A study of wild California sea lions provides the first neurobiological evidence for how a naturally occurring algal toxin affects both the brains and behavior of the animals, leading to significant deficits in spatial memory. The journal Science is publishing the findings, showing how domoic acid damages the sea lions’ hippocampus and disrupts an important neural network.
“We were able to correlate the extent of the hippocampal damage to specific behavioral impairments relevant to the animals’ survival in the wild,” says lead author Peter Cook, a post-doctoral fellow in the Center for Neuropolicy at Emory University. Cook conducted the sea lion research while a graduate student at the University of California, Santa Cruz, and he is continuing to expand on it at Emory.
“Our research provides a way to model the behavioral and biological effects of this toxin in a large-brain mammal,” Cook says. “Better understanding of these effects may also help us identify subtle effects in humans that may be at risk.”
Although cases of fatal human domoic acid poisoning are rare, due to careful monitoring of fisheries, it is unclear if there are effects that go undetected in communities that eat unmonitored seafood.
Neuroscientist Peter Cook with one of the sea lions that served as a control during the study. (Photos courtesy of the Marine Mammal Center.)