Fear and Emotion Flashcards
what are 4 reasons that we study fear?
adaptive mechanisms
long lasting
underlies disorders
easy to study
what are three fear responses?
behavioural
autonomic
hormonal
what are behavioural fear responses
movement appropriate to stituation (fight or flight)
what is autonomic fear responses
blood vessels constrict/ dilate
heart rate changes enabling the behavioural response
what is a hormonal fear response
hormones produced to reinforce the autonomic response
e.g. adrenalin
how do we study fear?
fear conditioning in rats
which brain area, with lesions, produce deficits in fear conditioning
the amygdala
describe fear and the role of the amygdala in rats fear conditioning
single neurons in the lateral nucleus of the anygdala increase their firing rate to conditioned stimuli following training in rats conditioning
what are the two brain areas activatated when rats hear CS tone
auditory thalamus
auditory cortex
what are the two brain areas activated when rats hear US footshock
aomatosensory thalamus
somatosensory cortex
what is the sequence of events that occur after CS and US stimuli presentation in rats
both thalamus’ and cortex’s activate the
lateral nucleus
–> central nucleus
–> central grey(freezing) , lateral hypthalamus (blood pressure), paravenicular (hormones)
how does the amygdala control the fear response?
all these regions are innervated by the central nucleus - different brain regions
describe fear conditioning process in humans
subjects are presented with one of two stimuli-
blue square (CS+) is paired with a shock
or
red square (CS-) is presented with no shock
do humans show a fear response to the CS+ relative to the CS-
humans show increased skin conductance response(sweating) to CS+ relative to CS-
what does human conditioning experiments represent
pavlovian fear conditioning
which brain region is activated in humans in response to fear
the amygdala
what are three ways to reduce fear?
extinction
cognitive regulation
reconsolidation
describe extinction of fear conditioning (2)
conditioned fear arises through the pairing of a cue with an aversive stimuli
if cue presented many times in absense of the shock, the conditioned response decreases
if the original memory is not erased then why do we stop being afraid?
activation in the amygdala is high during learning of conditioned fear but low during extinctions
what happens to the amygdala during extinction
its inhibited
where does amygdala inhibition come from during extinction
ventromedial prefrontal cortex
describe inhibition in the ventromedial prefrontal corte
neurons in vmPFC become active during extinction
this inhibits the fear response produced by the amygdala
electrical stimulation of vmPFC can speed up extinction
what is cognitive regulation
cognitive strategies can reduce conditioned fear
how does cognitive regulation work
reduces conditioned fear by decreasing activation in the amygdala
what happens to the amygdala during cognitive regulation
its inhibited by increase activation in the prefrontal cortex
what happens if memories are recalled
they become sensitive to change and must be reconsolidated
can we block memory (re)consolidation?
LTP is require for memory consolidation
LTP can be blocked by blocking protein synthesis
what is reconsolidation
previously consolidated memory is remembered
and memory becomes sensitive to change
what is required for reconsolidation
proteins
how can memories be erased
by stopping reconsolidation
