Neuroscientist Joseph LeDoux, left, and Psychiatrist Dr. Daniel Pine are working to spur more collaboration in their two fields to ensure clinical treatments keep pace with advances in neuroscience’s understanding of how the human brain handles threats. | Carla Schaffer/AAAS
How the human brain identifies and responds to threats has been misunderstood – a miscalculation that has impeded the development of more effective pharmaceuticals and psychiatric treatments for those suffering from fear and anxiety disorders, said a pair of neuroscience and psychiatry experts in two lectures at AAAS headquarters on 18 October.
Joseph LeDoux, a professor of science and director of two institutes at New York University, and Dr. Daniel Pine, chief of the National Institute of Mental Health Intramural Research Program, explored the brain’s responses to threats from different professional vantage points, although they have shared views that the existing understanding of how the brain deals with threats needs to be realigned to better incorporate current scientific research.
The evening presentations, the final in the 2016 Neuroscience & Society lecture series hosted by AAAS and sponsored by the Dana Foundation, underscored the importance of collaboration between neuroscientists and practicing psychiatrists. LeDoux and Pine recently collaborated on a paper entitled “Using Neuroscience to Help Understand Fear and Anxiety: A Two-System Framework,” published on 9 September in AJP in Advance, the online publication of the American Journal of Psychiatry.
“What they have raised here is that more partnerships between clinical professionals and basic scientists are absolutely critical in advancing neuroscience to the point where it becomes something that can help people,” said Mark Frankel, the director emeritus of AAAS’ Scientific Responsibility, Human Rights and Law program. “It is a good model that I believe should be practiced by others in the fields of mental health and neuroscience.”
In humans, according to LeDoux and Pine, threats trigger two distinct sets of the brain’s neural circuits. One group sets off conscious or emotional feeling in a person making them afraid or anxious. The second group prompts behavioral responses like freezing in place or physiological changes like a racing heart or sweating even when a person may not even be aware of something threatening them.
“While the first system generates conscious feeling, the second largely operates nonconsciously,” LeDoux and Pine wrote in their co-authored APJ Advance paper. “Conflation of these circuits and their functions has hampered clinical extension of basic research.”
LeDoux and Pine said recent findings that two neural systems are at play in the brain call for new treatments that target both the mechanism that delivers conscious feelings, as well as the mechanisms that set into motion behavioral and psychological changes for reasons that may elude the impacted person.
Previously, neuroscientists and psychiatrists long subscribed to the view that a single “fear center” in the brain was responsible both for the feelings of fear and the behavioral and physiological reactions to the brain’s detection and response to threats.
In their co-authored study, LeDoux and Pine pointed to several new research findings that rebut that position, including a 2013 study in Nature that found a woman suffering from a rare condition that damaged her amygdala, the deep brain’s almond-shaped feature considered the home of the “fear center,” was able to feel fear. That study and others make it clear that a single “fear center” was not alone in sparking human reactions to a threat.
Pine, who treats children and adolescents suffering from anxiety disorders, said strides in brain research are improving the ability of psychiatrists to understand the complexity of underlying causes of fear and anxiety disorders and opening the door to new treatments.
In his practice, Pine recommends cognitive behavioral therapy as the best first-line treatment for anxiety disorders in children and adolescents and said he has found selective serotonin reuptake inhibitors (SSRIs) medicines to be the most effective.
Still, both experts contend new drugs and therapies are needed. Pine noted as promising an alternative treatment known as attention retraining therapy that helps patients resist focusing on what sparks their fear or anxiety.
LeDoux contends that psychiatry has too long focused on the brain’s behavioral and psychological responses to threats and needs to target treatments toward conscious responses.
“The reason people see a therapist is because they feel bad and the way they decide whether they are cured or treated is if they feel better, so you cannot leave subjective experiences out of the equation,” he said in an interview after the presentation.