{
  "annotation_id": "fef5a6a7-a7c5-4c00-b824-894cfdeed057",
  "date_created": "2026-03-02T18:01:35.615000Z",
  "date_modified": "2026-03-02T18:01:35.615000Z",
  "file_hash": "f59692e059d67b65fc6c0a472b926bb219cc81b2348317c24538ec6eeec07a8a",
  "private": false,
  "record": {
    "abstract": "A natural sound can be described by dynamic changes in envelope (amplitude)\nand carrier (frequency), corresponding to amplitude modulation (AM) and\nfrequency modulation (FM) respectively. Although the neural responses to both\nAM and FM sounds are extensively studied in both animals and humans, it is\nuncertain how they are co-represented when changed simultaneously but\nindependently, as is typical for ecologically natural signals. This study\nelucidates the neural coding of such sounds in human auditory cortex using\nmagnetoencephalography (MEG). Using stimuli with both sinusoidal modulated\nenvelope (f_{AM}, 37 Hz) and carrier frequency (f_{FM}, 0.3 - 8 Hz), it is\ndemonstrated that AM and FM stimulus dynamics are co-represented in the neural\ncode of human auditory cortex. The stimulus AM dynamics are represented\nneurally with AM encoding, by the auditory Steady State Response (aSSR) at\nf_{AM}. For sounds with slowly changing carrier frequency ((f_{FM} \u003c 5 Hz), it\nis shown that the stimulus FM dynamics are tracked by the phase of the aSSR,\ndemonstrating neural phase modulation (PM) encoding of the stimulus carrier\nfrequency. For sounds with faster carrier frequency change ((f_{FM} \u003e= 5 Hz),\nit is shown that modulation encoding of stimulus FM dynamics persists, but the\nneural encoding is no longer purely PM. This result is consistent with the\nrecruitment of additional neural AM encoding over and above the original neural\nPM encoding, indicating that both the amplitude and phase of the aSSR at f_{AM}\ntrack the stimulus FM dynamics. A neural model is suggested to account for\nthese observations.",
    "arxiv_id": "q-bio/0602025",
    "authors": [
      "Huan Luo",
      "Yadong Wang",
      "David Poeppel",
      "Jonathan Z. Simon"
    ],
    "categories": [
      "q-bio.NC"
    ],
    "title": "Concurrent encoding of frequency and amplitude modulation in human   auditory cortex: MEG evidence",
    "url": "https://arxiv.org/abs/q-bio/0602025"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "3d94d781-151d-4e3b-894f-acb2db7b14ac",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}