On Thursday, the Korea Advanced Institute of Science and Technology (KAIST) announced a groundbreaking discovery by Professor Han Jin-hee’s research team from the Department of Biological Sciences. The team has identified, for the first time globally, a brain circuit specifically responsible for forming fear memories triggered by psychological anxiety and fear, without involving physical pain.
Through experiments on mice, the research team uncovered the posterior insular cortex and the parabrachial nucleus (pIC-PBN) circuit, a crucial brain pathway that regulates the formation of fear memories induced solely by psychological threats, without sensory pain.
The study revealed that mice display instinctive fear responses when faced with a rapidly approaching predator from above. This was demonstrated by projecting an expanding shadow on the ceiling, proving that fear memories can form through psychological threats alone, without physical pain.
Previously, scientists believed the brain’s lateral PBN only relayed pain information from the spinal cord. However, this study uncovered that the PBN also plays a vital role in fear learning when responding to non-painful threat stimuli.
Further analysis showed a direct connection between the pIC, crucial for processing negative emotions and pain, and the PBN.
Notably, the research confirmed that neurons in the pIC activate after visual threat stimuli, playing a critical role in PBN neuron activation.
The findings demonstrated that artificially suppressing the pIC-PBN circuit significantly reduces fear memory formation from visual threats, without affecting innate fear responses or pain-based fear learning.
Conversely, artificially activating this circuit alone can induce fear memories, indicating that the pIC-PBN circuit is key to processing psychological threat information and facilitating learning.
A KAIST spokesperson emphasized the significance of this study as this research provides the first experimental evidence that emotional pain and physical pain are processed by distinct neural circuits. Further adding by clearly identifying the pIC-PBN neural circuit specialized in conveying emotional pain, this study makes a substantial contribution to the field of neuroscience.
Professor Han highlighted the potential impact of this research, stating that this study lays a crucial foundation for understanding the mechanisms behind mental disorders characterized by emotional pain, such as post-traumatic stress disorder (PTSD), panic disorder, and anxiety disorders. Further, it could lead to the development of more targeted treatments for these conditions.
The findings of this study have been published in the prestigious international journal Science Advances.