Researchers have confirmed that animal studies of behavior are relevant for human behavior.
In a finding that could help other researchers develop strategies for treating patients with such anxiety disorders as PTSD and some phobias, the team identified a DNA alteration the brain-derived neurotrophic factor (BDNF) gene that “imparts similar anxiety-related behavior in both humans and mice,” confirming that the animals can be used to accurately study such human behavior.
"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," explained Dr. B.J. Casey, co-senior author of the study and professor of psychology in psychiatry, The Sackler Institute for Developmental Psychobiology, Weill Cornell Medical College.
To compare mice the human participants, the researchers “paired a harmless stimulus with an aversive one, which elicits an anxious-like response, known as conditioned fear.” Eventually, after exposing the subject to the harmless stimulus with the aversive stimulus, fear response should end.
"But both the mice and humans found to have the alternation in the BDNF gene took significantly longer to 'get over' the innocuous stimuli and stop having a conditioned fear response," explained Dr. Fatima Soliman, lead author of the study and a Tri-Institutional MD-PhD student.
The research didn’t end there; the team also performed functional MRI scans on human participants to determine if brain function was different between those with the abnormal BDNF gene and those without. In those with the abnormality, an alteration was seen in the brain circuit that involves the frontal cortex and the amygdala.
"Testing for this gene may one day help doctors make more informed decisions for treatment of anxiety disorders," explained Dr. Francis S. Lee, co-senior author and associate professor of psychiatry and pharmacology, Weill Cornell Medical College.
With no clear answer to whether the study of animals in behavioral experiments—which have long been a staple of psychological research—results in observations that are relevant for human behavior, Weill Cornell Medical College researchers recently sought to set the record straight.