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David Baxter

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What is consciousness?
Michael S. A. Graziano, TEDTalks
Feb 11, 2019

Explore the theories of human consciousness and the science of how your brain works to create a conscious experience.

 

Daniel

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in order to generate feelings, we need peripheral nerves, spinal and brain stem ganglia (such as the trigeminal ganglion), and a variety of nuclei in the brain stem core (such as the parabrachial nucleus). I would bet that the fundamentals of feeling are actually obtained from processes generated by those components of the nervous system.
 

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The emergence of consciousness from the anesthetized state may provide a practical and reproducible model for characterizing the real-time evolution of the core neural correlates required for consciousness of the world and of the self. Using recent data from general anesthesia in humans, we suggest that the arousal centers in the brainstem and diencephalon—in conjunction with even limited neocortical connectivity and recurrent processing—can result in primitive phenomenal consciousness.

By “reverse engineering,” we postulate that early mammals and birds possessing these structures (or their equivalents) are capable of phenomenal consciousness. However, the increased complexity of networks and a functionally dominant prefrontal cortex in the brain of H. sapiens likely accounts for the unique richness of the human experience.
 

Daniel

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The hard problem of consciousness is the problem of explaining why and how we have qualia or phenomenal experiences. This is in contrast to the "easy problems" of explaining the physical systems that give us and other animals the ability to discriminate, integrate information, and so forth.

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Are We in Anthropodenial? (1997)

I will call it anthropodenial: a blindness to the humanlike characteristics of other animals, or the animal-like characteristics of ourselves. Those who are in anthropodenial try to build a brick wall to separate humans from the rest of the animal kingdom.

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Animal welfare with and without consciousness (2017)

Conclusions

Although the pursuit of consciousness in both ourselves and other species is one of the most fascinating in the whole of biology, the extreme difficulty of the search means that understanding is still a long way off. Rather than pretend we understand it or that the difficulties are not real and likely to remain so for some time, I have argued that it is better to face up to the problems and admit that our ignorance is almost as great as it was when T.H. Huxley was wrestling with the same problem. We should not, therefore, base the science of animal welfare on the assumption that we understand consciousness or can decide which species are or are not conscious. Animal welfare is far too important to be made to wait until the hard problem of consciousness has been solved and deserves more than to be based on the pretence that we understand things that we do not. Animal welfare science has a much more secure future if it is based on hypotheses that can be tested now and on evidence than does not depend on the untestable. I have suggested two criteria–what keeps animals healthy and what they themselves want–that together constitute a necessary and at least partly sufficient basis for an objective, consciousness-free science of animal welfare.

Although I have stressed the difficulties of studying consciousness in other species, this does not mean that we should abandon the search for consciousness and understanding the baffling problem of the relationship between brains and experience in other species. On the contrary, facing up to the difficulties fairly and squarely could set us free to be more objective about what we do and do not understand. We can investigate the mechanisms of behaviour and whether or not they involve conscious pathways without the pressure of feeling that it is‘good’(for animal welfare) to prove consciousness in a given species or‘bad’(for animal welfare) or dangerous to question it (Bekoff,2012). The study of animal consciousness is far too important and far too difficult for us to pretend we have demonstrated it when have not or to underestimate the very real difficulties of making it demonstrable in the future.
 
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Daniel

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“To reconcile sensory consciousness in birds and mammals, one scenario would postulate that birds and mammals inherited the trait of consciousness from their last-common ancestor. If true, this would date the evolution of consciousness back to at least 320 million years when reptiles and birds on the one hand, and mammals on the other hand, evolved from the last common stem-amniotic ancestor.”
 

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Despite millennia of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and [also the] most mysterious aspect of our lives". Perhaps the only widely agreed notion about the topic is the intuition that consciousness exists.
 

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I feel therefore I am ... In this fascinating study, a neuropsychologist argues that the mystery of consciousness centres on emotions...

“If you do not feel something, it is not a feeling,” Solms notes. Emotions are intrinsically conscious in a way that sensory perceptions aren’t. Using poignant case studies of neurology patients – including children born with brain damage, yet plainly still capable of sadness and joy – he argues persuasively that consciousness ultimately arises not in the cortex, the seat of advanced intelligence, but in the more primitive brainstem, where basic emotions begin.



 
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Daniel

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In 2000, Allman's laboratory reported indentification of a class of neurons - large spindle-shaped cells - unique to humans and our closest relatives, the great apes. The spindle neurons were first located in layer V of the anterior cingulate cortex (ACC), and later found in the frontoinsular cortex.

Spindle neurons may develop abnormally in people with autistic disorders, and abnormalities may also be linked to schizophrenia and Alzheimer's disease, but research into these correlations is at a very early stage.

Allman's team has reported reduced ACC size and metabolic activity in autistic patients, and activity of the ACC is also reduced in patients diagnosed with attention deficit disorder (ADD) and depression, whereas ACC activity is increased in patients with obsessive-compulsive, phobic, post-traumatic stress, and anxietydisorders. The ACC is largely responsible for relaying waves of neural signals from deep within the brain to far flung regions, including Brodmann area 10.

Allman studies brain evolution in mammals from multiple perspectives, and has created a number of 3d reconstructions of mammalian brains.


At a Society for Neuroscience meeting in 2003, Allman reported on von Economo neurons his team found in another brain region, the fronto-insular cortex, a region which appears to have undergone significant evolutionary adaptations in mankind – perhaps as recently as 100,000 years ago.

This fronto-insular cortex is closely connected to the insula, a region that is roughly the size of a thumb in each hemisphere of the human brain. The insula and fronto-insular cortex are part of the insular cortex, wherein the elaborate circuitry associated with spatial awareness are found, and where self-awareness and the complexities of emotion are thought to be generated and experienced. Moreover, this region of the right hemisphere is crucial to navigation and perception of three-dimensional rotations.

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There is evidence that, in addition to its base functions, the insula may play a role in certain higher-level functions that operate only in humans and other great apes. The spindle neurons found at a higher density in the right frontal insular cortex are also found in the anterior cingulate cortex, which is another region that has reached a high level of specialization in great apes. It has been speculated that these neurons are involved in cognitive-emotional processes that are specific to primates including great apes, such as empathy and metacognitive emotional feelings. This is supported by functional imaging results showing that the structure and function of the right frontal insula is correlated with the ability to feel one's own heartbeat, or to empathize with the pain of others. It is thought that these functions are not distinct from the lower-level functions of the insula but rather arise as a consequence of the role of the insula in conveying homeostatic information to consciousness.[13][14]

The right anterior insula is engaged in interoceptive awareness of homeostatic emotions such as thirst, pain and fatigue,[15] and the ability to time one's own heartbeat. Moreover, greater right anterior insular gray matter volume correlates with increased accuracy in this subjective sense of the inner body, and with negative emotional experience.[16] It is also involved in the control of blood pressure,[17] in particular during and after exercise,[17] and its activity varies with the amount of effort a person believes he/she is exerting.[18][19]

The insular cortex also is where the sensation of pain is judged as to its degree.[20] Further, the insula is where a person imagines pain when looking at images of painful events while thinking about their happening to one's own body.[21] Those with irritable bowel syndrome have abnormal processing of visceral pain in the insular cortex related to dysfunctional inhibition of pain within the brain.[22]

Another perception of the right anterior insula is the degree of nonpainful warmth[23] or nonpainful coldness[24] of a skin sensation. Other internal sensations processed by the insula include stomach or abdominal distension.[25][26] A full bladder also activates the insular cortex.[27]

One brain imaging study suggests that the unpleasantness of subjectively perceived dyspnea is processed in the right human anterior insula and amygdala.[28]

The cerebral cortex processing vestibular sensations extends into the insula,[29] with small lesions in the anterior insular cortex being able to cause loss of balance and vertigo.[30]

Other noninteroceptive perceptions include passive listening to music,[31] laughter, and crying,[32] empathy and compassion,[33] and language.[34]
 
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Daniel

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Based on neuroimaging data with psilocybin, a classic psychedelic drug, it is argued that the defining feature of “primary states” is elevated entropy in certain aspects of brain function, such as the repertoire of functional connectivity motifs that form and fragment across time. Indeed, since there is a greater repertoire of connectivity motifs in the psychedelic state than in normal waking consciousness, this implies that primary states may exhibit “criticality,” i.e., the property of being poised at a “critical” point in a transition zone between order and disorder where certain phenomena such as power-law scaling appear.

Moreover, if primary states are critical, then this suggests that entropy is suppressed in normal waking consciousness, meaning that the brain operates just below criticality. It is argued that this entropy suppression furnishes normal waking consciousness with a constrained quality and associated metacognitive functions, including reality-testing and self-awareness...

This paper argues that the underlying neurodynamics of primary states are more “entropic” than secondary states i.e., primary states exhibit more pronounced characteristics of criticality and perhaps supercriticality than normal waking consciousness—implying that the latter is slightly sub-critical, if not perfectly critical. Secondary consciousness pays deference to reality by carefully sampling the world and learning from its encounters (Friston, 2010), whereas primary consciousness does this more haphazardly. Mechanistically, whereas the brain strives toward organization and constraint in secondary consciousness, processes are more flexible in primary consciousness...

The phenomenon of “magical thinking”14 (Frazer, 1900; Subbotskii, 2010; Hutson, 2012) is a potential product of primary consciousness. Magical thinking is a style of cognition in which supernatural interpretations of phenomena are made. Magical thinking is more likely in situations of high uncertainty because there is a greater opportunity for dreaming up explanations that lack an evidence base (Friston, 2010). Wishful beliefs are a classic product of magical thinking because they interpret the world according to what an individual wants to be true (in Freudian terms, they adhere to the pleasure principle). Wishful inferences are quick-fixes that reduce uncertainty but via simplistic explanations that satisfy fancies or desires before careful reason.

Another example of magical thinking is paranoia; in this case, an individual jumps to negative conclusions about a situation, even in the face of contradictory evidence, because to do so effectively suspends uncertainty while providing some narcissistic satisfaction. The popularity of magical thinking also suggests that there is some enjoyment in uncertainty, perhaps because it promotes imaginative and creative thinking—and that this is associated with positive affect...
 
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