After reading chapter 7 in Visual Intelligence make a mind map as you have been doing. Next post the following:
1) Make a list of the topics covered in Chapter #7. DO NOT discuss the reader.
2) Look up the topics covered in your reference text book.
3) For each topic write at least one paragraph about what your text has to say about it. If you text doesn't directly address the topic, then find a topic in your text that most closely matches the topic from your list and discuss that. It should be clear for each topic paragraphs that you understand the topic well enough to explain it to a student that has not yet taken this class.
4) What parts do you think you will remember from the reader and the text?
1.Phantom limb
Somatosensory cortex
Magnetic source imaging
Cutaneous rabbit
3. Phantom limb: my text uses this as an example of pain from within. It is reported by people who have had a limb amputated. They not only experience the missing limb as still being present but may also report feeling pain in the phantom limb. The text explains this by saying pain is influence by factors other than tissue damage like emotions, stress levels, and expectations.
-Somatosensory cortex: My textbook refers to the somatosensory cortex when talking about the structure of the brain. Connections that transmits signals from the skin to the brain appears to rival the visual system. Nerve fibers from receptors in the skin travel in bundles called peripheral nerves that enter the spinal cord through the dorsal root. Once entering the spinal cord, the nerve fibers go up the spinal cord. Fibers cross over to the other side of the body at some point and enter the thalamus. From the thalamus, signals travel to the somatosensory receiving area in the parietal lobe in the cortex.
-Magnetic source imaging: Unfortunately I couldn’t find anything in my text that was even remotely related to measuring brain activity; unless it mentions it in passing in a random chapter of the book.
-Cutaneous rabbit: My textbook directed me to cutaneous sensations, sensations based on the stimulation of receptors in the skin. This is exactly what the cutaneous rabbit is; just an explanation of the rabbit. The cutaneous sensations are described by the somatosensory system, which describes the pathways that transmit signals generated by these receptors up the spinal cord toward the brain (as mentioned in the somatosensory cortex explanation above). Looking at cutaneous sensations describes the perceptions sensed through the skin providing an opportunity to demonstrate a number of basic sensory principles that are also important in vision, audition, and other senses.
4. I will definitely remember the phantom limb because I’ve heard of this phenomena happening and it’s so interesting how our perception can influence our touch sensation. I will remember the cutaneous rabbit because of the image in the reader. The feeling of 3 separate taps making it feel like there are more taps in between each tap is really interesting.
1) Cutaneous rabbit, phantom limb, construction of touch
3) Cutaneous sensations are based on the stimulation of receptors in the skin. My book discusses how important cutaneous sensations are for safety. We rely on these cues to avoid burns, bruises, and breaks in our bones by reading sensations temperature and pressure. These receptors are based in the skin which is composed of 2 layers: the epidermis or the outer layer, and the dermis. In these layers sensory receptors are kept. The sensory endings can be basically categorized into three morphological groups: endings with expanded tips, such as Merkel's disks, encapsulated endings such as Meissner's corpuscle. And thirdly, other organs located in the dermis or subcutaneous tissue such as Ruffini endings, Pacinian corpuscles, Golgi-Mazzoni corpuscles, and Krause's end bulb; and bare nerve endings that are found in all layers of the skin.
Phantom limb is described in my textbook as the continued perception of a limb even after the limb as been amputated. Often times pain is perceived to be felt in the missing limb. This occurrence taught the world that pain can occur in the absence of outward stimulus. Factors other than tissue damage can cause pain, as is shown in the fact that people experience pain in a limb which does not exist any longer. One treatment that is mentioned is the mirror box which was developed by Vilayanur Ramachandran. Through the use of artificial visual feedback of placing the matching existing limb in a box with mirrors surrounding it to mirror the other limb, it gives the patient a visual example to work with in therapy. It becomes possible for the patient to "move" the phantom limb, and to unclench it from potentially painful positions.
Construction of touch is also discussed in my textbook in a more round-about way. My book discusses how 2 people will be given the same stimuli, and yet describe the intensity and sensation in different ways. We can prove this through examples like the phantom limb phenomena, or the cutaneous rabbit experience of hopping taps up an arm that is given in the reader. Without external stimuli, experiences of sensation are perceived by the person which means that we construct all pressure, temperature, and vibration sensations.
4) I think I will remember the concept of the phantom limb the best out of this chapter. This is something I’ve heard about before in other classes. It’s a very memorable story because it seems almost impossible. I also think I will remember the cutaneous rabbit because of the drawing in the reader. It helped to make the concept very clearly to me, and sums the whole theory up with a simple drawing. I don’t think I will remember all the information about cutaneous sensations that was presented in my textbook however, because of all the terminology that was used.
1. Phantom Limb, virtual tactility, cutaneous rabbit, and somatosensory cortex.
3. Phantom Limb is described at the end of chapter 11 in my text. I was surprised to see it doesn’t give any examples other than what it is. Phantom limb is when a person who has had a limb amputated still feels that the limb is present and feels pain in the limb. This proves that pain sensors still send pain to that area of the body even when it isn’t there. The pain receptors have a dead end to some degree. They perceive pain but don’t have a source that it’s coming from. I have a friend who lost his leg when he was four years old in a lawn mower accident. He has grown up with a prosthetic leg almost his entire life. When he was in high school he played football and today is married, has a daughter, and is an EMT and a volunteer firefighter. I asked him a couple of years ago if he ever felt that his leg was still there and he said he had. He said sometimes he will feel like his missing leg itches. He said he never has felt pain in the missing area but can sometimes feel like it’s still there.
Virtual tactility isn’t mentioned in the text exactly but tactile receptors are explained in chapter eleven. Tactile receptors are receptors in the skin. The receptors are located in the epidermis and the dermis. There are four types; merkel receptors, meissner corpuscles, ruffini cylinders, and pacinian corpuscles. Merkel are disk shaped receptors located near the border between the epidermis and the dermis. Meissner corpuscles are a stack of flattened cells located in the dermis just below the epidermis. Ruffini cylinder is branched fibers inside the rough cylinder capsules. Pacinian corpuscles are layered like an onion that surrounds the nerve fiber located deep in the skin. Pacinian are also located in the intestines and the joints. The text gives some good illustration of the four different types so they are easier to distinguish.
Cutaneous sensations play into the tactile receptors. Cutaneous sensations are based on the stimulation of the skins receptors. When you cut your finger the skin receptors tell your brain something is wrong with your finger and it hurts.
The Somatosensory Cortex is the area of the brain where pain signals are sent. You hurt your finger and a receptor takes that signal to the dorsal root and into your spinal cord into your brain to an area of the parietal lobe, the somatosensory receiving area. When it’s here your brain can tell your body to move your hand away from the stove etc. Without this area of your brain you would lack motor functions.
4. I will definitely remember the phantom limb because I have a personal relation to the subject. I can remember how it works. I will also remember what tactile receptors are but most likely not the four different kinds.
1.) Phantom Hand/Kinesthesia
Somatosensory Cortex
Magnetic Source Imaging/Magnetoencephalography
Tactile Agnosia
2.) Kinesthesia can be described as determining the position and movement of our body parts and the neural processing of information of the sensations we feel. This relates a lot to the reader when it talks about research done with phantom limbs. People with phantom limbs have sensations in their body even when the body part is not there. Kinesthesia explains how the receptors respond to encode and understand information from the world around us when contact is made with our skin. Our bodies are made to connect with our sensory receptors so they can monitor the positions of our body parts so that our movements and actions can be controlled. This may not be done consciously, as characters in the book talked about, but are used in reflex actions as well as giving us an understanding of our posture, sensations of weight of force, motor movements, as well as identifying objects.
-----The Somatosensory Cortex can be found in the upper right (parietal) section of the brain. Information is sent to the Somatosensory cortex from the opposite side of the body. This cortex encodes its information through fibers that respond mostly to touch. The Somatosensory Cortex is the most important neural pathway from the skin to the brain. The Somatosensory Cortex is kind of broken down into sections. Parts of the cortex are devoted to parts of the body more than others. The parts that we use more often are controlled more closely by the Somatosensory cortex. The pharynx is first, then the tongue, teeth, lips, face, nose, eye, thumb, etc.
-----The reader talked some about the use of Magnetic Source Imaging. This was used to measure brain activity with precision with having to open the skull. This procedure can be related to Magnetoencephalography. Magnetoencephalography, also known as MEG, maps the brain’s activity through changes in the brain’s magnetic field, which is caused by electrical activity of neurons. Researchers use this technique to understand what sections of the brain respond the quickest or late and use that to trace the process of sensory processing.
-----Tactile means touch. The Tactile Agnosia is the loss of ability to recognize objects, people, shapes, etc. The book talked about how the sense of touch can allow for good things to help people. It talks about the production of Braille. The sense of touch can really hurt a person, but also can help people too. Louis Braille created a tactile pattern alphabet. This gave blind people the chance to break down what they couldn’t see, translation by touch. The alphabet, later to be known as Braille, was patterns of raised dots on paper. People were shocked at how fast a blind person could read, obviously with lots of practice. But this is the positive side to tactile sensations.
3.) Things that stuck out the most to me after my time reading was Tactile Agnosia. This would be such a terrible and eye opening sensation to not have. I never realize how important my sense of touch is, but this chapter opened my eye a little bit, by saying that your tactile sensations are almost as important as your visual system. Another thing that was surprising to me was the information talking about phantom limbs. Even though the limb is gone, you still have sensations in those body parts. I can’t even imagine what a feeling like that would be. You feel a sensation somewhere and when asked to point at the missing limb and realizing that you are feeling something that is physically not there, but your mind tells you it felt something there. It would be a constant battle between the mind and eye to understand what was going on.
1) Phantom Limb
Somatosensory Cortex
Tactile Agnosia
2) Phantom Limb- is defined in the reader as many amputees report that they experience pain in or feeling in the limb that was amputated. If the amputee lost a hand they report feeling water trickle down their hand, when water is trickled down their systematic map, which is a map of where the hand is on different parts of the body such as the arm or face. The text goes on to say that the exact cause of phantom limb remains somewhat elusive, but tells us a great deal about kinesthesia, pain, and touch and about perception in general. Often pain is perceived not only the feeling of touch. Phantom limb is one of the cases that led people to believe that our feelings of touch are constructed. The patient many times can feel their limb moving.
Somatosensory Cortex- is the section of the brain that is used in processing touch and related sensations. The reader describes this section of the brain as a systematic map of the body on the somatosensory cortex, and when a hand for example is cut off then they hypothesis two things happening either the section of the somatosensory cortex loses signal or the sections next to this section namely the face and arms pick up the signal and that is why a person who lost their hand will have their systematic map on their face and arm. The text describes the somatosensory cortex as the ultimate destination of information from the skin receptors through the spinothalamusic and lemniscal systems. It deals with skin and the sensations to temperature, warm and cold, and pain.
Tactile Agnosia- is the inability to recognize objects by touch. You still have the basic sensations that go along with touch but you cannot recognize the object by touch. This has a lot to do with people thinking that you construct all you feel. This goes along with the cutaneous rabbit. The cutaneous rabbit is a sensation that is brought on by taps on the arm it can elicit a rabbit hoping up the arm and can do this anywhere on the body. The cutaneous rabbit also has a lot to do with us discovering that feel is constructed. The text doesn’t discuss tactile agnosia, but it does discuss rapidly adapting receptions which are particularly good at picking up vibrations on the skin and slowly adapting receptors which are good at picking up constant pressure on the skin. These receptors have a lot to do with the cutaneous rabbit.
3) I will definitely remember the idea of construction of feeling. I haven’t ever thought about this before. I thought touch was a constant and even if our eyes lied to use our touch or feeling wouldn’t. So I found this extremely interesting and this will be the idea and concept that will stick with me from the text and reader in this chapter along with phantom limb, because this is where the idea got started.
1) Cutaneous system, somatosensory cortex, phantom, virtual touch
3) Cutaneous system: The skin is the heaviest organ in the human body. Our main experience with the skin is its visible surface. This consists of dead skin cells, called the epidermis. There are 4 types of mechanoreceptors that are located in the epidermis and the dermis. The Merkel receptor is a disk-shaped receptor located near the border between the epidermis and the dermis. The Meissner corpuscle is a stack of flattened cells located in the dermis, just below the epidermis. The Pacinian corpuscle is a layered onion like capsule that surrounds a nerve fiber. Located deep in the skin, it can also be found in many other places, including the intestines and the joints.
Somatosensory cortex: From the thalamus, signals travel to the somatosenory receiving area in the parietal lobe. The cortex is organized into maps that correspond to locations in the body. The body map is called the homunculus (Latin for "little man"). The fiber carrying signals from a receptor in the finger enters the spinal cord through the dorsal root and then travels up along 2 pathways: the medial lemniscus and the spinothalamic tract. These pathways synapse in the ventrolateral nucleus of the thalamus and then send fibers to the somatosensory cortex in the parietal lobe.
Phantom pain: After introduction of the gate-control model, researchers discovered an effect called stimulation-produced analgesia. This showed that signals from the brain can reduce the perception of pain. This occurs when electrical stimulation of an area in the rat's mid-brain causes the rat to ignore pinching of its tail or paw. Central factors influence pain perception is the discovery link between chemicals called opioids and pain perception.
4) For the first time, I actually preferred my text over the reader for this chapter. The reader did not explain things in detail like the text did. I liked the definitions and how the touch receptors work. I thought it was interesting that touch isn't constant, which I thought it was. If our eyes lie to use, our touch or feeling can too. touch Chapter 7 in the reader was basically about stories from other experiences and made no sense at all. Also, it was really short so there was no room to explain. I will remember the text more than the reader in this case. (There are really good pictures/examples in the textbook too!)
1) Topics Covered in Chapter 7 of the Donald Hoffman Reader:
Touch Construction
Phantom Hand
Somatosensory Cortex
Cortical Plasticity
Magnetic Source Imaging
Tactile Agnosia
Virtual Reality
2) Above Topics as Covered in the E. Bruce Goldstein (2007) Textbook:
Touch Construction – Just as with our visual system, we have a specialized somatasensory system that allows us to construct touch through processing our cutaneous (skin) sensations. This process is a very involved and complex orchestration, but essentially: Neural receptors in our skin, called mechanoreceptors, take information from our skin to our somatasensory cortex.
Somatasensory Cortex – Located in the parietal lobe of the cortex, the somatasensory cortex is the portion of the brain that manages touch perception. It is organized into maps that correspond to locations on the body. The map is called the homunculus, which is latin for “little man”. The homunculus, drawn visually, clearly demonstrates the proportion of brain areas for each body area dedicated to the sensation of touch. For example, the lips and hands cover some of the largest surface area of the homunculus map within the sensory cortex – and so our touch receptors are far more sensitive in these areas.
Phantom Limb – The phenomenon of a phantom limp is briefly mentioned in the book in that many people continue to experience a phantom limb after an amputation. This experience is often coupled with pain in the limb. While the relationship between a phantom limb and pain is not specifically brought to bear in the textbook, we do learn that the experience of pain is complex. It is influence by our senses and our emotions/affect, as well as our expectation, attention, and distractions (more on this in the virtual reality section below).
Additionally, from the reader, we learn that phantom limb is particularly relevant to cortical plasticity, the next topic I will cover…
Cortical Plasticity – Researchers have discorved that he cortical areas dedicated to touch are plastic, even in adulthood. This plasticity means that a larger portion of the cortical area is dedicated to perceiving touch in a particular way. This plasticity is generally beneficial to learning, but can also present problems. Plasticity is helpful when it allows organisms to dedicate learn more specialized skills for touch sensations – such as required for learning Braille, or fine motor skills such as needle point embroidery. Unfortunately it can also be disabling, as with rare instance of “musicians cramp” – where musicians brains fuse the fine motor areas together causing focal distonia – an inability to make skilled hand movements in the affected hand. This is also quite problematic when an amputee develops pain disorders because his Somatasensory Cortex fuses and overlaps the former hand areas with other areas - creating multiple maps of the missing limb on areas such as the upper arm, and even the face - so that the touch sensations of pain can become unresolvable.
Magnetic Source Imaging – The textbook does not cover this technique specifically, but it applies to cortical plasticity (above). And is discussed in the textbook as it pertains to the fusion of the cortical areas of the homunculus – where the brain areas that construct sensation for the fingers responsible for playing an instrument are shown fused together in a cross section of the brain causing the dystonic hand also known as “musicians cramp”. The figure in my textbook shows that the left side of the brain is fused, causing the cramp in the right hand, while the leaft side remains normal – but this disables the musicians critical hand for the playing of the instrument.
Tactile Agnosia – Tactile agnosia is the ability to recognize objects by touch. Though it is not specifically addressed as a form of agnosia in the Goldstein text, there is important discussion of primate studies which demonstrate specialized neural firing according to specific shapes of objects. For example, when a monkey grabs a ruler there is different neural firing than when the monkey grabs a cylinder. If these neurons were damaged or destroyed, such as in the case of a stroke (like that presented in the reader), then the money would no longer have the ability to recognize or identify the object, even though the damage would not affect the primates ability to feel the shape, texture, or even temperature of the objects.
Virtual Reality – In the Goldstein text, virtual reality is presented as a promising technique for pain management. In an experiment to help burn victims, subjects were given a virtual reality task that allowed them to shift their attention and reduce their pain in the process. The VR subjects reported significantly lower pain than a control group who played simple video games.
3) Most Memorable Aspects of The Topics Pertaining to Touch Construction:
From the reader, the most memorable illustration of touch construction was the case of E.C.’s stroke that caused her to be unable to recognize objects with her right hand, even though every other touch sensation was normal. This really does show that we are expert constructors, as it is assumed that sensation and recognition go together, when they actually do not!
From the textbook, the section dealing with pain was the most interesting and pertinent. I hope to take a chance to explore some of the cited articles and references contained at the end of this chapter, such as the articles dealing with the subjects of “pathological pain”, and “accepting pain as a way of dealing with it.”
1)-Somatosensory cortex
-tactile agnosia/tactual stereognosis
-cortical plasticity/touch localization
2) The somatosensory cortex is discussed in my text. I will relate tactile agnosia from the reader to tactual stereognosis from my text. I will relate cortical plasticity from the reader to touch localization from my text.
3) Somatosensory cortex: The somatosensory cortex is a sensory area in the brain. It is a cortical region and is responsible for receiving and processing touch and pressure stimulation. Different parts of your body have different nerve fibers that send information about touch to your somatosensory cortex. Places with more nerve fibers, like your fingers or lips, are represented by a larger part of the somatosensory cortex and thus more sensitive to touch.
Tactual stereognosis: Tactual stereognosis is the ability to accurately perceive 3D shapes by examining them with the hands. With many items, this seems almost effortless for us. Every day, I reach into my coat pocket for my keys. As soon as I touch them, I know they're my keys. I'm sure most people can give an example of their frequent use of tactual stereognosis unless they have a certain condition preventing this. That condition is tactile agnosia which was covered in the reader.
Touch localization: Touch localization is the ability to distinguish what point on your body pressure is being applied to. As already stated, different parts of the body feel touch differently. This means that you can't locate touch as easily in some places on your body than others. For example, stimulation of the upper arm, thigh, and back is harder to locate where as stimulation of your face is easier to locate. This relates to cortical plasticity from the reader. Cortical plasticity, in context, means that when a part of the body is amputated, the neighboring parts of the somatosensory cortex can take the place of that amputated part. That effects your touch localization in that you can feel things in your amputated limb by applying pressure to another specific part of the body.
4) The reader chapter was pretty short and interesting and I think I will remember basically the whole chapter especially phantom limb and tactile agnosia. From the text, I will remember what I just wrote about and pain perception and variability in pain perception.
1).Phantom limb
Somatosensory cortex
Magnetic source imaging
Cutaneous rabbit
Virtual Reality
3).Phantom limb: This is something that occurs after someone has a limb amputated. People feel pain in the limb that is no longer attached or the "Phantom Limb" The text explains this by saying pain is influence by factors other than tissue damage like emotions, stress levels, and expectations.
Somatosensory cortex: The text talks about this in relationship to brain function. Nerve fibers from the skin travel in bundles called peripheral nerves that enter the spinal cord through the dorsal root. They then taravel up the spinal cord to fibers that cross over to the other side of the body at some point and enter the thalamus. Then signals travel to the somatosensory receiving area in the parietal lobe in the cortex.
Magnetic source imaging: I could not find this in my book anywhere.
Cutaneous rabbit: My textbook talked about cutaneous sensations, sensations based on the stimulation of receptors in the skin. The cutaneous sensations are in the somatosensory system, which is the pathways that transmit signals generated receptors up the spinal cord toward the brain. These provide sensory experiences through the skin which are needing in vision, audio, touch, and other senses.
Virtual Reality – In the book virtual Reality is a technique for pain management. There was an experiment with burn victims in the book who used a virtual reality game to significantly lower thier pain that those who just played a regular video game.
4). I think I will remember virtual reality and Phantom limb because those things were the things that interested me the most out of everything.
1. Phantom limb
Tactile Aganosia
Somatosensory Cortex
Cutaneous Rabbit
Virtual Touch
3. Phantom limb- my text describes phantom limb as the phenomena that people who have had a limb amputated but still experience having the limb. People can experience this differently, as some perceive themselves as having the limb as normal, and having it swing with them as they walk, and some people’s phantom limb stays in the same position, as if it were paralyzed. The cause of phantom limb is not known exactly, except for that it is caused by the brain, and even though the nerves that transmit the messages from the brain to the limb are no longer there, the brain is still sending these messages. The somatosensory cortex’s reorganization after amputation is thought to play a role in phantom limb. When the arm is amputated, other parts of the body take over the neurons from that area to compensate for the lost limb. The rest of the arm as well as the face are next to the forearm in the organization of the somatosensory cortex and so these parts take over the neurons that are no longer needed for the amputated limb, but when one is stimulated, it also stimulates the phantom limb. This explains why people experiencing phantom limb can have their missing limb stimulated by touching their stump or parts of the face. One really interesting thing that the text brought up that supports the idea that the somatosensory cortex plays a role that I hadn’t considered is the fact that some people who are born without a limb still experience this phenomena. Their brain is still intact, but once they are born without the limb, the neurons designated for that limb are taken over by neighboring areas.
Tactile Agnosia – Tactile Agnosia is not specifically addressed in my text, but it did have a pretty good section on passive and active touch. Passive touch is when the person experiencing the touch is being stimulated by someone else. In other words, they are not in control of what/ who is touching us. We relate this more with something touching us. Active touch, the more common of the two for most of us, is when we control the touch stimulation for ourselves, or us touching something. We use haptic perception, or the perception in which 3D objects are explored by the hand, a lot more in active touch because we have control over the situation. The reader gave the example of digging for your keys and getting them out, without using sight, and when this happens, we are using our haptic perception. Our haptic perception is a complex system with three separate parts; the sensory system, that senses how the touch feels, texture, temperature, etc., the motor system which moves your hands and fingers over the object, and the cognitive system, to take this information given to it by the sensory and motor system and determine what the object is. With these systems working together, researchers have found that most people can identify the majority of objects within two seconds. Based on the reader, tactile agnosia is when the cognitive system is not working properly to determine, from the information provided by the sensory and motor systems, what an object is.
Somatosensory Cortex- My text gives two important characteristics of the somatosensory cortex (aka S2). These characteristics are that there are maps of the body on it and there are neurons on these parts that fire to the corresponding parts of the body. Not all body parts are equally represented in the somatosensory cortex, and this is because we need more neurons certain places to process details, like the fingers. I found a map online that shows this unequal distribution of neurons (http://employees.csbsju.edu/hjakubowski/classes/ch331/signaltrans/brain-homunculus.gif) Research has found that tactile object recognition uses the somatosensory cortex and also we have found that it plays a role in phantom limb, and when the limb is amputated, neighboring areas of the S2 take over the neurons from this area.
Cutaneous Rabbit- This particular experiment wasn’t discussed but the cutaneous sensation is. The text describes the cutaneous sense as sensing based on the stimulation of receptors in the skin. The skin is the heaviest and largest organ on the human body and is very important because it keeps our insides inside, and outside things from escaping. We use four different types of receptors based on the location of the receptor on the skin to feel the things that we do- the Merkel receptor, the Meissner corpuscle, the Ruffini cylinder, and the Pacinian corpuscle.
Virtual Touch- I couldn’t really find anything in my text about new technology that is coming out that is related to the sense of touch, but I do have a 2002 edition of Goldstein’s Sensation and Perception book, so the technology that was new at the time, we might be pretty familiar with now. I did find a pretty interesting article online on prosthetic limbs that can feel though (http://www.technologyreview.com/biomedicine/19759/). Basically, up until recent years, people with prosthetic limbs couldn’t actually feel what they were touching, but just knew when they were grabbing onto something by using their sense of sight. Researchers found that if you took the nerves from a hand and put them in the chest, the person could feel the sensations of the hand in his chest and they are using this knowledge to make prosthetic limbs more like the real thing. Also, it mentioned that if the person with the nerves implanted in their chest was touched on the chest, they felt it in their prosthetic hand. This is very similar to what we know about people with phantom limbs.
4. I think I will mostly remember what I have learned about phantom limb. Pretty much everything in the reader and the text tied back into phantom limb and why they think that it occurs.
1.Phantom Limb
Somatosensory Cortex
Virtual Touch
Haptic Perception
Tactile Receptors
2. Phantom Limb- The text describes the phantom limb as perceived sensation from a physical amputated limb of the body. There is a relatively tight correspondence between different body parts and the somatosensory area 1. This can produce massive side effects when a person has a limb amputated. If the left arm is missing, there aren’t any mechanoreceptors sending any signals for that arm, but sporadic activity can continue in the area of the amputees right S1 corresponding to the arm which leads to the perception of the Phantom limb. Patients with this perception tend to have their limbs in uncomfortable positions which cause serve pain. Psychologist Vilayanur Ramachabdran, found that people who have amputated limbs often times report that they feel sensations in the face and other active limbs. To look at the confusion of this, it can be traced to an indiosyncrasy in the homunculus. The hand and arms are areas of S1 in which they are invaded by neurons carrying information from touch receptors in the face. When these neurons get confused and mixed up they invade the cortex that normally processes the hand. This shows how some people feel a tingling sensation in their face when an amputated limb is present due to the neurons being mixed up. Due to the fact that the brain listens to the hand and arm, it isn’t fully aware that that there are altered connections. Therefore they attribute activity in these areas to stimulation from the missing limb.
Somatosensory Cortex- is an area of the brain which processes input from the various systems in the body which are sensitive to touch. People often think of touch as a single sense, but in fact several different sensory experiences are involved in touch, including specific sensitivity to pain, sensitivity to temperature, and the body's proprioception system which monitors the body's place in space. The somatosensory system is organized into a spatial map which lays out the skin often called the sensory homunculus. It is located within the postcentral gyrus, a structure around the middle of the cerebral cortex. Different areas of the somatosensory cortex correspond to input from different groups of nerve cells; the largest areas correspond to areas such as the face, which are highly sensitive. The somatosensory system as a whole is extremely refined and highly sensitive, allowing people to detect and interpret a wide variety of sensations. They have two areas which are used for receiving touch in the cortex. When part of the somatosensory system becomes impaired, people can experience loss of sensation. Impairments can happen at any level along the way, from damage to the sensory neurons in the skin to an injury to the brain which interferes with the function of the somatosensory cortex. When neurological problems which interfere with sensation are identified, a neurologist can conduct tests to determine the source of the problem so that treatment recommendations can be made to the patient.
Virtual touch- my text references virtual touch by talking about virtual haptic environments. It talks about what a virtual environment really is. This is when you a sensed by a machine and filtered through a program which creates a stimulated world. This causes new events and outcomes that are feedback to the user through vision and audition. There are devices used today that are capable of creating diverse objects varying in shape, size, surface texture and softness. The text talked about other ways a virtual environment can be useful. On being applying this to training for physicians who are engaging in invasive surgery. In a virtual environment the patient’s body is replaced with a dummy and the surgical tool connects to the computer that tracks the trainees’ movements. The computer contains a simulation of the patient’s body that describes the body structures and their properties such as slipperiness and softness. When it tracks the surgeon’s actions with the tool it determines the effect it would have on the simulated patient. I think this is very useful because this prevents the surgeons from practicing on us as humans.
Haptic Perception- is the process of recognizing objects through touch. It involves a combination of somatosensory perception of patterns on the skin surface. This term refers to perceptual processing of inputs from multiple subsystems including those in skin muscles, tendons, and joints. It talks about two ways in which touch is active. These are action for perception and perception for action. When we use our hand to actively explore the world of surfaces and objects outside our bodies this is an action of Perception. When we use our somatosensation to control our impressive ability to grasp and manipulate objects in a stable and high correlated manor and to maintain proper posture and balance, that is action for perception. This is done very well with blind people because the have to constantly feel around in a high correlated manor to read brail and to feel around with theit walking stick. The loss of the sense of touch is a catastrophic deficit that can impair walking and other skilled actions such as holding objects or using tools.
• Tactile Receptors- Tactile receptors provide the sensations of touch, pressure, and vibration. Distinctions between them are not well defined. Fine touch and pressure receptors provide detailed information about a source of stimulation, including the exact location, shape, size, texture, and movement. These receptors are extremely sensitive and have relatively narrow receptive fields. Crude touch and pressure receptors provide poor localization and information. Tactile receptors range in complexity from free nerve endings to specialized sensory complexes complete with accessory cells and supporting structures. There are at least six tactile receptors on the skin in which they are called by various names according to the text. Free nerve endings are sensitive to touch and pressure. They are situated between epidermal cells and have no apparent differences in structure with those of the free nerve endings that provide temperature or pain sensations. Root hair plexus is made up of free nerve endings to detect hair movement. Merkel's discs are fine touch and pressure neurons located in the lower epidermal layer of the skin. Meissner's corpuscles are fine touch and pressure receptors located in the eyelids, lips, fingertips, nipples, and external genitalia. Pacinian corpuscles are large receptors sensitive to deep pressure and to pulsing or high-frequency vibrations. They are found in the skin, fingers, breasts, and external genitalia, as well as in joint capsules, mesenteries, the pancreas, and walls of the urinary bladder. Ruffini corpusles are located in the dermis of the skin and are sensitive to pressure and distortions of the skin.
3. I would say I would remember the information about the phantom limb and how they feel sensations on their face. This is due to the neurons crossing each other. Also I could remember the study that was used to assess the phantom limb which was the rabbit study and vibrations. It would be very difficult to remember all the tactile receptors and the various terms for the Somatosensory Cortex. The concepts used by the reader to describe the phantom limb made it easier to understand the material than the text did. It also was a little easier read as far as the flow is concerned.
1) Phantom Limb
Somatonsensory Cortex
Virtual touch
Tactile Agnosia
3) "Pain can occur in the absence of outward stimulation." This is one of the first sentences in my textbook talking about phantom limbs. They say that for a majority of cases an outward stimulation is present. For example when a person hits themselves on the hand with a hammer. A phantom limb is a lot like this because if you touch a certain part on a persons body they are able to feel it on their phantom limb. They are able to construct where the limb is in their imagination when in fact it isn't there. However people are able to say if their hand is facing up or down and what finger is being touched at a certain time.
Somatonsensory Cortex - My textbook talks about how you can shock different parts of peoples somatonsensory cortex. Saying that if you touch a certain part you will feel a tingling, tickling, or numbing feeling in that part of your body. When doing this type of research they use a local anesthetic because the person needs to be awake to be able to tell you what is happening. The text also talks about the importance of the somatonsensory cortex and how it helps transmit signals from the skin to the brain and than to the visual system. Basically this is the product that helps us build up what we are touching in our brain. Its a key element to your hand eye coordination.
Virtual touch - The textbook I had didn't talk about the virtual touch at all so I looked m ore into the visual process. It talked a lot about how we focus light into our retina using our cornea and lens. This is the way that we are able to see and picture things in our brain. Virtual touch is more important dealing with actually using our hands to reach out and touch different things and make up what they are in our mind.
Tactile Agnosia - The book doesn't talk specifically about tactile agnosia but it does talk about something a lot like this, which is tactile acuity. Its when you take two points of a pen or pointer touch on a persons body and ask them to tell you if they feel one or two points. Its a way of seeing what different parts of our body are more sensitive to touch or feeling. Which is why on our back you could have two points touching your back 4 inches a part and still think it is only one point in your back. The most sensitive areas are a persons lips and their hands. Because both of these are key to touching hot or cold parts and helps us in dangerous times. For example a dangerous time could be picking up a cup of coffee and trying to drink it but realizing that it is to hot once it hits your lips.
4) The part that sticks out the most is the way people are able to feel a phantom limb. Also the amount of information that we have learned about phantom limbs is incredible because it is a tough area to try and study. The only people that are able to tell you how they feel at a given time are the people that do have missing limbs. Its also interesting to notice that different parts of the somatonsensory cortex are able to develop a feeling in something that isn't even there. Its also weird how someone can develop pain in a limb that hasn't been attached to them for years. The phantom limb and touching different parts of your body to make it feel like a hand that isn't even there feel present is very interesting.
homunculus
Phantom limb.
somatosensory cortext.
(this is not on there but I hope this relates arc reflex relates to anatomy)
mechanical limbs (resse monkey and robotic limbs)
homunculus (Latin for little man)is the portion of the organized into maps were sensations corresponed to portions on the body. (text Goldstein 2007)
somatosensory cortex that is broken into two different parts (S1 Dorsal in the parietal lobe that receives inputs from the ventrolateral nucleus of the thalamus. S2 is Ventral covered partly by the temporal lobe.) (text:Goldstein 2007)
Phantom limbs- Human Anatomy & Physiology Hoehn & Marieb (2007) states that perceived pain exist in the spinal cord that the amputated limb is still present, thus with that in mind future epidural anesthetics is need to block neurotransmitters reducing incidence of phantom limb. the sensation of pain is due to is no a limb that is no longer attached called Phantom Limb the psychological pain is influenced by factors other such as emotions', stress levels', and expectations that one may not have the ability to use effecting a person mentally, and spiritually. I remember in cognitive psychology we talked about Ramachandran tried studies on sensation with the person putting the limb in to a mirror box making the person think the phantom limb is really there and is moving as it reflex's the image of the other limb (hand, arm, knee, leg etc.) This bring use to the arch reflex the sensation starts by by putting pressure in the skin or a part of the body which starts or make the body react by moving to see the full threshold that one can withstand. the message is sent from the pressure point that leads to the reflex by way of the neurons such as the meissner and pacinian receptor cells.
For example limbs in the arm area, bionic limbs can be used by the connecting patches of electrodes to the surface of the skin. The nerves that are used which are connected our the ulner nerve, media nerve, and the radial nerve. the other thing i recall from congitive psychology is how science is breaking through in connect electrodes to the brain of monkeys and connecting the neural singles to moving a mechanical robotic arm, I distinctly remember that the resse monkey move the robotic arm with it mind or the electrical singles of the brain as it grabs on to the table, i thought it is amazing in how science is braking through as singles our being recorded to simulate the message.
i think i will remember the phantom limb, and how it functions, and the connection between the how the neurons function in creating movement as it continues to send messages to the brain by the gray matter in the spinal cord as well as the white matter which is the outer side of the spinal cord.
1)Phantom Limb
Somatosensory cortex
Virtual touch
3)Phantom Limb- Being able to feel your limb still, after being amputated. People that experience the phantom limb have the perception that their limb is still present. Some even feel pain at times, depending on how they are perceiving their limb,paralysed or movable. It is thought that people experience the phantom limb because of signal being sent to and from the brain. Different areas of the brain controll different parts of our bodies. When a body part isn't a part of our body anymore,the somatosensory cortex is reorganized. Sometimes when a different part of the body, such as the face, is touched the individual actually feels as though the limb is experiencing what the face is actual experiencing, even though it is no longer a part of the body. This can severely affect people's everday lives because of the miscommunication.
Somatosensory cortex- part of the brain that processes information dealing with sensations such as touch. When information is traveling through the brain it travels throught the thalamus first and then to the somatosensory area for processing. The text also states that there maps of the body on the cortex and that specific neurons fire to specific types of stimuli. Areas of our bodies that have good detail perception, such as fingers,have a larger area of the cortex representing and working for them.This cortex also plays a role in creating a phantom limb for amputees.
Virtual Touch-this term was not in my textbook, but it is something that is heard of more and more today. It is associated a lot with video games. With technology things, including video games, are becoming more and more realistic. One way that manufacturers do this is by virtual touch. They make joysticks and other control devices more interactive. They vibrate and move according to actions being made on the screen, during a game. For example, if you were playing a game where you were driving a car and went over bumps, you may feel vibrations going with the movement being seen in the video. It makes the gamer feel more like they are actually in doing what the video shows them doing. There are a lot of possibilities for new things to be done by using virtual touch in the virtual gaming world.
4) I think that I will most likely remember the information on the phantom limb. I had already know some information on the topic and the reader gave a few great photos of what happens when someone is experiencing the phantom limb. I will most likely not remember specific information on specific areas of the brain as much, because it isn't all that interesting to me.
Phantom Limb, homunculus, cutaneous rabbit
Phantom Limb- Where people who have had a limb amputated continue to experience the limb. This perception is so convincing that amputees have been known to try stepping out of a bed onto phantom feet or legs or to attempt lifting a cup with a phantom hand. For many people the limb moves with the body, swingin while walking. For other people the limb is paralyzed so it is fixed in one position, and it is also not uncommon to experience pain in the phantom limb. Some researchers believe that what causes the perception of the phantom limb is by cutting the nerves that formerly transmitted signals from the limb to the brain does not eliminate the phantom. This means that the phantom is not caused by signals that are being sent from the stump that remains after the amputation or from a remaining part of the limb. The most convincing fact is that people who are born without one or more limbs also experience phantom limbs.
Homunculus- My text refers to this term as the "little man". The homunculus shows that some areas on the skin are represented by a disproportionately large area of the brain. For example, the area devoted to the thumb, is as large as the area devoted to the entire forearm.
cutaneous sensations- The cutaneous rabbit was not discussed in my text, but cutaneous sensations was. These are sensations based on the stimulation of receptors in the skin. The cutaneous sensations are served by the somatosensory system. Many of the tactile perceptions that we feel from stimulation of the skin can be traced to the four types of mechanoreceptors. They are: The Merkel receptor,(a disk shaped receptor near the border between the epidermis and the dermis). The Meissner corpuscle (flattened cells located in the dermis just below the epidermis). The Ruffini cylinder (fibers inside a roughly cylindrical capsule). And the pacinian corpuscle (An onionlike capsule that surrounds a nerve fiber located deep in the skin).
I think that I will remember a lot of information about the phantom lims because that topic has interested me the most. I also found the homunculus very fascinating and had no idea that the area devoted to the thumb is as large as the area devoted to the entire forearm.
1) Phantom Limb, Somatosensory Cortex
3) The text’s definition of Phantom Limb is a person’s continued feeling of limbs that are no longer attached to the body. The areas in the brain are assigned to manage all parts of the body. When one of these parts becomes lost; the area assigned to the lost limb starts to get reassigned to other parts of the body. When the newly assigned areas are activated (from the new body part) the feeling of the old limb still exists. The sensation can be pain, warm, cold and even fell like its touching things.
The text’s definition of the somatosensory cortex is the area of the brain in parietal lobe that receive information from the skin and the somatic senses. The somatic senses are feelings of touch, temperature and pain. Information from the right side of the body is process in the left side of the brain and information from the left side is processed in the right. The text then explains how the entire somatosensory system works from sensation on the skin to brain processing and reaction.
4) The information that I will remember is probably that the information on the right side of the brain is processed on the left side and vise versa. The reason for this is because I have learned this information many times and tend to have not forgotten it. Another thing that I will not forget is that all of the senses are processed in the parietal lobe. I forgot about this and was happy to relearn the information.
After reading chapter 7 in Visual Intelligence make a mind map as you have been doing. Next post the following:
1) Phantom Limb, Somatosensory Cortex, and construction of touch.
3) Phantom Limb-These people not only experience the missing limb as still being present but may also report feeling pain in the phantom limb. Pain can occur in the absence of outward stimulation. Although outward stimulation is sometimes present, as when a person hits their finger with a hammer, pain can occur even if no external stimulus is present.
Somatosensory Cortex-This is located in the parietal lobe of the cortex. Certain signals and information is transmitted to the somatosensory cortex such as pain, or feelings of touch etc. The information from the right side of the body and information from the left side of the body cross over and are transmitted to the somatosensory cortex.
Construction of touch-In the text it talks about how Gestalt psychologists are interested about how perceptions are constructed to the mind. It talks about how the mind processes touch through the mind and that if we touch something, our mind is the first to process the reaction of the feeling rather than our skin/visual system etc.
4) I will most likely remember the information about the phantom limb because I've come across that phrase a lot, and have a fairly good understanding of it. However; the technical information of the somatosensory cortex I will most likely not remember because it is so technical and such a complex phenomenon.
1) Phantom limb syndrome. Phantom Maps. Somatosensory ‘maps’. Construction of touch.
2) Ok
3) The book just barely mentions phantom limb syndrome specifically, however the rest of the main points discussed in the reader more than make up for this. A note at the end of the chapter simply explains that some people experience pains in limbs that have been lost or amputated. However, the rest of the information in the text more than explains how this is possible, and what is going on.
Phantom maps as described in VI are basically points on the body which when stimulated, systematically produce sensations in the missing limb. The text discusses the somatosensory maps in great detail, but plasticity in the brain gives the best description of phantom limb map’s from VI. We can imagine a brain that is used to getting lots of stimulus to areas of the hand and lower arm. After amputation just below the elbow the area of the part of the brain no longer get’s stimulated and thus the cells begin to die. Jenkins and Merzenich (1987) found that stimulating a specific area of the brain causes that area to expand. This type of plasticity causes the areas surrounding the now un-stimulated areas to move into their territory. The somatosensory maps explain why the various locations on the body which cause sensations in the phantom limb do so; viz. the face and upper arm surround the hand and lower arm sections so these are the areas which ‘creep in’.
The somatosensory maps were first documented around the 1950’s. Researchers found that stimulating various parts of the somatosesory cortex produced various sensations around the body. It was then a simple matter to make a map which placed the parts of the body that are stimulated onto the areas of the brain which stimulate them. Several common sense findings were found. We have large areas of the brain dedicated to face, lips, and hands, some of the most important parts of the body for experiencing and interacting with the world around us. Conversely the torso, thighs, and arms have a relatively small area of the brain for the same reason. Later findings uncovered that there are numerous maps in S1 and S2 areas of the brain and that due to plasticity of the brain they can fluctuate.
All of this information lends itself to the overall idea of how it is that we construct what we touch. Early experiments in psychophysics demonstrated that various parts of are body are more sensitive to stimuli than others by pushing two points close together on various parts of the body. The distance between the two points necessary before you recognize that it is two points (the two point threshold) is smaller for more sensitive parts like lips and hands, further apart for less sensitive parts like shoulders or your back. At the beginning of the chapter they discuss the four types of cells in the skin and these four cells transmit different information to the cortex. Just like with vision our minds take in all the different information and construct our experience based on rules.
When we grip onto a small ball with our hand we are given an ambiguous stimulus. Receptors in our hands individually provide us with information that the object is smooth, round, hard or soft, etc. Various neurons in the brain have become specialized to detect particular types of details in the environment whether it’s vibrations, texture, etc. Ordinarily all of this information is in addition to visual, olfactory, and auditory sensations so the whole process seems to be automatic. But when we cut off other senses we see that we must ‘actively touch’ all around the object to figure out what it is. We must construct the object out of the individual sensations our body experiences.
4) I really enjoyed the information about the phantom limbs and the somatosensory maps so I think I will remember this pretty easily. Also the more general information about different cells in the skin recognizing different aspects of touch, and similarly for neurons in the brain.