ALTERED NAVIGATIONAL DEMANDS INDUCE CHANGES IN A CORTICAL BRAIN REGION OF FREE-RANGING NORTHERN PACIFIC RATTLESNAKES (CROTALUS O. OREGANUS)
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1
California Polytechnic State University, Biological Sciences, United States
The cortical telencephalon of squamate reptiles has been implicated as a functional homologue to the avian and mammalian hippocampus. The role of the medial and dorsal cortices in spatial navigation and spatial memory has been demonstrated by multiple laboratory experiments and observational studies in the field. This study sought to experimentally manipulate the navigational demands placed on free-ranging northern Pacific rattlesnakes (Crotalus o. oreganus) to provide direct evidence of the relationship between spatial demands and neuroplasticity in the cortical telencephalon of the squamate brain. Twenty-two adult male snakes were radio-tracked for two months during which one of three treatments was imposed weekly. Treatments consisted of the following: 225 meter translocation in a random direction, 225 meter walk and release at that day’s capture site (handling control), and undisturbed control. Snakes were then sacrificed and brains were removed, embedded in gelatin, frozen, sectioned and Nissl-stained for quantification of cortical volumes. The volume of the medial cortex was significantly larger in the translocated group compared to undisturbed controls. No differences in dorsal or lateral cortical volume were detected among the groups. The range of the snakes measured by minimum convex polygon was larger in the translocated group compared to handled and undisturbed controls. A causal relationship between increased navigation in a free-ranging reptile and changes in brain morphology has been established. Furthermore, sex differences previously described in the medial cortex of Crotaline snakes may be a function of an increased amount of movement in males and not a genetically determined dimorphism.
Acknowledgements
National Science Foundation Pre-doctoral Fellowship to MLH
Keywords:
Medial Cortex,
neuroplasticity,
reptile,
Spatial Ecology,
translocation
Conference:
ISAREN 2011: 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology, Ann Arbor, United States, 11 Jul - 13 Jul, 2011.
Presentation Type:
Poster
Topic:
Brain and behavior
Citation:
Holding
ML,
Buskirk
KM,
Taylor
EN and
Strand
CR
(2011). ALTERED NAVIGATIONAL DEMANDS INDUCE CHANGES IN A CORTICAL BRAIN REGION OF FREE-RANGING NORTHERN PACIFIC RATTLESNAKES (CROTALUS O. OREGANUS).
Front. Endocrinol.
Conference Abstract:
ISAREN 2011: 7th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology.
doi: 10.3389/conf.fendo.2011.03.00019
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Received:
27 Jul 2011;
Published Online:
09 Aug 2011.
*
Correspondence:
Mr. Matthew L Holding, California Polytechnic State University, Biological Sciences, San Luis Obispo, CA, 93407-0401, United States, matthew.holding28@gmail.com