Emotion
= cluster of three distinct but interrelated kinds of responses (physiological responses, overt behaviors, and conscious feelings)
- small set of universal emotions
- different cultures —> same emotions, different ways of expressing them
Arousal/Fight-or-flight response
= collection of bodily responses, to prepare body to face a threat - either by fighting or by running away
- bodily changes mediated by ANS
brain senses threat —> ANS sends signal to adrenal glands —> glands release stress hormones —> hormones act throughout body to turn fight-or-flight response on and off
James-Lange Theory of Emotion
Emotional Stimulus —> Bodily response (arousal) —> conscious emotional feelings
- researchers should be able to evoke a given emotion in a person by inducing the corresponding bodily responses
- difficulty with theory: many emotion-provoking stimuli give rise to similar sets of biological responses; physiological can evoke emotion (e.g. simple induces happiness)
Modern emotional theories (Schachter)
- include the factor of cognitive assessment (context)
animals and emotion
- seem to behave as if they feel emotions —> but never know if they experience subjective feelings same way humans do
Influence of emotions on memory storage
- strong emotions can affect probability that a memory is encoded
- mood or emotion as one kind of memory cue
- flashbulb memories —> often imperfect
Influence of emotions on memory storage
- mood-congruency of memory
= easier to retrieve memories that match our current mood or emotional state
Learning Emotional Responses
- conditioned emotional responses
= behavioral and physiological CRs that occur in response to a CS that has been paired with an emotion-evoking US
- long-lasting and hard to extinguish
easily reinstated after extinction
Learning Emotional Responses
- conditioned avoidance
= organism learns to take action to avoid or escape from a dangerous situation
Learning Emotional Responses
- instrumental conditioning
= behavioral response of “avoiding” the place wher it was previously shocked
Learning Emotional Responses
- learned helplessness
= exposure to an uncontrollable punisher teaches an expectation that responses are ineffectual, which in turn reduces the motivation to attempt new avoidance responses
- suggested to be component of human depressiong
- have to show people how to escape
Brain Substrates
- Limbic system
= thalamus, hypothalamus, cingulate cortex, hippocampus, and amygdala
- each emotion: activates many different brain regions —> emotion as function of the brain as a whole
Brain Substrates
- Amygdala
- Lateral nucleus
- Basolateral nucleus
- Central nucleus
= small almond-shaped structure that lies at anterior tip of hippocampus, collection of more than 10 separate subregions (or nuclei)
- critical in learned emotional responses and in emotional modulation of memory storage
- Lateral nucleus:
- “where learning happens”
- input from thalamus and cortex
- Basolateral nucleus:
- output for memory storages
- Central nucleus:
- output to motor areas and ANS
Brain Substrates
- Amygdala
- two pathways for emotional learning
(1) “direct pathway”: thalamus —> amygdala
- faster, less detail
- react quickly in a life-and-death situation, activating fight-or-flight response
(2) “indirect pathway”: thalamus —> cortex —> amygdala
- slower, more detail
- terminates fear response if the stimulus is not dangerous after all
Brain Substrates
- Amygdala and hippocampus
- amydala causes emotional arousal and the release of stress hormones (norepinephrine), which a can strengthen memory formation by the hippocampus
- amount of norephinephrine predicts learning
- amydala: important for classical conditioning
- hippocampus —> episodic memory
Brain Substrates
- Frontal Lobes
- amygdala interacts with cortex
- frontal lobes as seat of executive function —> “control center”
- functions:
- balance between too little emotion and too much
- role in helping people “read” the expression of emotion in others
- processing emotional stimuli in a manner appropriate to the context in which the stimuli occur
- preservation
Clinical Perspectives
- Phobias
= excessive and irrational fear of an object, place, or situation
- how it arises:
- classical conditioning
- humans predisposed to fear some things
- treatments:
- systematic desensitization therapy
- virtual reality therapy
- blocking epinephrine
Clinical Perspectives
- PTSD
= psychological syndrome that can develop after exposure to a horrific events, symptoms include reexperiencing the event, avoidance of reminders fo the trauma, and heightened anxiety
- why it occurs:
- classical conditioning
- individuals with PTSD: smaller hippocampal volumes
- treatments:
- exposure to cues in absence of danger
- extinction therapy
Optogenetics
optogenetic tools = genetically encoded swathes that allow neurons to be turned on or off with bursts of light
- algae protein channel rhodopsin —> influx of positive ions in response to blue light —> on-switch
- reachable protein halorhodopsin —> influx of negatively charged ions in response to yellow light —> off-switch
- useful for Parkinson’s disease and epilepsy
- advantages: high SR and TR; no significant side effects found yet
- disadvantages: need lot of testing; goes all the way to genes
- negative emotions can be replaced by positive emotions at a neurobiological level
