Neural dynamics of natural speech: Microscale analysis from long-term intracortical recordings

Diplôme Master Neural dynamics of natural speech: Microscale analysis from long-term intracortical recordings eng 2026-01-27 2026-02-03 author Michaud Nizar Joan 0009-0008-3030-7325 410967 Département des neurosciences cliniques (OTONO) director Proix Timothée 907666 director Megevand Pierre Bastien 0000-0002-0427-547X 510484 Département des neurosciences cliniques (OTONO) 92 Neural representations of speech have been extensively characterized in controlled settings, yet their stability over extended timescales remains untested. We address this gap using continuous week-long intracortical recordings from a Utah microelectrode array in the right inferior parietal lobule of an epileptic patient during unconstrained natural behavior. This naturalistic paradigm required tailored computational approaches: fine-tuned Swiss-German speech recognition, encoding and decoding pipelines across multiple linguistic levels, and rigorous validation through synthetic spike train experiments. Decoding speech presence reached 62% and language identity 40-50% (for 50% and 33% chance levels, respectively), while stimulus-locked responses, word onsets and semantic content, remained at chance. Crucially, classifiers failed to generalize across time, and neural trajectories wandered continuously through state space rather than clustering by condition. These findings expose a tension between laboratory paradigms and ecological reality. Representations that appear stable in controlled sessions may be snapshots of drifting dynamics invisible to short experiments. We discuss implications for speech BCI development, where long-term stability cannot be assumed. Dewey 616.8 Interdisciplinary Master’s degree in Neuroscience 53 Département de neurosciences fondamentales 21A false 1361 Human Neuron Lab 1034 8fa843a4-421d-4918-8c6f-c59f9eb159fd Master thesis Restricted master_thesis_final_amended2_NM.pdf 66988921 application/pdf 0871604f7438a2b06e69921426f7aadd92f44f8ecf94b057898fe388a082e51c restrictedAccess Faculté de médecine / Section de médecine fondamentale / Département de neurosciences fondamentales

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