Scientific Understanding of Consciousness
Consciousness as an Emergent Property of Thalamocortical Activity

Emotions

Emotions along with cognitive functions guide actions to enhance survival of the body. My hypothesis is that emotions span a range from fear to pleasure.

According to Susan Greenfield's hypothesis, the most rudimentary consciousness is a pure emotion associated with fast interactions with the outside world. (Greenfield; Private Life of Brain, 175)

A wider range of emotions mediated by enhanced development of the limbic system and associated areas distinguishes mammals from reptiles. Although very primitive creatures such as sea slugs can be fear conditioned, mammals exhibit an extended range of emotions, especially humans.

Emotions may be considered the most complex of mental states or processes insofar as they mix with all other processes. (Edelman; Bright Air, 176)

Emotions are produced across cultures and are easily recognized because one part of the action, their facial expressions, is quite characteristic. (Damasio; Self Comes to Mind, 123)

Neural processing of emotions begins with the limbic system, a number of interconnected subcortical regions around the hypothalamus. (Johnston; Why We Feel, 119)

The amygdala is a critical structure in the processing of emotional information. (Vogt; Cingulate Neurobiology, 207)

Specialized bidirectional connections linking orbitofrontal cortex (OFC) with the amygdala may underlie emotional processing. (Zald & Rauch; Orbitofrontal Cortex, 62)

Deep in the brain there is a group of interconnected structures, all located near the base of the brain and distributed along the midline, constituting the reward circuit. (Linden; Compass of Pleasure, 9)

The reward circuit includes the ventral tegmental area, the nucleus accumbens, the medial forebrain bundle, and the septum, as well as portions of the thalamus and hypothalamus. (Linden; Compass of Pleasure, 9)

As a central player in your emotional life, your insula sends signals to and receives signals from other emotional centers in your brain including the amygdala, the autonomic nervous system (powered by the hypothalamus), and the orbitofrontal cortex, which is involved in nuanced emotional judgments. (Ramachandran; Tell-Tale Brain, 98)

Scientists attempts to find a single unified brain system-level emotion have not been successful. Bodily expressions occurring during emotions are similar among people all around the world. Universal facial expressions of emotion are similar across many different cultures. On the basis of facial expressions of emotion, some scientists list six basic emotions:

The anterior cingulate cortex (ACC) occupies approximately the anterior one third of the cingulate cortex and is implicated in emotion. The ACC is distinguished from the mid-cingulate cortex (MCC), which occupies approximately the middle third of the cingulate cortex and contains part of the caudal cingulate motor area that may be involved in response selection. (Vogt; Cingulate Neurobiology, 192)

Emotional-motivational output of the mammillary body reaches the cortex through the thalamus. (Arbib - Handbook of Brain Theory and Neural Networks; Mumford; Thalamus, 981)

Research Study — Bayesian Model of Category-Specific Emotional Brain Responses

Research Study — Differential Activation Patterns in the Same Brain Region Led to Opposite Emotional States

Happiness, Sadness, Fear, Anger, Surprise, Disgust

There is no universal consensus about the items in this list nor the number of items in the list.

Emotion and motivation are linked by the property that both involve rewards and punishers. (Rolls; Emotion Explained, 1)

Proposed definition of emotions -- emotions are states elicited by rewards and punishers. (Rolls; Emotion Explained, 11)

Emotion Diagram of Edmund Rolls

Stereotypical Expressions of Emotion

The basic program routines of emotions are stereotypical at all body levels at which they are executed -- external motions; visceral changes in the heart, lungs, gut, and skin; and endocrine changes. (Damasio; Self Comes to Mind, 123)

Emotions are unlearned, automated, and set by the genome. (Damasio; Self Comes to Mind, 124)

Facial expressions are controlled in large part by our unconscious minds. (Mlodinow; Subliminal, 38)

Expressions are a key way we communicate and are difficult to suppress or fake, which is why great actors are hard to find. (Mlodinow; Subliminal, 38)

There is a discrete part of the brain that is used to analyze faces. It is called the fusiform face area. (Mlodinow; Subliminal, 38)

The dynamic core of the thalamocortical system includes influence from emotions mediated by the limbic system with its connections to the cortex and brainstem. The orbitofrontal cortex has a special role in behaviors produced by rewards and punishers that encompass emotional and motivational behavior.

Damage to limbic system impairs the processing of primary emotion; damage to prefrontal cortices compromises the processing of secondary emotions. (Damasio; Descartes' Error, 139)

All of the extent and subtleties of emotion have been honed by natural selection to enhance survival. Fear reactions tend to produce actions to protect the body. Pleasure reactions tend to produce actions to seek food, to seek sexual activity, or to enhance family or social group survivability. In short, all animal behavior, including that of the human animal, is governed by four primary urges, the four F's: fleeing, feeding, fighting, and being fruitful.

Not precisely defined by the experts

Emotion with its many subtleties has not been defined precisely by the experts. Different researchers have somewhat different concepts about the classification of emotions and somewhat different connotations for the terms they use. Usually, English words are used in their lay connotations without explicit definition.

Emotions can be understood as dynamic interactions of brain areas that perform both bodily perception and cognitive appraisal. (Thagard; Brain and the Meaning of Life, 100)

Limbic System and Dopamine Pathway to Nucleus Accumbens

Neural processing of emotions begins with the limbic system, a number of interconnected subcortical regions around the hypothalamus. One major pathway from the limbic system via the hypothalamus functions to provide physiological adjustments to the body, such as changes in heart rate or blood pressure. A second output pathway, common to all feelings, is the pleasure pathway, which ultimately releases dopamine onto the nucleus accumbens. (Johnston; Why We Feel, 119)

Major modulatory systems of the brain. (1) noradrenergic, (2) adrenergic, (3) dopaminergic, (4) serotonergic, (5) cholinergic, (6) histaminergic. (Kandel; Principles of Neural Science, 890)

The dopamine pathway to the nucleus accumbens is closely associated with motivation and the control of motor behavior and is correlated with hedonic tone that is a fundamental aspect of all feeling states. (Johnston; Why We Feel, 119)

Limbic System Outputs Influence Arousal Systems

Limbic system outputs influence two major arousal systems of the brain, and these pathways provide a mechanism by which feelings can modulate cortical arousal. (Johnston; Why We Feel, 119)

Specific portions of the limbic system project to different areas of the cingulate gyrus, allowing different patterns of limbic activity to generate qualitatively different emotional feelings and to bias cognitive processes. (Johnston; Why We Feel, 119)

Primary Emotions

The word emotion usually brings to mind one of the six so-called primary or universal emotions: happiness, sadness, fear, anger, surprise, or disgust. (Damasio; Feeling of What Happens, 50) (Johnston; Why We Feel, 88)

Ekman's list of basic and universal emotions extends to seven emotions: fear, anger, sadness, disgust, contentment, surprise, and happiness. (Flanigan; Dissolution of hard problem, 149)

Disgust is a universal human emotion. (Pinker; How the Mind Works, 378)

An emotion researcher mentioned by LeDoux suggests eight basic emotions: - surprise, interest, joy, rage, fear, disgust, shame, anguish - controlled by 'hardwired' brain systems. (LeDoux; Emotional Brain, 112)

Another researcher had a slightly different set of words for eight basic emotions: - joy, acceptance, fear, surprise, sadness, disgust, anger, anticipation - (illustration) (LeDoux; Emotional Brain, 114)

Emotions are complicated collections of chemical and neural responses. (Damasio; Feeling of What Happens, 51)

Emotion and core consciousness are clearly associated. (Damasio; Feeling of What Happens, 122)

Unexpectedness contributes to the intensity of emotion. (Johnston; Why We Feel, 79)

Emotional responses, for the most part, are generated unconsciously. (LeDoux; Emotional Brain, 17)

Emotions evolved not as conscious feelings, but as brain states and bodily responses. (LeDoux; Emotional Brain, 302)

Disgust as a Basic Emotion

Scholars see disgust as a basic emotion that, like fear, anger, sadness and joy, is found across all cultures. All around the world pus, maggots, rotting food and scavenging animals such as rats produce the distinctive facial expression of disgust: nose wrinkled, mouth agape, lips raised. When severe, the feeling of revulsion can be accompanied by throat clenching, nausea and vomiting. In evolutionary terms, the adaptive value of such reactions seems to be to prevent people from eating contaminated foodstuffs and to get rid of any they have ingested. Disgust is related to bodily purity and integrity, with things that should be on the outside — such as faeces — kept out, and things that should be on the inside — such as blood — kept in. (Nature, 14 June 2007, 768)

Paul Ekman’s expanded list of Basic Emotions

In the 1990s Paul Ekman expanded his list of basic emotions, including a range of positive and negative emotions, not all of which are encoded in facial muscles. (http://en.wikipedia.org/wiki/Paul_Ekman)

1. Amusement

2. Contempt

3. Contentment

4. Embarrassment

5. Excitement

6. Guilt

7. Pride in achievement

8. Relief

9. Satisfaction

10. Sensory pleasure

11. Shame

Secondary Emotions

Secondary or social emotions; such as embarrassment, jealousy, guilt, pride. (Damasio; Feeling of What Happens, 51)

Secondary emotions - (diagram) (Damasio; Descartes’ Error, 137)

Secondary or self-conscious social feelings (guilt, pride, envy) develop somewhat later than the primary emotions. (Johnston; Why We Feel, 100)

Whereas primary emotions may be common to many species, secondary feelings appear to be a consequence of the unique history of humans. Children's facial expressions are automatic and controlled by subcortical centers within the extrapyramidal motor system. (Johnston; Why We Feel, 100-101)

Laughter seems to be unique to humans.

Reciprocal altruism requires the ability to recognize each other as individuals and the capability of remembering and quantifying many different kinds of goods and services. Generalized reciprocity and the secondary social emotions that monitor such transactions appear to be unique characteristics of human beings. (Johnston; Why We Feel, 100-101)

Specialized cortical networks in the right hemisphere and frontal lobes are responsible for secondary emotions and for modulating the more primal emotional responses of the amygdala and the limbic system. (Ratey; User's Guide to Brain, 174)

Casual voluntary mimicking of expressions of emotion is easily detected as fake. For most of us who are not actors, emotions are a fairly good index of our well-being. (Damasio; Feeling of What Happens, 49)

Background Emotions

Damasio introduces the concept he terms background emotions: well-being vs. malaise; calm vs. tension. (Damasio; Feeling of What Happens, 51)

Background feeling, a body state prevailing between emotions. When we feel happiness, anger, or another emotion, the background feeling has been superseded by an emotional feeling. (Damasio; Descartes' Error, 150)

Overlap of functions: (1) regulating homeostasis and signaling body structure and state, (2)processes of emotion and feeling, (3) processes of attention, (4) processes of wakefulness and sleep, (5) learning process. (Damasio; Feeling of What Happens, 272)

Feelings

Feelings are the conscious experiences of emotions. (LeDoux; Emotional Brain, 82)

Feelings are first and foremost about the body, the cognition of our visceral and musculoskeletal state. (Damasio; Descartes' Error, 159)

The term feeling should be reserved for the private, mental experience of an emotion, while the term emotion should be used to designate the collection of responses, many of which are publicly observable. (Damasio; Feeling of What Happens, 42)

Feelings, emergent properties of the nervous system. (Johnston; Why We Feel, 64)

Feelings act as active filters that define and exaggerate the reproductive consequences of environmental or social events associated with relatively minor fluctuations in reproductive potential. Each qualitatively different feeling appears to monitor a different aspect of reproductive success. (Johnston; Why We Feel, 83)

Normal consciousness can take stock of emotions in the form of feelings; feelings can generate a new line of emotions that confer behavior. In this way a reverberating cycle of emotion-to-feeling-to-emotion can ensue. (Damasio; Feeling of What Happens, 101)

Moods

Moods can be considered states of emotion that tend to become continuous over long periods of time. (Damasio; Feeling of What Happens, 341)

Research study — Amygdalar and Hippocampal substrates of Anxious Temperament

Music — Emotion and Movement

Our experience of music involves closely tied emotion and movement. Music and the movements of dance drive an emotional experience.

Emotions we experience in response to music involve structures deep in the primitive, reptilian regions of the cerebellar vermis and the amygdala. (Levitin; Your Brain on Music, 85)

Intense musical emotion -- what subjects described as "thrills and chills" -- was associated with brain regions thought to be involved in reward, motivation, and arousal -- the ventral striatum, the amygdala, the midbrain, and regions of the frontal cortex. (Levitin; Your Brain on Music, 185)

Tempo is a major factor in conveying emotion. (Levitin; Your Brain on Music, 58)

Cerebellum might be involved in musical emotion. (Levitin; Your Brain on Music, 178)

Emotions of Love

One of the most intriguing emotions is love. (Ratey; User's Guide to Brain, 244)

One researcher distinguishes three distinctly different physiological and emotional categories of love -- lust, attraction, and attachment. (Ratey; User's Guide to Brain, 244)

The intense, euphoric pleasure that comes with falling in love corresponds to strong activation of the dopaminergic pleasure circuit -- the VTA and its targets, like the caudate nucleus. The pattern of activation is similar to responses to cocaine or heroin. (Linden; Compass of Pleasure, 102)