In:
PLOS Computational Biology, Public Library of Science (PLoS), Vol. 17, No. 4 ( 2021-4-14), p. e1008783-
Abstract:
Current hypotheses suggest that speech segmentation—the initial division and grouping of the speech stream into candidate phrases, syllables, and phonemes for further linguistic processing—is executed by a hierarchy of oscillators in auditory cortex. Theta (∼3-12 Hz) rhythms play a key role by phase-locking to recurring acoustic features marking syllable boundaries. Reliable synchronization to quasi-rhythmic inputs, whose variable frequency can dip below cortical theta frequencies (down to ∼1 Hz), requires “flexible” theta oscillators whose underlying neuronal mechanisms remain unknown. Using biophysical computational models, we found that the flexibility of phase-locking in neural oscillators depended on the types of hyperpolarizing currents that paced them. Simulated cortical theta oscillators flexibly phase-locked to slow inputs when these inputs caused both (i) spiking and (ii) the subsequent buildup of outward current sufficient to delay further spiking until the next input. The greatest flexibility in phase-locking arose from a synergistic interaction between intrinsic currents that was not replicated by synaptic currents at similar timescales. Flexibility in phase-locking enabled improved entrainment to speech input, optimal at mid-vocalic channels, which in turn supported syllabic-timescale segmentation through identification of vocalic nuclei. Our results suggest that synaptic and intrinsic inhibition contribute to frequency-restricted and -flexible phase-locking in neural oscillators, respectively. Their differential deployment may enable neural oscillators to play diverse roles, from reliable internal clocking to adaptive segmentation of quasi-regular sensory inputs like speech.
Type of Medium:
Online Resource
ISSN:
1553-7358
DOI:
10.1371/journal.pcbi.1008783
DOI:
10.1371/journal.pcbi.1008783.g001
DOI:
10.1371/journal.pcbi.1008783.g002
DOI:
10.1371/journal.pcbi.1008783.g003
DOI:
10.1371/journal.pcbi.1008783.g004
DOI:
10.1371/journal.pcbi.1008783.g005
DOI:
10.1371/journal.pcbi.1008783.g006
DOI:
10.1371/journal.pcbi.1008783.g007
DOI:
10.1371/journal.pcbi.1008783.g008
DOI:
10.1371/journal.pcbi.1008783.g009
DOI:
10.1371/journal.pcbi.1008783.t001
DOI:
10.1371/journal.pcbi.1008783.t002
DOI:
10.1371/journal.pcbi.1008783.t003
DOI:
10.1371/journal.pcbi.1008783.t004
DOI:
10.1371/journal.pcbi.1008783.t005
DOI:
10.1371/journal.pcbi.1008783.s001
DOI:
10.1371/journal.pcbi.1008783.s002
DOI:
10.1371/journal.pcbi.1008783.s003
DOI:
10.1371/journal.pcbi.1008783.s004
DOI:
10.1371/journal.pcbi.1008783.s005
DOI:
10.1371/journal.pcbi.1008783.s006
DOI:
10.1371/journal.pcbi.1008783.s007
DOI:
10.1371/journal.pcbi.1008783.s008
DOI:
10.1371/journal.pcbi.1008783.r001
DOI:
10.1371/journal.pcbi.1008783.r002
DOI:
10.1371/journal.pcbi.1008783.r003
DOI:
10.1371/journal.pcbi.1008783.r004
DOI:
10.1371/journal.pcbi.1008783.r005
DOI:
10.1371/journal.pcbi.1008783.r006
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2021
detail.hit.zdb_id:
2193340-6
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