There have always been doubts on the use of laboratory animals as a research model for behavioural experiments relevant to humans. Now, researchers have made a novel discovery demonstrating that laboratory animals can be accurately used to study human behaviours.
They have identified an alteration to the DNA of a gene that imparts similar anxiety-related behaviour in both humans and mice.
The findings may help researchers develop new clinical strategies to treat humans with anxiety disorders, such as phobias and post-traumatic stress disorder (PTSD).
"We found that humans and mice who had the same human genetic alteration also had greater difficulty in extinguishing an anxious-like response to adverse stimuli," said Dr. B.J. Casey, co-senior author of the study and professor of psychology in psychiatry from The Sackler Institute for Developmental Psychobiology at Weill Cornell Medical College.
The researchers observed common behavioural responses between humans and mice that possess an alteration in the brain-derived neurotrophic factor (BDNF) gene.
The mice were genetically altered - meaning that they had a human genetic variation inserted within their genome.
During the study, researchers paired a harmless stimulus with an aversive one, which elicits an anxious-like response, known as conditioned fear.
The researchers also performed brain scans using functional magnetic resonance imaging (fMRI), on the human participants, to see if brain function differed between people with the abnormal BDNF gene and those with normal BDNF genes.
They found that a circuit in the brain involving the frontal cortex and amygdala - responsible for learning about cues that signal safety and danger - was altered in people with the abnormality, when compared with control participants who did not have the abnormality.
"Testing for this gene may one day help doctors make more informed decisions for treatment of anxiety disorders," said Dr. Francis S. Lee, co-senior author of the study and associate professor of psychiatry and pharmacology at Weill Cornell Medical College.
The study is published in the journal Science.