Neuroscience of Conscious Experiences (Qualia)

A very rare patient in which both brain hemispheres had a language ability was studied by neurologist Victor Mark in 1996. This patient was rare because 90% of people have their language ability located in the left hemisphere meaning their right hemisphere can't talk or understand language. This dual language patient clearly shows the lack of inter-hemispheric communication by conscious experiences. She has a split cognitive perception even though she still retains an integrated emotional personality due to her intact sub-cortical centers:​

Cristof Koch had this to say about a video he saw of this same patient:​

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When this medial temporal area is destroyed in humans by a mini-stroke or hemorrhage the victim cannot perceive motion. The effect this had on patient called L.M. is described below:​

This example also makes clear the informational update strategy used by the brain. The brain only updates itself when either it detects an emotionally  significant (high valued) environmental change or a certain amount of time has elapsed.

This brain region is also responsible for the waterfall illusion which occurs after looking at a constant motion for over a minute. Most of this region's neurons are sensitive to motion in one direction (Koch 2004). After looking at a constant motion for over a minute, those neurons responding to the visual image movement direction become fatigued so that when a person looks at a blank surface neural noise produces the illusion of motion in the opposite direction because those neurons are no longer inhibited by their opposing counterparts.

This example also shows an important general brain principle which is that all perception centers are balanced between opposing pairs.

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Dr. Sacks describes a patient who had completely lost awareness of her left side, she could not turn left, move eyes to the left, or perceive anything in her left visual field. Yet she was able to know of her predicament intellectually and learned to turn right all the way around in order to find something she inferred that she was missing. She did this when she inferred that a part of her meal was still missing if she was still hungry:

Space as a conscious experience is very interesting. We experience it and then assign other conscious experiences "out there." For example, a plant we see a few feet away has a certain color but that color is actually a conscious experience which is generated within our brains yet we assign it to the plant. The plant also generates conscious experiences of valuation (beauty, love, etc) but most people assign those as something internal to ourselves instead of "out there." Where we assign conscious experiences depends upon our brain wiring so once again the brain creates our reality.

References

Sacks, Oliver (1998) The Man who Mistook His Wife for a Hat and Other Clinical Tales, Touchstone, New York

In very rare cases people go “blind” to body limb positions while retaining the sense of limb belonging. This happens when the dorsal (back side) spinal sensory neurons are damaged. Oliver Sacks describes one such patient:​

This patient was able to move her body only by training her visual system to take over her body's internal position sensing. This took a year of physical therapy. If she closes her eyes or loses visual attention her body collapses.​

 The overlapping ability of vision to provide body position feedback (probably via the cerebellum) is the cause of various “out of body” illusions. The “rubber hand illusion” affects the conscious experience of one’s hand location. In this illusion people actually feel a touch on a fake rubber hand. To get this illusion, the test subject looks at a fake hand that is being stroked by a paintbrush in synchrony with stroking applied to the subject's own hand hidden in a nearby box. Synchronous stroking of the seen fake hand and one's own unseen (real) hand can induce the illusion that the fake hand “feels like it's my hand.” In this illusion the perceived location of the subject's hand drifts towards the fake hand. The illusory ownership and drift are much reduced when the stroking is asynchronous (Botvinick and Cohen 1998) (Tsakiris and Haggard 2005)

 Not only can body parts have their conscious location shifted but so can the whole body (Lenggenhager and all 2007). How this illusion works is to have the subject wear virtual reality goggles in which the subject is told is viewing their back but which in reality is someone else's back which has been shifted in position. Add to that various tactile and visual cues and the mind is fooled (Aspell and all 2009).​

The feelings of limb position tend to persist even when limbs have been amputated showing that the limb position perception is no longer being updated. Therefore it tends to persist. The U.S. Civil War surgeon Silas Weir Mitchell was one of the first to report phantom limb sensations from soldiers who had their limbs amputated due to injury (Mitchel, 1872):​

Dr. Sacks relays an observation from a man with an above-the-knee amputation:

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 The reward or pleasure center of the brain is localized in a different subcortical region called the nucleus accumbens. This is the region responsible for the feelings of pleasure. Its direct activation by certain drugs such as cocaine often leads to addiction.

 Recent research using rodents has narrowed down the neuron classes within the nucleus accumbens responsible for addiction. Cocaine addiction results when one class of neurons (D1 neurons) become more active while another class (D2 neurons) become less active (Lobo and all 2010). One would therefore suspect the D1 class of neurons to be responsible for the conscious experience of pleasure in humans. When a person drinks alcohol, endorphins are released in the Nucleus Accumbens and in the orbitofrontal part of the prefrontal cortex. So both the pleasure center and the goal defining region are affected by alcohol (Mitchell and all 2012).

 When we hear an unpleasant sound the amygdala sends feedback to our auditory cortex changing our state of perception. Researchers found that the activity of the amygdala and the auditory cortex varied in direct relation to the level of unpleasantness (Kumar and all 2012). One should not assume that all neurons in the amygdala represent fear. Like the nucleus accumbens other neurons exist within it to provide a counterbalance to fear and anxiety production (Ciocchi and all 2010).​

These examples from the Amygdala and Nucleus Accumbens demonstrate the fundamental balance strategy used in the brain. Not only does a global balance exist between fear and pleasure but also in defining what produces the feelings of fear and pleasure.

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Damage to the lateral distraction center releases inhibition on the medial allowing behaviors to be overly tenacious. This produces the dorsolateral syndrome which is a pseudo-depression where the patient loses the ability to initiate new behaviors. Yet when behaviors can be induced after much effort they tend to persist without stopping. In severe cases the patient will lie passively in bed, neither eating nor drinking.

Patients with this syndrome are no longer bothered by pain even though they can describe the pain they feel just like normal people. Laughing gas does the same thing. This means valuation is a separate independent conscious sensation from the underlying feeling. Conscious experiences themselves are not inherently good or bad. Some just seem to have inherent valuations (like bad smells) due to evolution and context.​

Most of these patients will also have anosognosia in which they are unable to perceive their limitations because they cannot place a valuation on it. As a result they have no motivation to undergo rehabilitation exercises. Minor or slowly developing dorsolateral syndromes can be very hard to recognize in people because their friends assume that the person is becoming lazy or simply becoming disinterested in things due to age.​

A stroke patient with mostly dorsolateral syndrome but who also had damage to her middle (medial) part of her prefrontal cortex is described by Antonio Damasio.

The patients with dorsolateral syndrome still have conscious experiences but they are unable to form goals and reason to achieve those goals because the valuation signal has been stripped off the underlying feelings.

In contrast to the dorsolateral syndrome, damage to the medial tenacity center causes the orbitofrontal syndrome. This is a condition in which the patient lacks any sort of tenacity. The patient is emotionally dis-inhibited and impulsive. They are not able to defer immediate gratification and cannot see the consequences of their actions. They will say what is on their minds without regard to the social consequences (Goldberg 2001, page 144). The earliest celebrity example of this was Phineus Gage who had a railroad tamping iron go through the middle of his brain in 1848.​

A patient with orbitofrontal syndrome from a cancerous tumor was reported on by clinical neurologist Oliver Sacks. This patient, one Mrs. B, was a female research chemist. She seemed to realize she had lost her sense of valuation about social situations. Oliver Sacks says this:​

Valuation is also dependent on perceptual context which suggests that it is easily changeable via emotional propagation. Heterosexual men find a perceived touch by a woman more enjoyable than that from a man. If men can be fooled by an experiment into thinking a woman is doing the touching then a man's touch is just as enjoyable. This perceptual valuation effect even shows up in their brain scans (Gazzola and all, 2012).​

Consciousness experiences comes in two varieties because of how goal paths are created in space. The space we experience is not a network like a road map but is continuous. Deep experiences provide valuation about the goal itself as in whether we want to get it or if we want to flee from it. These we call our deep feelings. Shallow experiences are constraints which help guild our path (whole body or hand) toward or away from a goal. These conscious experiences are involved in spatial perception, vision, body position, etc.​

Laughing gas affects the valuation of pain and other things and often induces light heartedness like that seen in patient Mrs. B above. My college roommate went to the dentist and experienced a light dose saying it "hurt like hell but I didn't care." The underlying conscious experience was there but not its valuation.

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In 1853 the great physicist Michael Faraday showed this Ouija movement effect was due to “quasi-involuntary action” when he investigated a similar séance activity called table moving. In this activity people sat around a sliding table, placed their hands on it, and asked the spirits questions. The table then seemed to move in response. At the time people thought spirits were actually moving the table.

Faraday reasoned that if spirits were moving the table then the table would pull their hands after itself. To test this he placed several layers of cardboard as hand place-mats for each person with each card attached to the other by a flexible, but non-rebounding (no springiness) rubber cement. He marked the cards relative to each other on their backsides so that after the séance he could tell if the hands lagged or led the table movement. The result was that the hands led the table showing that the people moved the table without generating the feeling of will (Faraday 1853)

 The feeling of will is also lacking in schizophrenic patients who believe that the voices in their head are not made by them but come from somewhere else.

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By the mid 1980's experiments testing visually triggered emotional reactions were also showing this conscious experience timing effect in what is now known as subliminal suggestion (LeDoux 1998, page 53). The key person in this research was Robert Zajonc who first demonstrated the phenomena known as the exposure effect in which otherwise emotionally neutral but familiar things are preferred over novel objects.

In one early subliminal suggestion experiment Zajonc presented pictures to people so fast that they had no conscious recollection of what they saw yet they still exhibited this exposure effect. Zajonc took his initial findings further by subliminally presenting an emotionally charged picture (a smiling or frowning face) just before presenting an emotionally neutral picture. The result was that his test subjects had a tendency to either like or dislike the neutral images according to what emotionally charged images appeared just prior to their appearance. These emotionally charged objects can be innate or previously learned associations (de Lange and all 2011). Previously learned associations which rewire the brain to produce new triggers for feelings are the subconscious.

These simple experiments show two things: 

1. Conscious experiences were generated separately and later than material-based neural sensory signals.

2. Sensory signals activity by themselves can prime the brain pathways to create short term expectations for conscious experiences. This priming is a short term memory and it also represents the short term subconscious.

More recent subliminal experiments use attention diversion (masking) to block conscious experiences. In this sort of research, the subliminal bias is called the “prime” because it primes the choice by setting up the neural pathways. The bias image is prevented from entering consciousness by the use of a perceptually antagonistic“mask” which shuts down the prime’s neural signal before it has time to become conscious. The masks are presented right after the primes and they are presented for a longer period of time. The test subject must also be paying attention to the task because subliminal suggestion does not happen in the absence of attention Naccache and all 2002).

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