Mirror neuron areas help us understand the emotions of other people by some form of inner imitation. Our mirror neurons fire when we see others expressing their emotions, as if we were making those facial expressions ourselves. By means of this firing, the neurons also send signals to emotional brain centers in the limbic system to make us feel what other people feel.
— Marco Iacoboni, Mirroring People

Emotion Structures: brain structures concerned with emotional behavior and evaluation of the emotional significance, and potential value of events in the external world. (Ramachandran, 116) 

The “anterior cingulate cortex” is a crucial center of “emotional intelligence,” as is the “insula.” Allows you to monitor your behavior for mistakes. Allows you to correct and avoid errors, to evaluate context. Allows you to plan and carry out actions that have emotional and motivational significance. (Blakeslee, 189) The “amygdala” reads the emotional aspect of whatever we perceive and then processes that information subliminally, beneath the conscious awareness. Creates the same feeling in us that it sees in another. Makes it possible to transmit feelings from one person to another, and to another rapidly (and without any verbal communication). In a group, these feelings can spread quickly – i.e. become contagious. (Goleman, 16) “Mirror neuron” areas, the insula, and emotional brain areas in the “limbic system,” particularly the amygdala, are activated while subjects are observing faces. (Iacoboni, 118-119)

Amygdala: one of the principle structures of the “limbic system.” (Kolb, 55) Regulates emotional expression via modulation of the “hypothalamus.” (Patestas, 344) Receives sensory information from the “thalamus.” Extracts emotional meaning from inputs. (Goleman, 15) Connects to many parts of the brain and thus receives a wide array of input—some of it routed through the high-level processing center of the “prefrontal cortex,” and some of it wired indirectly, bypassing the prefrontal cortex. (Ratey, 62) Amygdala cells receive inputs from the sensory world constantly, but ignore the majority of them. They do get worked up though, when the right kind of stimulus is present - one that signifies danger or some other biologically significant event. (LeDoux, 61) Can evoke primitive hard-wired behaviors via the hypothalamus and also make us feel emotions that correspond to those behaviors. (Lynch, 76) Brain imaging studies have shown that when we perceive a “scent,” the amygdala becomes activated. (Herz, 3) Because smell directly stimulates the amygdala, smell directly stimulates emotions. (Medina, 213) Supervises not only the formation of emotional experiences, but also the memory of emotional experiences. (Ratey, 62) The place where fear is registered and generated. (Carter, 17) Involved in the association of feelings, such as fear or happiness, with events. (Kandel, 132) Plays a key role in linking strong emotions to experiences, to people, and to memories. (Blakeslee, 189) In the 1930‘s, biologist Heinrich Kluver and Paul Bucy demonstrated that damage to the amygdala in monkeys led to a constellation of symptoms including ‘lack of fear,’  ‘blunting of emotion,’ and ‘overreaction.’ (Eagleman, 153) Yale Professor Jose Manuel Rodriguez Delgado found in experiments with psychiatric patients, that electrical stimulation in different regions in or near the amygdala could produce intense rage, earnest affection, or despondent sadness. (Lynch, 77) Also referred to as ‘amygdaloid body.’

Anterior Cingulate Cortex (ACC): a C-shaped ring of “cortical” tissue abutting and partially encircling the front part of the “corpus callosum.” (RamachandranTTB, 295) Frontal part of the cingulate cortex. The ‘highest’ part of the limbic system. It is linked to the “orbital frontal cortex” via “spindle cells.” Directs our attention and coordinates our thoughts, our emotions, and the body’s response to our feelings. (Goleman, 66) It ‘lights up’ in many brain imaging studies. Thought to be involved in ‘free will,’ vigilance, and “attention.” (RamachandranTTB, 295) In every study done to date (2007), the ACC and the right frontal insula light up together. (Blakeslee, 190) A brain structure closely linked to the “prefrontal cortex,” which is particularly active in situations of uncertainty (Goldberg, 35) Part of the "frontal lobe" that may be key to the "neuronal correlates of consciousness." The ACC monitors complex behaviors and is particularly active when incorrect behavior or errors occur. (Koch, 329) A high-level “brain map” involved in several crucial mental functions, including the ability to recognize, correct, and learn from mistakes, to plan and execute actions with respect to emotions and goals, and to modulate pain sensations based on context and expectation. (Blakeslee, 211) Also referred to as the ‘anterior cingulate.’

Insula: a region of “cerebral cortex” in addition to the four lobes. Covered by a lip of frontal lobe and “parietal lobe.” (Blumenfeld, 25) Submerged within and forms the floor of the “lateral sulcus.” Completely circumscribed by the “circular sulcus.” Believed to be associated with taste. (Patestas, 75) “Mesocortex” is found in the insula. (Patestas, 402) Functionally, the insula has a remarkable pattern of anatomical connections with a large number of brain areas. It is the (only) brain region with well-documented connections to both mirror neurons and limbic areas. (Iacoboni, 117) Map-rich brain area in which “visceral” and “homeostatic” information is processed. Plays key roles in emotional awareness, "empathy," and physiological self-regulation. (Blakeslee, 213) The medial insula is activated during romantic love. (Goleman, 370) Crucial center of emotional cognition. Contains “mirror neurons.” Also necessary for attending to feelings that arise from your body. (Blakeslee, 181) Also referred to as the ‘insular cortex’ and ‘island of Reil.’

Operculi: cortical coverings over the “insula.” (Fisch, 286) Adjective - ‘opercular.’

Right Frontal Insula: circuits involve empathy. (Discover, 2007) People with greater empathy have more gray matter in their right frontal insulas than those less empathetic. (Blakeslee, 181) Lights up when you feel emotions, "love," "disgust," empathy, etc. Also active when you feel physical "pain" or the pain of rejection. Active when someone is treating you unfairly. Active when you think something is funny. (Blakeslee, 188) Connects the state of your body to the brain’s sensory "perceptions," "abstract" thoughts, "linguistic" processing, and "motivations" occurring elsewhere in the (cerebral) cortex. Integrates “homeostatic” information from your body and your brain. Activates when your mirror neurons are activated by another person’s emotional state, when you sense fear in a crowd, when you crave drugs, and when you see someone cheat. Has strong connections with the amygdala, the orbitofrontal cortex, and the ACC. Always lights up together with the ACC on brain imaging studies of human emotion. (Blakeslee, 189-190)

Orbitofrontal Cortex: undersurface (and part) of the frontal lobe. (Fisch, 278 A brain region critical for self-discipline. (Blakeslee, 213) Plays a central role in a variety of emotional and social behaviors as well as in eating. (Kolb, 398) Lights up together with the “ACC” on brain imaging studies of human emotion. (Blakeslee, 190) (Damage can cause) abnormal sexual appetite, for example, sudden ‘pedophilia.’ (Eagleman, 155) Key brain structure for empathy and matching emotions located in the orbitofrontal (near the eyes and near the front of the cortex) area of the prefrontal cortex. Neuron projections from the eyes lead directly to this area. When two people’s eyes meet, they have interlinked their orbitofrontal areas, which are especially sensitive to face-to-face cues. These social “pathways” play a crucial role in recognizing another’s emotional state. Connects directly, neuron to neuron, three major regions of the brain: the cerebral cortex, the amygdala, and the “brain stem.” This tight connection suggests a rapid and powerful linkage, one that facilitates instantaneous coordination of thought, feeling, and action. (Goleman, 63-64) Also referred to as ‘orbitofrontal gyrus.’