Lecture 1 - Consciousness

Question 1

What is consciousness?

Answer 1

Consciousness is the state or quality of awareness – awareness of thoughts, perceptions, memories, and feelings.

Question 2

Define lobotomy

Answer 2

A lobotomy is a procedure that splits the white fibres in the frontal lobe.

This used to be a popular treatment for depression, psychosis, and anxiety.

This procedure was fazed out once anti-psychotic medications were introduced

Question 3

Define split-brain surgery

Answer 3

A split-brain surgery is a procedure that splits the white fibres which connect the left and right hemispheres so that they can no longer talk to one another.

This used to be a popular treatment for epileptic seizures.

While the hemispheres can no longer communicate, coordinated movement is still possible thanks to the brainstem and the spinal cord

Question 4

What are the cerebral hemispheres responsible for?

Answer 4

The cerebral hemispheres are critical for our ability to consciously process sensory information (sights, sounds, touch, etc.), and for our ability to consciously (purposefully) move our body in space (e.g., hand and leg movements).

Each cerebral hemisphere is responsible for one half of the body, but the nerve fibers mostly crisscross

Question 5

What is the left hemisphere responsible for?

Answer 5

The left brain is largely responsible for the right side of the body.

Question 6

What is the right hemisphere responsible for?

Answer 6

The right brain is largely responsible for the left side of the body.

Question 7

How does damage to a hemisphere affect the body?

Answer 7

Damage to one hemisphere will affect coordination of the opposite side of the body

Ex: damage to the left cerebral hemisphere will selectively disrupt movements and sensory processing on the right half of the body

Question 8

How do the eyes process things in our field of vision?

Answer 8

When you look at something (a fixation point), everything you see to the left of that spot is processed by the right brain, and everything you see to the right of that spot is processed by the left brain.

This is because in biology, the left side always processes for the right side of the body and vice versa

Question 9

What is the Corpus Callosum?

Answer 9

The Corpus Callosum is a collection of myelinated nerve fibres that connect the left and right hemispheres of the brain

• This is the part of the brain that facilitates conversation between the hemispheres so that each side knows what the other side is perceiving and doing.

Question 10

What happens if the Corpus Callosum is cut?

Answer 10

If the corpus callosum is cut, the two cerebral hemispheres cannot directly talk to each other. However, they can still send information downwards (to the brainstem and spinal cord) to control muscles.

These lower brain areas process information beneath conscious awareness, and they help coordinate movements by integrating the information they receive from the two cerebral hemispheres.

Question 11

What were the findings of independent scientists after examining 26 patients who received split-brain surgery in Rochester, NY, around 1940

Answer 11

Independent scientists found that the patients’ improvements were short-lived or exaggerated, and that cutting the corpus callosum did not significantly impact their condition. Subsequently, Roger Sperry at Caltech conducted clean surgeries on cats and monkeys and suggested that the corpus callosum is important for cognitive functions, as it caused cognitive peculiarities in these animals.

Question 12

What were the effects of the split-brain surgery on patients?

Answer 12

Some of these patients began to say that their left hand sometimes had a mind of its own. Their left hand sometimes actively worked against what the person was consciously trying to accomplish. One patient reported that one time his left hand suddenly started to attack his wife, and he had to use his right hand to protect her, to thwart his left hand.

It seemed that the left hand of split-brain patients was controlled by processes outside their conscious awareness. The right hand, controlled by the left brain, never acted out of the ordinary. Its actions were always consistent with the person’s conscious intentions.

Question 13

What tests were run on split-brain patients, and what were the results?

Answer 13

Touch: When a split-brain patient closes their eyes and touches a familiar but unidentified object with their left hand, they cannot identify the object out loud.

Vision: When a split-brain patient sees an image only in their left peripheral vision, which is processed on the right side of the brain, they cannot verbalize what they see.

Split brain patients cannot say out loud something that only the right brain sees. Studies on Split Brain Patients Split brain patients appear to be unconscious of – cannot verbalize – any stimuli directed exclusively to their right brain.

Split brain patients were largely unaware and unbothered by their deficits in perception. With practice on any given task, they could smoothly choreograph the movements of their body. One hemisphere seemed to take the lead in controlling behaviour in a situation dependent manner, and well-practiced bimanual skills were well coordinated by subcortical structures.

Question 14

Where is language comprehension/ability located in the brain?

Answer 14

Most human language ability – comprehension of language and ability to talk and write – is generally located in the left cerebral hemisphere.

Question 15

How does language comprehension/ability work in the right hemisphere of the brain?

Answer 15

The right hemisphere of the cerebral cortex has very limited language abilities (in 90% of people).

However, Sperry discovered that the mute right cerebral cortex of some split-brain patients could understand simple phrases. The right brain seemed to retain a bit of a “dictionary” and could understand simple numbers, letters, and short statements.

He also found split-brain patients could use their left hand (controlled by their mute right brain) to indicate answers to simple questions.

Question 16

How did split-brain patients justify their responses during experiments?

Answer 16

When split-brain patients were asked to explain in words why they performed an action that had been initiated by their right hemisphere, they sometimes made up a post hoc answer.

Ex: When the command ‘laugh’ was directed to the right hemisphere of one patient, he laughed. When asked why he was laughing, he said “you guys come up and test me every month – what a way to make a living!”

Ex: When a patient’s right brain was instructed to walk, he walked out of the room. When asked why he did that, he immediately responded “to get a Coke.”

It seemed that the left brain was constantly generating explanations for actions that were instigated by the right brain.

Question 17

Explain Gazzaniga’s Interpreter Theory

Answer 17

Gazzaniga’s Interpreter Theory says that behaviour is fully controlled by unconscious processes, and that the function of our left-brain consciousness is simply to create narratives with the information it has in an attempt to make sense of the world.

Accordingly, consciousness doesn’t directly influence behaviour, at least not in real time (i.e., not in the current moment). Rather, it weaves disparate points of information into a story that has meaning (after the fact).

Basically, free will is an illusion; our conscious mind does not directly control our behaviour, despite our intuition.

Consciousness is just storytelling, and since storytelling relies on language, consciousness is only located in the left cerebral hemisphere of the human brain.

Consciousness: Involves awareness of — and ability to tell others about — our thoughts, perceptions, memories, and feelings

Question 18

How did people understand the world before the Scientific Revolution?

Answer 18

Before the scientific revolution, experiments and mathematical formalizations were rare and underappreciated. People relied more on intuition than math (e.g., it certainly doesn’t feel like the earth is moving).

Question 19

Define the idea that the world is deterministic

Answer 19

In accordance with the laws of physics there might be an unbroken chain of cause and effect stretching back to the origin of the universe, and humans can only witness, not interfere, with this chain of events.

Question 20

What is mind-body dualism?

Answer 20

While the body may be a mechanical device and the world deterministic, the mind (or soul) is something else, something immaterial that exists outside the body.

But, if the movement of all atoms can be well explained by the physical laws of nature, how can our immaterial souls control our material bodies? This paradox is known as the Cartesian impasse.

Question 21

How did neural networks evolve?

Answer 21

Neural networks evolved to sense the internal and external world and to coordinate movements of the organism.

In addition to automatic responses (e.g., pull your hand back if it feels too hot), neural networks give rise to thoughts (e.g., my hand is burning hot).

Question 22

Describe the characteristics of thoughts

Answer 22

Thoughts do not produce preordained, automatic behavioural responses.

Thoughts and ideas exist as patterns of brain activity that are independent of any sensory input or motor output. They are their own things.

There is no physical law that says ideas have to exist, yet they do exist. Neural network activity generates ideas, the most important being that things have meaning, that things happen for a reason. We theorize and create stories about the meaning of things.

Yet, when we look at the laws of physics, we don’t find any meaning. We only find equations that faithfully describe the interactions of all physical matter.

Question 23

Is the world deterministic?

Answer 23

In a deterministic world, all events, including human actions, are ultimately determined by causes that are independent (external) of free will.

In a deterministic world, everything is preordained, following a path determined by the laws of physics. There is no inherent meaning in a deterministic world. Stuff just happens.

Yet, we know it doesn’t make sense to say, “the molecule made me to do it.” Molecules don’t have any inherent meaning to them. They just are.

Sure, we may understand the physical cause and effect of a molecule moving around, but what that movement means to an organism, what it represents, is entirely different.

Our brains construct a world of ideas on top of the laws of nature, a world in which things have meaning. The world of ideas represents a distinct layer of our reality, a layer that harnesses (directs, constrains) the physical laws of nature, controlling how the world will play out.

Question 24

How do thoughts have influence/power?

Answer 24

Thinking is not just calculating. It is a creative act, which gives rise to abstract ideas that direct and constrain how the organism will act in the future.

Thinking is an act of creation that involves theorizing, not only about what we are and how the world is, but how these things ought to be, how they might otherwise be.

It is by imagining future possibilities and theorizing about cause and effect that we develop the idea that things happen for a reason, that things have meaning.

Self-awareness grows out of the realization that our thoughts do influence the future.

By envisioning a potential future, neural networks take control over the future. They construct the future.

Question 25

What are our main important questions regarding the brain?

Answer 25

1. How is it we feel things? What are feelings and why do they feel so personal? What is consciousness, how does it work, and what has it?
2. What is thinking and how does it work? Do we have free will because we think, or is thinking just the calculation of predetermined answers?
3. What is mental illness and how should we treat it? It is difficult for us to understand mental illness – a disturbance in how someone feels or thinks – when we don’t really understand the neural basis of feeling and thinking.

Question 26

What things do we know about the brain?

Answer 26

• We know what the brain is made of and how things works at the cellular level.
• We know how neurons communicate with each other.
• We understand how sensory stimuli is transduced and initially processed. We also know the function of the last few cells in the motor system pathway.
• However, once we get a few cells deep into the network, we don’t really understand what is happening or how information is processed. This leaves us with a very limited understanding of the neural bases of cognition, emotion, consciousness, decision making, etc.