Mysteries of the Brain

[Radrook]

There is also the fact that all perceptual experience occurs in the brain, so whether the limb is present or absent, sensations from it are experienced in the brain and referred to the limb... The mapping for bodily sensations in the brain persists in the absence of the limb, so that area can still generate sensations.

You can fool the sensory mapping in the brain of an amputee using an illusion similar to the rubber hand illusion, by placing a mirror so as to make a reflection of the existing limb look like the missing limb. For subjects with a painful phantom 'clenched fist' sensation in the missing hand, clenching and relaxing the existing hand while looking at the reflection can provide welcome relief, as the brain matches its phantom limb sensation to the appearance of the illusory phantom limb replacement.

True, that's why a bullet through the occipital lobe where neural transmissions from the optic nerves are processed will result in blindness. All sensations, olfactory, visual, gustatory, auditory, tactile, are brain-dependent.

 

[FrumiousBandersnatch]

True, that's why a bullet through the occipital lobe where neural transmissions from the optic nerves are processed will result in blindness. All sensations, olfactory, visual, gustatory, auditory, tactile, are brain-dependent.

Exactly. An interesting example in the visual system is blindsight, where damage to the first stage processing area of the visual cortex (known as V1), at the back of the brain, causes blindness as far as conscious awareness is concerned, but the blind individual is able to accurately guess where things are in their visual field because there's alternate 'low-level' pathway by which visual signals are processed for rapid autonomous or reflexive responses (e.g. ducking out of the way of something before you're consciously aware of it, hitting or catching rapidly moving objects like balls, etc). Signals from this subconscious system don't directly reach conscious awareness, but can be accessed intuitively as guesses and hunches.

 

[Radrook]

Exactly. An interesting example in the visual system is blindsight, where damage to the first stage processing area of the visual cortex (known as V1), at the back of the brain, causes blindness as far as conscious awareness is concerned, but the blind individual is able to accurately guess where things are in their visual field because there's alternate 'low-level' pathway by which visual signals are processed for rapid autonomous or reflexive responses (e.g. ducking out of the way of something before you're consciously aware of it, hitting or catching rapidly moving objects like balls, etc). Signals from this subconscious system don't directly reach conscious awareness, but can be accessed intuitively as guesses and hunches.

Very interesting and still hard to fathom since once the visual signals are absent exactly what is it that the brain is sensing in order to tell us to move out of the way? Not that I do not believe it since I experienced something similar. You see, when I practiced Pai Lum Kung Fu we practiced blindfolded in order to heighten that same mysaterious awareness. So what you mentioned seems to correspond to this sense or a sort of subconscious precognition of where things are going to be. I began to develop it but stopped before it reached an advanced stage and always wondered just how it functioned.

 

[Larniavc]

This video focuses on areas of the brain which are fascinatingly mysterious and still under intense study.

It things like this that make psychology my favourite science.

 

[Larniavc]

The hallucinations that hallucinatory drugs produce are dependent on how the human brain is hard wired. As humans we all share a similar brain structure. So why should we be surprised when a certain drug might produce a similar reaction in all of us? Please note that the phantom limb experience is triggered after amputation is a COMMON human brain reaction to amputation. So commonality of experience can simply mean a similar brain.

I agree.

What have you done with the real Radrook?

 

[FrumiousBandersnatch]

Very interesting and still hard to fathom since once the visual signals are absent exactly what is it that the brain is sensing in order to tell us to move out of the way?

The visual signals are not absent in these cases. The whole visual pathway from the eyes to the visual cortex is intact and working, but the damage is in the processing areas that generate high-level visual perception and mapping for conscious access (across the cortex to the forebrain for focus of attention, etc).

But the visual signals from the optic nerve are also processed by a high-speed auxilliary system integrated with the cerebellum, that handles movement, balance, and coordination, etc. The multiple feedback loops between the various processing levels & systems mean that these auxilliary processing results are indirectly accessible, but are not sufficient to cross the stimulus threshold for conscious awareness.

Not that I do not believe it since I experienced something similar. You see, when I practiced Pai Lum Kung Fu we practiced blindfolded in order to heighten that same mysaterious awareness. So what you mentioned seems to correspond to this sense or a sort of subconscious precognition of where things are going to be. I began to develop it but stopped before it reached an advanced stage and always wondered just how it functioned.

If you were blindfolded, then your experience was something completely different from blindsight, because you were receiving no visual signals.

It is certainly possible to sense the world around you through other senses (primarily sound, but also air currents, vibrations, and radiant heat). There are blind people who can navigate very well by clicking with their tongues and listening to the echoes (like bats) - and at least one man does it well enough to be able to safely ride a bike on public roads.

In such cases, the auditory processing may eventually recruit areas of the intact visual cortex to generate visual images of the surroundings. This is far more limited in cases where vision is still intact and blindfolding is relatively short term, because the visual cortex isn't deprived of stimulation long-term, and will tend to reject 'cross-talk' from other sensory areas as noise. But there has been some success with visually impaired subjects, and experimenters blindfolded for days at a time, using skin and tongue stimulators based on arrays of electrodes, or blunt pins that move in response to video camera images.

 

[Radrook]

I agree.

What have you done with the real Radrook?

I don't understand your question.

 

[Radrook]

The visual signals are not absent in these cases. The whole visual pathway from the eyes to the visual cortex is intact and working, but the damage is in the processing areas that generate high-level visual perception and mapping for conscious access (across the cortex to the forebrain for focus of attention, etc).

But the visual signals from the optic nerve are also processed by a high-speed auxilliary system integrated with the cerebellum, that handles movement, balance, and coordination, etc. The multiple feedback loops between the various processing levels & systems mean that these auxilliary processing results are indirectly accessible, but are not sufficient to cross the stimulus threshold for conscious awareness.

If you were blindfolded, then your experience was something completely different from blindsight, because you were receiving no visual signals.

It is certainly possible to sense the world around you through other senses (primarily sound, but also air currents, vibrations, and radiant heat). There are blind people who can navigate very well by clicking with their tongues and listening to the echoes (like bats) - and at least one man does it well enough to be able to safely ride a bike on public roads.

In such cases, the auditory processing may eventually recruit areas of the intact visual cortex to generate visual images of the surroundings. This is far more limited in cases where vision is still intact and blindfolding is relatively short term, because the visual cortex isn't deprived of stimulation long-term, and will tend to reject 'cross-talk' from other sensory areas as noise. But there has been some success with visually impaired subjects, and experimenters blindfolded for days at a time, using skin and tongue stimulators based on arrays of electrodes, or blunt pins that move in response to video camera images.

So the visual signals bypass the damaged occipital lobe are shunted to the cerebellum?
Fascinating information indeed! Thanks for the feedback.

 

[Larniavc]

I don't understand your question.

It was a dry reference to how you and I very rarely agree an I was light heartedly asserting that you had been kidnapped and someone else was posting on your behalf; evidenced by my agreeing with your post: which is incredibly rare.

It is a common trope in informal debate (i.e. conversation) used to explore infrequent incongruity in position, paradoxical agreement and to lighten the mood in discussion.

who are you and what have you done with someone - Wiktionary

It was a joke.

 

[Radrook]

It was a dry reference to how you and I very rarely agree an I was light heartedly asserting that you had been kidnapped and someone else was posting on your behalf; evidenced by my agreeing with your post: which is incredibly rare.

It is a common trope in informal debate (i.e. conversation) used to explore infrequent incongruity in position, paradoxical agreement and to lighten the mood in discussion.

who are you and what have you done with someone - Wiktionary

It was a joke.

Ah! In my haste I failed to see the otherwise obvious. Thanks for the clarification.

 

[FrumiousBandersnatch]

So the visual signals bypass the damaged occipital lobe are shunted to the cerebellum?
Fascinating information indeed! Thanks for the feedback.

Not quite; the cerebellum and subcortical areas get feeds from the subsidiary pathway. The two pathways are normally complementary and function together in undamaged individuals, so when one pathway is damaged, the other continues as before (if the secondary pathway is damaged instead, I would expect the individual to be bumping into things, and have difficulty with things involving rapidly moving objects and coordination, such as ball sports).

It may be that, in the long term, additional connections are established to strengthen the intuitive hunches, I don't know. Some parts of the brain have more plasticity than others.

 

[Radrook]

Not quite; the cerebellum and subcortical areas get feeds from the subsidiary pathway. The two pathways are normally complementary and function together in undamaged individuals, so when one pathway is damaged, the other continues as before (if the secondary pathway is damaged instead, I would expect the individual to be bumping into things, and have difficulty with things involving rapidly moving objects and coordination, such as ball sports).

It may be that, in the long term, additional connections are established to strengthen the intuitive hunches, I don't know. Some parts of the brain have more plasticity than others.

Definitely a very crucial part of our brain:
[Cerebellum Function]
The cerebellum is involved in several functions. The cerebellum processes information from the brain and peripheral nervous system for balance and body control. Activities such as walking, hitting a ball, and playing a video game all involve the cerebellum. The cerebellum helps us to have fine motor control, while inhibiting involuntary movement.

• Fine Movement Coordination
• Balance and Equilibrium
• Muscle Tone
• Sense of Body Position
• What is the Cerebellum?[/quote]

There are some questions which I have concerning this.

1. You say that when the occipital lobe is damaged the cerebellum gets additional responsibilities or is it an intensification of the ones it has already?

2. When the brain is divided via surgery into two hemispheres, the cerebellum isn't affected?


3. The pathways you mention emerge from the occipital lobe to the cerebellum? Or are the pathways associated indirectly with the optic nerve? Exactly what is it that these nerve pathways enable the blind person to detect?

 

[FrumiousBandersnatch]

1. You say that when the occipital lobe is damaged the cerebellum gets additional responsibilities or is it an intensification of the ones it has already?

#51: "The two pathways are normally complementary and function together in undamaged individuals, so when one pathway is damaged, the other continues as before".

2. When the brain is divided via surgery into two hemispheres, the cerebellum isn't affected?

No.

3. The pathways you mention emerge from the occipital lobe to the cerebellum? Or are the pathways associated indirectly with the optic nerve? Exactly what is it that these nerve pathways enable the blind person to detect?

I'm not up to date on this stuff, but it goes something like this:

The involvement of the cerebellum is indirect. The optic nerve has connections to both the lateral geniculate nucleus (LGN), and the superior colliculus (SC) in the mid-brain. The LGN (part of the thalamus) is the main route to the primary visual cortex, but has some fibres that bypass the visual cortex V1 area (where blindsight damage occurs) going direct to the middle temporal complex and the extrastriate cortex (see below).

The superior colliculus (which deals with visual following and orientation), routes signals to the to the pulvinar (non-conscious attention & awareness) and then to the extrastriate cortex (motion sensitivity & proprioception). The extrastriate cortex sends processed signals to many areas of the brain, including cortical motor areas and the cerebellum.

All these nuclei receive feedback from areas they output to (and many others).

It's obviously difficult to be certain of exactly what blindsight detects because sufferers aren't conscious of it, and it doesn't seem to be exactly the same for all individuals, but generally they can locate objects, and detect motion and edges.

Some researchers suggest that the blindsight pathway (via the SC?) is the remnant of an early (ancient) vertebrate visual system, to a large extent superseded by more sophisticated visual processing as consciousness developed and a more detailed internal model and mapping of the visual world was required.

 

[Radrook]

#51: "The two pathways are normally complementary and function together in undamaged individuals, so when one pathway is damaged, the other continues as before".

No.

I'm not up to date on this stuff, but it goes something like this:

The involvement of the cerebellum is indirect. The optic nerve has connections to both the lateral geniculate nucleus (LGN), and the superior colliculus (SC) in the mid-brain. The LGN (part of the thalamus) is the main route to the primary visual cortex, but has some fibres that bypass the visual cortex V1 area (where blindsight damage occurs) going direct to the middle temporal complex and the extrastriate cortex (see below).

The superior colliculus (which deals with visual following and orientation), routes signals to the to the pulvinar (non-conscious attention & awareness) and then to the extrastriate cortex (motion sensitivity & proprioception). The extrastriate cortex sends processed signals to many areas of the brain, including cortical motor areas and the cerebellum.

All these nuclei receive feedback from areas they output to (and many others).



It's obviously difficult to be certain of exactly what blindsight detects because sufferers aren't conscious of it, and it doesn't seem to be exactly the same for all individuals, but generally they can locate objects, and detect motion and edges.

Some researchers suggest that the blindsight pathway (via the SC?) is the remnant of an early (ancient) vertebrate visual system, to a large extent superseded by more sophisticated visual processing as consciousness developed and a more detailed internal model and mapping of the visual world was required.

Maybe that's one reason that rabbit punches are illegal in boxing.
Thanks for the info.

BTW
Of course we differ in our final assessment of what organized all this but that is off topic.

 

[Radrook]

Any guesses on what the next video will be?

Instead of trying to goad-why not contribute something meaningful to the discussion?

 

[FrumiousBandersnatch]

Maybe that's one reason that rabbit punches are illegal in boxing.

Rabbit punches pose a risk of spinal damage; I don't really see how that's relevant.

 

[Radrook]

Rabbit punches pose a risk of spinal damage; I don't really see how that's relevant.

Thanks for the clarification. I assumed that it was illegal for the wrong reason.

 

[Radrook]

You committed a fallacy which is confusing the "How" and "Why" questions.

How it happens? Science.
Why it happens? God.

How do we have seasons? Earth-tilt.
Why do we have seasons? No purpose?

No purpose for the 9.8ms^-2 acceleration due to gravitional force, no purpose due to Earth-Sun distance and difference in masses, No purpose for our symmetry, No purpose that we are the only specy that own the power to dominate through our unique brains, also no purpose that this intelligence was not found into the bodies of Elephants or Cats, or even fish, yet it was put into a body that is able to manipulate that intelligence perfectly, no purpose for the laws of physics themselves, no purpose for existence?

I agree that the religious commit a fallacy when they answer the How with God, but not the Why.

I don't think I am confused. They are saying that natural processes are not the "how".

That is not what religion says. Religion says that the source of the how is an ID.

 

[Radrook]

But what about symmetry? You may impose that physical symmetry is a human mind product too, but that doesn't explain its appliance in reality, here we come to reality out of human mind, same logic applies to mathematics, and its real life appliance, how can human mind products achieve that amount of accuracy when it comes to reality? Are they truly invented by the human mind or maybe... discovered?

The real question is what is reality? Neurotransmissions are translated representations of images and sensations
which we assume are the exact replicas of what exists in a realm exterior to our minds. The problem is that not all creatures perceive identical stimuli in a similar way. For example, a bee perceives a flower via its compound eyes in a manner totally different than we do. So which is the real flower, the one the bee perceives or the one we perceive or neither of the twain?

See Like A Bee: Ultraviolet Flower Photography

 

[Loudmouth]

That is not what religion says.

You yourself claim that abiogenesis didn't happen. Your own words contradict your claims.