Nov. 4, 2009 -- The first detailed anatomical atlas of a living wildlife species has been constructed by researchers.

Mapping the California sea lion's (Zalophus californianus) brain with a combination of magnetic resonance imaging (MRI) and volumetric measuring, scientists want to better understand how toxins in the water are causing neurological damage among marine mammal populations.

Eric Montie, a postdoctoral researcher at the University of South Florida, spearheaded the study, which was published in The Anatomical Record in October.

The brain atlas is a first step toward determining whether exposure to manmade chemicals, such as DDT and polychlorinated biphenyls (PCBs), increase California sea lions' susceptibility to life-threatening brain damage from domoic acid, a neurotoxin naturally produced by certain types of algae.

Past studies have concluded that domoic acid, which accumulates in the sea lion's system from ingesting prey that feed on algae, causes the mammal's hippocampus to shrink. Research has also linked domoic acid to acute and chronic epilepsy and seizures in sea lions.

But exactly how that neurotoxin-induced brain damage progresses is still unclear.

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"We don't know enough about the endocrinology and neurobiology of these animals," Montie told Discovery News. "That's why you start with baby steps like an atlas."