Emotion Flashcards
Emotion is a combination of three components. What are these?
Behavior, physiology, feeling
Why do we have emotion?
- Recognizing emotion in others
- Having emotions yourself makes it possible to react to certain situations.
What disorders can occur when there’s too much emotion?
- Major depression
- Phobias
- Anxiety
- Compulsive disorder
- Borderline personality disorder
- Drug / Alcohol abuse
Emotions are subjective feelings, associated with certain physiological states. Emotion is further defined by its valence and intensity. What is the meaning of valence and intensity?
- Valence → can be positive or negative
- Intensity → the strength of emotion from low to high levels.
Besides the valence and intensity of emotions, emotions can also be quantified on a different level. How?
Emotion is always subjective, so valence and intensity don’t always mean the same thing.
Emotional states are also expressed through the visceral motor system (heart rate, blushing/turning pale, sweating).
So autonomic changes allow for quantification of emotional responses.
How does emotion relate to the body?
Emotions are an important consequence of the regulation of the autonomic nervous system. The autonomic nervous system can be divided into the parasympathetic (rest and digest) and sympathetic nervous system (fight or flight).
By what is the autonomic nervous system regulated?
By the hypothalamus and preganglionic centres in the brainstem/spinal cord.
What are autonomic nervous system responses during activation of the sympathetic nervous system?
- Pupil dilation
- Inhibition of salivation
- Accelerated heartbeat
- Inhibition of intestinal activity
What is another type of emotional regulation?
Facial expressions
There’s a subtle difference between a real smile (Duchenne smile) and a fake smile. How did they research this?
In an experiment, they looked at how facial neurons are involved in facial expression. They saw that a smile can be generated by activating certain muscle groups. However, this smile was not the same smile as when someone was genuinely smiling. So smiling is not only a matter of activating certain facial muscles, but emotion is a really important part in this.
So what does this fake and real (Duchenne) smile say about the regulation of emotion?
That there are two different pathways for the motor control to express emotions → one for the voluntary movement of facial muscles (generating only the (fake) smile) and one for the involuntary movement of facial muscles (generating a real smile). The latter involves the regulation of neural systems for emotional expression.
What do the following two patients confirm?
- Patient 1 → lesions in right hemisphere motor cortex → has difficulty symmetrically contracting facial muscles voluntarily but has no problem with genuinely smiling.
- Patient 2 → tumour in left thalamus → has no difficulty with symmetrically contracting fascial muscles voluntarily but has problems with symmetrical smiling genuinely.
These patients have the same causes in opposite brain regions and therefore have the same but opposite symptoms.
It confirms that there are two specific pathways → one for voluntary facial movement and one for involuntary facial movement.
What brain regions seems to be important for the behavioral output of emotion? And where is this finding based on?
The hypothalamus. It’s seen that without the hypothalamus, emotions are absent and when the hypothalamus is cut in half in mice, the mice show aggressive emotions.
Note: this led to the idea that cortical brain regions do not necessarily mediate emotional responses. This is found to be not true anymore, we now know that cortical regions are important.
In another experiment, optogenics were used for controlling the activity of hippothalamal neurons. What happened to the mice when neurons were stimulated with light to be active?
When these neurons were stimulated, the mice showed aggressive behaviour.
Note: from this, we don’t know if the mice really shows the emotion aggression, or that the brain’s activity causes aggressive behavior.
What other brain regions seem to be important for emotions?
The limbic system (amygdala, basal ganglia, mediodorsal nucleus of thalamus etc.)
Describe the characteristics of the amygdala.
- The amygdala lies deep in the temporal lobe and consists of a basal-lateral, medial and central group.
- The amygdala is highly conserved across species.
- The amygdala is highly connected with other limbic brain regions and also directs inputs from sensory inputs → it can link sensory inputs and can activate programs that are associated with this sensory input).
What are the key amygdala structures?
- Basolateral nuclei
- Central nucleus
What is fear conditioning?
This is a form of classical conditioning. Here, an aversive stimulus is paired with either a neutral context or stimulus. This results in the expression of a fear response in the presence of the context or the stimulus alone.
During fear conditioning, you can train a mouse so that is displays contextual fear or cued fear. What is the difference between the two?
- Contextual fear → the mouse is trained so that it associates an aversive stimulus with its context (e.g. a specific room).
- Cued fear → the mouse is trained so that it associates an aversive stimulus with a tone.
How does the brain associate behaviour with fear?
Auditory and somatosensory information is processed by the thalamus and cortex and then transmitted to the lateral amygdala. Here, the lateral amygdala interacts with the central nucleus of the amygdala. Next, the behavioral outputs (freezing, blood pressure, hormones) are mediated by the hypothalamus.
How does learning take place in amgydala? (for this answer take fear conditioning as an example).
For this, it’s important to remember the concept of associativity in long-term potentiation. Here, a weak stimulus (e.g.) the tone is paired with a strong stimulus (e.g. a shock). This creates plasticity in term of long-term potentiation, where the weak stimulus is associated with the strong stimulus.
“Neurons that fire together, wire together.”
Why does contextual fear, and not cued fear, require hippocampal activity?
Contextual fear conditioning is dependent on the hippocampus. This is because contextual fear is about fear conditioning in regard to the context (e.g. a room or another location) and the hippocampus provides information about the location. Cued fear is fear conditioning in regard to the tone, which isn’t processed by the hippocampus.
What is seen in patients with Urbach-Wiethe disease (bilateral calcification and atrophy of medial temporal lobes)?
These patients have no fear and are unable to recognize facial expressions of fear in others (because also the amygdala is affected).
The amygdala has a very high connectivity with other brain regions. What does this suggest?
That there’s integration of emotional brain circuits with cognitive brain circuits.
What is seen in PTSD patients when showing unconditioned or conditioned situations?
There’s hyperactivity of the amygdala and hypoactivity of the prefrontal cortex. This causes PTSD patients to have an overfearfull reaction to certain stimuli. This fear response stays hyperactive and doesn’t change anymore (whereas in healthy people, the fear response can still go down).
