Phasic vs Sustained Fear in Rats and Humans: Role of the Extended Amygdala in Fear vs Anxiety

By Michael Davis, D. Walker, Leigh Miles, Christian Grillon. Neuropsychopharmacology, 2009

1,369 citations recorded by the source corpus.

Data will be reviewed using the acoustic startle reflex in rats and humans based on our attempts to operationally define fear vs anxiety. Although the symptoms of fear and anxiety are very similar, they also differ. Fear is a generally adaptive state of apprehension that begins rapidly and dissipates quickly once the threat is removed (phasic fear). Anxiety is elicited by less specific and less predictable threats, or by those that are physically or psychologically more distant. Thus, anxiety is a more long-lasting state of apprehension (sustained fear). Rodent studies suggest that phasic fear is mediated by the amygdala, which sends outputs to the hypothalamus and brainstem to produce symptoms of fear. Sustained fear is also mediated by the amygdala, which releases corticotropin-releasing factor, a stress hormone that acts on receptors in the bed nucleus of the stria terminalis (BNST), a part of the so-called ‘extended amygdala.’ The amygdala and BNST send outputs to the same hypothalamic and brainstem targets to produce phasic and sustained fear, respectively. In rats, sustained fear is more sensitive to anxiolytic drugs. In humans, symptoms of clinical anxiety are better detected in sustained rather than phasic fear paradigms.

Subfields: Behavioral Neuroscience, Biological Psychiatry, Cognitive Neuroscience

View Paper: https://www.semanticscholar.org/paper/93b1d616c6362fe66898d651087e9d44818b3dab

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Citations in the corpus

The ecology of human fear: survival optimization and the nervous system (2015, background): “The BNST is implicated in threat monitoring and vigilance and strongly interconnected with the CeA and insula and has been suggested to act as a relay center that coordinates motor, autonomic and defensive reactions during sustained threat (Davis et al., 2010).”
Don't fear ‘fear conditioning’: Methodological considerations for the design and analysis of studies on human fear acquisition, extinction, and return of fear (2017, positive): “Both modes of conditioning have been proposed to model diverse features of anxiety disorders (Baas et al., 2004; Grillon, 2002a; Grillon et al., 2006a,b) and rely on different neural pathways (Davis et al., 2010).”
Pain-relief learning in flies, rats, and man: basic research and applied perspectives (2014, background): “…reflex (Koch 1999), such that the neural mechanisms of the startle response itself and of its modulations are known in quite some detail in rodents (Fendt and Fanselow 1999; Davis 2006; Davis et al. 2009), monkeys (Davis et al. 2008), and man (Davis et al. 2008, 2009, van Well et al. 2012).”
Phasic and sustained fear in humans elicits distinct patterns of brain activity (2010, positive): “To identify the neural mechanisms that underlie fear expression, however, it may be more advantageous to examine instructed fear in humans rather than fear conditioning (Davis et al., 2010b).”
An intracranial dissection of human escape circuits (2024, unknown): “SEEG allows simultaneous recordings from cortical and subcortical regions 34 – 37 , enabling a comprehensive view of neural dynamics across the entire brain during escape.”