Wen Li, a professor of psychology at Florida State University, has written two papers that show how the brain’s sensory cortex plays a much bigger role in processing possible threats than scientists thought before.
“We are translating basic science done in the lab into treatment at the clinic,”
Li said. Researchers are developing new treatments for these debilitating and difficult-to-treat conditions by isolating specific neural mechanisms and inventing non-invasive methods to target these mechanisms.
The sensory cortex comprises all cortical brain regions involved in sensory processing. Its primary function is to detect data such as body temperature, touch, texture, and pain.
A New Threat Network Frontier
Li, also affiliated with the Neuroscience Program at Florida State University, dispels the myth that the sensory cortex is incapable of active threat evaluation and is subservient to top-down instructions from other brain regions in processing threat information.
“Identification of this new frontier, the sensory cortex, in the threat network will open many new opportunities and promises major breakthroughs in the research of threat processing and its various disorders that have affected humankind in general, for which there is still extremely limited remedy,”
Li and co-author Andreas Keil of the University of Florida synthesized peer-reviewed research and findings from human and animal models.
They examined research on human brain activity, magnetic fields produced by neuron activity, and blood flow associated with brain activity. They also reviewed how specific areas of brain damage affect behaviour and cognition.
This research was supplemented with a thorough review of animal studies involving optogenetics, which uses light and genetic engineering to control and track neural activity, providing more precise information about which brain areas are involved in threat processing.
Li’s concept of a new roadmap for how threats are processed in the sensory cortex is supported by mounting evidence from human and animal studies.
“This theory fills a long-standing gap and resolves an important controversy and myth in the research of threat processing,”
Scientists have long considered the amygdala, an almond-shaped structure in the brain’s center, to be the “center of fear” and largely responsible for how an individual responds to frightening situations or perceives threats. Li’s previous research, published in 2022, revealed a new pathway to fear via the sensory cortex.
Sensory Cortex and Memory
The sensory cortex of the brain stores long-term mnemonic representations of threat, allowing humans to relive the past or simulate future scenarios by incorporating memory features into their assessment of a new situation. This feature causes the brain to store information about perceived environmental threats in the memory system.
The resulting threat-filled sensory neurons activate downstream threat processing in the amygdala and other brain areas.
“These ideas motivate a sensory account of threat processing, involving an initial threat evaluation in the sensory cortex and extending throughout the brain’s networks. This understanding has the potential to revolutionize the conceptualization of threat-related disorders and their treatment,”
For decades, researchers have focused on a narrow view of how the brain can quickly identify and respond to threats — a critical survival skill.
“Dr. Li has consistently been at the forefront of new, much broader models of threat processing involving many sensory systems. This work is reshaping how scientists understand fear and anxiety and may ultimately underpin new treatment methods. This review paper appears in one of the leading journals in the field and is very likely to be a seminal paper that will influence work in the area for the next decade,”
said Distinguished Research Professor and Director of FSU’s Anxiety and Behavioral Health Clinic Brad Schmidt.
Mnemonic Threat Representations
Li’s work in The Neuroscientist supplements the research in Trends in Cognitive Sciences by providing an in-depth analysis of how mnemonic representations of threat are stored in the brain’s sensory cortex.
“Particularly, this research highlights the powerful content-addressable memory, arising from the architecture of the sensory cortex, that is capable of supporting smart—fast and precise—threat processing,”
Li and co-author Donald Wilson of New York University School of Medicine and the Nathan S. Kline Institute for Psychiatric Research conducted this study using similar review techniques, delving deeper into the brain’s basic cellular and microcircuit processes.
“The sensory cortex stores engrams that hold our threat memories, and the simple, well-understood architecture of the olfactory, or piriform, cortex provides a primal entry point for research to unlock this mystery,”
Both studies serve as a springboard for future scientific research into the brain’s highly complex network of neural processes, and they represent a radical departure from the long-held belief that threat conceptualization is centred on the amygdala or limbic system.
- Li W, Wilson DA. Threat Memory in the Sensory Cortex: Insights from Olfaction. The Neuroscientist. 2023;0(0). doi:10.1177/10738584221148994
- Wen Li et al. Sensing fear: fast and precise threat evaluation in human sensory cortex. Trends in Cognitive Sciences (2023). DOI: 10.1016/j.tics.2023.01.001