Anterior Cingulate Cortex Projections to the Amygdala in Primates: Topographic and Layer-Specific Organization Underlying Emotion and Mood Regulation
- Kei Kimura1,2,*,
- Yuki Soga1,*,
- Rintaro Yoshino1,*,
- Andi Zheng2,
- Satoshi Nonomura2,
- Gaoge Yan2,
- Soshi Tanabe2,
- Shinya Nakamura1,
- Shinya Ohara1,
- Ken-ichi Inoue2,3,
- Masahiko Takada1,2,4 and
- Ken-Ichiro Tsutsui1
- 1Laboratory of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Miyagi 980-8577, Japan
- 2Institute for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi 484-8506, Japan
- 3Department of Integrative Anatomy, Graduate School of Medical Sciences and Medical School, Nagoya City University, Nagoya, Aichi 467-8601, Japan
- 4Department of Neurology, The University of Osaka Graduate School of Medicine, Suita, Osaka 565-0871, Japan
- Correspondence should be addressed to Masahiko Takada at primasa4208{at}gmail.com or Ken-Ichiro Tsutsui at tsutsui{at}tohoku.ac.jp.
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Author contributions: M.T. and K-I.T. designed research; K.K., Y.S., R.Y., A.Z., S.N., G.Y., S.T., S.N., S.O., and K-i.I. performed research; K.K., Y.S., and R.Y. analyzed data; K.K., Y.S., R.Y., M.T., and K-I.T. wrote the paper.
Abstract
Emotion and mood regulation critically depends on interactions between the anterior cingulate cortex (ACC) and the amygdala. However, the detailed architecture of ACC projections to their major targets, the basal (BA) and accessory (AcBA) basal nuclei of the amygdala, remains unclear. To address this issue, a combined retrograde and anterograde tracing with viral vectors was performed in macaques of either sex to map the projection patterns from the pregenual (pgACC), subgenual (sgACC), and dorsal (dACC) subareas. Data revealed that ACC neurons projecting to the BA arose predominantly from the superficial layers (II/III) of all subareas and the deep layers (V/VI) of the sgACC, whereas ACC neurons projecting to the AcBA originated mainly in the deep layers of the sgACC and dACC. The present study defines the topographic and layer-specific organization of ACC–amygdala connectivity in primates and subserves to provide an anatomical basis for future causal and translational approaches, such as targeted interventions against ACC-related mood disorders.
Footnotes
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This work was supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT)/Japan Society for the Promotion of Science (JSPS) KAKENHI under grant numbers 24K23229, 25K18578, 26K00009 (to K.K.), 22H04922 (AdAMS; to K.K. and K-i.I.), 22H05157 (to K-i.I.), 24K02338 (to M.T.), 24223004, 26112009, 26560455, 17H01014, 19H05725, 20H00104, 23H00073, and 24H00700 (to K-I.T.); the Moonshot Research and Development Program (Goal 9) of the Japan Science and Technology Agency (JST) under grant numbers JPMJMS2295-12 (to K-i.I.) and JPMJMS2292 (to K-I.T.); JST K Program Grant Number JPMJKP25Y8 (to K-I.T.); Suzuken Memorial Foundation under grant number 24-069 (to K.K.). We are grateful to M. Fujiwara, M. Nakano, E. Sumiya, E. Tanaka, W. Lu, X. Zhao, H. Minegishi, and T. Moritani for their technical assistance. Generative AI and AI-assisted technologies were used in the writing process for correcting and improving upon grammatical and spelling errors to improve readability. The authors reviewed and edited the content as needed and take full responsibility for the content of the published article.
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↵*K.K., Y.S., and R.Y. are co-first authors.
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The authors declare no competing financial interests.
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This paper contains supplemental material available at: https://doi.org/10.1523/JNEUROSCI.0671-26.2026
- Received April 22, 2026.
- Revision received July 15, 2026.
- Accepted July 31, 2026.
- Copyright © 2026 Kimura et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.
