by Tom Cloyd - 3 min. read - (reviewed 2023-02-13:1615 PT)
New research1 indicates that a crucial part of our brain detects faces expressing fear without our conscious awareness of them. There are obvious adaptive advantages to possessing this skill, but for individuals struggling with trauma and dissociation disorders this indicates an additional source of stress that needs to be managed intelligently.
While previous research has shown that a key part of the mid-brain - the amygdala - is activated when there is unconscious perception of fearful faces, there has been no real-time observation of this activity until now.
Eighteen patients with drug-resistant epilepsy were monitored with micro-electrode implants in various regions of their brain, while being neurologically evaluated for surgical treatment of their epilepsy.
Carefully designed images of fearful faces, presented so as to evade conscious recognition, caused “rapid cellular responses in the amygdala, but not in the visual cortex or other [brain] regions.”2 Presentation of non-fearful faces did not evoke this response. Response to fearful faces was at times as fast as 1/10 of a second. There was no involvement of the cerebral cortex (the “thinking” part of the brain) in causing this response.
It seems clear at this point that certain types of threat indicators are directly perceived by the part of the brain that produces affect and feelings - the mid-brain, and that this can happen without conscious awareness. As the investigators put it: “These findings provide direct evidence for the existence of a subcortical pathway specific for rapid fear detection in the amygdala and demonstrate that the subcortical pathway can function without conscious awareness and under minimal influence from cortical areas.”3
This presents a critical challenge to individuals with brains affected by traumatic stress and dissociation disorders.
Schore (2009) has published a review of the association between overwhelming emotional experience and dissociation, an association first noted over a hundred years ago.4 He notes that “developmental psychologists have demonstrated a strong link between early attachment trauma and dissociation”, such that “from a developmental neuroscience point of view, early abuse and neglect have an immediate impact on the right brain during a critical growth period; this produces an immature right brain that has a limited capacity to regulate intense affective states.” He presents considerable evidence that these “neuroloogical scars” persist into adolescence and adulthood, predisposing affected individuals both to posttraumatic stress and pathological dissociation5
The implication of this is clear:
Special attention by individuals with posttraumatic stress or dysfunctional dissociation, or both, needs to be given to identifying known and likely threating stimuli (triggers), both internal and environmental, and limiting contact with such stimuli until adequate resolution of traumatic memories occurs, typically in association with a trauma-trained mental health professional.
Costandi, M. (2023-02-13). Your brain is wired to detect fear, outside of your conscious awareness. Big Think. https://bigthink.com/neuropsych/brain-fear-unconscious-awareness/
Schore, A. N. (2009). Attachment trauma and the developing right brain: Origins of pathological dissociation. In P. F. Dell & J. A. O’Neil (Eds.), Dissociation and the dissociative disorders: DSM-V and beyond (pp. 107–141). Routledge; /Library.
Wang, Y., Luo, L., Chen, G., Luan, G., Wang, X., Wang, Q., & Fang, F. (2023). Rapid processing of invisible fearful faces in the human amygdala. Journal of Neuroscience. https://doi.org/10.1523/JNEUROSCI.1294-22.2022
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