L1: Fear and Anxiety
Brain Substrates of Emotion in Animals and Humans
Emotional states and associated responses
Evolutionary considerations
Rat as a model system
The emotional brain
Overview and classic milestones
Fear and Anxiety
Conditioned fear and the amygdala
Classical fear conditioning
Functional-anatomical model
Lateral/ central amygdala in conditioned fear
Plasticity in LA neurons
Human amygdala
Hippocampus
Ventral hippocampus in conditioned/ unconditioned responses
Hippocampus and anxiety disorders
Brain Substrates of Emotion in Animals
and Humans
Defining emotion in a way that can be objectively measured.
Emotional states and associated responses
Emotions are
states elicited by
rewarding or
aversive stimuli
S or S and
their omission ( )
or termination !.
These states
comprise thoughts
(feelings) and
physiological/behavioural
L1 Fear and Anxiety 1
, responses
to emotional
stimuli
Responses can be
measured
unambiguously in
humans and non-
human animals
Evolutionary considerations
Responses to aversive/ positive stimuli have fundamental survival value,
and thus preserved through evolution
Similar in different animals (including humans)
The principal organisation of the brain is very similar among all
mammalian species— preserved blueprint of the brain
Cross-species similarities in emotion expression — in this case, anger/aggression
Rat as a model system
L1 Fear and Anxiety 2
, Advantages
Easy to breed/ keep
Well-established behavioural tests
Brain large enough to apply manipulations to distinct brain structures
Brain anatomy is very well characterised
Disadvantages
Genetic manipulations (used to be) difficult
The alternative was a mouse
The emotional brain
Overview and classic milestones
Hippocampus, amygdala, and
hypothalamus:
Papez theory of emotion 1937
Sensory input into the thalamus
diverged into upstream and
downstream — the separate
streams of 'thought' (cortex) and
'feeling' (hypothalamus). Key structures within a generalised
emotional brain.
Klüver and Bucy syndrome 1939
description of temporal lobe lesion
effects in monkeys
Amygdala area. Dramatically
changed behaviour— interpreted
as rage
Established amygdala as essential
for emotion.
MacLean‘s limbic system theory
1949
Hippocampus as a keyboard of
emotion. Emotions are integrated
L1 Fear and Anxiety 3
Brain Substrates of Emotion in Animals and Humans
Emotional states and associated responses
Evolutionary considerations
Rat as a model system
The emotional brain
Overview and classic milestones
Fear and Anxiety
Conditioned fear and the amygdala
Classical fear conditioning
Functional-anatomical model
Lateral/ central amygdala in conditioned fear
Plasticity in LA neurons
Human amygdala
Hippocampus
Ventral hippocampus in conditioned/ unconditioned responses
Hippocampus and anxiety disorders
Brain Substrates of Emotion in Animals
and Humans
Defining emotion in a way that can be objectively measured.
Emotional states and associated responses
Emotions are
states elicited by
rewarding or
aversive stimuli
S or S and
their omission ( )
or termination !.
These states
comprise thoughts
(feelings) and
physiological/behavioural
L1 Fear and Anxiety 1
, responses
to emotional
stimuli
Responses can be
measured
unambiguously in
humans and non-
human animals
Evolutionary considerations
Responses to aversive/ positive stimuli have fundamental survival value,
and thus preserved through evolution
Similar in different animals (including humans)
The principal organisation of the brain is very similar among all
mammalian species— preserved blueprint of the brain
Cross-species similarities in emotion expression — in this case, anger/aggression
Rat as a model system
L1 Fear and Anxiety 2
, Advantages
Easy to breed/ keep
Well-established behavioural tests
Brain large enough to apply manipulations to distinct brain structures
Brain anatomy is very well characterised
Disadvantages
Genetic manipulations (used to be) difficult
The alternative was a mouse
The emotional brain
Overview and classic milestones
Hippocampus, amygdala, and
hypothalamus:
Papez theory of emotion 1937
Sensory input into the thalamus
diverged into upstream and
downstream — the separate
streams of 'thought' (cortex) and
'feeling' (hypothalamus). Key structures within a generalised
emotional brain.
Klüver and Bucy syndrome 1939
description of temporal lobe lesion
effects in monkeys
Amygdala area. Dramatically
changed behaviour— interpreted
as rage
Established amygdala as essential
for emotion.
MacLean‘s limbic system theory
1949
Hippocampus as a keyboard of
emotion. Emotions are integrated
L1 Fear and Anxiety 3
