Struggling to forget
Memory researcher studies the causes of post-traumatic stress disorder in hopes of a cure.
Mar. 17, 2016
Adapted from a piece by Andrea Kingwell, UToday.
Why is it that after a shocking or terrifying experience some people can move on with life while others — unable to control or contain fear memories — suffer with the stultifying effects associated with post-traumatic stress disorder (PTSD)?
It’s a question that compels memory expert Maria Morena, a postdoctoral scholar in the Hotchkiss Brain Institute at the Cumming School of Medicine, who is looking to the brain’s circuitry and chemistry for answers. She studies how memories are created, how those memories are tagged with significance like “danger” or “fear”, and how the brain works to dim or detag those associations over time.
A key player in that memory mechanism appears to be the endocannabinoid system, a part of the brain that reacts to cannabinoids like marijuana, and also creates its own cannabis-like chemicals. Morena’s hope is that a pharmacological fix can be found that enhances that system when the brain’s detagging or fear extinction process goes awry, as it does in memory disorders like PTSD.
Morena is one of 24 University of Calgary postdoctoral scholars to earn a prestigious Alberta Innovates – Health Solutions (AIHS) postgraduate fellowship this year.
University of Calgary scholars earned 24 of the 34 awards from AIHS, which supports highly competitive and internationally recognized training awards in the area of health and translational research. The university’s recipients (full list below) work in the Cumming School of Medicine, the Faculty of Veterinary Medicine, the Faculty of Kinesiology, the Faculty of Science and the Schulich School of Engineering.
“With the support of AIHS, the University of Calgary is progressively building our understanding of important mental health challenges like post-traumatic stress disorder,” says Ed McCauley, vice-president (research). “These exceptional early career researchers, like Maria, are making invaluable contributions to our leading research teams.”
“Mental health research is a priority for Alberta,” says Dr. Pam Valentine, CEO Interim of Alberta Innovates – Health Solutions. “AIHS is committed to supporting advancements in our fundamental understanding of brain mechanisms underlying mental health issues that will ease the burden on Albertans and people throughout the world. AIHS is also proud to play a role in supporting the next generation of researchers, like Dr. Morena, who will ultimately contribute to a highly skilled workforce within the province.”
A highly complementary collaboration
Morena’s fear memory research focuses on the chemical pathways and brain regions associated with their creation and extinction.
“That process is a little bit complicated,” says an understated Morena, who in addition to an AIHS fellowship has earned the Eyes High, Cumming School, and The Mathison Centre for Mental Health Research & Education postdoctoral scholarships and is the winner of the 2015 HBI Postdoctoral Researcher of the Year award. “Fear extinction is not the erasure of memory. It’s not forgetting; it’s the untangling of fear from an associated memory.”
A native of Italy, Morena completed her PhD at Sapienza University of Rome. She was drawn to the University of Calgary to work with her supervisor, Matthew Hill, PhD, a Cumming School of Medicine researcher and professor, member of the HBI, and Tier II Canada Research Chair in Neurobiology.
“It’s a highly complementary fit; Maria brings a lot of knowledge and expertise to the lab,” Hill says. This research combines Hill’s expertise on stress and its impact on neural functioning and behaviour with Morena’s knowledge about in memory systems, consolidation and extinction.
“This is an excellent training environment,” Morena says. “There is a rich collaboration between labs, I have access to the equipment, the techniques, the tools to do my work, and feel very supported.”
Unchecked fear and anxiety likened to a runaway, reinless horse carriage
Morena is searching for clues about fear memory extinction in two parts of the brain — the amygdala and the prefrontal cortex — and in the communication between the two. The amygdala is the part of the brain that assigns environmental and experiential cues what neuroscientists call valence, or emotional significance. The prefrontal cortex regulates thoughts and governs social control.
“Think of the amygdala as the horses on a carriage, and the prefrontal cortex as the reins,” Hill says. What brain imaging demonstrates is that when the amygdala is running unchecked, there is more fear, more omnipresence of a memory, more anxiety. By contrast people who have a more active prefrontal cortex (i.e. a lot of control over the reins) are really good at extinguishing bad memories.
The buffer between those two regions could be the endocannabinoid system, which responds to the brain’s own version of cannabis in much the same way as the brain produces and responds to endorphins, its own version of morphine.
Okay, so what about cannabis?
It is widely documented that some people with PTSD self-medicate with cannabis, but what isn’t yet understood, Morena and Hill say, is whether there is any scientific basis to support the claims that marijuana can help.
Morena’s AIHS-funded research which examines the involvement of the endocannabinoid system in fear memory extinction in animal models will bring more sound data to that scientific discussion.
Could the introduction of a cannabinoid from outside the brain boost the endocannabinoid system, and get fear memory extinction back on track? That’s what Morena is trying to find out with research that is paving the way, perhaps, for a new potential therapeutic intervention: a drug that could at once calm the horses and strengthen the reins as it were, alleviating the anxiety and stress associated with memory disorders like PTSD.
March 14 – 20 marks Brain Awareness Week, a global campaign to increase public awareness of the progress and benefits of brain research.
View the complete list of 2015 AIHS Postdoctoral awardees and their areas of study.
Back to AIHS e-newsletter, Vol. 2, Iss. 3
Public event: medical cannabis & clinical research in Canada
Register now to hear Dr. Morena discuss research findings related to the use of cannabinoids for treatment of post-traumatic stress disorder (PTSD).
February 2, 2017
Aloft Calgary University
Read more about Dr. Morena’s work:
Wiping out the fear by Rob Alexander, Apple Magazine, Summer 2016
U of C studies marijuana link to possible PTSD cure, by Bill Kauffman, Calgary Herald, March 17, 2016
Testing pot to help PTSD, by Bill Kaufmann, Calgary Sun, March 17, 2016