Emotion Lecture Flashcards
Emotion vs Mood
Emotion: complex feeling-state involving conscious experience and internal and overt physical responses that tend to facilitate or inhibit motivated behavior. Fast, overt, stimulus-locked (internal or external), time-locked. Feeling/mood: more diffuse, mild, and longer-lasting emotional episodes.
What can animal brains teach us about human emotion?
LeDoux’s survival circuit perspective of emotion - a quest for homeostasis. Emotion a conscious representation of ancient mamillian homeostatic avoidant/approach systems. Other animals have same hardware with generating emotion. Subnuclei of human amygdala comparable to chimpanzee. Bacteria even do basic approach/avoid.
LeDoux’s survival circuit perspective of emotion
Different neural systems mediate distinct homeostatic drives (e.g. defense, nutrition, fluid balance, procreation, etc.). Brain circuits involved in these key survival functions conserved across mammals. These evolved to perform basic survival functions not to generate human emotions not to generate human emotion. The activation of these basic circuits is the neural foundation for emotion, but it’s not enough to account for human emotion. If you do stimuli at too fast of a rate for consciousness, things will light up, but people don’t report fear.
The conscious experience of human emotion
We experience emotion when we become aware of activation of neural circuitry. Activation of survival circuits are held in working memory by higher order systems, integrated with computational information, memories, cognition, appraisals, etc. The collective sum of these subcortical survival circuits and cortical cognitive processes generates our conscious experience of emotion. Different evolutionary forces drove the development of survival circuits and the prefrontal processes that allow us to be conscious of survival circuit activation. We don’t know if animals have conscious representation. Humans vs. apes - visual and prefrontal cortex drive differences. Different cultures will generate different concepts of ancient motivational systems. People with depression and anxiety represent emotional states differently.
Pillars of the emotional brain
Threat circuitry: defensive threat system, combo of cognitive representation and motivational system that drives fear, reward/pleasure emotion circuitry, executive/cognitive control circuitry all connected to ANS, brainstem, hypothalamus which are involved in homeostasis and the viscera of the body.
Hypothalamus
Bridge between brain and body. Links nervous system to endocrine system; regulates body temp, hunger, thirst, sleep, drives; regulates stress response and ANS. Facilitation of survival, procreation, and homeostasis. Drives neuroendocrine system (slow/sustained response) - cortisol, sex hormones, oxytocin. Also drives ANS, (not hormones, this is neurotransmission), fast. The hormonal response sometimes operates on its own and other times in response to a stimulus.
Threat circuitry
Amygdala. Small piece in larger emotion phenomenon. There are two - bilateral. Associated with fear but actually associated with a lot of things. Sort of a fire alarm. Overall involved in salience. Negative stimuli are highly salient (but also mates, food). Amygdala response to both negative and positive stimuli - a salience index (e.g. whites of eyes). Negativity bias. Natural selection over sexual selection, overreactivity negative over positive. Low vs high road: jump at snake like thing and then realize later it’s a stick. Things go to the thalamus, some input directly to amygdala, other directed to sensory cortices (more refined processing)
Amygdala provocateurs
Whites of eyes are a strong provoker (people who are afraid have these showing, something relevant in the environment probably there), innate - snakes and spiders activate but not scary other things like texting and driving, activating to stimuli relevant for ancient times. However, people have learned guns are bad, so that has a response, associative learning. You both learn and have primed innateness, amygdala show us evolutionary history.
Amygdala central to fear conditioning
Pavlov - reinforcement, neutral tone and a positive stimulus (food), CS+ positively predicts a stimulus, CS- negatively predicts, learns not associated with new info. Skinner - associative learning around fear. Grid that shocks (UCS - don’t have to learn to respond to shocks), tone is CS+ before shocks. Fear learning happens in the amygdala. Humans CS+ and CS-, shocked at blue square, amygdala will activate to blue square. Extinction - unlearning an association, this happens in prefrontal cortex.
Subdivisions of the amygdala
LA (lateral amygdala) site of associative fear learning, central to forming associations between CS+ and UCS in fear/threat. Amygdala then needs to inform the rest of the brain. CE (central amygdala) - site of efferent outputs to the hypothalamus, facilitates freezing behavior (but sometimes need to run, BA to striatum - motor movement towards what is rewarding (safety stimuli as a reward). BA - basal nucleus is site of efferent output to ventral striatum.
Anatomical pathways of threat/fear learning
Stimulus goes to basolateral amygdala, then central amygdala, then to different areas that produce responses. Activation of threat through SNS, amygdala drives the fear responses, established pathways that drive fear responses, different nuclei drive different components. There’s also output from CE to entire brain. When in state of fear, entire brain is in alarm mode - v1, emotional state modulating perception. Amygdala not generating fear but part of network that makes salient arousal states in brain and the cortical representation of threat generates fear.
Uncinate Fasiculus
Pathway between PFC and portions of the subcortex - white matter (highway of brain). Integrity of this is important for emotion regulation, poor structural integrity associated with disorders.
Individual Differences in threat stimuli
Variability in responses - personality etc. Anxious/inhibited temperament/neuroticism associated with faster, longer, and greater amygdala response to faces. Harder time differentiating familiar and nonfamiliar faces.
The insula, threat, and embodied emotion
Insula looks like mini brain - implicated in bladder distension and orgasm, to cigarette craving, maternal love, decision-making, attention, pain perception. From olfactory to moral disgust. Implicated in threat-related decision-making. Re-representation of interoception - brain/body bridge. It doesn’t do anything but is networked with stuff, what it does is viscerotopy. It lights up to disgusting stimuli and moral disgust (PFC connnects to insula). This is why moral disgust carries emotive heat. There are lots of paradigms that activate the insula, it’s you being grounded in your own body, involved in risk - more insula activity tends to be more risk averse. Implicated in consciousness.
Reward/pleasure emotion circuitry
Insula and amygdala also involved in positive emotion to (nonduality of emotional states). Distinction in emotion between wanting and getting - wanting is dopaminergic, mesolimbocortical system, gets you to move towards what you want. Opiod/cannabinoid is enjoying what you’re getting - lots of opiod in striatum but driven by dopamine receptors.
