Amygdala: a structure that lies deep within each of the temporal lobes of the brain. Connects to several other structures, among them the “hypothalamus” and the “prefrontal cortex.” (Kandel4, 57) Part of the temporal lobe, although it has a subcortical structure. What this means is that it has nuclei or clusters of neurons instead of the layering structure of the cortex. (Campbell, BSP210) 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) The amygdala determines what emotion is recruited any any given time, and the hypothalamus carries it out. Increased activity of the amygdala may account for the hopelessness, sadness, and mental anguish that people with ‘major depression’ feel. (Kandel4, 64-66) 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) Critical for “implicit” learning of emotion, particularly fear. (Kandel4, 113) Plays a key role in linking strong emotions to experiences, to people, and to memories. (Blakeslee, 189) Once our amygdala recognizes anything as a threat, it triggers fear, sending our limbic system, which regulates emotion, into high alert. Instantly our thinking (conscious) brain shuts down, the better to free up the physchological resources we’ll need for fight or flight. (Cron2, 43-44) 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) Consistently implicated in both “major depression” and “bipolar disorder.” Divided functionally into two regions. One region, thought to be involved in emotional processes and autonomic functions, has extensive connections to the hippocampus, amygdala, orbital prefrontal cortex, anterior insula, and the nucleus accumbens (an important part of the brain’s dopamine reward and pleasure circuit. The other region is thought to be involved in cognitive processes and in the control of behavior. It connects to the prefrontal cortex, secondary motor cortex, and posterior cingulate cortex. Both regions function abnormally in people with mood disorders. The region concerned with emotion is consistently overactive during major depressive episodes and the depressive phase of bipolar disorder. Successful treatment with antidepressant drugs is correlated with decreased activity in this region. (Kandel4, 65) 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) You can't see from the surface. It's located within the lateral sulcus between the temporal, frontal, and parietal lobes, sort of where they come together. And this is where “interoception” appears to be processed. (Campbell, BSP210) “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) A small island of neurons lying deep within the frontal and parietal lobes that translates bodily emotion into conscious awareness. It assesses bodily responses, such a s degree of pain, and monitors what is going on in the viscera and muscles. (Kandel4, 181) 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) Defective functioning of the insular cortex may account for why people with depression are without vitality, why they often feel dead inside. (Kandel4, 66) Also referred to as the ‘insular cortex,’ ‘insular lobe’ and ‘island of Reil.’

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

Right Anterior Insula: region where self-awareness and social experience come together. Connects to the hypothalamus. Receives information from our senses about the physiological state of our body and, in response, generates emotions that inform our actions and decisions. (Kandel4, 65) Author’s note: critical node in the neural circuit of depression.

Right Frontal Insula: (Neural pathways in this area) 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 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.’

Subcallosal Cingulate Cortex: region where thought, motor control, and drive come together. Rich in neurons that produce “serotonin” “transporters”— proteins that remove serotonin from the synapse. Serotonin transporters are particularly active in depressed people. Studies of depression suggest that whenever area 25 becomes hyperactive, the components of the neural circuit concerned with emotion are literally disconnected from the thinking brain, leading to a loss of personal identity. (Kandel4, 65-66) Also referred to as ‘cortical area 25’ and ‘area 25.’ Author’s note: critical node in the neural circuit of depression.

Ventromedial Prefrontal Cortex: a region involved in the neural (pathway) of fear— and of anger. Also important for what we would call ‘moral emotions,’ indignation, compassion, embarrassment, and shame. (Kandel4, 181) Important for integrating emotional signals into decision making. (Kandel4, 194) The ventromedial prefrontal cortex and the orbitofrontal cortex are… regions that are extremely important for emotion, decision making, and moral behavior. In his book Descartes’ Error, Antonio Damasio describes the case of a man named Elliot. In 1982, a small tumor was discovered in the ventromedial prefrontal cortex region of Elliot’s brain. The tumor was removed by a team of surgeons, but the resulting damage to his brain changed his behavior dramatically. As Damasio would later write, “Elliot emerged as a man with a normal intellect who was unable to decide properly, especially when the decision involved personal or social matters.” (Kandel4, 189-191)