An MRI protocol for anatomical and functional evaluation of the California sea lion brain

Peter F Cook; Vanessa A Hoard; Sudipto Dolui; Blaise deB Frederick; Richard Redfern; Sophie E Dennison; Barbie Halaska; Josh Bloom; Kris T Kruse-Elliott; Emily R Whitmer; Emily J Trumbull; Gregory S Berns; John A Detre; Mark D'Esposito; Frances M D Gulland; Colleen Reichmuth; Shawn P Johnson; Cara L Field; Ben A Inglis

doi:10.1016/j.jneumeth.2021.109097

An MRI protocol for anatomical and functional evaluation of the California sea lion brain

J Neurosci Methods. 2021 Apr 1:353:109097. doi: 10.1016/j.jneumeth.2021.109097. Epub 2021 Feb 10.

Authors

Peter F Cook¹, Vanessa A Hoard², Sudipto Dolui³, Blaise deB Frederick⁴, Richard Redfern⁵, Sophie E Dennison⁶, Barbie Halaska², Josh Bloom⁷, Kris T Kruse-Elliott⁷, Emily R Whitmer², Emily J Trumbull², Gregory S Berns⁸, John A Detre⁹, Mark D'Esposito¹⁰, Frances M D Gulland¹¹, Colleen Reichmuth¹², Shawn P Johnson², Cara L Field², Ben A Inglis¹³

Affiliations

¹ Department of Biopsychology, New College of Florida, 5800 Bay Shore Road, Sarasota, FL, 34243, USA.
² The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA, 94965, USA.
³ Department of Radiology, University of Pennsylvania Perelman School of Medicine, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
⁴ Department of Psychiatry, Harvard University Medical School, 25 Shattuck St, Boston, MA, 02115, USA; McLean Hospital Brain Imaging Center, 115 Mill St., Belmont, MA, 02478, USA.
⁵ Henry H. Wheeler, Jr. Brain Imaging Center, 188 Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, CA, 94720, USA.
⁶ TeleVet Imaging Solutions, PLLC, Oakton, VA, 22124, USA.
⁷ AnimalScan Advanced Veterinary Imaging, 934 Charter St, Redwood City, CA, 94063, USA.
⁸ Psychology Department, Emory University, 36 Eagle Row, Atlanta, GA, 30322, USA.
⁹ Department of Radiology, University of Pennsylvania Perelman School of Medicine, 3400 Spruce Street, Philadelphia, PA, 19104, USA; Department of Neurology, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA.
¹⁰ Henry H. Wheeler, Jr. Brain Imaging Center, 188 Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, CA, 94720, USA; Helen Wills Neuroscience Institute, University of California, 132 Barker Hall, Berkeley, CA, 94720, USA.
¹¹ School of Veterinary Medicine Wildlife Health Center, University of California at Davis, 1089 Veterinary Medicine Dr, Davis, CA, 95616, USA.
¹² Long Marine Laboratory, Institute of Marine Sciences, University of California at Santa Cruz, 115 McAllister Way, Santa Cruz, CA, 95060, USA.
¹³ Henry H. Wheeler, Jr. Brain Imaging Center, 188 Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, CA, 94720, USA. Electronic address: binglis@berkeley.edu.

PMID: 33581216
DOI: 10.1016/j.jneumeth.2021.109097

Abstract

Background: Domoic acid (DOM) is a neurotoxin produced by some harmful algae blooms in coastal waters. California sea lions (Zalophus californianus) exposed to DOM often strand on beaches where they exhibit a variety of symptoms, including seizures. These animals typically show hippocampal atrophy on MRI scans.

New method: We describe an MRI protocol for comprehensive evaluation of DOM toxicosis in the sea lion brain. We intend to study brain development in pups exposed in utero. The protocol depicts the hippocampal formation as the primary region of interest. We include scans for quantitative morphometry, functional and structural connectivity, and a cerebral blood flow map.

Results: High-resolution 3D anatomical scans facilitate post hoc slicing in arbitrary planes and accurate morphometry. We demonstrate the first cerebral blood flow map using MRI, and the first structural tractography from a live sea lion brain.

Comparison with existing methods: Scans were compared to prior anatomical and functional studies in live sea lions, and structural connectivity in post mortem specimens. Hippocampal volumes were broadly in line with prior studies, with differences likely attributable to the 3D approach used here. Functional connectivity of the dorsal left hippocampus matched that found in a prior study conducted at a lower magnetic field, while structural connectivity in the live brain agreed with findings observed in post mortem studies.

Conclusions: Our protocol provides a comprehensive, longitudinal view of the functional and anatomical changes expected to result from DOM toxicosis. It can also screen for other common neurological pathologies and is suitable for any pinniped that can fit inside an MRI scanner.

Keywords: California sea lion; Domoic acid; Epilepsy; Hippocampus; MRI; Pinniped.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Brain / diagnostic imaging
Hippocampus
Magnetic Resonance Imaging
Sea Lions*