Using New Techniques, Caltech Professor Gains Insight on the Human Mind Through the Brains of Animals

A Caltech biology professor says scientists are increasing their understanding of the human mind by studying the brains of animals in new ways using new techniques which may lead to applications in human psychiatry.

Medical researchers and biologists have long depended on experimentation on animals, such as mice, to glean knowledge about how similar systems in humans work.

But when it comes to studying the human mind and treating psychiatric conditions, animal studies have major limitations, Professor David J. Anderson explained.

“There’s ongoing debate about whether those are the right sort of models to use for testing drugs to treat emotional disorders,” Anderson said. “And part of the reason for that is that people can’t even agree on whether animals have emotions or not.”

But using new techniques, including optagenetics and calcium imaging, scientists are working to better understand the inner working of animal brains, rather than relying on merely studying their behavior.

“The hope was that bringing some hard-nosed basic neuroscience to this problem could help bridge the gap between psychology, which studies how humans think and feel, and ethology, which is the science of animal behavior that studies what animals do, but doesn’t really pay much attention to what’s going on inside their brains,” Anderson said.

As it stands, “There’s still a lot of debate about whether the rodent brain, and particularly the part that deals with emotion, is close enough to the human brain to make it a viable test system,” he said. “And that’s been reinforced by the fact that there hasn’t been a fundamentally new drug for treating any kind of psychiatric disorder in the last 50 years, with the possible exception of ketamine, and that’s because most of the new drugs that have been tested in animal models for psychiatric disorders have failed in the clinic when they’ve then been tested in humans.”

Through optagenetics, researchers are able to manipulate the activity of neurons inside animals’ brains, and with calcium imaging, brain activity can be measured in detail never possible before.

“These are both invasive techniques, meaning you have to put things into the brain to be able to use them, so they can’t be used in human studies,” according to Anderson. “But they’re very powerful.”

Using the tools, Anderson said his goal is to “better understand the brain states that are activated when animals are engaged in behaviors that are associated with emotions in humans, like aggression or fear or mating behavior,” he said. “Patterns of activity underlying similar emotional states in a rat or a mouse and a human might be similar, even if the behavior isn’t, for example.”

“When a mouse is threatened, it will rattle its tail,” Anderson said. “You can’t test the ability of a drug to block tail rattling in humans because we don’t have tales to rattle, but it could be that the same groups of neurons, or similar neurons in similar brain regions, are affected by a threat in an animal and in a human.”

“And that if we found a drug that could block the change in brain activity that causes the stress that produces the tail rattle in rodents, we could test humans to see if the drug similarly affected patterns of brain activity associated with fear and stress in a human,” he said. “So that we would be comparing sort of the signal inside the brain, rather than the external behavior of the animals of the humans.”

Anderson will discuss these new developments in a presentation Wednesday evening.

“The Inner Life of the Brain: Fear, Sex, and Violence,” will be held at 5 p.m. via Zoom, according to Caltech.

Anderson is Caltech’s Seymour Benzer Professor of Biology. He also serves as Tianqiao and Chrissy Chen Institute for Neuroscience Leadership chair; investigator for the Howard Hughes Medical Institute; and director of the Tianqiao and Chrissy Chen Institute for Neuroscience.

Pre-registration for the Zoom presentation is required and can be completed online at caltech.edu/campus-life-events/master-calendar/watson-lecture-2020-12. A recording is scheduled to be uploaded to Caltech’s YouTube page at youtube.com/user/caltech at 8 p.m.