Lecture 6: Amygdala, Fear and Emotion Flashcards
Emotions are mechanisms for _
adaptation
What can promote adaptation during important life events?
Emotion
Short lived biopsychosocial phenomenon
- Activate biological and physiological systems
- Promote action via a motivational state of personal significance
- Express to others how we interpret our present situation
When are emotions Adaptive?
when they prioritize behaviors that optimize adjustment to ongoing demands
- Fear of being bitten by experimental animals motivates a graduate student to take a firm grip when scruffing a mouse, exerting control
When are emotions Maladaptive?
When emotions prioritize behaviors that interfere with effective adaptations, they are maladaptive
- Fear of being bitten by experimental animals motivates the graduate student to allow volunteers “the opportunity to learn to handle mice.
What are two ways we can resolve an issue (emotions)?
Maladaptive or adaptive behaviors
- Adaptive if they optimize adjustment to ongoing demand.
- Maladaptive if emotions interfere with effective adaptations.
Explain the difference between emotions vs. moods
- Emotions: Short-lived biopsychosocial phenomenon that can promote adaptation (ex. fear)
- Moods: consist of persistent biases that prepare the organism for emotional events. (ex. anxiety)
T/F: Anxiety is an emotion
False, it is a mood-> persisent state that biases your thought processes
Fear an emotion or mood?
Fear is an emotion
What is fear?
- Consists of physiological changes for action (fight or flight)
- Fight or Flight
- Short lived
What is anxiety?
- Moods consist of biases that prepare the organism for emotional events.
- Persistent
- Anxiety consists of sustained arousal, vigilance and apprehension of vague, potential threats.
How is anxiety (mood) adaptive or maladaptive?
-
Adaptive to the extent that the mood promotes conditions that enhance functional responses to emotional events.
- If mood enhances functional responses to emotional events
-
Maladaptive to the extent that the mood interferes with day-to-day functioning and/or contributes to dysfunctional responses to emotional events.
- If mood interferes with day/day functioning
The circuits mediating fear overlap considerably with those mediating _
anxiety
Posttraumatic stress disorder (PTSD) and Anxiety disorders affect approximately _% of US adults each year
18%
What are some Anxiety disorders?
- Panic disorder
- Generalized Anxiety Disorder
- Social Anxiety Disorder
- Phobias
Posttraumatic stress disorder (PTSD) and Anxiety disorders are characterized by what?
By a dysregulated fear/anxiety response
- The response is disproportionate to the event and produces maladaptive behavior
- Overgeneralized response that occurs outside of situations should be expected to occur and produces maladaptive behavior.
What is the most common symptom of anxiety disorder?
Overgeneralized fear/anxiety
- The response occurs outside of situations it should be expected to occur and produces maladaptive behavior.
What is important to understand and treat anxiety disorders?
Understanding the neurocircuitry that mediates the experience, expression and learning of fear and anxiety
Who and what first proposed that specific brain circuits are devoted to emotional experience and expression?
James Papez and Broca’s Limbic Lobe
- Emotional system on the medial wall of the brain linking cortex with the hypothalamus
- Cortex forming a ring around corpus callosum: Cingulate gyrus, medial surface temporal lobe, hippocampus
Emotions are found in one or many brain regions?
many brain regions, not a fixed state
- state of constant flux as a consequence of interactions between multiple brain regions
What is the septum/septal area responsible for? What happens when you lesion the septum?
- Responsible for temperance/regulation of emotional responses
- Disinhibit the hypothalamus which results in extremes of emotion, including explosive violence
What regions are involved in emotion/mood? And what they are responsible for?
Broca’s Limbic Lobe
-
Thalamus: Responsible for processing sensory
inputs - Cingulate Gyrus: Responsible for emotional experience.
- Hippocampus: Responsible for understanding the context of the experience.
- Hypothalamus: Responsible for emotional expression
- Neocortex: Responsible for emotional coloring
What happens when a temporal lobectomy happens? What is a syndrome with this? What area is also affected?
Because you probably cut the amygdala as well
- Decreased fear and aggression
- Decreased vocalizations and facial expressions
Probably related to the destruction of the amygdala
- Klüver-Bucy Syndrome
- Amygdala
What is Klüver-Bucy Syndrome?
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
What happens in animals with bilateral amygdalectomy?
- Reduces fear and aggression
- Anger, sadness, and disgust also affected
- Inability to recognize fear in facial expressions
- S.M. case study: Inability to recognize fear in facial expressions
similar to the temporal lobe
What happens when we stimulate the amygdala
Increased vigilance or attention
Fearful faces produce greater _ activity than
happy/neutral faces
Amygdala which shows that the amygdala is involved in some kind of assessment of emotional states
What are all the structures involved in fear?
Amygdala
- Baso-lateral Amygdala (BLA)-> Lateral Amygdala (LA), Basal Amygdala (B), Accessory-Basal Amygdala (AB)
- Central Nucleus (CEA)->Lateral (CEl) andMedial (CEm)
Intercalated Cells (ITC)
Extended Amygdala
- Bed Nucleus of the Stria Terminalis
(BNST) - Medial Extended Amygdala (MEA)
Hypothalamus
- Releases regulatory hormones->e.g. corticotropin-releasing hormone
What are the different areas of the amygdala?
Baso-lateral Amygdala (BLA)
- Lateral Amygdala (LA)
- Basal Amygdala (B)
- Accessory-Basal Amygdala (AB)
Central Nucleus (CEA)
- Lateral (CEl)
- Medial (CEm)
What are intercalated cells (ITC) involved in mediating?
Extinction
Extended amygdala recieve projections from where?
basal later amygdala+ central nucleus
The _ is a substrate for learning fear
Amygdala
How do the amygdala and associated brain circuits receive inputs?
- The amygdala receives input from several sources and projects to regions that mediate physiological and behavioral responses.
- With experience, the amygdala changes how it responds to sensory inputs that are paired with aversive stimuli.
When is fear conditioning used?
study the role of various brain regions in the manifestation of fear
- Cue elicited
- Contextual
How does fear conditioning work?
- Unconditioned Stimulus (ex. Shock)→Unconditioned Response (ex. fear)
- Neutral Stimuli (Cue or Context) + US (ex. Shock) → UR (ex.fear)
Then: - Conditioned Stimuli (Cue or Context) →Conditioned Response (ex. Freezing)
How can fear conditioning be established?
Fear conditioning can be established in a single CS-US pairing; can be established to both a cue and a context; is difficult to extinguish; and can be recovered if extinguished.
Explain what is going on with extinction in the different phases
- Extinction of fear conditioning is often context dependent. If previous context is reintroduced (i.e. placing mouse in green/purple room), the conditioned fear response will still be present.
- 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.
What NTs and modulators are released during fear and how does that contribute to learning?
- Fear-inducing stimuli activate stress hormones (CRF, ACTH, cortisol) and neurotransmitter (Glu, NE, ACh, DA) release
- These neuromodulators can facilitate learning and strengthen associations
Explain the function and action of Glutamate released during fear
NTs
- Expression→Primary transmitter during expression
- Consolidation & Extinction→NMDA/AMPA mediated LTP for both consolidation and extinction
Explain the function and action of GABA released during fear
NTs
- Expression→Tightly regulates fear expression
Explain the function and action of Glucortiocids released during fear
Hormones (CRF, ACTH,cortisol)
- Experience→↑ physiological arousal/energy utlization
Explain the function and action of Epinephrine released during fear
NTs
- Experience→↑ physiological arousal
Explain the function and action of Norepinephrine released during fear
NTs
- Consolidation→↑ by β agonist
- Extinction→↓ by β antagonist in IL ctx
Explain the function and action of Dopamine released during fear
NTs
- Consolidation→ ↑ by D2 agonist in VTA
- Extinction→↓ by D1 antagonist in IL ctx
Explain the function and action of Acetylcholine released during fear
NTs
- Consolidation→ ↑ by nACh agonist in Hcc, ↓ by ⍺7 nACh antagonist
- Extinction→ ↓ by nACh agonist