Brain protein may play role in innate and learned fear

In a paper published in the November 2005 issue of Cell, researchers reported that the protein stathmin is essential for the fear response – both the expression of innate fear and the formation of memory for learned fear.

Previous studies had shown that the amygdala, a brain structure important for emotional responses, is the place where fear memory is formed.

“This is the first time it has been shown that the protein called stathmin – the product of the stathmin gene – is linked to fear conditioning pathways,” said Vadim Bolshakov, PhD, director of the Cellular Neurobiology Laboratory at McLean Hospital. The study is the collaborative effort of Bolshakov’s lab at McLean and those of Eric Kandel at Columbia University and Gleb Shumyatsky of Rutgers. Kandel is the winner of the 2000 Nobel Prize in physiology or medicine.

The researchers for some time have been studying how changes in the brain may affect learning and memory. In earlier animal studies, Bolshakov and Kandel were able to measure changes in the brain and correlate them with changes in behavior associated with learning.

This study, using mice, demonstrated that those that were genetically modified so they would not produce stathmin showed deficits in neural transmission and exhibited decreased memory in fear conditioning and the failure to recognize danger in innately aversive environments. Learned fear develops after conditioning and lasts for life.

“The evidence that stathmin is important in the regulation of fear suggests that stathmin knockout mice can be used as a model of anxiety states or mental disorders with innate and learned fear components,” the paper said.

In the future, these animal models may be used to develop new anti-anxiety drugs, Bolshakov added.