The Halloween season is almost here. Americans are already planning their Halloween costumes and eerie themed meals. Children are especially excited to spook their neighbors with clever pranks and realistic makeup and to go door-to-door collecting candy. Adults, on the other hand, are planning to explore the haunted houses for that adrenaline rush. Threatening figures jumping out of the shadows, and your eyes widening and heart racing. Your body is telling you instinctively to freeze and flee. Most of them like the ‘jump scare’. Let’s explore the science behind it today. A University of Colorado Boulder research team has recently unraveled the science behind the ‘jump scare’. The findings of the study are published in Molecular Psychiatry. How the brain responds to fear Most of us like the thrill of ‘jump scares’, but what’s really happening in our bodies during that time? The researchers wanted to find out the same, and they identified a novel brain circuit responsible for orchestrating this threat response. This neural circuit orchestrates and adapts the innate threat response. This innate threat response is key to survival, if you think about it on an evolutionary level. The novel brain circuit responsible for orchestrating this threat response is known as the interpeduncular nucleus (IPN). This dense cluster of specialized neurons not only jump-starts that freeze-and-flee reaction but dials it down when animals learn there’s no real danger. The researchers added that this circuit may be broken in people with anxiety or post-traumatic stress disorder (PTSD). Though the findings are fascinating, they could also lead to new therapies and help explain why some people have a greater appetite for risk than others. “The brain’s threat system is like an alarm. It needs to sound when danger is real, but it needs to shut off when it’s not. Our study shows how the brain learns to fine-tune those responses through experience, helping us adapt to the world,” first author Elora Williams, a graduate student in the Department of Psychology and Neuroscience, said in a statement. The study To understand this ‘jump scare’, the researchers created something similar to a ‘mouse haunted house’ in which mice were exposed to predator-like shadows or ‘visual looming stimulus’, for three days. They noticed that the mice froze and hid when the shadow appeared on the first day. Freezing is a fundamental stress-response, enabling animals, including humans, to focus their heightened senses on detecting where a danger might be coming from, and how fast it’s approaching. However, by the third day, they largely ignored it. Their brain activity also changed. Brain scans revealed that a cluster of neurons in the interpeduncular nucleus (IPN) fired strongly at first but quieted as the mice learned the shadow was harmless.“Collectively, these findings implicate the IPN as a critical circuit for helping us process potential threats and adapt accordingly when we learn they aren’t putting us in danger,” Susanna Molas, assistant professor in the Department of Psychology and Neuroscience, and senior author, said. The new study is the first to identify the lesser-known IPN, a tiny part of the ancient midbrain, as a key tool in enabling animals to get past unwarranted fears.“Identifying the neuronal circuits underlying threat processing and adaptive learning is vital to understanding the neuropathology of anxiety and other stress-related conditions,” Williams added.