Exam3Lec6Amygdala,Fear,andEmotion Flashcards
What is an emotion?
Short lived biopsychosocial phenomenon that can promote adaptation.
Emotions can be ____ or ____
adaptive: if they optimize adjustment to ongoing demand.
maladaptive: if emotions interfere with effective adaptations.
Example of an emotion
Fear
Short lived
Consists of physiological changes for action (fight or flight)
What is a mood?
Moods consist of persistent biases that prepare the organism for emotional events.
What is an example of a mood?
Anxiety: Consists of sustained arousal, vigilance and apprehension of vague potential threats.
A mood can be ____ or ____
adaptive: Adaptive if mood enhances function responses to emotional events
maladaptive: Maladaptive if mood interferes with day/day functioning
What are 4 examples of disorders of fear/anxiety?
- Panic Disorder
- Generalized Anxiety Disorder
- Social Anxiety Disorders
- Phobias.
Disorders of fear/ anxiety is characterized by what?
a dysregulated fear/anxiety response
- Disproportionate response to the event and produces maladaptive behavior.
- Overgeneralized response which occurs outside of situations it should be expected to occur and produces maladaptive behavior.
What are regions involved in Emotion/Mood? and what are they responsible for?
Broca’s Limbic Lobe
1. Thalamus: Responsible for processing sensory inputs
2. Cingulate Gyrus: Responsible for emotional experience.
3. Hippocampus: Responsible for understanding context of the experience.
4. Hypothalamus: Responsible for emotional expression
5. Neocortex: Responsible for emotional coloring
Septum/Septal Area
Temporal lobe/Amygdala
You get home after a long day of studying and as soon as you turn on the lights of your apartment, someone jumps out and screams at you!
Explain how each region below plays a role in your emotion/mood
* Thalamus
* Hippocampus
* Hypothalamus
* Neocortex
- Thalamus: Sensory Inputs – People screaming at you out of nowhere.
- Hippocampus: Context – This person is a friend and other friends are here too; Today is my birthday. This is a surprise birthday party!
- Hypothalamus: Emotional expression – vasodilation, flushing – Joy/Happiness
- Neocortex: Emotional coloring – I’m exhausted; I have a ton of work to do tonight and want to get to it so I can sleep – ambivalence, frustration.
How is the septum/septal area involved in emotion/mood? Lesions of the septum leads to what?
- Responsible for temperance/regulation of emotional responses.
- Lesions of the septum disinhibit the hypothalamus which leads to explosive violence and extremes of emotions.
How is the temporal lobe/amygdala involved in emotion/mood?
- Temporal lobectomy leads to decreased fear, aggression, vocalizations and facial expressions
- Klüver-Bucy Syndrome
What is Klüver-Bucy syndrome?
is a very rare cerebral neurological disorder associated with damage to both temporal lobes resulting in abnormalities in memory, social and sexual functioning and idiosyncratic behaviors.
How does the amygdala play a role in fear?
The Amygdala is a substrate for learning fear. With experience, the amygdala changes how it responds to sensory inputs that are paired with aversive stimuli.
What occurs if you stimulate the amygdala?
Stimulation of the amygdala causes increases vigilance or attention.
Fearful faces produce greater amygdala activity than happy/neutral faces
What occurs if you have a bilateral amygdalectomy?
reduces fear and aggression in animals.
S.M. case study: Inability to recognize fear in facial expressions
Explain fear conditiong with the rat
Unconditioned Stimulus (Shock) ->Unconditioned Response (Fear)
Neutral Stimulus (Cue or Context) + US (Shock) ->UR (Fear)
Conditioned Stimulus (Cue or Context) -> Conditioned Response (Freezing)
Extinction of fear conditioning depends on what?
Context
our minds can associate fear with a specific context
Explain the experiment where they performed extinction training on the rat in blue room
Fear acquisition
Fear Retrieval
Extinction acquisition
Fear renewal
Fear reinstatement
Spontaneous recovery
If previous context is reintroduced (i.e. placing mouse in green/purple room), the conditioned fear response will still be present.
If the mouse was placed in the blue room, it will learn that it’s safe there because as they sounded the tone over time with no shock, the rat learned that its safe in the blue room only.
In other words, mammals have an innate ability to distinguish safe from unsafe spaces. During fear/anxiety disorders, the ability to distinguish between safe and unsafe spaces in impaired.
if you have anxiety or fear this extinction is inhibited ( can distinguifh a safe or unsafe environement)
Glutamate
1. Function
2. Action
hy
Function 1: expression
* Action: primary transimitter driving expression
Function 2: Consolidation and Extinction
* Action: NMDA/AMPA mediated LTP for both consolidation and extinction
hy
GABA
1. Function
2. Action
- Function: expression
- Action: tightly regulates fear expression
Fill in the black boxes. What are the function and actions?
Fear-inducing stimuli activate stress hormones____ and neurotransmitter ____ release which facilitate learning and strengthen associations.
Fear-inducing stimuli activate stress hormones (CRF, ACTH, cortisol) and neurotransmitter (Glu, NE, ACh, DA) release which facilitate learning and strengthen associations.
What structures within the amygdala are involved in fear?
Amygdala
Basolateral (BLA)
* Lateral Amygdala (LA)
* Basal Amygdala (B)
* Accessory-Basal Amygdala (AB)
Central Nucleus (CEA)
* Lateral (CEI)
* Medial (CEm)
What structures within the extended amygdala are involved in fear?
Extended Amygdala
* Bed Nucleus of the Stria Terminalis (BNST)
* Medial Extended Amygdala (MEA)
What is the role of the Lateral nucleus of the amygdala (LA) and fear
It is the The substrate for learning to be afraid (CS->US pairing) and experiencing fear
What do lesions of the LA impair?
Lesions of the LA impair emotional responding to shock (experinecing fear).
Lesions of the LA impairs both cued and contextual fear conditioning.
Explain what occured in this experiment and results
Experiment: mice had lesions in the Basolateral Amy (BL) and Hippocampul formation (HF) and no lesions in the control (SH)
Results: there was a significant decr in freezing for context and tone/cued conditional stimulation in mice with lesion in BL.
The trial mice were not experiencing fear further strengthening the theory that the LA is responsible for fear conditioning.
How do the LA neurons fire during fear condition?
LA neurons fire sooner and more frequently.
These activity changes are in response to LTP (Consolidation – Glutamate) between the LA and thalamus, NOT the sensory cortex.
Fear conditioning causes neuronal action potentials to bypass the cortex (higher order thinking) and strengthens the connection between the thalamus and the Lateral Amygdala. In the presence of the conditioned stimulus, bypassing the cortex allows our fear response to be significantly faster
Does the amygdala work alone in fear conditioning?
NO, lesions of the hippocampal formation impair the ability to learn to fear the context, but not the cue, associated with shock
basically: hipppocamus is responsible for contextual learning, not cued learning
What type of neurons are present in basal and acessory bassal amygdala?
Anterior “aversion” neurons
posterior “ reward” neurons
Anterior “Aversion” Neurons
Express?
Respond to?
Reciprocal connections with?
Inhibitroy interneuron connection with?
- express r-spondin 2 (Rspo2)
- Respond to negative valence stimuli
- Reciprocal connections with PL cortex
- Inhibitory interneuron connections with posterior “reward” BA neurons
PL is part of the prefrontal cortex
Posterior “Reward” Neurons
Express?
Respond to?
Reciprocal connections with?
Inhibitroy interneuron connection with?
- Express: protein phosphatase 1-regulatory inhibitor subunbit 1b (Ppp1r1b)
- Respond to positive valence stimuli
- Reciprocal connections with IL cortex
- Inhibitory interneuron connections with anterior “aversion” BA neurons
IL cortex part of pre-frontal cortex
Extinction of fear is associated with increased inhibition of ____ neurons and decreased inhibition of ____ neurons.
anterior
posterior
The hippocampus (Hcc) in conjunction with the amygdala (basal& basal acessory) mediate what? Inactivation of Hcc impairs what?
Context dependent activated of extinction cue elicited fear (contextual control of extinction)
Inactivation of the Hcc impairs the retrieval of CS-Context associations (overgeneralization)
Pathways of contextual control of extinctions
- Hcc->BLA & Hcc->PL-> BLA are involved in context dependent expression of fear
- Hcc->IL->CEA involved in suppression (extinction) of fear responses following extinction
Remember:
Anterior “Aversion” Neurons of the BLA respond to negative valence stimuli and have reciprocal connections with the PL cortex. Hence their role in EXPRESSION of fear along with the Hippocampus.
Posterior “Reward” Neurons of the BLA respond to positive valence stimuli and have reciprocal connections with the IL cortex. Hence their role in SUPPRESION of fear along with the Hippocampus.
What is the Lateral central nucleus (CEI) repsonsible for?
It acts like the LA of the amy (fear conditioning)
* NMDA antagonism blocks acquisition of fear conditioning
* Hcc and Ctx inputs also involved in context mediated extinction of cue elicited fear
The CEA is the interface with motor systems and damage to the CE interferes with the expression of conditioned fear responses.
What is the medial central nucleus (CEm) responsible for?
Primary output for expression or lack of expression of fear
- ____ neurons are involved in the inhibition of amygdala outputs
- Extinction of fear mediated by ____ inputs from the hippocampus.
- GABAergic neurons are involved in the inhibition of amygdala outputs
- Extinction of fear mediated by glutamatergic inputs from the hippocampus.
gabaergic neurons modulated expression of fear via CEm
What does Prolonged activation of the basolateral amygdala by long duration “diffuse” cues leads to?
- Activation of the BNST (part of extended amy)
- Inhibition of the Cem
The Bed Nucleus of the Stria Terminalis (BNST) is a part of the extended amygdala.
Expain the pathway of how prolonged activation of the basolateral amygdala
factor (CRF) onto the BNST produces a heightened state of arousal and vigilance (anxiety).
Individuals suffering from PTSD exhibit difficulty with what? How so?
difficulty using contexts to limit fear responses
1. Impaired Hcc and vmPFC activation and exaggerated dPFC activation.
2. Absence of LTP in the PFC impairs the contextual regulation of the fear response.
3. have suppressed levels of BDNF.
BDNF is critical for extinction of fear (Hcc->IL-PFC).
Fill in boxes
What are 3 types of Anxiety Disorders?
- Panic Disorder: Associated with increased arousal in AMY, vmPFC, dlPFC and brain stem; low GABAA receptor binding.
- Social Anxiety Disorder: Exaggerated amygdala activation only consistent finding
- Specific Phobias: AMY and dlPFC hyperresponsive to specific cues
What treatment is 1st line for anxiety disorders?
Cognitive Behavioral Therapy (CBT)
constructive restructuring of thoughts around fear inducing stimuli
What are four psychotherapies for PTSD?
- Cognitive Processing Therapy
- Prolonged Exposure Therapy
- Eye Movement Desensitization and Reprocessing
- Stress Inoculation Training
What are 4 pharmaceuticals useds for treatment of anxiety disorders?
- SSRI’s and SNRI’s
- Benzodiazepines
- Pregablin
- MDMA-assisted psychotherapy
