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

Parapharse Highlights — Antonio Damasio

Descartes' Error

Massively recurrent circuit arrangements, feedforward and feedback loops; some of the loops are purely chemical. (Damasio; Descartes' Error, 122)

Small collections of neurons can deliver a dose of dopamine, norepinephrine, serotonin or acetylcholine to widespread regions of the brain including the cerebral cortex and basal ganglia. (Damasio; Descartes' Error, 120)

Feeling of What Happens

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)

All that core consciousness requires is a very brief, short-term memory. (Damasio; Feeling of What Happens, 113)

Short-term memory -- lasts about forty-five seconds. (Damasio; Feeling of What Happens, 118)

Core consciousness cannot depend on these vast brain regions: Temporal region damage, hippocampus and medial cortices overlying it, polar temporal region, a sizable sector of the lateral and inferior temporal regions, amygdala. (Damasio; Feeling of What Happens, 121)

Sensation of consciousness lags (~500 milliseconds) the biological mechanisms of consciousness. (Damasio; Feeling of What Happens, 127)

Biological antecedents of the sense of self; a single, bounded, living organism bent on maintaining stability to maintain its life. Survival, a boundary, regulation of internal states, maintain life within a narrow range of the internal states. (Damasio; Feeling of What Happens, 136)

Kinds of self - (diagram); Autobiographical self, Core self, Proto-self (Damasio; Feeling of What Happens, 174)

Continuity of consciousness is based on the steady generation of consciousness pulses, which correspond to the endless processing of myriad objects, whose interaction, actual or recalled, constantly modifies the proto-self. (Damasio; Feeling of What Happens, 176)

Autobiographical self -- dual dependency on both continuous pulses of core consciousness and continuous reactivations of autobiographical memories. (Damasio; Feeling of What Happens, 199)

Working memory is precisely the ability to hold images in mind for long enough time that they can be manipulated intelligently. (Damasio; Feeling of What Happens, 200)

Core consciousness is part of the standard equipment of complex organisms such as we are; it is put in place by the genome with help from the early environment. (Damasio; Feeling of What Happens, 200)

Early sensory cortices of various modalities support neural patterns that are likely to be the basis of mental images. (Damasio; Feeling of What Happens, 219)

Brain forms memories in a highly distributed manner. (Damasio; Feeling of What Happens, 220)

Memories are not stored in facsimile fashion; they must undergo a complex process of reconstruction during retrieval. (Damasio; Feeling of What Happens, 227)

Cingulate might make the critical contribution to the "feeling of knowing," the high-order feeling that defines core consciousness. (Damasio; Feeling of What Happens, 264)

Core consciousness depends most critically on the activity of a restricted number of phylogenetically old brain structures -- beginning with brain stem and ending with somatosensory and cingulate cortices. (Damasio; Feeling of What Happens, 271)

Consciousness is anchored on ancient neural structures intimately associated with the regulation of life, rather than on modern neural structures of the neocortex, those which permit fine perception, language, and high reason. (Damasio; Feeling of What Happens, 275)

Core consciousness is the process of achieving a neural and mental pattern that brings together, in about the same instant, the pattern for the object, the pattern for the organism, and the pattern for the relationship between the two. (Damasio; Feeling of What Happens, 194)

Sensors located throughout the body -- in the skin, in the muscles, in the retina, and so on -- help construct the neural patterns that map the organism's interaction with the object. Neural pattern or map is based on the momentary selection of neurons and circuits engaged in the interaction. (Damasio; Feeling of What Happens, 320)

Looking for Spinoza

Feelings of pain or pleasure or some quality in between are the bedrock of our minds. (Damasio; Looking for Spinoza, 3)

Human emotions involved in life regulation include joy and sorrow and fear, as well as pride and shame and sympathy. (Damasio; Looking for Spinoza, 34)

Feelings are at the very top of the innate automated life governance machine -- the homeostasis machine. (Damasio; Looking for Spinoza, 34)

Emotions proper -- disgust, fear, happiness, sadness, sympathy, and shame -- aim directly at life regulation by staving off dangers or helping the organism take advantage of an opportunity, or indirectly by facilitating social relations. (Damasio; Looking for Spinoza, 39)

Social emotions include sympathy, embarrassment, shame, guilt, pride, jealousy, envy, gratitude, admiration, indignation, and contempt. (Damasio; Looking for Spinoza, 45)

Social emotion "contempt" borrows the facial expression of "disgust," a primary emotion that evolved in association with the automatic and beneficial rejection of potentially toxic food. (Damasio; Looking for Spinoza, 45)

Some of the brain regions now identified as emotion triggering sites are the amygdala, the ventromedial prefrontal cortex, the supplementary motor area, and the cingulate. (Damasio; Looking for Spinoza, 59)

Amygdala is an important interface between visual and auditory emotionally competent stimuli and the triggering of emotions, in particular, though not exclusively, fear and anger. (Damasio; Looking for Spinoza, 60)

Ventromedial prefrontal region is tuned to detect the emotional significance more complex stimuli, natural as well as learned, competent to trigger social emotions. (Damasio; Looking for Spinoza, 61)

Emotion-execution sites include the hypothalamus, the basal forebrain, and some nuclei in the brain stem tegmentum. (Damasio; Looking for Spinoza, 62)

Hypothalamus is the master executor of many chemical responses that are part of emotions. (Damasio; Looking for Spinoza, 62)

Behaviors experienced as rewarding and pleasurable depend on the release of dopamine from the ventral tegmental area (VTA) in the brainstem and its availability in the nucleus accumbens in the basal forebrain. (Damasio; Looking for Spinoza, 63)

Brainstem is a very small region of the central nervous system and is jam-packed with nuclei and circuitry involved in different functions. (Damasio; Looking for Spinoza, 63)

When emotions, appetites, and simpler regulatory reactions are mapped back in the central nervous system, subcortically and cortically, the result is feelings, the foundational components of our minds. (Damasio; Looking for Spinoza, 79)

Feelings are perceptions, and the necessary support for their perception occur in the brain's body maps. These maps refer to parts of the body and states of the body. (Damasio; Looking for Spinoza, 85)

Body sensing areas -- cingulate cortex, somatosensory cortices of insula and S2, nuclei in the brainstem tegmentum. (Damasio; Looking for Spinoza, 99)

Regions involved in producing the emotive responses behind pleasurable states -- right orbitofrontal cortices, left ventral striatum. (Damasio; Looking for Spinoza, 103)

Drugs such as Valium that remove the affect component of pain but leave the sensation of pain imtact -- you "feel" the pain but do not care. (Damasio; Looking for Spinoza, 104)

Feelings occur over several seconds, two to twenty seconds being common. (Damasio; Looking for Spinoza, 112)

Right somatosensory cortices -- insula, S2, and S1 regions of the right cerebral hemisphere. This is the set of regions in which the brain accomplishes the highest level of integrated mapping of body state. Feelings occur over several seconds, two to twenty seconds being common. (Damasio; Looking for Spinoza, 117)

Brain can achieve the modifications of body maps very rapidly, in the time scale of hundreds of milliseconds or less. (Damasio; Looking for Spinoza, 118)

First-person accounts of some substance abuses -- it felt like a total body orgasm; a relaxed feeling like you get after sex, but better; feels like every cell and bone in your body is jumping with delight; a generalized tingly, warm sensation. (Damasio; Looking for Spinoza, 122)

Both natural feelings and feelings experienced via substances of abuse have the cingulate cortex and the insula as the dominating sites of engagement. (Damasio; Looking for Spinoza, 123)

All feelings contain some aspect of pain or pleasure as a necessary ingredient. (Damasio; Looking for Spinoza, 123)

Images in the stream of mind are a collection of brain maps, i.e., a collection of patterns of neuron activity and inactivity (neural patterns) in the various sensory regions. (Damasio; Looking for Spinoza, 197)

Sense of self brings orientation -- sense of self introduces the notion that all the current activity represented in brain and mind pertain to a single organism whose auto-preservation needs are the basic cause of most events currently represented. (Damasio; Looking for Spinoza, 208)

The most basic kind of self or consciousness is a second-order idea based on two first-order ideas -- (1) idea of the object that we are perceiving and (2) idea of our body as modified by the perception of the object. (Damasio; Looking for Spinoza, 215)

We go from the "neural-map" level to the "mental" level via emergent properties. There is nothing magical about those emergent properties. (Damasio; Looking for Spinoza, 327)

Self Comes to Mind

Signals related to the body's interior come to constitute feelings. (Damasio; Self Comes to Mind, 93)

The neural correlates of feelings are not confined to the insula. The anterior cingulate cortex tends to become active in parallel with the insula when we experience feelings. (Damasio; Self Comes to Mind, 118)

Social emotions are identified as having an unequivocal social setting. Examples include -- compassion, embarrassment, chain, guilt, content, jealousy, envy, pride, admiration. (Damasio; Self Comes to Mind, 125)

We have inherited from many prior species, abundant networks of dispositions that run our basic mechanisms of life management. They include the nuclei that control our endocrine system and the nuclei that serve the mechanisms of reward and punishment in the triggering and execution of the emotions. (Damasio; Self Comes to Mind, 135)

The perception cascade would follow, in general, a caudo-rostral direction, culminating in anterior temporal and frontal cortices, where the most integrated representations of the ongoing multisensory apprehension of reality are presumed to occur. (Damasio; Self Comes to Mind, 137)

Cell ensembles at the top levels of the processing hierarchies would not hold explicit representation of the maps for objects and events. Rather, the ensembles would hold know how, i.e. dispositions, for the eventual reconstruction of explicit representations when they become needed. (Damasio; Self Comes to Mind, 140)

Convergence divergence zones (CDZs) record the coincidence of activity in neurons hailing from different brain sites, neurons that had been made active by, for example, the mapping of a certain object. (Damasio; Self Comes to Mind, 141)

Cortical dispositional space includes all the higher-order association cortices in temporal, parietal, and frontal regions. (Damasio; Self Comes to Mind, 143)

CDZs are microscopic and are located within convergence-divergence regions (CDRegions), which are macroscopic.(Damasio; Self Comes to Mind, 145)

Damasio envisions the number of CDZs to be on the order of many thousands. (Damasio; Self Comes to Mind, 145)

Knowledge retrieval would be based on relatively simultaneous, attended activity in many early cortical regions, engendered over several iterations of reactivation cycles. (Damasio; Self Comes to Mind, 148)

Mental imagery -- the process of imagination consists of the recall of images and their subsequent manipulation. (Damasio; Self Comes to Mind, 149)

Images constructed during perception are reconstructed during the process of imagery. They are approximations rather than replicas, attempts at getting back at past reality and thus not quite as vivid or accurate. (Damasio; Self Comes to Mind, 149)

Images are the main currency of our minds, and the term refers to patterns of all sensory modalities, not just visual, and to abstract as well is concrete patterns. (Damasio; Self Comes to Mind, 160)

The core and extended or autobiographical kinds of consciousness are not rigid categories. (Damasio; Self Comes to Mind, 171)

Core consciousness does not require language. (Damasio; Self Comes to Mind, 172)

Autobiographical consciousness relies extensively on language. (Damasio; Self Comes to Mind, 172)

The self is built in stages. The simplest stage emerges from the part of the brain that stands for the organism (the proto-self) and consists of gathering of images that describe a relatively stable aspects of the body and generate spontaneous feelings of the living body (primordial feelings). (Damasio; Self Comes to Mind, 180)

Conscious states require early sensory engagement and the engagement of association cortices. (Damasio; Self Comes to Mind, 189)

The brain stem is not a mere pass-through of the body signals to the cerebral cortex. It is a decision station, capable of sensing changes and responding in predetermined but modulated ways. (Damasio; Self Comes to Mind, 191)

Sight, sound, spatial balance, taste, and smell all depend on sensory portals not far from one another, all located in the head. We can think of the head is a multidimensional surveillance device. (Damasio; Self Comes to Mind, 198)

Michael Gazzaniga advanced the notion of "interpreter" as a way of explaining the generation of consciousness. He has related it to the machinery of the left hemisphere and to the language processes therein. (Damasio; Self Comes to Mind, 204)

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