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Lecture 7

PSY260H1 Lecture Notes - Lecture 7: Papez Circuit, Striatum, Pedunculopontine Nucleus


Department
Psychology
Course Code
PSY260H1
Professor
Martin Ralph
Lecture
7

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What%do%we%actually%remember%when%we%remember%an%emotion?
You%suddenly%feel%just%as%happy%or%sad%you%are%when%remembering%an%event
How%are%emotions%remembered?%
Can%emotions%be%remembered?
No%scientific%definition%-it's%a%signal,%an%outward%expression%of%our%feelings
Controlled%by%distinct%neuronal%circuits%within%the%brain%-various%parts%of%the%
brain%becomes%active
We%experience% emotions%consciously%-there%is%a%cognitive%element,%most%likely%
involving%the%cerebral%cortex
Emotions%can%be%viewed%as%an%outcome%of%the%interaction%of%peripheral%and%
central%factors%-linkage%is%the%emotion
How%are%different%emotions%separated?
Why%do%we%feel%different?
Feelings are%the%things%we%feel,%things%we%are%consciously%aware%of,%
reactions%that%our%body%creates%that%makes%us%aware%of%ourselves%(Hunger%
that%elicits%other%feelings%-might%be%a%primary%feeling)
Emotions are%the%way%we%react%to%those%feelings,%expression%of%those%
feelings,%needs%to%give%off%a%signal%to%tell%ourselves%what%is%going%in%our%
bodies
!"#$%#&'()*+','(-**.%&/'
Outward%expression%of%a%feeling
Primary%senses%tell%us%about%what%we%need
Emotions%tell% us%something%about%our%relationship%with%the%world,%
especially%with%other%people
Emotions%help%us%communicate%that%relationship%and%tell% others%what%we%
feel
Emotions%strengthen%our%recollection%of%other%images
We%remember%the%events%that%occurred%based%on%our%emotions%felt%
during%the%event
01.,*(#-(*"#$%#&
What%is%emotion?
Transfer%of%past%learning%to%new%situations%and%problems
Generalization%gradient%-changes%in%physical%properties%of%stimuli%
correspond%to%changes%in%responding
Generalization -an%event%can%generate%our%emotional%response,%event%through%
an%inanimate%object%which%sends%signals
Perception%of%differences%between%stimuli
Discrimination -we%choose%what%we%pay%attention%to,%most%we%go%through%
everyday%never%reach%the%conscious%level
Hedonic property%of%stimuli%-things%we%don't%need%but%represent%things%
that%we%need
Motivational property%of%stimuli%-we%react%to%things%based%on%the%feeling%
of%needing%it%(food)
Wanting%vs.%liking%(hedonic%vs.%motivational)
Extension%of%Skinner's%operant%conditioning
In%general,%we%are%operantly%conditioned%all%the%time
The%opportunity%to%perform%a%highly%frequent%behaviour%can%reinforce%a%
less%frequent%behaviour
We%are%driven%by%our%emotional%response%(even%in%the%process%of%
acquiring%food)%-not%necessarily%driven%by%our%cortex
Response%deprivation%hypothesis%-by%restricting%the%ability%to%execute%
almost%any%response,%you%can%make%the%opportunity%to%perform%that%
response%reinforcing
2+*"134(5+%&3%5.*
Rats%are%conditioned%to%anticipate%food
Expression%of%their%conditioning
They%put%all%their%foraging%resources%to%get%food%-running%around%the%
running%wheel
Scheduled%chocolate%access%produced%increased%activity%briefly%prior%and%
at%the%moment%of%chocolate%delivery
67#3#.1$*(*&$+1%&"*&$(8+1$'
Generalization%vs.%Discrimination
The%reward%system%originates%in%the%ventral%tegmental%area%(VTA),%which%
is%composed%of%two%major%cell%types,%the%dopamine%neurons%and%the%γ-
aminobutyricacid%(GABA)%neurons
The%dopamine%neurons%(blue)%project%to%the%ventral%striatum,%the%nucleus%
accumbens%(NAc),%the%prefrontal%cortex%(PFC)%and%the%hippocampus
It%also%receives%local%inhibitory%feedback%from%the%GABA%
interneurons%in%the%VTA
The%VTA%receives%inhibitory%projections%(red)%back%from%the%NAc%and%from%
the%pedunculopontine% nucleus% (PPT)
Excitatory%projections%(green)%from%the%PFC,%the%PPT,%the%amygdala,%the%
lateral%hypothalamus%(LH),%the%laterodorsal%tegmental%nucleus%(LDTg)%and%
the%bed% nucleus%of%the%stria%terminalis%(BNST)
involves%emotional%response
Limbic%system%-systems%that%underlie%the%emotional%response%-ascending%
pathway%that%gets%the%brain%aroused
PFC%-decision%making%system%which%a%allows%to%interpret%innate%cognitive%
functions
Emotions%are%felt%peripherally
Two%purposes%-draw%attention%to%the%brain,%communicate%the%emotions
Peripheral%responses%prepare%the%body%for%action
Communicate%emotions%to%other%people
Increased%heart%rate%&%respiration
Dry%mouth
Tense%muscles
Sweaty palms
Example%fear:
Peripheral%Responses
Most%changes%that%accompany%emotional%states%are%mediated%by%ANS%-changes%
in%the%periphery
The%ANS%is%primarily%an%effector%system%-involuntary
Sympathetic%-fight%or%flight%response
Parasympathetic
Enteric
Three%divisions%(See%slides)
ANS%and%Emotion
There%is%an%integration%among%central%and%peripheral%systems%
Central%systems%receive%information%from%the%ambient%world%
Messages%are%sent%to%peripheral%systems,%changing%peripheral%activity
Activity%in%peripheral%systems%is%also%detected%by%the%central%systems%
Central%systems%distinguish%among%sensory%and%internally%generated%signals,%
thereby%discriminating%between%sensory%input%and%“feelings”
Summary:
Proposed%that%there%is%an%emotion%system%that%links%the%cortex%to%the%
hypothalamus
Emotion%is%determined%by%the%activity%of%the%cingulate%cortex
Emotional%expression%is%governed%by%the%hypothalamus
Lesions%to%various%parts%of%the%brain%caused%different%kinds%of%emotional%
impairments
James%Papez-1930’s
A%group%of%structures,%each%connected%to%the%next%by%a%major%fiber%tract
The%cingulate%cortex%projects%to%the%hippocampus,%which%projects%to%the%
hypothalamus%through%the%fornix;%the%hypothalamus%projects%to%the%
anterior%nuclei%of%the%thalamus,%which%reach%back%to%the%cortex
Sensory%information%enters%the%brain%through%the%thalamus
Hypothalamus%helps%regulate%the%body's%response%to%emotion
The%Papez%Circuit
The%Papez%Circuit%(see%slides%and%book)
Emotional%expression%precedes%emotional%experience
§
Physiological%changes%occur%in%response%to%stimuli,%then%we%feel%
emotion
§
Proposed%that%the%experience%we%call%emotion%occurs%after%the%cortex%
receives%signals%about%physiologic%changes
We%feel%sorry%because%we%cry
§
The%physiological%changes%are%the%emotion%
§
Emotion%is%the%consequence%of%information%from%the%periphery
Emotions%are%experienced% even%if%physiological%changes%arent%
sensed
§
Patients%&%animals%with%transected%spinal%cords%do%not%have%
lessened%emotions%
§
The%same%physiological%changes%accompany%different%emotions%and%
can%have%other%causes%(e.g%.%fear,%anger%&%disease%can%all%increase%
heart%rate%&%cause%sweating)
§
Critique%of%James%&%Lange
9%..%1"(:1"*'(;(<1+.(=1&/*(8:1"*'(;(=1&/* >??@
Stimulus%can%simultaneously%evoke%both%emotions%and%arousal
Stimuli%cause%emotional%experience
Emotional%experience% can%occur%independently%of%emotional%expression
The%thalamus%plays%a%pivotal%role%in%emotional%sensations
Emotions%are%produced%when%signals%reach%the%thalamus%directly%from%
sensory%receptors%or%by%descending%cortical%input
The%emotion%is%determined%by%the%pattern%of%activation%of%the%thalamus
91.$*+(61&&#&(1&A(27%..%5(B1+A(C61&&#&(;(B1+A(>DEFG
Theories%of%Emotion%
H$1&.*I(H3713$*+ -there%are%two%pathways%because%the%brain%have%to%evaluate
Emotion%is%context-dependent -our%expectations%of%circumstances%and%the%
circumstances%itself
The%cortex%constructs%emotion%out%of%signals%received%from%the%periphery - this%
is%called% the%somatic%marker%hypothesis
Depends%expectations,%experience,%social%context
Thus%the%same%responses%can%accompany%different%emotions
Emotion%is%a%story%the%brain%concocts%to%explain%bodily%reactions
The%Somatic%Marker%Hypothesis
J,3.*,'(133,"K*&' -recruits%orbitofrontal%cortex,%thalamus,%motor%cortex,%etc.,%
involved%in%approach,%attention%to%goals,%and%action%control%
Lesions%to%the%amygdala%will%interfere%in%the%fear%response
Lateral%nucleus%-information%input%(unconditioned%stimuli),%first%
step%in%processing%emotional%output
§
Amygdala%is%made%up%of%sub%nuclei%with%specific%functions
L"I/A1.1 -regulates%many%cortical%and%subcortical%areas%involved%in%attention%
to%affectively%relevant%stimuli%activates%brainstem%structures%that%orchestrate%an%
emotional%response%(predominant%associated%with%the%fair%responses)
MI5#$71.1",' -regulates%limbic,%cortical%and%brainstem%systems,%ventral%
striatum,%autonomic%nervous%system,%according%to%organismic%goals,%drive%
states,%territorial%aggression,%bodily%needs,%etc.%
B+1%&('$*" -ascending%neuromodulators%recruit%activation%of%all% areas%of%cortex%
and%limbic%system,%in%support%of%focused%perception%and%action%
Cingulate%gurus%-connection%between%the%frontal%cortex%and%the%limbic%system%
(two-way%communication)
Subcortical%epicentres%of%self-regulation%-Limbic%system%(p.%412%Figure%10.13%is%
important)
Two%pathways%to%amygdala%-direct%to%lateral%amygdala,%indirect%through%cortex
Lateral%amygdala%(responsible%for%the%input%of%information)%%is%a%key%site%of%
plasticity%in%fear%conditioning
Conditioned%fear%-fear%conditioned%to%particular%cues
The%LA%is%the%main%site%of%synaptic%changes%underlying%learning%and%
memory
LA%is%the%site%where%the%CS%and%US%pathways%converge
Le%Doux%1993
Consolidation%of%fear%conditioning%is%inititated%by%the%activation%of%receptors%at%
the%post-synaptic%neuron
This%in%turn%triggers%cascades%of%intracellular% events%that%regulate%the%activity%of%
mitogen-activated%protein%kinase%(MAPK)
MAPK%controls%transcription%factors,%such%as%CREB%proteins,%which%regulate%
transcription%of%certain%genes
Gene%activation%leads%to%a%new%RNA%and%new%protein%synthesis%and%thus,%
structural%changes%in%the%post-synaptic%neuron
Plausible%mechanisms%of%retrograding%signaling%from%the%post-synaptic%neuron%
induce%changes%in%the%pre-synaptic%neuron
When%the%animal%is%returned%to%the%same%environment,%it%generally%will%
demonstrate%a%freezing%response%(absence%of%movement%except%for%
respiration)%if%it%remembers%and%associates%that%environment%with%the%
aversive%stimulus
Contextual%fear%conditioning%-involves%taking%and%animal%and%placing%it%in%a%
novel%environment,%providing%an%aversive%stimulus%and%then%removing%it
Cued%fear%conditioning%-similar%to%the%contextual%fear%conditioning%except%there%
is%a%presence%of%a%CS
Reward%signals%that%are%mediated%through%prelimbic%area%trigger%glutamate%
release%within%the%core%nucleus%accumbens
In%general,%excessive%release%of%glutamate%within%the%core%of%nucleus%accumbens%
heightens%the%motivation%or%craving
Dopamine%that%originates%from%the%VTA%augment%glutamate%function%and%
together%they%create%insatiable%craving%symptoms
A%cue%can%also%trigger%craving%symptoms%aside%from%the%reward%signals
Cue-primed%symptoms%are%mediated%through%the%baso-lateral%amygdala
Stress%can%also%trigger%craving%symptoms
Stress-primed%craving%symptoms%are%mediated%through%the%stria%terminals%and%
extended%amygdala
The%amydgala%plays%the%central%role%in%the%CNS%in%processing%afferent%and%
efferent%connections%related%to%emotional%functioning
The%amygdala%receives%input%directly%from%sensory%thalamus,%
hippocampus%(via%multiple%projections),%entorhinal%cortex,%sensory%
association%areas%of%cortex,%polymodal%sensory%association%areas%of%
cortex,%and%from%various%midbrain%and%brainstem%arousal%systems%via%the%
RAS
The%amygdala%processes%and%determines%the%emotional%value%of%simple%
sensory%input,%complex%multisensory%perceptions%and%complex%cognitive%
abstractions,%even%responding%specifically%to%complex,%socially%relevant%
stimuli
The%amygdala%orchestrates%the%response%to%this%emotional%information%by%
sending%projections%to%brain%areas%involved%in%motor%(behavioral),%
autonomic%nervous%system%and%neuroendocrine%area%of%the%CNS
The%'site'%of%perception%of%anxiety%is%likely%to%be%the%amygdala
It%is%in%these%limbic%areas%that%the%patterns%of%neuronal%activity%associated%
with%threat,%and%mediated%by%the%monoamine%neurotransmitters%systems%
of%the%reticular%activating%system,%become%an%emotion
Amygdala%cells%are%ready%to%respond%to%emotional%stimuli
Some%are%more%sensitive%than%others%at%any%one%time
CREB%levels%are%hypothesized%to%be%a%key%determinant%of%sensitivity
Cn%we%erase%learned%associations%by%removing%these%specific%cells?
Add%CREB-cre%recombinase
Make%it%conditionally%active
Activate%fear%conditioning
Erasing%fear%memories%-Josselyn%et.%al%(read%article)
Activation%of%amygdala%and%insula,%recruiting%prefrontal%circuits%
mediating%decision-making
§
Adolescents%considering%risky%actions:
Activation%of%amygdala,%insula,%and%medial%PFC,%mediating%
perception%of%social%judgment%(Work%by%Abigail%Baird)
§
Adolescents%considering%being%judged%by%peers:%
9%$7%&(%&A%)%A,1.'N
Activation%of%amygdala,%insula,%ventral%ACC,%OFC,%and%deactivation%
of%DLPFC%and%dorsal%ACC%(Mayberg,%Pizzagalli,%Drevets,%and%
colleagues)
§
Depressive
Activation%of%pons,%midbrain,%hypothalamus,%insula,%and%dorsal%ACC,%
deactivation%of%OFC%(Damasio%et%al.,%2000)
§
Aggressive
Adolescent%boys%show%enhanced%activation%of%the%nucleus%
accumbens,%focusing%their%attraction%on%risky%activities (Preliminary%
data%by%Abigail%Baird)
§
Adolesceve
L3+#''(%&A%)%A,1.'O
Regulatory%configurations%vary%
The%amygdala%is%the%critical% structure
Also%involves%the%hypothalamus%&%ANS
Kluver-Bucy Syndrome
Electrical% stimulation%experiments
Patients%with%damage%to%the%amygdala
Demonstrated%by:
Fear%&%Anxiety
bilateral%removal%of%the%temporal%lobes%in%monkeys%(which%contains%the%
amygdala%&%hippocampal%formation)
increased%and%bizarre%sexual%behaviour
highly%oral
temporal%lobe%destruction%of%visual%cortices
§
failed%to%recognize%familiar%objects%(psychic%blindness)
absence%of%fear -amygdala%missing%
§
emotionally%flat
Radical%changes%in%emotional%behaviour
Klüver-Bucy%Syndrome%(Heinrich%Kluver &%Paul%Bucy -1939)
Structure%critical%to%emotional%part%of%Kluver-Bucy syndrome%is%the%amygdala
The%amygdala%is%part%of%the%limbic%system
Human%patients%with%damaged%amygdala shave%reduced%ability%to%recognize%fear%
in%others
Electrical% stimulation%leads%to%fear%and%anxiety
A%learned%fear%response,%where%pain%is%associated%with%a%sensory%input,%may%
involve%a%circuit%through%the%basolateral nuclei%&%central%nucleus%of%the%
amygdala
These%effects%are%mediated%through%the%hypothalamus%&%autonomic%nervous%
system
Ablation%experiments%indicate%that%the%amygdala%is%also%involved%in%
aggression%-amygdalectomy reduces%aggression
Predatory%aggression%-cortex%>%amygdala%>%lateral%hypothalamus%>%
mfb>%ventral%tegmental%area
§
Affective%aggression%-cortex%>%amygdala%>%medial%hypothalamus%>%
dlf>%periaqueductal%gray%matter
§
Two%pathways%for%aggression:
Led%to%psychosurgical%procedures%to%destroy%amygdala%in%humans%(frontal%
lobotomy%is%another%example%of%psychosurgery)
Possible%Role%of%the%Amygdala
The%Amygdala
Output%from%the%amygdala%would%initiate%a%fear%response
The%1"I/A1.1 -critical% in%both%learned%emotional%responses%and%the%emotional%
modulation%of%memory%storage%and%retrieval
Lateral%nucleus -primary%entry%for%sensory%information%from%the%thalamus%
or%cortex%into%the%amygdala
Central%nucleus -receives% inputs%from%other%amygdala%nuclei%and%projects%
out%of%the%amygdala%to%the%ANS%driving%expression%of%physiological%
responses%such%as%arousal%and%release%of%stress%hormones%and%behavioural%
responses%such%as%freezing%and%startle
Basolateral%nucleus -receives%input%from%LA%and%projects%to%the%cerebral%
cortex,%basal%ganglia,%hippocampus%and%providing%pathway%by%which%
amygdala%can%modulate%memory%storage%and%retrieval
The%amygdala%is%consisted%of%different%nuclei:
P71.1",' -first%site%in%the%brain%where%most%kinds%of%sensory%input%converge%
and%are%processed%(relays%the%information%to%the%amygdala%and%cortex)
6#+$*Q -processes%sensory%information%more%fully%(also%relays%information%to%the%
amygdala)
Hippocampus%-critical% for%new%episodic%(event)%memory%formation
PFC%-helps%people%read%the%expression%of%emotion%in%others
Allows%us%to%process%emotional%stimuli%in%a%manner%appropriate%to%the%
context%in%which%the%stimuli%occur
Turns%off%or%inhibits%the%normal%emotional%response%provoked%by%
amygdala%stimulation
Medial%prefrontal%cortex%-active%when%the%facial%expression%is%recognized%as%
fearful%rather%than%in%neutral%faces
Brain%Substrates
Emotional)Memory
Tuesday,% October% 21,%2014
11:03%AM

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

What%do%we%actually%remember%when%we%remember%an%emotion?
You%suddenly%feel%just%as%happy%or%sad%you%are%when%remembering%an%event
How%are%emotions%remembered?%
Can%emotions%be%remembered?
No%scientific%definition%-it's%a%signal,%an%outward%expression%of%our%feelings
Controlled%by%distinct%neuronal%circuits%within%the%brain%-various%parts%of%the%
brain%becomes%active
We%experience% emotions%consciously%-there%is%a%cognitive%element,%most%likely%
involving%the%cerebral%cortex
Emotions%can%be%viewed%as%an%outcome%of%the%interaction%of%peripheral%and%
central%factors%-linkage%is%the%emotion
How%are%different%emotions%separated?
Why%do%we%feel%different?
Feelings are%the%things%we%feel,%things%we%are%consciously%aware%of,%
reactions%that%our%body%creates%that%makes%us%aware%of%ourselves%(Hunger%
that%elicits%other%feelings%-might%be%a%primary%feeling)
Emotions are%the%way%we%react%to%those%feelings,%expression%of%those%
feelings,%needs%to%give%off%a%signal%to%tell%ourselves%what%is%going%in%our%
bodies
!"#$%#&'()*+','(-**.%&/'
Outward%expression%of%a%feeling
Primary%senses%tell%us%about%what%we%need
Emotions%tell% us%something%about%our%relationship%with%the%world,%
especially%with%other%people
Emotions%help%us%communicate%that%relationship%and%tell% others%what%we%
feel
Emotions%strengthen%our%recollection%of%other%images
We%remember%the%events%that%occurred%based%on%our%emotions%felt%
during%the%event
01.,*(#-(*"#$%#&
What%is%emotion?
Transfer%of%past%learning%to%new%situations%and%problems
Generalization%gradient%-changes%in%physical%properties%of%stimuli%
correspond%to%changes%in%responding
Generalization -an%event%can%generate%our%emotional%response,%event%through%
an%inanimate%object%which%sends%signals
Perception%of%differences%between%stimuli
Discrimination -we%choose%what%we%pay%attention%to,%most%we%go%through%
everyday%never%reach%the%conscious%level
Hedonic property%of%stimuli%-things%we%don't%need%but%represent%things%
that%we%need
Motivational property%of%stimuli%-we%react%to%things%based%on%the%feeling%
of%needing%it%(food)
Wanting%vs.%liking%(hedonic%vs.%motivational)
Extension%of%Skinner's%operant%conditioning
In%general,%we%are%operantly%conditioned%all%the%time
The%opportunity%to%perform%a%highly%frequent%behaviour%can%reinforce%a%
less%frequent%behaviour
We%are%driven%by%our%emotional%response%(even%in%the%process%of%
acquiring%food)%-not%necessarily%driven%by%our%cortex
Response%deprivation%hypothesis%-by%restricting%the%ability%to%execute%
almost%any%response,%you%can%make%the%opportunity%to%perform%that%
response%reinforcing
2+*"134(5+%&3%5.*
Rats%are%conditioned%to%anticipate%food
Expression%of%their%conditioning
They%put%all%their%foraging%resources%to%get%food%-running%around%the%
running%wheel
Scheduled%chocolate%access%produced%increased%activity%briefly%prior%and%
at%the%moment%of%chocolate%delivery
67#3#.1$*(*&$+1%&"*&$(8+1$'
Generalization%vs.%Discrimination
The%reward%system%originates%in%the%ventral%tegmental%area%(VTA),%which%
is%composed%of%two%major%cell%types,%the%dopamine%neurons%and%the%γ-
aminobutyricacid%(GABA)%neurons
The%dopamine%neurons%(blue)%project%to%the%ventral%striatum,%the%nucleus%
accumbens%(NAc),%the%prefrontal%cortex%(PFC)%and%the%hippocampus
It%also%receives%local%inhibitory%feedback%from%the%GABA%
interneurons%in%the%VTA
The%VTA%receives%inhibitory%projections%(red)%back%from%the%NAc%and%from%
the%pedunculopontine% nucleus% (PPT)
Excitatory%projections%(green)%from%the%PFC,%the%PPT,%the%amygdala,%the%
lateral%hypothalamus%(LH),%the%laterodorsal%tegmental%nucleus%(LDTg)%and%
the%bed% nucleus%of%the%stria%terminalis%(BNST)
involves%emotional%response
Limbic%system%-systems%that%underlie%the%emotional%response%-ascending%
pathway%that%gets%the%brain%aroused
PFC%-decision%making%system%which%a%allows%to%interpret%innate%cognitive%
functions
Emotions%are%felt%peripherally
Two%purposes%-draw%attention%to%the%brain,%communicate%the%emotions
Peripheral%responses%prepare%the%body%for%action
Communicate%emotions%to%other%people
Increased%heart%rate%&%respiration
Dry%mouth
Tense%muscles
Sweaty palms
Example%fear:
Peripheral%Responses
Most%changes%that%accompany%emotional%states%are%mediated%by%ANS%-changes%
in%the%periphery
The%ANS%is%primarily%an%effector%system%-involuntary
Sympathetic%-fight%or%flight%response
Parasympathetic
Enteric
Three%divisions%(See%slides)
ANS%and%Emotion
There%is%an%integration%among%central%and%peripheral%systems%
Central%systems%receive%information%from%the%ambient%world%
Messages%are%sent%to%peripheral%systems,%changing%peripheral%activity
Activity%in%peripheral%systems%is%also%detected%by%the%central%systems%
Central%systems%distinguish%among%sensory%and%internally%generated%signals,%
thereby%discriminating%between%sensory%input%and%“feelings”
Summary:
Proposed%that%there%is%an%emotion%system%that%links%the%cortex%to%the%
hypothalamus
Emotion%is%determined%by%the%activity%of%the%cingulate%cortex
Emotional%expression%is%governed%by%the%hypothalamus
Lesions%to%various%parts%of%the%brain%caused%different%kinds%of%emotional%
impairments
James%Papez-1930’s
A%group%of%structures,%each%connected%to%the%next%by%a%major%fiber%tract
The%cingulate%cortex%projects%to%the%hippocampus,%which%projects%to%the%
hypothalamus%through%the%fornix;%the%hypothalamus%projects%to%the%
anterior%nuclei%of%the%thalamus,%which%reach%back%to%the%cortex
Sensory%information%enters%the%brain%through%the%thalamus
Hypothalamus%helps%regulate%the%body's%response%to%emotion
The%Papez%Circuit
The%Papez%Circuit%(see%slides%and%book)
Emotional%expression%precedes%emotional%experience
§
Physiological%changes%occur%in%response%to%stimuli,%then%we%feel%
emotion
§
Proposed%that%the%experience%we%call%emotion%occurs%after%the%cortex%
receives%signals%about%physiologic%changes
We%feel%sorry%because%we%cry
§
The%physiological%changes%are%the%emotion%
§
Emotion%is%the%consequence%of%information%from%the%periphery
Emotions%are%experienced% even%if%physiological%changes%arent%
sensed
§
Patients%&%animals%with%transected%spinal%cords%do%not%have%
lessened%emotions%
§
The%same%physiological%changes%accompany%different%emotions%and%
can%have%other%causes%(e.g%.%fear,%anger%&%disease%can%all%increase%
heart%rate%&%cause%sweating)
§
Critique%of%James%&%Lange
9%..%1"(:1"*'(;(<1+.(=1&/*(8:1"*'(;(=1&/* >??@
Stimulus%can%simultaneously%evoke%both%emotions%and%arousal
Stimuli%cause%emotional%experience
Emotional%experience% can%occur%independently%of%emotional%expression
The%thalamus%plays%a%pivotal%role%in%emotional%sensations
Emotions%are%produced%when%signals%reach%the%thalamus%directly%from%
sensory%receptors%or%by%descending%cortical%input
The%emotion%is%determined%by%the%pattern%of%activation%of%the%thalamus
91.$*+(61&&#&(1&A(27%..%5(B1+A(C61&&#&(;(B1+A(>DEFG
Theories%of%Emotion%
H$1&.*I(H3713$*+ -there%are%two%pathways%because%the%brain%have%to%evaluate
Emotion%is%context-dependent -our%expectations%of%circumstances%and%the%
circumstances%itself
The%cortex%constructs%emotion%out%of%signals%received%from%the%periphery - this%
is%called% the%somatic%marker%hypothesis
Depends%expectations,%experience,%social%context
Thus%the%same%responses%can%accompany%different%emotions
Emotion%is%a%story%the%brain%concocts%to%explain%bodily%reactions
The%Somatic%Marker%Hypothesis
J,3.*,'(133,"K*&' -recruits%orbitofrontal%cortex,%thalamus,%motor%cortex,%etc.,%
involved%in%approach,%attention%to%goals,%and%action%control%
Lesions%to%the%amygdala%will%interfere%in%the%fear%response
Lateral%nucleus%-information%input%(unconditioned%stimuli),%first%
step%in%processing%emotional%output
§
Amygdala%is%made%up%of%sub%nuclei%with%specific%functions
L"I/A1.1 -regulates%many%cortical%and%subcortical%areas%involved%in%attention%
to%affectively%relevant%stimuli%activates%brainstem%structures%that%orchestrate%an%
emotional%response%(predominant%associated%with%the%fair%responses)
MI5#$71.1",' -regulates%limbic,%cortical%and%brainstem%systems,%ventral%
striatum,%autonomic%nervous%system,%according%to%organismic%goals,%drive%
states,%territorial%aggression,%bodily%needs,%etc.%
B+1%&('$*" -ascending%neuromodulators%recruit%activation%of%all% areas%of%cortex%
and%limbic%system,%in%support%of%focused%perception%and%action%
Cingulate%gurus%-connection%between%the%frontal%cortex%and%the%limbic%system%
(two-way%communication)
Subcortical%epicentres%of%self-regulation%-Limbic%system%(p.%412%Figure%10.13%is%
important)
Two%pathways%to%amygdala%-direct%to%lateral%amygdala,%indirect%through%cortex
Lateral%amygdala%(responsible%for%the%input%of%information)%%is%a%key%site%of%
plasticity%in%fear%conditioning
Conditioned%fear%-fear%conditioned%to%particular%cues
The%LA%is%the%main%site%of%synaptic%changes%underlying%learning%and%
memory
LA%is%the%site%where%the%CS%and%US%pathways%converge
Le%Doux%1993
Consolidation%of%fear%conditioning%is%inititated%by%the%activation%of%receptors%at%
the%post-synaptic%neuron
This%in%turn%triggers%cascades%of%intracellular% events%that%regulate%the%activity%of%
mitogen-activated%protein%kinase%(MAPK)
MAPK%controls%transcription%factors,%such%as%CREB%proteins,%which%regulate%
transcription%of%certain%genes
Gene%activation%leads%to%a%new%RNA%and%new%protein%synthesis%and%thus,%
structural%changes%in%the%post-synaptic%neuron
Plausible%mechanisms%of%retrograding%signaling%from%the%post-synaptic%neuron%
induce%changes%in%the%pre-synaptic%neuron
When%the%animal%is%returned%to%the%same%environment,%it%generally%will%
demonstrate%a%freezing%response%(absence%of%movement%except%for%
respiration)%if%it%remembers%and%associates%that%environment%with%the%
aversive%stimulus
Contextual%fear%conditioning%-involves%taking%and%animal%and%placing%it%in%a%
novel%environment,%providing%an%aversive%stimulus%and%then%removing%it
Cued%fear%conditioning%-similar%to%the%contextual%fear%conditioning%except%there%
is%a%presence%of%a%CS
Reward%signals%that%are%mediated%through%prelimbic%area%trigger%glutamate%
release%within%the%core%nucleus%accumbens
In%general,%excessive%release%of%glutamate%within%the%core%of%nucleus%accumbens%
heightens%the%motivation%or%craving
Dopamine%that%originates%from%the%VTA%augment%glutamate%function%and%
together%they%create%insatiable%craving%symptoms
A%cue%can%also%trigger%craving%symptoms%aside%from%the%reward%signals
Cue-primed%symptoms%are%mediated%through%the%baso-lateral%amygdala
Stress%can%also%trigger%craving%symptoms
Stress-primed%craving%symptoms%are%mediated%through%the%stria%terminals%and%
extended%amygdala
The%amydgala%plays%the%central%role%in%the%CNS%in%processing%afferent%and%
efferent%connections%related%to%emotional%functioning
The%amygdala%receives%input%directly%from%sensory%thalamus,%
hippocampus%(via%multiple%projections),%entorhinal%cortex,%sensory%
association%areas%of%cortex,%polymodal%sensory%association%areas%of%
cortex,%and%from%various%midbrain%and%brainstem%arousal%systems%via%the%
RAS
The%amygdala%processes%and%determines%the%emotional%value%of%simple%
sensory%input,%complex%multisensory%perceptions%and%complex%cognitive%
abstractions,%even%responding%specifically%to%complex,%socially%relevant%
stimuli
The%amygdala%orchestrates%the%response%to%this%emotional%information%by%
sending%projections%to%brain%areas%involved%in%motor%(behavioral),%
autonomic%nervous%system%and%neuroendocrine%area%of%the%CNS
The%'site'%of%perception%of%anxiety%is%likely%to%be%the%amygdala
It%is%in%these%limbic%areas%that%the%patterns%of%neuronal%activity%associated%
with%threat,%and%mediated%by%the%monoamine%neurotransmitters%systems%
of%the%reticular%activating%system,%become%an%emotion
Amygdala%cells%are%ready%to%respond%to%emotional%stimuli
Some%are%more%sensitive%than%others%at%any%one%time
CREB%levels%are%hypothesized%to%be%a%key%determinant%of%sensitivity
Cn%we%erase%learned%associations%by%removing%these%specific%cells?
Add%CREB-cre%recombinase
Make%it%conditionally%active
Activate%fear%conditioning
Erasing%fear%memories%-Josselyn%et.%al%(read%article)
Activation%of%amygdala%and%insula,%recruiting%prefrontal%circuits%
mediating%decision-making
§
Adolescents%considering%risky%actions:
Activation%of%amygdala,%insula,%and%medial%PFC,%mediating%
perception%of%social%judgment%(Work%by%Abigail%Baird)
§
Adolescents%considering%being%judged%by%peers:%
9%$7%&(%&A%)%A,1.'N
Activation%of%amygdala,%insula,%ventral%ACC,%OFC,%and%deactivation%
of%DLPFC%and%dorsal%ACC%(Mayberg,%Pizzagalli,%Drevets,%and%
colleagues)
§
Depressive
Activation%of%pons,%midbrain,%hypothalamus,%insula,%and%dorsal%ACC,%
deactivation%of%OFC%(Damasio%et%al.,%2000)
§
Aggressive
Adolescent%boys%show%enhanced%activation%of%the%nucleus%
accumbens,%focusing%their%attraction%on%risky%activities (Preliminary%
data%by%Abigail%Baird)
§
Adolesceve
L3+#''(%&A%)%A,1.'O
Regulatory%configurations%vary%
The%amygdala%is%the%critical% structure
Also%involves%the%hypothalamus%&%ANS
Kluver-Bucy Syndrome
Electrical% stimulation%experiments
Patients%with%damage%to%the%amygdala
Demonstrated%by:
Fear%&%Anxiety
bilateral%removal%of%the%temporal%lobes%in%monkeys%(which%contains%the%
amygdala%&%hippocampal%formation)
increased%and%bizarre%sexual%behaviour
highly%oral
temporal%lobe%destruction%of%visual%cortices
§
failed%to%recognize%familiar%objects%(psychic%blindness)
absence%of%fear -amygdala%missing%
§
emotionally%flat
Radical%changes%in%emotional%behaviour
Klüver-Bucy%Syndrome%(Heinrich%Kluver &%Paul%Bucy -1939)
Structure%critical%to%emotional%part%of%Kluver-Bucy syndrome%is%the%amygdala
The%amygdala%is%part%of%the%limbic%system
Human%patients%with%damaged%amygdala shave%reduced%ability%to%recognize%fear%
in%others
Electrical% stimulation%leads%to%fear%and%anxiety
A%learned%fear%response,%where%pain%is%associated%with%a%sensory%input,%may%
involve%a%circuit%through%the%basolateral nuclei%&%central%nucleus%of%the%
amygdala
These%effects%are%mediated%through%the%hypothalamus%&%autonomic%nervous%
system
Ablation%experiments%indicate%that%the%amygdala%is%also%involved%in%
aggression%-amygdalectomy reduces%aggression
Predatory%aggression%-cortex%>%amygdala%>%lateral%hypothalamus%>%
mfb>%ventral%tegmental%area
§
Affective%aggression%-cortex%>%amygdala%>%medial%hypothalamus%>%
dlf>%periaqueductal%gray%matter
§
Two%pathways%for%aggression:
Led%to%psychosurgical%procedures%to%destroy%amygdala%in%humans%(frontal%
lobotomy%is%another%example%of%psychosurgery)
Possible%Role%of%the%Amygdala
The%Amygdala
Output%from%the%amygdala%would%initiate%a%fear%response
The%1"I/A1.1 -critical% in%both%learned%emotional%responses%and%the%emotional%
modulation%of%memory%storage%and%retrieval
Lateral%nucleus -primary%entry%for%sensory%information%from%the%thalamus%
or%cortex%into%the%amygdala
Central%nucleus -receives% inputs%from%other%amygdala%nuclei%and%projects%
out%of%the%amygdala%to%the%ANS%driving%expression%of%physiological%
responses%such%as%arousal%and%release%of%stress%hormones%and%behavioural%
responses%such%as%freezing%and%startle
Basolateral%nucleus -receives%input%from%LA%and%projects%to%the%cerebral%
cortex,%basal%ganglia,%hippocampus%and%providing%pathway%by%which%
amygdala%can%modulate%memory%storage%and%retrieval
The%amygdala%is%consisted%of%different%nuclei:
P71.1",' -first%site%in%the%brain%where%most%kinds%of%sensory%input%converge%
and%are%processed%(relays%the%information%to%the%amygdala%and%cortex)
6#+$*Q -processes%sensory%information%more%fully%(also%relays%information%to%the%
amygdala)
Hippocampus%-critical% for%new%episodic%(event)%memory%formation
PFC%-helps%people%read%the%expression%of%emotion%in%others
Allows%us%to%process%emotional%stimuli%in%a%manner%appropriate%to%the%
context%in%which%the%stimuli%occur
Turns%off%or%inhibits%the%normal%emotional%response%provoked%by%
amygdala%stimulation
Medial%prefrontal%cortex%-active%when%the%facial%expression%is%recognized%as%
fearful%rather%than%in%neutral%faces
Brain%Substrates
Emotional)Memory
Tuesday,% October% 21,%2014 11:03%AM

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

What%do%we%actually%remember%when%we%remember%an%emotion?
You%suddenly%feel%just%as%happy%or%sad%you%are%when%remembering%an%event
How%are%emotions%remembered?%
Can%emotions%be%remembered?
No%scientific%definition%-it's%a%signal,%an%outward%expression%of%our%feelings
Controlled%by%distinct%neuronal%circuits%within%the%brain%-various%parts%of%the%
brain%becomes%active
We%experience% emotions%consciously%-there%is%a%cognitive%element,%most%likely%
involving%the%cerebral%cortex
Emotions%can%be%viewed%as%an%outcome%of%the%interaction%of%peripheral%and%
central%factors%-linkage%is%the%emotion
How%are%different%emotions%separated?
Why%do%we%feel%different?
Feelings are%the%things%we%feel,%things%we%are%consciously%aware%of,%
reactions%that%our%body%creates%that%makes%us%aware%of%ourselves%(Hunger%
that%elicits%other%feelings%-might%be%a%primary%feeling)
Emotions are%the%way%we%react%to%those%feelings,%expression%of%those%
feelings,%needs%to%give%off%a%signal%to%tell%ourselves%what%is%going%in%our%
bodies
!"#$%#&'()*+','(-**.%&/'
Outward%expression%of%a%feeling
Primary%senses%tell%us%about%what%we%need
Emotions%tell% us%something%about%our%relationship%with%the%world,%
especially%with%other%people
Emotions%help%us%communicate%that%relationship%and%tell% others%what%we%
feel
Emotions%strengthen%our%recollection%of%other%images
We%remember%the%events%that%occurred%based%on%our%emotions%felt%
during%the%event
01.,*(#-(*"#$%#&
What%is%emotion?
Transfer%of%past%learning%to%new%situations%and%problems
Generalization%gradient%-changes%in%physical%properties%of%stimuli%
correspond%to%changes%in%responding
Generalization -an%event%can%generate%our%emotional%response,%event%through%
an%inanimate%object%which%sends%signals
Perception%of%differences%between%stimuli
Discrimination -we%choose%what%we%pay%attention%to,%most%we%go%through%
everyday%never%reach%the%conscious%level
Hedonic property%of%stimuli%-things%we%don't%need%but%represent%things%
that%we%need
Motivational property%of%stimuli%-we%react%to%things%based%on%the%feeling%
of%needing%it%(food)
Wanting%vs.%liking%(hedonic%vs.%motivational)
Extension%of%Skinner's%operant%conditioning
In%general,%we%are%operantly%conditioned%all%the%time
The%opportunity%to%perform%a%highly%frequent%behaviour%can%reinforce%a%
less%frequent%behaviour
We%are%driven%by%our%emotional%response%(even%in%the%process%of%
acquiring%food)%-not%necessarily%driven%by%our%cortex
Response%deprivation%hypothesis%-by%restricting%the%ability%to%execute%
almost%any%response,%you%can%make%the%opportunity%to%perform%that%
response%reinforcing
2+*"134(5+%&3%5.*
Rats%are%conditioned%to%anticipate%food
Expression%of%their%conditioning
They%put%all%their%foraging%resources%to%get%food%-running%around%the%
running%wheel
Scheduled%chocolate%access%produced%increased%activity%briefly%prior%and%
at%the%moment%of%chocolate%delivery
67#3#.1$*(*&$+1%&"*&$(8+1$'
Generalization%vs.%Discrimination
The%reward%system%originates%in%the%ventral%tegmental%area%(VTA),%which%
is%composed%of%two%major%cell%types,%the%dopamine%neurons%and%the%γ-
aminobutyricacid%(GABA)%neurons
The%dopamine%neurons%(blue)%project%to%the%ventral%striatum,%the%nucleus%
accumbens%(NAc),%the%prefrontal%cortex%(PFC)%and%the%hippocampus
It%also%receives%local%inhibitory%feedback%from%the%GABA%
interneurons%in%the%VTA
The%VTA%receives%inhibitory%projections%(red)%back%from%the%NAc%and%from%
the%pedunculopontine% nucleus% (PPT)
Excitatory%projections%(green)%from%the%PFC,%the%PPT,%the%amygdala,%the%
lateral%hypothalamus%(LH),%the%laterodorsal%tegmental%nucleus%(LDTg)%and%
the%bed% nucleus%of%the%stria%terminalis%(BNST)
involves%emotional%response
Limbic%system%-systems%that%underlie%the%emotional%response%-ascending%
pathway%that%gets%the%brain%aroused
PFC%-decision%making%system%which%a%allows%to%interpret%innate%cognitive%
functions
Emotions%are%felt%peripherally
Two%purposes%-draw%attention%to%the%brain,%communicate%the%emotions
Peripheral%responses%prepare%the%body%for%action
Communicate%emotions%to%other%people
Increased%heart%rate%&%respiration
Dry%mouth
Tense%muscles
Sweaty palms
Example%fear:
Peripheral%Responses
Most%changes%that%accompany%emotional%states%are%mediated%by%ANS%-changes%
in%the%periphery
The%ANS%is%primarily%an%effector%system%-involuntary
Sympathetic%-fight%or%flight%response
Parasympathetic
Enteric
Three%divisions%(See%slides)
ANS%and%Emotion
There%is%an%integration%among%central%and%peripheral%systems%
Central%systems%receive%information%from%the%ambient%world%
Messages%are%sent%to%peripheral%systems,%changing%peripheral%activity
Activity%in%peripheral%systems%is%also%detected%by%the%central%systems%
Central%systems%distinguish%among%sensory%and%internally%generated%signals,%
thereby%discriminating%between%sensory%input%and%“feelings”
Summary:
Proposed%that%there%is%an%emotion%system%that%links%the%cortex%to%the%
hypothalamus
Emotion%is%determined%by%the%activity%of%the%cingulate%cortex
Emotional%expression%is%governed%by%the%hypothalamus
Lesions%to%various%parts%of%the%brain%caused%different%kinds%of%emotional%
impairments
James%Papez-1930’s
A%group%of%structures,%each%connected%to%the%next%by%a%major%fiber%tract
The%cingulate%cortex%projects%to%the%hippocampus,%which%projects%to%the%
hypothalamus%through%the%fornix;%the%hypothalamus%projects%to%the%
anterior%nuclei%of%the%thalamus,%which%reach%back%to%the%cortex
Sensory%information%enters%the%brain%through%the%thalamus
Hypothalamus%helps%regulate%the%body's%response%to%emotion
The%Papez%Circuit
The%Papez%Circuit%(see%slides%and%book)
Emotional%expression%precedes%emotional%experience
§
Physiological%changes%occur%in%response%to%stimuli,%then%we%feel%
emotion
§
Proposed%that%the%experience%we%call%emotion%occurs%after%the%cortex%
receives%signals%about%physiologic%changes
We%feel%sorry%because%we%cry
§
The%physiological%changes%are%the%emotion%
§
Emotion%is%the%consequence%of%information%from%the%periphery
Emotions%are%experienced% even%if%physiological%changes%arent%
sensed
§
Patients%&%animals%with%transected%spinal%cords%do%not%have%
lessened%emotions%
§
The%same%physiological%changes%accompany%different%emotions%and%
can%have%other%causes%(e.g%.%fear,%anger%&%disease%can%all%increase%
heart%rate%&%cause%sweating)
§
Critique%of%James%&%Lange
9%..%1"(:1"*'(;(<1+.(=1&/*(8:1"*'(;(=1&/* >??@
Stimulus%can%simultaneously%evoke%both%emotions%and%arousal
Stimuli%cause%emotional%experience
Emotional%experience% can%occur%independently%of%emotional%expression
The%thalamus%plays%a%pivotal%role%in%emotional%sensations
Emotions%are%produced%when%signals%reach%the%thalamus%directly%from%
sensory%receptors%or%by%descending%cortical%input
The%emotion%is%determined%by%the%pattern%of%activation%of%the%thalamus
91.$*+(61&&#&(1&A(27%..%5(B1+A(C61&&#&(;(B1+A(>DEFG
Theories%of%Emotion%
H$1&.*I(H3713$*+ -there%are%two%pathways%because%the%brain%have%to%evaluate
Emotion%is%context-dependent -our%expectations%of%circumstances%and%the%
circumstances%itself
The%cortex%constructs%emotion%out%of%signals%received%from%the%periphery - this%
is%called% the%somatic%marker%hypothesis
Depends%expectations,%experience,%social%context
Thus%the%same%responses%can%accompany%different%emotions
Emotion%is%a%story%the%brain%concocts%to%explain%bodily%reactions
The%Somatic%Marker%Hypothesis
J,3.*,'(133,"K*&' -recruits%orbitofrontal%cortex,%thalamus,%motor%cortex,%etc.,%
involved%in%approach,%attention%to%goals,%and%action%control%
Lesions%to%the%amygdala%will%interfere%in%the%fear%response
Lateral%nucleus%-information%input%(unconditioned%stimuli),%first%
step%in%processing%emotional%output
§
Amygdala%is%made%up%of%sub%nuclei%with%specific%functions
L"I/A1.1 -regulates%many%cortical%and%subcortical%areas%involved%in%attention%
to%affectively%relevant%stimuli%activates%brainstem%structures%that%orchestrate%an%
emotional%response%(predominant%associated%with%the%fair%responses)
MI5#$71.1",' -regulates%limbic,%cortical%and%brainstem%systems,%ventral%
striatum,%autonomic%nervous%system,%according%to%organismic%goals,%drive%
states,%territorial%aggression,%bodily%needs,%etc.%
B+1%&('$*" -ascending%neuromodulators%recruit%activation%of%all% areas%of%cortex%
and%limbic%system,%in%support%of%focused%perception%and%action%
Cingulate%gurus%-connection%between%the%frontal%cortex%and%the%limbic%system%
(two-way%communication)
Subcortical%epicentres%of%self-regulation%-Limbic%system%(p.%412%Figure%10.13%is%
important)
Two%pathways%to%amygdala%-direct%to%lateral%amygdala,%indirect%through%cortex
Lateral%amygdala%(responsible%for%the%input%of%information)%%is%a%key%site%of%
plasticity%in%fear%conditioning
Conditioned%fear%-fear%conditioned%to%particular%cues
The%LA%is%the%main%site%of%synaptic%changes%underlying%learning%and%
memory
LA%is%the%site%where%the%CS%and%US%pathways%converge
Le%Doux%1993
Consolidation%of%fear%conditioning%is%inititated%by%the%activation%of%receptors%at%
the%post-synaptic%neuron
This%in%turn%triggers%cascades%of%intracellular% events%that%regulate%the%activity%of%
mitogen-activated%protein%kinase%(MAPK)
MAPK%controls%transcription%factors,%such%as%CREB%proteins,%which%regulate%
transcription%of%certain%genes
Gene%activation%leads%to%a%new%RNA%and%new%protein%synthesis%and%thus,%
structural%changes%in%the%post-synaptic%neuron
Plausible%mechanisms%of%retrograding%signaling%from%the%post-synaptic%neuron%
induce%changes%in%the%pre-synaptic%neuron
When%the%animal%is%returned%to%the%same%environment,%it%generally%will%
demonstrate%a%freezing%response%(absence%of%movement%except%for%
respiration)%if%it%remembers%and%associates%that%environment%with%the%
aversive%stimulus
Contextual%fear%conditioning%-involves%taking%and%animal%and%placing%it%in%a%
novel%environment,%providing%an%aversive%stimulus%and%then%removing%it
Cued%fear%conditioning%-similar%to%the%contextual%fear%conditioning%except%there%
is%a%presence%of%a%CS
Reward%signals%that%are%mediated%through%prelimbic%area%trigger%glutamate%
release%within%the%core%nucleus%accumbens
In%general,%excessive%release%of%glutamate%within%the%core%of%nucleus%accumbens%
heightens%the%motivation%or%craving
Dopamine%that%originates%from%the%VTA%augment%glutamate%function%and%
together%they%create%insatiable%craving%symptoms
A%cue%can%also%trigger%craving%symptoms%aside%from%the%reward%signals
Cue-primed%symptoms%are%mediated%through%the%baso-lateral%amygdala
Stress%can%also%trigger%craving%symptoms
Stress-primed%craving%symptoms%are%mediated%through%the%stria%terminals%and%
extended%amygdala
The%amydgala%plays%the%central%role%in%the%CNS%in%processing%afferent%and%
efferent%connections%related%to%emotional%functioning
The%amygdala%receives%input%directly%from%sensory%thalamus,%
hippocampus%(via%multiple%projections),%entorhinal%cortex,%sensory%
association%areas%of%cortex,%polymodal%sensory%association%areas%of%
cortex,%and%from%various%midbrain%and%brainstem%arousal%systems%via%the%
RAS
The%amygdala%processes%and%determines%the%emotional%value%of%simple%
sensory%input,%complex%multisensory%perceptions%and%complex%cognitive%
abstractions,%even%responding%specifically%to%complex,%socially%relevant%
stimuli
The%amygdala%orchestrates%the%response%to%this%emotional%information%by%
sending%projections%to%brain%areas%involved%in%motor%(behavioral),%
autonomic%nervous%system%and%neuroendocrine%area%of%the%CNS
The%'site'%of%perception%of%anxiety%is%likely%to%be%the%amygdala
It%is%in%these%limbic%areas%that%the%patterns%of%neuronal%activity%associated%
with%threat,%and%mediated%by%the%monoamine%neurotransmitters%systems%
of%the%reticular%activating%system,%become%an%emotion
Amygdala%cells%are%ready%to%respond%to%emotional%stimuli
Some%are%more%sensitive%than%others%at%any%one%time
CREB%levels%are%hypothesized%to%be%a%key%determinant%of%sensitivity
Cn%we%erase%learned%associations%by%removing%these%specific%cells?
Add%CREB-cre%recombinase
Make%it%conditionally%active
Activate%fear%conditioning
Erasing%fear%memories%-Josselyn%et.%al%(read%article)
Activation%of%amygdala%and%insula,%recruiting%prefrontal%circuits%
mediating%decision-making
§
Adolescents%considering%risky%actions:
Activation%of%amygdala,%insula,%and%medial%PFC,%mediating%
perception%of%social%judgment%(Work%by%Abigail%Baird)
§
Adolescents%considering%being%judged%by%peers:%
9%$7%&(%&A%)%A,1.'N
Activation%of%amygdala,%insula,%ventral%ACC,%OFC,%and%deactivation%
of%DLPFC%and%dorsal%ACC%(Mayberg,%Pizzagalli,%Drevets,%and%
colleagues)
§
Depressive
Activation%of%pons,%midbrain,%hypothalamus,%insula,%and%dorsal%ACC,%
deactivation%of%OFC%(Damasio%et%al.,%2000)
§
Aggressive
Adolescent%boys%show%enhanced%activation%of%the%nucleus%
accumbens,%focusing%their%attraction%on%risky%activities (Preliminary%
data%by%Abigail%Baird)
§
Adolesceve
L3+#''(%&A%)%A,1.'O
Regulatory%configurations%vary%
The%amygdala%is%the%critical% structure
Also%involves%the%hypothalamus%&%ANS
Kluver-Bucy Syndrome
Electrical% stimulation%experiments
Patients%with%damage%to%the%amygdala
Demonstrated%by:
Fear%&%Anxiety
bilateral%removal%of%the%temporal%lobes%in%monkeys%(which%contains%the%
amygdala%&%hippocampal%formation)
increased%and%bizarre%sexual%behaviour
highly%oral
temporal%lobe%destruction%of%visual%cortices
§
failed%to%recognize%familiar%objects%(psychic%blindness)
absence%of%fear -amygdala%missing%
§
emotionally%flat
Radical%changes%in%emotional%behaviour
Klüver-Bucy%Syndrome%(Heinrich%Kluver &%Paul%Bucy -1939)
Structure%critical%to%emotional%part%of%Kluver-Bucy syndrome%is%the%amygdala
The%amygdala%is%part%of%the%limbic%system
Human%patients%with%damaged%amygdala shave%reduced%ability%to%recognize%fear%
in%others
Electrical% stimulation%leads%to%fear%and%anxiety
A%learned%fear%response,%where%pain%is%associated%with%a%sensory%input,%may%
involve%a%circuit%through%the%basolateral nuclei%&%central%nucleus%of%the%
amygdala
These%effects%are%mediated%through%the%hypothalamus%&%autonomic%nervous%
system
Ablation%experiments%indicate%that%the%amygdala%is%also%involved%in%
aggression%-amygdalectomy reduces%aggression
Predatory%aggression%-cortex%>%amygdala%>%lateral%hypothalamus%>%
mfb>%ventral%tegmental%area
§
Affective%aggression%-cortex%>%amygdala%>%medial%hypothalamus%>%
dlf>%periaqueductal%gray%matter
§
Two%pathways%for%aggression:
Led%to%psychosurgical%procedures%to%destroy%amygdala%in%humans%(frontal%
lobotomy%is%another%example%of%psychosurgery)
Possible%Role%of%the%Amygdala
The%Amygdala
Output%from%the%amygdala%would%initiate%a%fear%response
The%1"I/A1.1 -critical% in%both%learned%emotional%responses%and%the%emotional%
modulation%of%memory%storage%and%retrieval
Lateral%nucleus -primary%entry%for%sensory%information%from%the%thalamus%
or%cortex%into%the%amygdala
Central%nucleus -receives% inputs%from%other%amygdala%nuclei%and%projects%
out%of%the%amygdala%to%the%ANS%driving%expression%of%physiological%
responses%such%as%arousal%and%release%of%stress%hormones%and%behavioural%
responses%such%as%freezing%and%startle
Basolateral%nucleus -receives%input%from%LA%and%projects%to%the%cerebral%
cortex,%basal%ganglia,%hippocampus%and%providing%pathway%by%which%
amygdala%can%modulate%memory%storage%and%retrieval
The%amygdala%is%consisted%of%different%nuclei:
P71.1",' -first%site%in%the%brain%where%most%kinds%of%sensory%input%converge%
and%are%processed%(relays%the%information%to%the%amygdala%and%cortex)
6#+$*Q -processes%sensory%information%more%fully%(also%relays%information%to%the%
amygdala)
Hippocampus%-critical% for%new%episodic%(event)%memory%formation
PFC%-helps%people%read%the%expression%of%emotion%in%others
Allows%us%to%process%emotional%stimuli%in%a%manner%appropriate%to%the%
context%in%which%the%stimuli%occur
Turns%off%or%inhibits%the%normal%emotional%response%provoked%by%
amygdala%stimulation
Medial%prefrontal%cortex%-active%when%the%facial%expression%is%recognized%as%
fearful%rather%than%in%neutral%faces
Brain%Substrates
Emotional)Memory
Tuesday,% October% 21,%2014 11:03%AM
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