Neural Noise

Corticospinal excitability as neurophysiological marker in acquired glycine receptor antibody syndrome

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  • Corticospinal excitability is a distinctive neurophysiological feature of acquired glycine receptor antibody syndrome.1
  • Assessment of corticospinal excitability in this syndrome is reported in Clinical Neurophysiology and is relevant to BCI and neurotech electrophysiology.1 1

Weekly enrichment (2026-07-20)

  • The source article, “Corticospinal excitability as distinctive neurophysiological feature of acquired glycine receptor antibody syndrome,” was published in Clinical Neurophysiology (2026) by Antenucci, Rocchi, Raho, Laudisi, Sensi, Pugliatti, Latorre, and Capone (Italian clinical-neurophysiology groups, including Ferrara and Cagliari).2
  • The paper frames altered corticospinal excitability, assessed with transcranial magnetic stimulation (TMS)—the standard tool for probing corticospinal output and intracortical inhibitory/excitatory circuits—as a distinctive marker of this autoimmune syndrome.2 3
  • Acquired glycine receptor (GlyR) antibody syndrome most often manifests as progressive encephalomyelitis with rigidity and myoclonus (PERM), a stiff-person-spectrum disorder with muscular rigidity, spasms, myoclonus, hyperekplexia (exaggerated startle), and prominent brainstem and autonomic signs.4
  • The glycine receptor is a pentameric ligand-gated chloride channel densely expressed in the brainstem and spinal cord; glycine binding opens chloride influx that hyperpolarizes and suppresses post-synaptic excitation, so loss of this inhibition disinhibits motor neurons and produces stiffness and spasms.5
  • Patient IgG autoantibodies are pathogenic: in cultured spinal motor neurons they nearly abolished glycinergic synaptic currents within about 15 minutes, and they drive cross-linking, internalization, and lysosomal degradation of surface GlyRs, mechanistically linking the antibody to motor-neuron hyperexcitability.6
  • In the largest characterized cohort (41 patients with GlyR-antibody PERM), median age was 58 years and 88% were male; brainstem presentations such as dysphagia and trismus occurred in 56%, the median modified Rankin Scale score at nadir was 5, and 11 patients died (8 from PERM complications).7
  • In that cohort, relapses occurred in 28% of patients surviving beyond 6 months and all responded to immunotherapy, 70% of non-fatal cases reached a good functional outcome (mRS <3) at a median 24 months, and older age plus intensive-care admission independently predicted worse outcomes.7
  • Alpha1-GlyR autoantibodies are detectable in serum or CSF in roughly half of PERM patients, and their discovery reframed the disease as immunotherapy-responsive—context that makes corticospinal-excitability metrics attractive as objective electrophysiological readouts for BCI-adjacent monitoring and treatment tracking.4 3

Footnotes

  1. https://www.sciencedirect.com/science/article/pii/S1388245725013318?dgcid=rss_sd_all ↩ ↩2 ↩3

  2. https://web.unica.it/unica/it/ateneo_s07_ss01_sss05_ssss01.page?contentId=SHD297817 ↩ ↩2

  3. https://doi.org/10.1002/mdc3.14328 ↩ ↩2

  4. https://www.medlink.com/articles/progressive-encephalomyelitis-with-rigidity-and-myoclonus-and-glycine-recep ↩ ↩2

  5. https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.1021437/full ↩

  6. https://doi.org/10.1111/nan.12666 ↩

  7. https://doi.org/10.1212/nxi.0000000000200473 ↩ ↩2

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