Scientists Identify a New Neural Pathway Involved in High-Intensity Fear Responses
Summary:
Scientists have recently uncovered a previously unknown connection between the prefrontal cortex and the amygdala that plays a critical role in how the brain transitions to high-intensity fear responses. This breakthrough discovery sheds light on the importance of the prefrontal cortex in emotional regulation and decision-making during fearful situations. The findings have the potential to lead to innovative treatments for psychiatric conditions, including anxiety disorders and PTSD.
Key Facts:
- Researchers have unveiled a novel neural pathway that governs the shift to high-intensity fear behaviors, essential for survival, by establishing a connection between the prefrontal cortex and the amygdala.
- An imbalance in this pathway can contribute to the development of psychiatric disorders such as anxiety disorders and post-traumatic stress disorder, underscoring the significance of comprehending and treating these conditions.
- In the study, advanced techniques such as in vivo calcium imaging, chemogenetic, and optogenetic manipulation were employed to investigate and influence this pathway in mice, opening new possibilities for therapeutic interventions.
Researchers Discover New Brain Pathway Involved in High-Intensity Fear Behaviors
Scientists have made a groundbreaking discovery, published in Nature, revealing a new neural pathway that underlies the brain’s encoding of high-intensity fear response behaviors crucial for survival. The study, co-authored by Jones Parker, Ph.D., the assistant professor of Neuroscience, of Pharmacology, and of Psychiatry and Behavioral Sciences, sheds light on how the amygdala, a brain structure, plays a role in generating survival responses and transitioning between different high-intensity fear behaviors, such as freezing and escaping, in the face of perceived threats.
Psychiatric conditions resulting from the dysregulation of fear responses, such as post-traumatic stress disorder (PTSD) and anxiety and panic disorders, have long been a challenge to understand and treat effectively. However, the current study, using mouse models developed by Jonathan Fadok, Ph.D., the Burk-Kleinpeter Inc. Professor in Science and Engineering at Tulane University, revealed and characterized the neural circuits responsible for the escalation of behavioral responses to high-intensity fearful situations.
Employing techniques such as in vivo calcium imaging, the researchers identified an unexpected connection between the prefrontal cortex, responsible for emotional regulation and adaptive decision-making, and the amygdala. Furthermore, utilizing chemogenetic and optogenetic techniques, the team observed a new neuronal projection between excitatory neurons in the underexplored dorsal peduncular region of the prefrontal cortex and neurons in the amygdala.
According to Parker, “We have the cortex, which is projecting to this ancient brain structure involved in fear processing, that taps into the amygdala and directly scales the level of fear that the animals are experiencing.” Moreover, molecularly characterizing the brain regions involved in the regulation of fear responses may contribute to the identification of potential therapeutic targets for various psychiatric illnesses.
Referring to the significance of the prefrontal cortex and its influence on the fear circuit, Parker highlights, “This links the prefrontal cortex—this area that expanded over evolution in humans, an area involved in expectations and predictions about our environment—to the ancient brain circuit that controls fear, so this could contribute to pathologies involving fear and how we conceptualize them.”
The researchers are currently focusing on a physiological analysis of the dorsal peduncular region of the prefrontal cortex in order to gain a better understanding of its overall function and the neuronal population residing within it. By unraveling the mechanisms of what is known as top-down control, the cortical control over ancient structures governing fear, the researchers aim to make significant advances in the development of improved treatments for psychiatric disorders, according to Fadok.
About the Research
Source: Northwestern University
Author: Marla Paul
Original Research: Closed access.
Researchers have detailed their findings in the article “Top-down control of flight by a non-canonical cortico-amygdala pathway” published in the journal Nature.
