PMID- 31996454
OWN - NLM
STAT- MEDLINE
DCOM- 20200831
LR  - 20200904
IS  - 1529-2401 (Electronic)
IS  - 0270-6474 (Print)
IS  - 0270-6474 (Linking)
VI  - 40
IP  - 10
DP  - 2020 Mar 4
TI  - Robust Rate-Place Coding of Resolved Components in Harmonic and Inharmonic 
      Complex Tones in Auditory Midbrain.
PG  - 2080-2093
LID - 10.1523/JNEUROSCI.2337-19.2020 [doi]
AB  - Harmonic complex tones (HCTs) commonly occurring in speech and music evoke a 
      strong pitch at their fundamental frequency (F0), especially when they contain 
      harmonics individually resolved by the cochlea. When all frequency components of 
      an HCT are shifted by the same amount, the pitch of the resulting inharmonic tone 
      (IHCT) can also shift, although the envelope repetition rate is unchanged. A 
      rate-place code, whereby resolved harmonics are represented by local maxima in 
      firing rates along the tonotopic axis, has been characterized in the auditory 
      nerve and primary auditory cortex, but little is known about intermediate 
      processing stages. We recorded single-neuron responses to HCT and IHCT with 
      varying F0 and sound level in the inferior colliculus (IC) of unanesthetized 
      rabbits of both sexes. Many neurons showed peaks in firing rate when a 
      low-numbered harmonic aligned with the neuron's characteristic frequency, 
      demonstrating "rate-place" coding. The IC rate-place code was most prevalent for 
      F0 > 800 Hz, was only moderately dependent on sound level over a 40 dB range, and 
      was not sensitive to stimulus harmonicity. A spectral receptive-field model 
      incorporating broadband inhibition better predicted the neural responses than a 
      purely excitatory model, suggesting an enhancement of the rate-place 
      representation by inhibition. Some IC neurons showed facilitation in response to 
      HCT relative to pure tones, similar to cortical "harmonic template neurons" (Feng 
      and Wang, 2017), but to a lesser degree. Our findings shed light on the 
      transformation of rate-place coding of resolved harmonics along the auditory 
      pathway.SIGNIFICANCE STATEMENT Harmonic complex tones are ubiquitous in speech 
      and music and produce strong pitch percepts when they contain frequency 
      components that are individually resolved by the cochlea. Here, we characterize a 
      "rate-place" code for resolved harmonics in the auditory midbrain that is more 
      robust across sound levels than the peripheral rate-place code and insensitive to 
      the harmonic relationships among frequency components. We use a computational 
      model to show that inhibition may play an important role in shaping the 
      rate-place code. Our study fills a major gap in understanding the transformations 
      in neural representations of resolved harmonics along the auditory pathway.
CI  - Copyright (c) 2020 the authors.
FAU - Su, Yaqing
AU  - Su Y
AUID- ORCID: 0000-0002-8544-6284
AD  - Eaton-Peabody Labs, Massachusetts Eye & Ear, Boston, Massachusetts 02114.
AD  - Department of Biomedical Engineering, Boston University, Boston, Massachusetts 
      02215, and.
FAU - Delgutte, Bertrand
AU  - Delgutte B
AUID- ORCID: 0000-0003-1349-9608
AD  - Eaton-Peabody Labs, Massachusetts Eye & Ear, Boston, Massachusetts 02114, 
      Bertrand_delgutte@meei.harvard.edu.
AD  - Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts 
      02115.
LA  - eng
GR  - R01 DC002258/DC/NIDCD NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20200129
PL  - United States
TA  - J Neurosci
JT  - The Journal of neuroscience : the official journal of the Society for 
      Neuroscience
JID - 8102140
SB  - IM
MH  - Animals
MH  - Auditory Pathways/physiology
MH  - *Computer Simulation
MH  - Evoked Potentials, Auditory/physiology
MH  - Female
MH  - Inferior Colliculi/*physiology
MH  - Male
MH  - *Models, Neurological
MH  - Neurons/*physiology
MH  - Pitch Perception/*physiology
MH  - Rabbits
PMC - PMC7055142
OTO - NOTNLM
OT  - auditory midbrain
OT  - harmonic complex tone
OT  - harmonic template
OT  - pitch
OT  - rate-place code
OT  - unanesthetized rabbits
EDAT- 2020/01/31 06:00
MHDA- 2020/09/01 06:00
PMCR- 2020/09/04
CRDT- 2020/01/31 06:00
PHST- 2019/09/25 00:00 [received]
PHST- 2020/01/12 00:00 [revised]
PHST- 2020/01/16 00:00 [accepted]
PHST- 2020/01/31 06:00 [pubmed]
PHST- 2020/09/01 06:00 [medline]
PHST- 2020/01/31 06:00 [entrez]
PHST- 2020/09/04 00:00 [pmc-release]
AID - JNEUROSCI.2337-19.2020 [pii]
AID - 2337-19 [pii]
AID - 10.1523/JNEUROSCI.2337-19.2020 [doi]
PST - ppublish
SO  - J Neurosci. 2020 Mar 4;40(10):2080-2093. doi: 10.1523/JNEUROSCI.2337-19.2020. 
      Epub 2020 Jan 29.