Emotion has a signaling function, for example for a threat to integrity.
Emotions trigger adaptive responses. From evolutionary perspective: we use it for responses that are adaptive.
Emotions are universal, the basic emotions are: happiness, surprise, fear, anger, disgust and sadness.
- Primary reinforcers: satisfy for example hunger, thirst and safety
- Secondary reinforcers: money, social recognition
3 biosystems from evolutionary perspective:
- Reptilian brain: life support system, reflexive behavior
- Paleomammalian: motivation / emotion
- Neomammalian: higher level control
Limbic system = the emotional brain.
ANS controls the involuntary muscles.
When you encounter a threat, your autonomic nervous system responds:
- Sympathetic: fight / flight
- Parasympathetic: rest & digest
Hormones: HPA-axis. Releases glucocorticoids, which regulates stress.
Fear response: LeDoux model. The amygdala is the important structure. He proposed there are different routes, a fast route and a slow route.
The information enters the BLA (basolateral) amygdala. Then projections are sent to the central amygdala, from where the projections run to the (hypo)thalamus.
‘Emotion’ areas of PFC:
- Anterior cingulate cortex (ACC)
- Subgenual subdivision of ACC (vmPFC)
- Orbitofrontal cortex
Amygdala is involved in fear conditioning.
The CS will elict conditioned (fear) response:
- Yes, with intact amygdala + startle
- With skin conductance: only if learning takes place
The ACC and the anterior insula are consistently activated in response to threat.
In a study, no constant amygdala activation was found during fear. Why?
- FMRI resolution too low (amygdala contains different, quite small areas)
- FMRI time course (typically modelled as same response to each trial, whereas conditioning is a learning process that develops over time)
- Human fear conditioning is only mild threat
A fearful expression will slow down the reaction time in a stroop task. Also when the face is masked and the face is no longer recognizable.
There is no amygdala activation when the attention to the fearful stimulus was explicitely directed away.
There is no anatomical evidence for the fast route of LeDoux. There is however some evidence, such as affective blindsight, binocular rivalry.
Evidence that non-attended or unconsciously processed information can activate amygdala does not necessarily mean that this information has been processed (exclusively) through subcortical channels.
There should also be focus on networks, not only on isolated brain areas. Such as the salience network.
Summary:
- Emotion is an important driver of behavior
- There are several levels of neural system involved in
- Generating emotional response
- Learning adaptive responses
- Interactions between emotion and cognition
- Responses are regulated through mutual connectivity
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