Fear Flashcards
Definition of fear
Emotion that results from presence of or imminent threat. Anxiety when the aversive stimulus is abstract or remote in time or space. Three levels of threats - potential, distal, and proximal.
Development of fear
Adaptions and counter-adaptions between predator and prey. Adaptive. Fear mechanism - shortcuts to make fast responses. In other circumstances, fear allows us to make slow and strategic responses to threat. Phylogenetically newer parts of brain attempt to minimize encounters with predators.
Proximity of threat
as the virtual predator grew closer, brain activity shifted from the ventromedial prefrontal cortex to the periaqueductal gray. This shift showed maximal expression when a high degree of pain was anticipated.
Tarantula test
As a tarantula was placed closer to a subject’s foot, increased experiences of fear coincided with augmented activity in a cascade of fear-related brain networks including the periaqueductal gray, amygdala, and bed nucleus of the stria terminalis. Conversely, the orbitofrontal cortex was engaged as the tarantula grew more distant, suggesting that this region emits safety signals or expels fear.
Tedeschi
Higher confidence that somebody will not mess up an activity and shock you leads to decreased anxiety and downregulation of pain areas. pINS activity is decreased. Perception of another person’s ability to protect us reduces anticipation of harm.
Low intensity threat
Anxiety and activity in the sgACC/vmPFC and amygdala
High intensity threat
Evokes older structures like the PAG
Tracking direction of threat
BNST (Bed Nucleus of Stria Terminalis)
Expectancy Errors
Amygdala - perceiving the threat as bigger than it really is.
Courage area
sgACC - successful mental effort to overcome fear
Selfish Herd Theory
Reducing predation with risk-dilution, confusion, many eyes, mobbing
Development of threat response, from far away to near
Prefrontal Cortex -> ACC -> Amygdala (Avoid) -> Amygdala (Arousal) -> Hypothalamus (Escape) -> PAG (Panic)
Periaqueductal grey
Fight, flight, freezing. Panic responses. Activates when threat is close.
Ventromedial PFC
Subgenual Cingulate Cortex (sgACC) inolved in control of emotion or value of threat.
Amygdala
Emotional hub for fear responses
