Dr. Stanley is Assistant Professor of Biomedical Engineering in the Division of Engineering and Applied Sciences at Harvard University. He is the ultimate voyeur. He jacks into brains and extracts video.
Using cats selected for their sharp vision, in 1999 Garret Stanley and his team recorded signals from a total of 177 cells in the lateral geniculate nucleus - a part of the brain’s thalamus [the thalamus integrates all of the brains sensory input and forms the base of the seven-layered thalamocortical loop with the six layered neocortex] - as they played 16 second digitized (64 by 64 pixels) movies of indoor and outdoor scenes. Using simple mathematical filters, the Stanley and his buddies decoded the signals to generate movies of what the cats actually saw. Though the reconstructed movies lacked color and resolution and could not be recorded in real-time [the experimenters could only record from 10 neurons at a time and thus had to make several different recording runs, showing the same video] they turned out to be amazingly faithful to the original.
going to have to look up some of his work in the primary research literature and check it out. if its all sound science, that is pretty fucking amazing.
the problem with that is the brain's ability to retain detail information on such visual input, I wouldn't be suprised if the bottleneck of the generated images was the cat's brain itself, not to mention the time elapsed between the actual input and the final output which would dramaticaly affect the outcome.
in any case it'll be interesting to see the type of detail a human brain can retain, or for that matter be put to shame by thecapabilities of other animals
That stuff is incredible. I think it really breaks down the barrier of how we define ourselves in terms of perception and image processing. That right there shows the network that is our brains clearly just represents the world around us in an almost direct manner. It will be extremely interesting to view how this direct representation of the world gets progressively deconstructed or altered as the representation of it in the brain progresses to more interpretational areas. This will help answer exactly where our brains are doing the processing and specifically how. Damn cool stuff!
Canis wrote:That stuff is incredible. I think it really breaks down the barrier of how we define ourselves in terms of perception and image processing. That right there shows the network that is our brains clearly just represents the world around us in an almost direct manner. It will be extremely interesting to view how this direct representation of the world gets progressively deconstructed or altered as the representation of it in the brain progresses to more interpretational areas. This will help answer exactly where our brains are doing the processing and specifically how. Damn cool stuff!
The lateral geniculate nucleus of the thalamus is the first relay for the visual signal - so it's straight outta the retina - and has a retinotopic organization - i.e. we know that the pattern of signals will reflect what's sensed by the retina spatially.
The brain doesn't view the word in a direct manner, and everything you perceive is an abstraction. The representation in the visual cortex is very, very different from the representation in the LGN, and would be orders of magnitude more complicated to recreate. For example it's possible selectively to lose the perception of motion, so that a moving object in your visual field seems to skip from place to place rather than slide, or your ability to fix your concentration on one side of your visual field, so you just don't pay any attention to half of the universe, even though you can see it.
Canis wrote:That stuff is incredible. I think it really breaks down the barrier of how we define ourselves in terms of perception and image processing. That right there shows the network that is our brains clearly just represents the world around us in an almost direct manner. It will be extremely interesting to view how this direct representation of the world gets progressively deconstructed or altered as the representation of it in the brain progresses to more interpretational areas. This will help answer exactly where our brains are doing the processing and specifically how. Damn cool stuff!
The lateral geniculate nucleus of the thalamus is the first relay for the visual signal - so it's straight outta the retina - and has a retinotopic organization - i.e. we know that the pattern of signals will reflect what's sensed by the retina spatially.
The brain doesn't view the word in a direct manner, and everything you perceive is an abstraction. The representation in the visual cortex is very, very different from the representation in the LGN, and would be orders of magnitude more complicated to recreate. For example it's possible selectively to lose the perception of motion, so that a moving object in your visual field seems to skip from place to place rather than slide, or your ability to fix your concentration on one side of your visual field, so you just don't pay any attention to half of the universe, even though you can see it.
It is an almost direct manner of image processing. Starting with the most primary nervous tissue involved in image processing, the field of rods and cones in the eye pick up essentially a bitmap of what is viewed by the eye. That "image" is then progressively relayed to the brain where it progresses through layers of interpretation in ways we dont really understand. However, even in the brain there's a representative map of what is viewed in the eye. These maps are present everywhere: Somatosensory cortex (homunculus), auditory cortex, visual cortex, etc. Of course these maps get disproportionated with respect to what the sensory stimulus was as the brain further interprets the signals, but they all start out as fairly linear representations of the original stimulus.
Canis wrote:That stuff is incredible. I think it really breaks down the barrier of how we define ourselves in terms of perception and image processing. That right there shows the network that is our brains clearly just represents the world around us in an almost direct manner. It will be extremely interesting to view how this direct representation of the world gets progressively deconstructed or altered as the representation of it in the brain progresses to more interpretational areas. This will help answer exactly where our brains are doing the processing and specifically how. Damn cool stuff!
The lateral geniculate nucleus of the thalamus is the first relay for the visual signal - so it's straight outta the retina - and has a retinotopic organization - i.e. we know that the pattern of signals will reflect what's sensed by the retina spatially.
The brain doesn't view the word in a direct manner, and everything you perceive is an abstraction. The representation in the visual cortex is very, very different from the representation in the LGN, and would be orders of magnitude more complicated to recreate. For example it's possible selectively to lose the perception of motion, so that a moving object in your visual field seems to skip from place to place rather than slide, or your ability to fix your concentration on one side of your visual field, so you just don't pay any attention to half of the universe, even though you can see it.
It is an almost direct manner of image processing. Starting with the most primary nervous tissue involved in image processing, the field of rods and cones in the eye pick up essentially a bitmap of what is viewed by the eye. That "image" is then progressively relayed to the brain where it progresses through layers of interpretation in ways we dont really understand. However, even in the brain there's a representative map of what is viewed in the eye. These maps are present everywhere: Somatosensory cortex (homunculus), auditory cortex, visual cortex, etc. Of course these maps get disproportionated with respect to what the sensory stimulus was as the brain further interprets the signals, but they all start out as fairly linear representations of the original stimulus.
but just because our eyeballs are pointing in a certain direction, that by far does not mean that 1/3rd or 1/4 of the way through interpretation that it would have anything to do with what is been 'seen' with the eyes. Ask any student who has had to sit through lectures, and you will realise that you're not always going to be seeing the room. Ask anyone with day-to-day hallucination/mental illness problems (for lack of better terms) and they will tell you that just because you see it, that doesn't mean it is there (or even has anything to do with the current situation).
I would have to disagree, our brain does not interpret vision in anything close to a linear fashion
Canis wrote:That stuff is incredible. I think it really breaks down the barrier of how we define ourselves in terms of perception and image processing. That right there shows the network that is our brains clearly just represents the world around us in an almost direct manner. It will be extremely interesting to view how this direct representation of the world gets progressively deconstructed or altered as the representation of it in the brain progresses to more interpretational areas. This will help answer exactly where our brains are doing the processing and specifically how. Damn cool stuff!
The lateral geniculate nucleus of the thalamus is the first relay for the visual signal - so it's straight outta the retina - and has a retinotopic organization - i.e. we know that the pattern of signals will reflect what's sensed by the retina spatially.
The brain doesn't view the word in a direct manner, and everything you perceive is an abstraction. The representation in the visual cortex is very, very different from the representation in the LGN, and would be orders of magnitude more complicated to recreate. For example it's possible selectively to lose the perception of motion, so that a moving object in your visual field seems to skip from place to place rather than slide, or your ability to fix your concentration on one side of your visual field, so you just don't pay any attention to half of the universe, even though you can see it.
It is an almost direct manner of image processing. Starting with the most primary nervous tissue involved in image processing, the field of rods and cones in the eye pick up essentially a bitmap of what is viewed by the eye. That "image" is then progressively relayed to the brain where it progresses through layers of interpretation in ways we dont really understand. However, even in the brain there's a representative map of what is viewed in the eye. These maps are present everywhere: Somatosensory cortex (homunculus), auditory cortex, visual cortex, etc. Of course these maps get disproportionated with respect to what the sensory stimulus was as the brain further interprets the signals, but they all start out as fairly linear representations of the original stimulus.
It depends. In the visual cortex, there's a much higher level of abstraction which is very far from being a bitmap; what we "see" is reassembled from that abstraction, which is part of the reason why you don't see your visual field jump around with your saccadic eye movements; i.e. what the eye sees is not the same thing as what the brain perceives. The visual cortex is designed (fuck, got all ID there; sorry, evolved) to extract meaning from the visual field, and actually tends to fill in much of the dull stuff for itself (likes edges, ignores fields of single colour - which is analogous to what happens in most senses). There's also colour assignment, and compression of the scale of light amplitudes, etc.
i.e. the LGN is basically just a switching centre with a small amount of abstraction (large and small cells), so the fact that it's retinotopic doesn't actually mean a whole lot.
Geebs wrote:
The lateral geniculate nucleus of the thalamus is the first relay for the visual signal - so it's straight outta the retina - and has a retinotopic organization - i.e. we know that the pattern of signals will reflect what's sensed by the retina spatially.
The brain doesn't view the word in a direct manner, and everything you perceive is an abstraction. The representation in the visual cortex is very, very different from the representation in the LGN, and would be orders of magnitude more complicated to recreate. For example it's possible selectively to lose the perception of motion, so that a moving object in your visual field seems to skip from place to place rather than slide, or your ability to fix your concentration on one side of your visual field, so you just don't pay any attention to half of the universe, even though you can see it.
It is an almost direct manner of image processing. Starting with the most primary nervous tissue involved in image processing, the field of rods and cones in the eye pick up essentially a bitmap of what is viewed by the eye. That "image" is then progressively relayed to the brain where it progresses through layers of interpretation in ways we dont really understand. However, even in the brain there's a representative map of what is viewed in the eye. These maps are present everywhere: Somatosensory cortex (homunculus), auditory cortex, visual cortex, etc. Of course these maps get disproportionated with respect to what the sensory stimulus was as the brain further interprets the signals, but they all start out as fairly linear representations of the original stimulus.
It depends. In the visual cortex, there's a much higher level of abstraction which is very far from being a bitmap; what we "see" is reassembled from that abstraction, which is part of the reason why you don't see your visual field jump around with your saccadic eye movements; i.e. what the eye sees is not the same thing as what the brain perceives. The visual cortex is designed (fuck, got all ID there; sorry, evolved) to extract meaning from the visual field, and actually tends to fill in much of the dull stuff for itself (likes edges, ignores fields of single colour - which is analogous to what happens in most senses). There's also colour assignment, and compression of the scale of light amplitudes, etc.
i.e. the LGN is basically just a switching centre with a small amount of abstraction (large and small cells), so the fact that it's retinotopic doesn't actually mean a whole lot.
Well I dont disagree with that at all, as the more we get away from the direct map of what we percieve as sensed through our sensory system (skin, retina, vibration points of the basilar membrane in the cochlea, etc.) the information spreads out and becomes "interpreted" where it progressively becomes less linear. It gets reorganized based on the dynamics of the directly percieved "map" as the various specialized neurons and neural networks perceive motion, alignment of contrasting colors, etc. Nevertheless there is an initial linear representation with the environment that penetrates through some levels of the visual system before the processing distorts the neural representation of what was seen to where it's no longer linear (kinda convoluted, but i hope it makes sense).
