How does a person tick? Exploring the brain’s sensory network to understand threat perception

Summary: The sensory cortex is much more involved in the processing and perception of threats than previously thought.

Source: FSU

The work of a Florida State University researcher to understand exactly which part of the brain is involved in disorders such as anxiety, PTSD and other phobias gives scientists and clinicians valuable insight into treating such disorders.

Wen Li, a professor of psychology at FSU, has published two papers demonstrating how the brain’s sensory cortex is much more involved in processing potential threats than scientists previously thought.

“We are translating basic research done in the lab into treatment in the clinic,” Li said. “By isolating specific neural mechanisms and inventing non-invasive techniques to target these mechanisms, we are developing new treatments for these debilitating and difficult-to-treat diseases.” .”

The results of their latest study were published in this month The neuroscientist along with a review article in Trends in the cognitive sciences.

The sensory cortex refers to all of the cortical brain areas associated with sensory functions. Its main task is to recognize information such as body temperature, touch, texture or pain. Li, who is also a member of FSU’s Neuroscience Program, debunks the myth that the sensory cortex is absent from active threat assessment and is subject to top-down direction from other parts of the brain when processing threat information.

“The identification of this new frontier – the sensory cortex – in the threat network will open up many new possibilities and promises major breakthroughs in the study of threat processing and its various disorders that have affected humanity in general, for which there are still extremely limited remedies.” said Li.

in the in Trends in the cognitive sciencesLi and co-author Andreas Keil of the University of Florida have synthesized a wide range of existing peer-reviewed research and results from both human and animal models.

Li and Keil reviewed studies of human brain activity, the magnetic fields generated by neuron activity, and the blood flow associated with brain activity. They also looked at how specific areas of damage in the brain affect behavior and cognition.

They complemented this work with a thorough review of animal studies using optogenetics, which uses light and genetic engineering to control and track neural activity, providing more accurate information about which areas of the brain are involved in processing threats.

Increasing evidence from human and animal studies supports Li’s concept of a new roadmap for how threats are processed in the sensory cortex.

“This theory fills a long-standing gap and resolves an important controversy and myth in threat processing research,” Li said.

The amygdala, an almond-shaped structure in the center of the brain, has long been considered by scientists to be the “center of fear” and largely responsible for how an individual reacts to frightening circumstances or perceives threats. Research published by Li in 2022 revealed a new pathway to fear through the sensory cortex.

The brain’s sensory cortex stores long-term mnemonics of threats, meaning people can relive the past or simulate future scenarios by incorporating features of a memory into their assessment of a new situation. This function causes the brain to input information into the memory system about perceived environmental threats.

The resulting threat-filled sensory neurons then trigger downstream threat processing in the amygdala part of the brain and other areas of the brain.

“These ideas motivate a sensory representation of threat processing that involves initial threat assessment in the sensory cortex and extends throughout brain networks,” Li said.

“This understanding has the potential to revolutionize how threat-related disorders are conceptualized and how they are treated.”

For the last few decades, researchers had focused on a narrow view of how precisely the brain is able to quickly identify and respond to threats – a crucial survivability skill.

“DR. Li has always been at the forefront of new, much broader models of threat processing that involve many sensory systems,” said Brad Schmidt, distinguished research professor and director of FSU’s Anxiety and Behavioral Health Clinic.

“This work is changing how scientists understand fear and anxiety and may ultimately underpin new treatments. This review appears in one of the leading journals in this field and is likely to be seminal work that will influence work in this field for the next decade.”

The sensory cortex refers to all of the cortical brain areas associated with sensory functions. The image is in the public domain

Li’s work in The neuroscientist is a complement to the research in tendencies and provides an in-depth analysis of how mnemonic representations of threats are stored in the brain’s sensory cortex.

“Specifically, this research highlights the powerful content-addressable memory that emerges from the architecture of the sensory cortex and is capable of supporting intelligent — fast and precise — threat processing,” Li said.

Li and co-author Donald Wilson of the New York University School of Medicine and the Nathan S. Kline Institute for Psychiatric Research used similar review techniques to conduct this research, digging deeper into the brain’s basic cellular and microcircuit processes.

“The sensory cortex stores engrams that contain our threat memories, and the simple, well-understood architecture of the olfactory, or piriform, cortex provides a first entry point for research to unravel this mystery,” Li said.

Both studies provide a springboard for further scientific exploration of the brain’s highly complex network of neural processes and represent a disruptive break with the long-held notion that conceptualization of threats focuses on the amygdala, or limbic system.

Financing: This work was supported by funding from the National Institutes of Health.

About this news from neuroscientific research

Author: Kathleen Haughney
Source: FSU
Contact: Kathleen Haughney—FSU
Picture: The image is in the public domain

Original research: Closed access.
“Threat memory in the sensory cortex: insights from olfaction” by Wen Li et al. The neuroscientist

Open access.
“Perceiving Fear: Rapid and Accurate Threat Assessment in the Human Sensory Cortex” by Wen Li et al. Trends in cognitive neuroscience


Threat memory in the sensory cortex: insights from olfaction

The amygdala has long held the central place in the neural base of threat conditioning. However, a rapidly growing literature has elucidated circuitry outside of the amygdala in this process, emphasizing the sensory cortex for its crucial role in the mnemonic aspect of the process.

While this literature largely focuses on the auditory system, significant insights into the olfactory system in humans and rodents have emerged.

The unique nature of olfactory neuroanatomy and its close association with emotion compels a review of this recent literature to shed light on its unique contribution to threat memory.

Here, incorporating recent findings in human and animal models, we postulate that the olfactory (piriform) cortex is a primary and necessary component of the distributed threat memory network supporting acquired threat mnemonic ensemble encoding.

We further highlight the fundamental circuit architecture of the piriform cortex, which is characterized by distributed, autoassociative connections fundamental to highly efficient content-addressable memory computation in support of threat memory.

Given the primordial role of the piriform cortex in cortical evolution and its simple, well-defined circuitry, we propose that the sense of smell may be a model system for understanding (transmodal) sensory cortical mechanisms underlying threat memory.


Recognizing fear: rapid and accurate threat assessment in the human sensory cortex

Animal models of threat processing have evolved beyond the amygdala to incorporate a distributed neural network.

In human research, evidence has intensified in recent years to challenge canonical threat circuits centered on the amygdala, urging a revision of threat conception.

A surge of research into processing threats in the sensory cortex over the past decade has yielded particularly useful insights to underpin the conceptualization.

Here we compile insights from animal and human research and highlight sensitive, specific, and adaptive threat representations in the sensory cortex that result from experience-based design of sensory coding networks.

We therefore propose that the human sensory cortex can drive intelligent (rapid and accurate) threat assessment by generating threat-infused sensory afferents to evoke network-wide threat responses.

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