Emotions consist of a physiological response to the stimulus (1), a behavioural response (2) and a feeling (3). The function of emotions is activating the fight/flight response (1), making quick decisions based on emotional value (2) and anticipating the consequences of a decision (3)

Basic emotions (anger, sadness, happiness, disgust, surprise, fear) are innate and universal emotions that correspond to facial expressions. Complex emotions are learned emotions, shaped by the culture and the environment. Emotions can differ on arousal (subjective intensity of emotion) and valence (positive/negative experience). Emotions are not traceable to specific brain regions.

The James-Lange theory states that emotion has three components: cognition (1), readiness for action (2) and feeling (3). Emotion is a label to our responses. This theory is a flawed, as the autonomous nervous system is not differentiated enough to account for all emotions (1), hormonal feedback from the body is too slow to induce emotions (2) and hormone injections can cause different emotions (3).

The hypothalamus is responsible for the readiness for action component of emotion. The sympathetic nervous system is involved in action. Cortical processing is involved in experiencing feelings. The anterior insula is involved in the awareness of bodily responses. The ventromedial prefrontal cortex is involved in using emotions for decision making. If the ventromedial prefrontal cortex is damaged, there is emotional perseverance (e.g., no fear extinction).

The somatic marker theory states that the ventromedial prefrontal cortex starts an internal simulation to evaluate the emotional outcomes of decisions and these emotional outcomes (somatic markers) are used to guide decision making.

The amygdala receives information from the entire brain and can influence the entire brain. It responds to emotional stimuli and neutral stimuli predicting motivating stimuli. It judges the emotional value of the stimulus and is imperative for fear conditioning. The fear-stimulus can reach the amygdala through two routes:

1. Fast route (low route)
   From the thalamus to the amygdala. It is fast and there is no conscious control.
2. Slow route (high route)
   From the thalamus to the neocortex to the amygdala. It is slow and there is conscious control.

In the Klüver-Bucy syndrome, there is reduced fear and aggression. The syndrome occurs if the amygdala is either removed or non-functional.

There is hemispherical asymmetry in emotions. The right-hemisphere is involved in feeling emotions and: is better at responding to strong emotional stimuli, is better at discriminating between emotions, includes predominantly negative emotions. The left-hemisphere is involved in cognitive control of emotions and: is better at focussing on context, includes predominantly positive emotions.

Lesions to the right hemisphere lead to indifference. Lesions to the left hemisphere lead to more extreme emotions. Bodily reactions are not necessary for experiencing emotions but contribute to the intensity of emotion.

The Cannon-Bard diencephalon theory states that the thalamus and the hypothalamus are the most important areas for emotion and that there is parallel processing; the bodily responses are useful for experiencing emotion, but not necessary.

Cognitive reappraisal is giving other meaning to an emotional event. It suppresses the amygdala and activates the dorsolateral prefrontal cortex, superior parietal lobe and anterior cingulate gyrus network. The attentional blink effect does not hold if the second target is emotionally significant. People tend to derive emotion from the eyes.