Emotion 1 Flashcards
(33 cards)
What are the components of emotional states?
Physiological responses, behavioral responses, perception, feelings/thoughts
What stimuli elicit emotions?
Rewarding stimuli (S+), aversive stimuli (S-), omission of rewarding stimuli (⊘), termination of aversive stimuli (!)
What brain regions are involved in emotion?
- Meso-corticolimbic dopamine system: originates from the ventral tegmental area (TGA) in the midbrain, which sends dopaminergic projections to the forebrain, including the nucleus accumbens (NAc). Release of dopamine in the NAc is what signals rewards.
Amygdala, hippocampus, prefrontal cortex, hypothalamus
What is the role of the amygdala in conditioned fear?
Lateral nucleus - associating neutral cues with aversive stimuli, Central nucleus - coordinating fear responses
What conditioned fear responses are mediated by central amygdala outputs?
Freezing behavior, autonomic/physiological responses
What is the role of the hippocampus in fear/anxiety?
Ventral hippocampus involved in conditioned freezing and innate anxiety
What is the effect of lesions on the hippocampus?
Reduced innate anxiety in elevated plus maze (anxiolytic effect)
What is the evidence for hippocampal role in human anxiety disorders?
Decreased hippocampal benzodiazepine receptor binding in panic disorder patients
Where is the mesolimbic dopamine system located?
Ventral tegmental area (VTA), nucleus accumbens (NAc), involved in reward/positive emotion
What is the advantage of using rat models?
Well-established behavioral tests, ability to target distinct brain regions
What are the key brain regions in Papez’s theory?
Hippocampus, amygdala, hypothalamus
What is Papez’s theory?
Papez’s theory, proposed in 1937, describes a neural circuit involved in emotion and memory called the Papez circuit. The key points are:
Papez Circuit
Starts in the hippocampus (subiculum region)
Travels through the fornix to the mammillary bodies
Then through the mammillothalamic tract to the anterior thalamic nucleus
Reaches the cingulate gyrus and entorhinal cortex
Returns to the hippocampus, forming a loop
Papez proposed this circuit as the anatomical basis for emotional experience and expression.
However, later research showed it plays a more significant role in memory functions like episodic and spatial memory.
Damage to structures in this circuit can lead to amnesia and memory impairment.
What are the three components associated with rewards?
Wanting (feeling of desire), liking (feeling of pleasure), and approach behaviors.
What is a potential mechanism underlying addiction?
Alterations in the brain substrates of reward-related processes.
What are some classical techniques used to identify brain substrates of reward?
Intracranial self-stimulation, intracerebral microdialysis, intracranial drug self-administration, instrumental conditioning.
What happens to nucleus accumbens dopamine levels when animals consume rewarding substances like food, drugs of abuse, or receive electrical stimulation of self-stimulation sites?
Nucleus accumbens dopamine levels increase.
What was observed in human neuroimaging studies during reward anticipation?
Increased dopamine release (measured by raclopride displacement) in the nucleus accumbens.
What are some inputs to the mesolimbic dopamine system implicated in reward processing?
Cholinergic projections from the pedunculopontine tegmental nucleus (PPTg) to the ventral tegmental area (VTA), and glutamatergic projections from the medial prefrontal cortex (mPFC) to the VTA.
Is the increase in nucleus accumbens dopamine during rewarding stimuli consistent with the hypothesis that dopamine causes pleasure (liking)?
No, it is more consistent with the hypothesis that dopamine causes desire (wanting).
How can researchers dissociate the brain substrates of “liking” from “wanting” in animal studies?
By measuring facial expressions (objective measure of liking) in response to rewarding/aversive tastes, and separating the effects of drug manipulations on liking vs. wanting behaviors.
What brain region and neurotransmitter system have been implicated in the “liking” component of rewards?
The nucleus accumbens shell and opioid receptors.
What evidence suggests an overlap between brain substrates of positive and negative emotions?
The nucleus accumbens, dopamine, and amygdala play roles in both reward-related and fear-related processes.
What is the role of the vmPFC in emotion regulation?
The vmPFC plays a crucial role in regulating and inhibiting emotional responses. It helps control emotional reactions in social situations by integrating emotional information with plans and environmental cues
How does vmPFC damage affect emotion regulation?
Damage to the vmPFC causes impairments in behavioral control and decision-making rooted in emotional dysregulation. Patients exhibit poorly regulated anger, frustration, lack of empathy, irresponsibility, and poor decision-making.
