Parallel Processing and Consciousness

Information travels in parallel to multiple parts of the brain, with each area potentially doing something unique simultaneously.
Example: The visual system, where information from the retinas goes to multiple pathways.

At least two pathways originate from the retina.
One pathway goes to the thalamus, and another goes to the superior colliculus.
Information goes to both the thalamus and superior colliculus concurrently via different axons.

Gazzaniga's experiment highlights how visual information is processed in split-brain patients.
Each eye receives information from both the left and right visual fields in humans, unlike animals with eyes on the sides of their heads.
Information from the left visual field goes to the right hemisphere (and vice versa).
The lateral parts of the eyes stay on the same side, while medial parts cross over at the optic chiasm.
Understanding this diagram clarifies Gazzaniga's film.

The relationship between brain function and consciousness is a fundamental question in psychology and philosophy.
A materialistic view suggests consciousness arises from activity within the central nervous system, specifically the brain.
The challenge is to understand how electrical impulses in neurons give rise to subjective conscious experience.
The cortex plays a key role in conscious experience. Damage to specific cortical areas can lead to loss of specific conscious abilities.
Example: Damage to the fusiform face area results in the inability to consciously recognize faces.

Binocular rivalry is an experimental method to study the neural correlates of consciousness.
Different images are presented to each eye (e.g., a face to one eye and a house to the other eye).
Subjects experience a fluctuating perception, where they alternate between seeing the face and the house.
Both eyes receive sensory input constantly, but only one image is consciously perceived at a time.
This design allows researchers to identify brain activity related to the subjective experience rather than the sensory stimulus itself.

Functional magnetic resonance imaging (fMRI) is used to measure brain activity during binocular rivalry.
The occipital lobe is active regardless of whether the subject is consciously perceiving a face or a house.
The fusiform face area is more active when the person reports seeing a face, while the parahippocampal place area is more active when they report seeing a house.
Activity in these areas is directly linked to the conscious experience of the subjects.

The cingulate cortex is thought to play a role in attention and conscious awareness.
Activity in the cingulate cortex is correlated with activity in specific cortical regions during conscious perception.
Example: During binocular rivalry, activity in the cingulate cortex is correlated with activity in the fusiform face area when the person is seeing a face, and with activity in the parahippocampal place area when the person is seeing a house.
Global workspace hypothesis: only specific things happening are elevated in conscious awareness and other cortical areas are suppressed through the thalamic filter relating to sensory information.
The cingulate cortex may act as a spotlight, highlighting certain cortical regions and amplifying their activity, leading to conscious awareness of the information being processed in those regions.

Information travels in parallel to multiple parts of the brain, with each area potentially doing something unique simultaneously.
Example: The visual system, where information from the retinas goes to multiple pathways.

At least two pathways originate from the retina.
One pathway goes to the thalamus, and another goes to the superior colliculus.
Information goes to both the thalamus and superior colliculus concurrently via different axons.

Gazzaniga's experiment highlights how visual information is processed in split-brain patients.
Each eye receives information from both the left and right visual fields in humans, unlike animals with eyes on the sides of their heads.
Information from the left visual field goes to the right hemisphere (and vice versa).
The lateral parts of the eyes stay on the same side, while medial parts cross over at the optic chiasm.
Understanding this diagram clarifies Gazzaniga's film.

The relationship between brain function and consciousness is a fundamental question in psychology and philosophy.
A materialistic view suggests consciousness arises from activity within the central nervous system, specifically the brain.
The challenge is to understand how electrical impulses in neurons give rise to subjective conscious experience.
The cortex plays a key role in conscious experience. Damage to specific cortical areas can lead to loss of specific conscious abilities.
Example: Damage to the fusiform face area results in the inability to consciously recognize faces.

Binocular rivalry is an experimental method to study the neural correlates of consciousness.
Different images are presented to each eye (e.g., a face to one eye and a house to the other eye).
Subjects experience a fluctuating perception, where they alternate between seeing the face and the house.
Both eyes receive sensory input constantly, but only one image is consciously perceived at a time.
This design allows researchers to identify brain activity related to the subjective experience rather than the sensory stimulus itself.

Functional magnetic resonance imaging (fMRI) is used to measure brain activity during binocular rivalry.
The occipital lobe is active regardless of whether the subject is consciously perceiving a face or a house.
The fusiform face area is more active when the person reports seeing a face, while the parahippocampal place area is more active when they report seeing a house.
Activity in these areas is directly linked to the conscious experience of the subjects.

The cingulate cortex is thought to play a role in attention and conscious awareness.
Activity in the cingulate cortex is correlated with activity in specific cortical regions during conscious perception.
Example: During binocular rivalry, activity in the cingulate cortex is correlated with activity in the fusiform face area when the person is seeing a face, and with activity in the parahippocampal place area when the person is seeing a house.
Global workspace hypothesis: only specific things happening are elevated in conscious awareness and other cortical areas are suppressed through the thalamic filter relating to sensory information.
The cingulate cortex may act as a spotlight, highlighting certain cortical regions and amplifying their activity, leading to conscious awareness of the information being processed in those regions.

The question of free will arises:
- Does our brain activity determine our choices before we are even aware of them?
- Experiments