells, J.A. Garrido, & A. Guimerà-Brunet. Switchless Multiplexing of Graphene Active Sensor Arrays for Brain Mapping, Nanoletters (2020). read
- R. Garcia-Cortadella, E. Masvidal‐Codina, J.M. De la Cruz, N. Schäfer, G. Schwesig, C. Jeschke, J. Martinez‐Aguilar, M.V. Sanchez‐Vives, R. Villa, X. Illa, A. Sirota, A. Guimerà, & J.A. Garrido. Distortion‐Free Sensing of Neural Activity Using Graphene Transistors, Small, 1906640 (2020). read
- N. Schaefer, R. Garcia-Cortadella, J. Martínez-Aguilar, G. Schwesig, X. Illa, A.M. Lara, S. Santiago, C. Hebert, G. Guirado, R. Villa, A. Sirota, A. Guimer, & J.A. Garrido. Multiplexed neural sensor array of graphene solution-gated field-effect transistors, 2D Materials 7, 2 (2020). read
- S. Rainey, H. Maslen, & J. Savulescu. When Thinking is Doing: Responsibility for BCI-Mediated Action, AJOB Neuroscience, 11(1), 46-58 (2020). read
- H. Maslen & S. Rainey. Control and Ownership of Neuroprosthetic Speech, Philosophy & Technology (2020). read
- N. Schaefer, R. Garcia-Cortadella, A.B. Calia, N. Mavredakis, X. Illa, E. Masvidal-Codina, J.D.L. Cruz, E.D. Corro, L. Rodríguez, E. Prats-Alfonso, J. Bousquet, J. Martínez-Aguilar, A.P. Pérez-Marín, C. Hébert, R. Villa, D. Jiménez, A. Guimerà-Brunet, & J.A. Garrido. Improved metal-graphene contacts for low-noise, high-density microtransistor arrays for neural sensing, Carbon, 161, 647-655 (2020) (2020). read
- A.G. Polyravas, V.F. Curto, N. Schaefer, A. Bonaccini Calia, A. Guimera-Brunet, J.A. Garrido, & G.G. Malliaras. Impact of contact overlap on transconductance and noise in organic electrochemical transistors, Flexible and Printed Electronics, 4, 044003 (2019). read
- S. Rainey, C. Bublitz, H. Maslen, & H. Thornton. Data as a Cross-Cutting Dimension of Ethical Importance in Direct-to-Consumer Neurotechnologies, AJOB Neuroscience, 10(4), 180-182 (2019). read
- N. Mavredakis, W. Wei, E. Pallecchi, D. Vignaud, H. Happy, R.G. Cortadella, A.B. Calia, J.A. Garrido, & D. Jiménez. Velocity Saturation Effect on Low Frequency Noise in Short Channel Single Layer Graphene Field Effect Transistors, Applied Electronic Materials, 1(12) 2626-2636 (2019). read
- A.E. Rochford, A. Carnicer-Lombarte, V.F. Curto, G.G. Malliaras, & D.G. Barone. When Bio Meets Technology: Biohybrid Neural Interfaces, Advanced Materials, 1903182 (2019). read
- S. Rainey, H. Maslen, P. Mégevand, LH. Arnal, E. Fourneret, & B. Yvert. Neuroprosthetic Speech: The Ethical Significance of Accuracy, Control and Pragmatics, Cambridge Quarterly of Healthcare Ethics, 28(4), 1-14 (2019). read
- E. Masvidal-Codina, X. Illa, M. Dasilva, A. Bonaccini Calia, T. Dragojević, E.E: Vidal-Rosas, E. Prats-Alfonso, J. Martínez-Aguilar, J.M. De la Cruz, R. Garcia-Cortadella R, P. Godignon, G. Rius, A. Camassa, E. Del Corro, J. Bousquet, C. Hébert, T. Durduran, R. Villa, M.V. Sanchez-Vives, J.A. Garrido, & A. Guimerà-Brunet. High-resolution mapping of infraslow cortical brain activity enabled by graphene microtransistors, Nature Materials, 18, 280–288 (2019). read
- M. Bernert & B. Yvert. An Attention-Based Spiking Neural Network for Unsupervised Spike-Sorting, International Journal of Neural Systems, 29(8), 1850059 (2019). read
- S. Rainey. ‘A Steadying Hand’: Ascribing Speech Acts to Users of Predictive Speech Assistive Technologies, Journal of Law and Medicine, 26(1), 44-53 (2018). read
- J. Pas, A.L. Rutz, P.P. Quilichini, A. Slézia, A. Ghestem, A. Kaszas, M.J. Donahue, V.F. Curto, R.P. O’Connor, C. Bernard, A. Williamson, & G.G. Malliaras. A bilayered PVA/PLGA-bioresorbable shuttle to improve the implantation of flexible neural probes, Journal of Neural Engineering, 15, 065001 (2018). read
- B. Pesaran, M. Vinck, G. T Einevoll, A. Sirota, P. Fries, M. Siegel, W. Truccolo, C. E Schroeder, & R. Srinivasan. Investigating Large-scale Brain Dynamics Using Field Potential Recordings: Analysis and Interpretation, Nature Neuroscience, 21, 903–919 (2018). read
- J. Rivnay, S. Inal, A. Salleo, R.M. Owens, M. Berggren, & G.G. Malliaras. Organic electrochemical transistors, Nature Reviews Materials, 3, 17086 (2018). read
- F. Bocquele, T. Hueber, L. Girin, S. Chabardès, & B. Yvert. Key considerations in designing a speech brain-computer interface, Journal of Physiology-Paris, 10(4), Part A, 392-401 (2016). read