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An exploratory fNIRS study on directional asymmetry in segmental discrimination: Lateral-rhotic (/la-ra/) and labial-dorsal (/ba-ga/) contrasts tested in 5- and 9-month-old Japanese infants.

Code ↔ Paper

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The 4 matches · all tie a paragraph to a whole file, not to given lines: weak matches, whose lines are not tinted
  1. [1] § Materials and methods › Analysis ↔ figure56.ipynb, the whole file · a weak match · score 0.85 · 5–25 seconds, deoxy Hb, left hemisphere, right hemisphere, ROIs, raw
  2. [2] § Results › NIRS experiment ↔ figure56.ipynb, the whole file · a weak match · score 0.78 · individual channels, Bonferroni corrected, deoxy Hb, right hemisphere, ROIs, Cohen
  3. [3] § Materials and methods › Analysis ↔ ROI2ch.ipynb, the whole file · a weak match · score 0.75 · deoxy Hb, left hemisphere, right hemisphere, raw, Channels, 0.01 Hz
  4. [4] § Results › NIRS experiment ↔ ROI2ch.ipynb, the whole file · a weak match · score 0.73 · Bonferroni corrected, deoxy Hb, right hemisphere, Cohen, ba ga, channels

Paper

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The authors' code

Jupyter notebook · 137 lines · 747 KB · no license · 2 matches

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Overview

Authors: Yoritaka Akimoto1,2, Miki Takahasi2, Naoto Yamane2, Natsumi Shibata2, Rachel Ka-Ying Tsui2, Reiko Mazuka2,3
ORCID iDs: Yoritaka Akimoto, Rachel Ka-Ying Tsui
  1. Information and Management Systems Engineering, Nagaoka University of Technology, Kamitomioka, Nagaoka, Niigata, Japan
  2. RIKEN Center for Brain Science, Wako, Saitama, Japan
  3. Department of Psychology and Neuroscience, Duke University, Durham, North Carolina, United States of America
Institutions: RIKEN Center for Brain Science (Japan); Nagaoka University of Technology (Japan); Duke University (United States)
Journal: PloS one, volume 21, issue 9, article e0358044
Dates: received 17 September 2025; accepted 26 August 2026; published online 11 September 2026
Type: Research article · Language: English
License: CC BY
Identifiers: DOI 10.1371/journal.pone.0358044 · PMID 42726786 · PMCID PMC13567765 · OpenAlex W7204744715
Open access: gold, a free copy (OpenAlex)
Preprint: osf.io/xh6pm
Status: code verified
Categories: fNIRS (modality), human (organism), developmental (subfield)
Methods: Spectral & time-frequency, Statistics, Preprocessing, fMRI & imaging
MeSH: Discrimination, Psychological*, Speech Perception*, Female, Hemodynamics, Humans, Infant, Japan, Male, Oxyhemoglobins, Spectroscopy, Near-Infrared, Temporal Lobe (* major topic)
Journal subjects: People and Places, Population Groupings, Age Groups, Children, Infants, Families, Physical Sciences, Physics, Acoustics, Research and Analysis Methods, Spectrum Analysis Techniques, Infrared Spectroscopy, near-Infrared Spectroscopy, Social Sciences, Linguistics, Speech, Grammar, Phonology, Medicine and Health Sciences, Hematology, Hemodynamics, Syllables, Biology and Life Sciences, Neuroscience, Cognitive Science, Cognitive Psychology, Perception, Sensory Perception, Psychology
Topic: Hemispheric Asymmetry in Neuroscience (Cognitive Neuroscience, Neuroscience), according to OpenAlex
Funding: Japan Society for the Promotion of Science (16K12451, 16H06319, 20H05617); RIKEN (RIKEN Pioneering Research Project (Neurophysiological mechanisms toward input-driven language development))
Citations: not cited yet (Europe PMC); 58 references in the paper

Abstract

Directional asymmetry refers to the order-dependent difference in segmental discrimination; however, its underlying cortical mechanisms remain unclear. This exploratory study used near-infrared spectroscopy to measure hemodynamic responses in 5- and 9-month-old Japanese infants (N = 30 [14 girls, 16 boys] and N = 40 [16 girls, 24 boys], respectively) to the lateral–rhotic /la–ra/ and labial–dorsal /ba–ga/ contrasts and to examine whether directional asymmetry was observed. Post hoc analysis revealed significant directional asymmetry for the /la–ra/ contrast in 5-month-old infants, characterized by decreased oxyhemoglobin levels in the right middle-anterior temporal channels, specifically for the /ra/-to-/la/ change. This localized response in the middle portion of the superior temporal gyrus, a region associated with tracking acoustic properties, suggests that infants at this age may rely on acoustic-level processing rather than on fully established phonological categories. This relative deactivation, observed in 5-month-olds but not in 9-month-olds and in the direction that appeared more difficult to discriminate, suggests a potential association between discrimination difficulty and the hemodynamic response. Specifically, the acoustic complexity of the /ra/ standard stimuli could have imposed a higher computational load, potentially leading to incomplete encoding during the baseline periods. This incomplete processing may have elevated hemodynamic activity, thereby resulting in a relative decrease in response to the subsequent change to /la/ stimuli. This phenomenon aligns with the perceptual space learning account, in which hemodynamic activity potentially reflects the computational load involved in the continuous calibration of an infant’s developing perceptual space. Future studies should directly assess this hypothesis.

Reproduced under the paper's license (CC BY), from the paper cited above.

Repository

Its files are read in the Code ↔ Paper reader above, with 4 matches between paragraphs and lines of code.

OSF xh6pm

License: none: the authors keep all their rights
State: the link answers, verified on 26 September 2026
Evidence: files inventoried
Languages: Jupyter (5)
Size: 15 files, 5 scripts
Software Heritage: not checked
Found in: “Data Availability”
Holds: 5 notebooks
Not found: README, license file, CITATION.cff, environment file, tests, continuous integration, documentation
Tools: NumPy (5 files), pandas (5 files), Matplotlib (4 files), Pingouin (4 files), SciPy (3 files), seaborn (2 files)
Availability: 1 check, the latest on 26 September 2026: the link answers (HTTP 200)
  • 26 September 2026: the link answers (HTTP 200)
5 files, to read at the source

This repository has no license: its authors keep all rights. Read it at the source.

At the source: osf.io/xh6pm/

The paper's code and data availability statement is in the Data section.

Tracing map

Proposed by the machine: these links were found in the paper and verified at the source, without human review. The map will receive a Zenodo DOI once one of the paper's authors has validated it with their ORCID.

What the map holds:

  • 1 repository of the authors' code, each at its verified commit, with its license and how the link was found in the paper;
  • 5 scripts, each with its path and the digest of its content;
  • 4 matches between paragraphs of the paper and lines of the code (method lexical-v1);
  • neither the text of the paper nor the code itself.

Its JSON (tracing-map.json) is deposited on Zenodo with its DOI once the map is validated.

Data

No dataset and no data link were found in the paper.

Data Availability

Processed data and analysis code used for statistical analyses, except for the analysis of variance (ANOVA), are openly available on the Open Science Framework (OSF) (https://osf.io/xh6pm/). ANOVA analyses were conducted using the R package “Anovakun” (https://riseki.cloudfree.jp/?ANOVA%E5%90%9B) (https://riseki.cloudfree.jp/?ANOVA君).

Reproduced under the paper's license (CC BY), from the paper cited above.

Versions

The history of this record: each version stored by the harvester or made by a correction of its authors or of the maintainers of its code, and what changed in its facts. The texts of the paper (its abstract, its availability statements) are not part of it; versions that changed only those are not listed.

Version 1, 27 September 2026: the first record

Recorded: type, language, journal, volume, issue, pages, dates, 6 authors, 11 MeSH terms, 2 funders, 56 references.

Cite

This paper

Akimoto, Y., Takahasi, M., Yamane, N., Shibata, N., Tsui, R. K.-Y., & Mazuka, R. (2026). An exploratory fNIRS study on directional asymmetry in segmental discrimination: Lateral-rhotic (/la-ra/) and labial-dorsal (/ba-ga/) contrasts tested in 5- and 9-month-old Japanese infants. PloS one, 21(9), e0358044. https://doi.org/10.1371/journal.pone.0358044

BibTeX

@article{akimoto2026exploratory,
author = {Akimoto, Yoritaka and Takahasi, Miki and Yamane, Naoto and Shibata, Natsumi and Tsui, Rachel Ka-Ying and Mazuka, Reiko},
title = {{An exploratory fNIRS study on directional asymmetry in segmental discrimination: Lateral-rhotic (/la-ra/) and labial-dorsal (/ba-ga/) contrasts tested in 5- and 9-month-old Japanese infants}},
journal = {PloS one},
year = {2026},
month = sep,
volume = {21},
number = {9},
pages = {e0358044},
publisher = {PLOS},
issn = {1932-6203},
doi = {10.1371/journal.pone.0358044},
url = {https://doi.org/10.1371/journal.pone.0358044},
pmid = {42726786},
pmcid = {PMC13567765}
}

RIS

TY - JOUR
AU - Akimoto, Yoritaka
AU - Takahasi, Miki
AU - Yamane, Naoto
AU - Shibata, Natsumi
AU - Tsui, Rachel Ka-Ying
AU - Mazuka, Reiko
TI - An exploratory fNIRS study on directional asymmetry in segmental discrimination: Lateral-rhotic (/la-ra/) and labial-dorsal (/ba-ga/) contrasts tested in 5- and 9-month-old Japanese infants
T2 - PloS one
J2 - PLoS One
PY - 2026
DA - 2026/09/11
VL - 21
IS - 9
SP - e0358044
SN - 1932-6203
PB - PLOS
DO - 10.1371/journal.pone.0358044
UR - https://doi.org/10.1371/journal.pone.0358044
LA - en
ER -

CSL-JSON

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