Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract
The thalamocingulate tract is a key component of the Papez circuit that connects the anterior thalamic nucleus (ATN) to the cingulum bundle. While the other white matter connections, consisting of the fornix, cingulum bundle and mammillothalamic tract, were well defined in Papez’s original 1937 pape...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-02-01
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| Series: | Frontiers in Neuroanatomy |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fnana.2019.00014/full |
| _version_ | 1819079405946798080 |
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| author | Joshua Weininger Elena Roman Paul Tierney Denis Barry Hugh Gallagher Paul Murphy Kirk J. Levins Veronica O’Keane Erik O’Hanlon Darren W. Roddy Darren W. Roddy |
| author_facet | Joshua Weininger Elena Roman Paul Tierney Denis Barry Hugh Gallagher Paul Murphy Kirk J. Levins Veronica O’Keane Erik O’Hanlon Darren W. Roddy Darren W. Roddy |
| author_sort | Joshua Weininger |
| collection | DOAJ |
| description | The thalamocingulate tract is a key component of the Papez circuit that connects the anterior thalamic nucleus (ATN) to the cingulum bundle. While the other white matter connections, consisting of the fornix, cingulum bundle and mammillothalamic tract, were well defined in Papez’s original 1937 paper, the anatomy of the thalamocingulate pathway was mentioned only in passing. Subsequent research has been unable to clarify the precise anatomical trajectory of this tract. In particular, the site of thalamocingulate tract interactions with the cingulum bundle have been inconsistently reported. This review aims to synthesize research on this least studied component of the Papez circuit. A systemic approach to reviewing historical anatomical dissection and neuronal tracing studies as well as contemporary diffusion magnetic resonance imaging studies of the thalamocingulate tract was undertaken across species. We found that although inconsistent, prior research broadly encompasses two differing descriptions of how the ATN interfaces with the cingulum after passing laterally through the anterior limb of the internal capsule. The first group of studies show that the pathway turns medially and rostrally and passes to the anterior cingulate region (Brodmann areas 24, 33, and 32) only. A second group suggests that the thalamocingulate tract interfaces with both the anterior and posterior cingulate (Brodmann areas 23 and 31) and retrosplenial region (Brodmann area 29). We discuss potential reasons for these discrepancies such as altering methodologies and species differences. We also discuss how these inconsistencies may be resolved in further research with refinements of terminology for the cingulate cortex and the thalamocingulate tract. Understanding the precise anatomical course of the last remaining unresolved final white matter tract in the Papez circuit may facilitate accurate investigation of the role of the complete Papez circuit in emotion and memory. |
| first_indexed | 2024-12-21T19:28:28Z |
| format | Article |
| id | doaj.art-5219225dc0634350bcf7c55c4cc9de82 |
| institution | Directory Open Access Journal |
| issn | 1662-5129 |
| language | English |
| last_indexed | 2024-12-21T19:28:28Z |
| publishDate | 2019-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neuroanatomy |
| spelling | doaj.art-5219225dc0634350bcf7c55c4cc9de822022-12-21T18:52:46ZengFrontiers Media S.A.Frontiers in Neuroanatomy1662-51292019-02-011310.3389/fnana.2019.00014427434Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate TractJoshua Weininger0Elena Roman1Paul Tierney2Denis Barry3Hugh Gallagher4Paul Murphy5Kirk J. Levins6Veronica O’Keane7Erik O’Hanlon8Darren W. Roddy9Darren W. Roddy10REDEEM Group, Department of Psychiatry, Trinity College Dublin, Dublin, IrelandREDEEM Group, Department of Psychiatry, Trinity College Dublin, Dublin, IrelandDepartment of Anatomy, Trinity College Dublin, Dublin, IrelandDepartment of Anatomy, Trinity College Dublin, Dublin, IrelandDepartment of Anaesthesia, Intensive Care and Pain Medicine, St. Vincent’s University Hospital, Dublin, IrelandDepartment of Anaesthesia, Intensive Care and Pain Medicine, St. Vincent’s University Hospital, Dublin, IrelandDepartment of Anaesthesia, Intensive Care and Pain Medicine, St. Vincent’s University Hospital, Dublin, IrelandREDEEM Group, Department of Psychiatry, Trinity College Dublin, Dublin, IrelandREDEEM Group, Department of Psychiatry, Trinity College Dublin, Dublin, IrelandREDEEM Group, Department of Psychiatry, Trinity College Dublin, Dublin, IrelandDepartment of Physiology, School of Medicine, University College Dublin, Dublin, IrelandThe thalamocingulate tract is a key component of the Papez circuit that connects the anterior thalamic nucleus (ATN) to the cingulum bundle. While the other white matter connections, consisting of the fornix, cingulum bundle and mammillothalamic tract, were well defined in Papez’s original 1937 paper, the anatomy of the thalamocingulate pathway was mentioned only in passing. Subsequent research has been unable to clarify the precise anatomical trajectory of this tract. In particular, the site of thalamocingulate tract interactions with the cingulum bundle have been inconsistently reported. This review aims to synthesize research on this least studied component of the Papez circuit. A systemic approach to reviewing historical anatomical dissection and neuronal tracing studies as well as contemporary diffusion magnetic resonance imaging studies of the thalamocingulate tract was undertaken across species. We found that although inconsistent, prior research broadly encompasses two differing descriptions of how the ATN interfaces with the cingulum after passing laterally through the anterior limb of the internal capsule. The first group of studies show that the pathway turns medially and rostrally and passes to the anterior cingulate region (Brodmann areas 24, 33, and 32) only. A second group suggests that the thalamocingulate tract interfaces with both the anterior and posterior cingulate (Brodmann areas 23 and 31) and retrosplenial region (Brodmann area 29). We discuss potential reasons for these discrepancies such as altering methodologies and species differences. We also discuss how these inconsistencies may be resolved in further research with refinements of terminology for the cingulate cortex and the thalamocingulate tract. Understanding the precise anatomical course of the last remaining unresolved final white matter tract in the Papez circuit may facilitate accurate investigation of the role of the complete Papez circuit in emotion and memory.https://www.frontiersin.org/article/10.3389/fnana.2019.00014/fullthalamocingulate tractthalamuscingulumPapez circuitcingulate cortexanterior thalamic radiation |
| spellingShingle | Joshua Weininger Elena Roman Paul Tierney Denis Barry Hugh Gallagher Paul Murphy Kirk J. Levins Veronica O’Keane Erik O’Hanlon Darren W. Roddy Darren W. Roddy Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract Frontiers in Neuroanatomy thalamocingulate tract thalamus cingulum Papez circuit cingulate cortex anterior thalamic radiation |
| title | Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract |
| title_full | Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract |
| title_fullStr | Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract |
| title_full_unstemmed | Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract |
| title_short | Papez’s Forgotten Tract: 80 Years of Unreconciled Findings Concerning the Thalamocingulate Tract |
| title_sort | papez s forgotten tract 80 years of unreconciled findings concerning the thalamocingulate tract |
| topic | thalamocingulate tract thalamus cingulum Papez circuit cingulate cortex anterior thalamic radiation |
| url | https://www.frontiersin.org/article/10.3389/fnana.2019.00014/full |
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