Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe
The brains of odontocetes (toothed whales) look grossly different from their terrestrial relatives. Because of their adaptation to the aquatic environment and their reliance on echolocation, the odontocetes' auditory system is both unique and crucial to their survival. Yet, scant data exist abo...
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crroyalsociety:10.1098/rspb.2015.1203 2024-09-30T14:44:59+00:00 Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe Berns, Gregory S. Cook, Peter F. Foxley, Sean Jbabdi, Saad Miller, Karla L. Marino, Lori 2015 http://dx.doi.org/10.1098/rspb.2015.1203 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2015.1203 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2015.1203 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Proceedings of the Royal Society B: Biological Sciences volume 282, issue 1811, page 20151203 ISSN 0962-8452 1471-2954 journal-article 2015 crroyalsociety https://doi.org/10.1098/rspb.2015.1203 2024-09-02T04:21:08Z The brains of odontocetes (toothed whales) look grossly different from their terrestrial relatives. Because of their adaptation to the aquatic environment and their reliance on echolocation, the odontocetes' auditory system is both unique and crucial to their survival. Yet, scant data exist about the functional organization of the cetacean auditory system. A predominant hypothesis is that the primary auditory cortex lies in the suprasylvian gyrus along the vertex of the hemispheres, with this position induced by expansion of ‘associative′ regions in lateral and caudal directions. However, the precise location of the auditory cortex and its connections are still unknown. Here, we used a novel diffusion tensor imaging (DTI) sequence in archival post-mortem brains of a common dolphin ( Delphinus delphis ) and a pantropical dolphin ( Stenella attenuata ) to map their sensory and motor systems. Using thalamic parcellation based on traditionally defined regions for the primary visual (V1) and auditory cortex (A1), we found distinct regions of the thalamus connected to V1 and A1. But in addition to suprasylvian-A1, we report here, for the first time, the auditory cortex also exists in the temporal lobe, in a region near cetacean-A2 and possibly analogous to the primary auditory cortex in related terrestrial mammals (Artiodactyla). Using probabilistic tract tracing, we found a direct pathway from the inferior colliculus to the medial geniculate nucleus to the temporal lobe near the sylvian fissure. Our results demonstrate the feasibility of post-mortem DTI in archival specimens to answer basic questions in comparative neurobiology in a way that has not previously been possible and shows a link between the cetacean auditory system and those of terrestrial mammals. Given that fresh cetacean specimens are relatively rare, the ability to measure connectivity in archival specimens opens up a plethora of possibilities for investigating neuroanatomy in cetaceans and other species. Article in Journal/Newspaper toothed whales The Royal Society Proceedings of the Royal Society B: Biological Sciences 282 1811 20151203 |
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The Royal Society |
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English |
description |
The brains of odontocetes (toothed whales) look grossly different from their terrestrial relatives. Because of their adaptation to the aquatic environment and their reliance on echolocation, the odontocetes' auditory system is both unique and crucial to their survival. Yet, scant data exist about the functional organization of the cetacean auditory system. A predominant hypothesis is that the primary auditory cortex lies in the suprasylvian gyrus along the vertex of the hemispheres, with this position induced by expansion of ‘associative′ regions in lateral and caudal directions. However, the precise location of the auditory cortex and its connections are still unknown. Here, we used a novel diffusion tensor imaging (DTI) sequence in archival post-mortem brains of a common dolphin ( Delphinus delphis ) and a pantropical dolphin ( Stenella attenuata ) to map their sensory and motor systems. Using thalamic parcellation based on traditionally defined regions for the primary visual (V1) and auditory cortex (A1), we found distinct regions of the thalamus connected to V1 and A1. But in addition to suprasylvian-A1, we report here, for the first time, the auditory cortex also exists in the temporal lobe, in a region near cetacean-A2 and possibly analogous to the primary auditory cortex in related terrestrial mammals (Artiodactyla). Using probabilistic tract tracing, we found a direct pathway from the inferior colliculus to the medial geniculate nucleus to the temporal lobe near the sylvian fissure. Our results demonstrate the feasibility of post-mortem DTI in archival specimens to answer basic questions in comparative neurobiology in a way that has not previously been possible and shows a link between the cetacean auditory system and those of terrestrial mammals. Given that fresh cetacean specimens are relatively rare, the ability to measure connectivity in archival specimens opens up a plethora of possibilities for investigating neuroanatomy in cetaceans and other species. |
format |
Article in Journal/Newspaper |
author |
Berns, Gregory S. Cook, Peter F. Foxley, Sean Jbabdi, Saad Miller, Karla L. Marino, Lori |
spellingShingle |
Berns, Gregory S. Cook, Peter F. Foxley, Sean Jbabdi, Saad Miller, Karla L. Marino, Lori Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
author_facet |
Berns, Gregory S. Cook, Peter F. Foxley, Sean Jbabdi, Saad Miller, Karla L. Marino, Lori |
author_sort |
Berns, Gregory S. |
title |
Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
title_short |
Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
title_full |
Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
title_fullStr |
Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
title_full_unstemmed |
Diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
title_sort |
diffusion tensor imaging of dolphin brains reveals direct auditory pathway to temporal lobe |
publisher |
The Royal Society |
publishDate |
2015 |
url |
http://dx.doi.org/10.1098/rspb.2015.1203 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2015.1203 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2015.1203 |
genre |
toothed whales |
genre_facet |
toothed whales |
op_source |
Proceedings of the Royal Society B: Biological Sciences volume 282, issue 1811, page 20151203 ISSN 0962-8452 1471-2954 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rspb.2015.1203 |
container_title |
Proceedings of the Royal Society B: Biological Sciences |
container_volume |
282 |
container_issue |
1811 |
container_start_page |
20151203 |
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1811645940828733440 |