While it is outside the scope of this paper to provide a comprehensive description of the neurobiology of anxiety, it is important to review the most salient information. An overview will be provided to orient the reader to the most important aspects of affective neuroscience as it pertains to anxiety. When discussing the neurobiology of anxiety, it is critical to understand the limbic system. Some of the main functions of the limbic system include emotional and behavioral control, as well as storage and retrieval of memory (van der Kolk, 1999). An overview of the limbic system includes brain structures such as thalamus, amygdala, hippocampus, hypothalamus, pituitary gland, and the prefrontal cortex (PFC).
The amygdala, specifically the basolateral amygdala, receives information from all sensory systems and scans all incoming information for potential threats (Sapolsky, 2017). When a situation is perceived as stressful or fearful, the amygdala is activated to identify an adaptive way to respond to the stressor. The amygdala is sensitive to fear-provoking stimuli, even when the stimuli are not consciously detected (Sapolsky, 2017). Some incoming sensory information can bypass the cortex and go directly to the amygdala so that the amygdala can trigger an immediate response to any threatening stimuli (Sapolsky, 2017). The information is then transmitted to the brain stem and hypothalamus, which produce the autonomic arousal and behavioral activation consistent with a fear response (Garakani, Mathew, & Charney, 2006). However, the incoming threatening information received by the amygdala does not always represent an actual threat, but nonetheless causes the individual to react as if there were an imminent threat (Sapolsky, 2017).
Additionally, the activation of the amygdala leads to the release of neurochemicals such as glucocorticoids, norepinephrine, dopamine, and cortisol (CITE).
Garakani, A., Mathew, S. J., & Charney, D. S. (2006). Neurobiology of Anxiety Disorders and Implications for Treatment. Mount Sinai Journal of Medicine, 73(7), 941–949.
Look at the developmental psychopathology of anxiety book