Tuesday, July 30, 2013

Neurological Perception and Errors of Vision

Apophenia, the "unmotivated seeing of connections" accompanied by a "specific experience of an abnormal meaningfulness", but it has come to represent the human tendency to seek patterns in random information in general (such as with gambling), paranormal phenomena, and religion.

Pareidolia is a type of apophenia involving the perception of images or sounds in random stimuli, for example, hearing a ringing phone while taking a shower, images of animals or faces in clouds, etc.

Now a few examples of the above are as follows (Respectively):

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn’t mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

FINISHED FILES ARE THE RE
SULT OF YEARS OF SCIENTI
FIC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS…

What this means is that our brains rely more on context than on detail.  We derive meaning from patterns, such as language, by interrelating common characteristics and applying them to previous experience, resulting in unique interpretation of characteristics that may be historically similar, but are contextually independent.  But in the case of language, we have cause to find meaningful patterns in what may sometimes seem like complete chaos.  Language is, by definition a static pattern of visual, auditory and (most importantly) conceptual characters.

Now how is it related to Scoptoma. It’s a phenomenon when the eyes sees what the mind believes, more like the mind sees what it wants to see. So its safe to say that its not about the complex involvement of cognitive function but just the projection of an idea of our mind into our mind through the eyes.

But what is Scotoma then. Its another name for blind spot. Its the are of our retina which is posterior and medially located, from which the optic nerve arises, called as optic disk. Its named so because it lacks the receptors of light and colour. But we dont see a spot (except pathologically) in our field of vision, because the brain fills up the area in our perceptual area by arranging what could have been present. Most of the time we know what would be there without noticing, so our cortex turns it into an virtual reality.

Inattentional Blindness is an inability to perceive something that is within one's direct perceptual field because one is attending to something else. This is because perception is an limited and confined process though the stimuli are multiple at the same time. More the attention towards an particular event or events is paid, the lesser attention is towards the surrounding environment. In short, cognitive attention is towards something upon which more concentration is held. Hence this is also categorized into Cognitive Blindness.

Tuesday, July 16, 2013

Neuropsychiatry of Love


Why do we search and try being in relationships. Most of the psychiatrists say our brains are hard wired for intimate and meaning for connections with someone, hence we long for love. Reality is that it lands us in heartache and leave us either bruised or shattered. But still we try playing those odds and keep trying to get the right one. When we find the right person, yeah all the past wounds are healed, even if the relation isnt completed, even the heartfelt memory is goanna support us for rest of our lives whenever we are truly and completely alone.

So what I wanna tell now is, how is love and its effects neurologically related. Upon encountering someone that we like, they have influence over our synapse and neurotransmitters, leading to attraction, arousal, even into obsession. Now these are triggered by our continues thoughts on them, making an neurological picture of them, their thoughts, behavior. Now when we meet them in person again, our mind's map of them and their actual self vary. So question arises, do we fall in love with the person or do we love the inception of them into us which grows in our minds through time?

Following are the neurological aspects of Physiology of Love:
(These are a few aspects which as a combine, play their role in establishing this feeling)

Internal model also referred as mental model, an representation of an reality, in this case a person, in our minds. This works in this way; when we think about them all the time, we build up an internal model, an simulation which helps us predict whats gonna be their thoughts, whats their reaction towards an event or word and their feelings.

Feed forward stimulation, is a method usually used in teaching and learning where few illustrations are used for future learning and also an goal directed state of teaching, so that these are made interesting. Now best example is, to show a movie trailer to audience which could serve this purpose. Hence as a result, a person would have his own idea and structure build within his mind about that concerning thing. In fields of Behavioral and Cognitive Science, its called as "images of adaptive future behavior" or "mental time travel". In this case, it has major role in projection as love, where it prepares a mind to various outcomes, the way one has to behave and above all how to handle a particular situation during conversation. So depending on these, people judge on how charming and witty one is. Apart for that, a focus towards the goal, the ideas for that goal and the actions, hence the outcome, all these are served by this neurological process.

Error signaling and post error adaptation, this is other neurological phenomenon which is useful to maintain goal directed behavior in changing, challenging and distractive environment, where one needs to focus as well as continuously monitor ones on performance and adjust it in cases of unfavorable out comes. This is another most important process involving self assessment and surveillance of once state of mind continuously.

Temporal difference (TD) learning. This has a bit less importance, but is useful again as prediction method by sampling the environment where prediction is adjusted by supervision of observation. Example, when you are wooing a girl, its only a matter of time you will know if she would accept or reject you, so to change the outcome you depend on situations where its positive, like music, etc. which you dont plan but as per surroundings you behave or change and hence changes the outcome.
And lastly an endocrine importance in the love. Oxytocin, a mammalian neurohypophysial hormone that acts primarily as a neuromodulator in the brain which plays important role in sexual reproduction, released by the pituitary gland notably during orgasm and childbirth. It increases empathy and communication, key to sustaining a relationship between people and promotes social attraction which helps being appealing.

So as I was saying earlier, what can be love, and how would you define it as? But what if its not just their projection is what thats attractive but instead our projection about them attracts us?

Saturday, July 13, 2013

Basics of Neuroplasticity.



What is an abnormal brain? And how can it effect someone's behavior. Can it turn someone into an lame or monstrous ways. Or it would more likely manifest in some less dramatic ways. Some abnormalities are structural, showing up in scans or autopsies. But most of them are sneakier ones, mostly insidious, which are neurochemical in nature so we dont know if they are there. Few of them are treatable by surgeries, few by pills, but most of them arent actually manifesting in such that others can notice.

Now what I wanna say about is, do people really change? Is personality genetically pre programed or its shaped by oneself?

For example see how memory works in an average person, the things you see or experience remain longer if you keep reminding them. This makes the neuron circuitery active and when required its on its potential always. In the same way the everything we learn, experienced, these have greatest influence.

The science of Neuroplasticity suggests that our brain can change and grow (neuronally speaking) throughout out lives, our experiences rewire us, they can make us think or do things previously unthinkable, provoking us into forming new thoughts and ideas, teaching us valuable lessons making us less inclined into making the same mistakes of past. The brain is a constant state of flux suggesting nothing in life is permanent.

Neuroplasticity refers to changes in neural pathways and synapses which are due to changes in behavior, environment and neural processes, as well as changes resulting from bodily injury. It occurs on a variety of levels, ranging from cellular changes due to learning, to large-scale changes involved in cortical remapping in response to injury.

One of the fundamental principles of how neuroplasticity functions is linked to the concept of synaptic pruning, which is an neurological regulatory process, by reducing the overall number of neurons and synapses, leaving more efficient synaptic configurations. So individual connections within the brain are constantly being removed or recreated, largely depending upon how they are used.

Other principal involved is, if there are two nearby neurons that often produce an impulse simultaneously, their cortical maps may become one. This idea also works in the opposite way, i.e. that neurons which do not regularly produce simultaneous impulses will form different maps.
NMDA (N-methyl-D-aspartate) is the name of aselective agonist that binds to NMDA receptors, aglutamate receptor, is the predominant molecular device for controlling synaptic plasticity and memory function.

Long-term potentiation (LTP) is a persistent increase in synaptic strength following high-frequency stimulation of a chemical synapse. Synapses that have undergone LTP tend to have stronger electrical responses to stimuli than other synapses and lasts a very long time compared to other processes that affect synaptic strength.

Long-term potentiation (LTP), which is an increase in synaptic strength, and long- term depression (LTD), which is a decrease in synaptic strength. After only minutes of synaptic activity, there can be changes that last hours or are relatively permanent. The molecular and cellular biologies of LTP and LTD are being intensively studied, and a fascinating set of cellular processes have been discovered, which are triggered and regulated by the influx of calcium at the active synapses. It is important to recognize as well that a decrease in inhibition will facilitate changes in synaptic strength, and this links unmasking to LTP and LTD.

Understanding neuroplastic mechanisms allows us to recognize how the brain tries to repair itself. Several important principles emerge:
1. Body parts can compete for representation in the brain and use of a body part can enhance its representation. Representation areas increase or decrease depending on use. A body part is represented in various areas of the brain, both motor and sensory. The sensory representations are those that are active when sensory stimulation of that body part occurs. The motor representations are those whose activity produces movement of that body part. Representations can be determined with many techniques, including TMS and neuroimaging. A body part is not used, its representation area shrinks. For example, the representation area of the tibialis anterior is smaller after the ankle is immobilized in a cast for several weeks. In case of a stroke that damages a body part representation in the primary motor cortex, plasticity permits some reorganization that will restore a representation. This process must be competitive with all the body parts.
2. The premotor cortex can substitute for the motor cortex to control motion. While the primary motor cortex has the largest and most powerful contribution to the function of the corticospinal tract, the premotor cortex also contributes. We know, from both anatomical and physiological studies, that there are contributions of the premotor cortex to the function of the corti-cospinal tract, but stimulation thresholds of the pre-motor cortex are higher than that of the primary motor cortex. So, while the main output of the pre-motor cortex is ordinarily to the primary motor cortex, the premotor cortex can also be the source of supraspinal control signals.
3. The contralesional hemisphere can take over motor control if all else fails. Although rather weak in humans, there are ipsilateral, corticospinal neural pathways. Although these pathways innervate many more proximal than distal muscles, they can be documented in normal humans, even in distal muscles, with the use of TMS. Such pathways are necessarily involved in recovery of patients with hemispherectomy. Although controversial, these pathways may possibly be relevant in stroke recovery. Another possible role of the undamaged hemisphere could be its interactions with the damaged hemisphere; there are transcallosal connections that are not completely characterized. Some of these transcallosal connections are inhibitory, and improvement might occur if these connections were themselves inhibited. Functional magnetic resonance imaging studies show that the damaged hemisphere has increased blood flow when bilateral movements are made; these data are consistent with the idea that activity of the undamaged hemisphere might support the damaged hemisphere. Another possibility is that the ipsilateral hemisphere helps with activity of the premotor cortex rather than the motor cortex itself.
4. Neuroplastic mechanisms can be facilitated and this is a good basis for intervention. Intensive, focused physical therapy should help restore motor function, and evidence shows that the earlier and more intensive the therapy, the better the outcome. This concept has been most fully demonstrated by the multiple successes of constraint induced (CI) movement therapy. This method forces patients to use the hemiplegic limb by constraining the good limb.



Investigations thats applied for these are, Motor Cortical (M1) plasticity with transcranial magnetic stimulation (TMS),Non-invasive brain stimulation (NBS), Repetitive transcranial magnetic stimulation (rTMS), and a few more.

Tuesday, July 9, 2013

Prosopagnosia; Face Blindness

Prosopagnosia, prosopon means face and agnosia means not knowing, also called face blindness. Face blindness is a brain disorder characterized by the inability to recognize faces.



It is thought to be the result of abnormalities, damage, or impairment in the right fusiform gyrus, a fold in the brain that appears to coordinate the neural systems that control facial perception and memory.



Face blindness can result from stroke, traumatic brain injury, or certain neurodegenerative diseases which can be of congenital reason as well. It is a disorder of face perception where the ability to recognize faces is impaired, while other aspects of visual processing (e.g., object discrimination) and intellectual functioning (e.g., decision making) remain intact. Prosopagnosia has also been associated with other disorders that are associated with nearby brain areas: left hemianopsia (loss of vision from left side of space, associated with damage to the right occipital lobe), achromatopsia (a deficit in color perception often associated with unilateral or bilateral lesions in the temporo-occipital junction) and topographical disorientation (a loss of environmental familiarity and difficulties in using landmarks, associated with lesions in the posterior part of the parahippocampal gyrus and anterior part of the lingual gyrus of the right hemisphere).

Prosopagnosia is not a unitary disorder (i.e., different people may show different types and levels of impairment), it has been argued that face perception involves a number of stages, each of which can cause qualitative differences in impairment that different persons with prosopagnosia may exhibit. The prototypical face has a specific spatial layout (eyes are always located above nose, and nose located above mouth), it is beneficial to use a holistic approach to recognize individual/specific faces from a group of similar layouts. This holistic processing of the face is exactly what is damaged in prosopagnosics. They are able to recognize the specific spatial layout and characteristics of facial features, but they are unable to process them as one entire face.

Types:

Apperceptive prosopagnosia has typically been used to describe cases of acquired prosopagnosia with some of the earliest processes in the face perception system. The brain areas thought to play a critical role in apperceptive prosopagnosia are right occipital temporal regions. People with this disorder cannot make any sense of faces and are unable to make same-different judgments when they are presented with pictures of different faces. They are unable to recognize both familiar and unfamiliar faces. However, they may be able to recognize people based on non-face clues such as their clothing, hairstyle or voice.

Associative prosopagnosia has typically been used to describe cases of acquired prosopagnosia with spared perceptual processes but impaired links between early face perception processes and the semantic information we hold about people in our memories. Right anterior temporal regions may also play a critical role in associative prosopagnosia. People with this form of the disorder may be able to say whether photos of people's faces are the same or different and derive the age and sex from a face (suggesting they can make sense of some face information) but may not be able to subsequently identify the person or provide any information about them such as their name, occupation, or when they were last encountered.

Developmental prosopagnosia(DP) is a face-recognition deficit that is lifelong, manifesting in early childhood, and that cannot be attributed to acquired brain damage. It has been suggested that a genetic factor is responsible for the condition. The term “hereditary prosopagnosia” was introduced if DP affected more than one family member, essentially accenting the possible genetic contribution of this condition. There are many developmental disorders associated with an increased likelihood that the person will have difficulties in face perception, of which the person may or may not be aware. The mechanism by which these perceptual deficits take place is largely unknown. A partial list of some disorders that often have prosopagnosiac components would include nonverbal learning disorder, Alzheimer's Disease, and autism spectrum disorders in general.

There are few neuropsychological assessments that can definitively diagnose prosopagnosia. One commonly used test is the famous faces tests, where individuals are asked to recognize the faces of famous persons. However, this test is difficult to standardize. The Benton Facial Recognition Test (BFRT) is another test used by neuropsychologists to assess face recognition skills.

Monday, July 1, 2013

A few Doctors to remember on the Doctors Day, for their contributions to make the world a Better Place.


On this day, July 1st being Doctor's Day, I would like you to have a look at the nine famous names to grace the medical profession and their achievements is short.


1. Christiaan Barnard. The South African physician served as a cardiothoracic surgeon at Groote Schuur Hospital in 1958, where he established the hospital's first heart unit. He had been experimenting for several years with animal heart transplants after he performed the first successful kidney transplant in South Africa in 1959. following the first successful kidney transplant in 1954 — Barnard performed the first kidney transplant in South Africa in 1959. Assisted by Dr. Michael DeBakey, he performed the first heart transplant in 1967. The operation lasted nine hours, and required a team of thirty people.
2. Sigmund Freud. The Austrian neurologist is renowned for inventing modern psychoanalysis, and for his groundbreaking theories of sexual symbology, dream interpretation, and the unconscious mind. He’s less well know for his career as a neurologist – he was one of the first doctors to research palsy, publishing several medical papers on the subject. Freud also believed that cocaine was a virtual cure-all, and prescribed it as a stimulant, and antidepressant, and as a cure for morphine addiction.

 3. Emil Theodor Kocher. Winner of the 1909 Nobel Prize for his work involving the thyroid gland, he founded the Kocher Institute in Berne, Switzerland. He was a pioneering researcher, and published works on antiseptic treatments, surgical infectious diseases, gunshot wounds, acute osteomyelitis, the theory of strangulated hernia, and abdominal surgery. Kocher has several instruments and surgical techniques named after him, as well as Kocher-Debre-Semelaigne syndrome.

 4. Benjamin Spock. Was the first pediatrician to study psychoanalysis as it relates to children's needs and family dynamics. After hundreds of years of child rearing that stressed discipline and obedience, Dr. Spock’s theory that parents should be more affectionate with their children and to treat them as individuals was groundbreaking, no matter how obvious it seems today.

 5. Oliver Sacks. Author of a number of popular books about his patients, the British neurologist writes very entertaining, anecdotal books that go light on the clinical details and long on the personal memoir. His most famous books are “Awakenings” (which was made into a movie starring Robert De Niro and Robin Williams) and “The Man Who Mistook His Wife for a Hat.”

6. Frederick Banting. With diabetes on the rise today, people should thank Banting on a regular basis. He, with the help of Dr. Macleod, discovered the use of insulin in the treatment of the disease.

 7. Charles F. Drew. Anyone who has ever required a blood transfusion should have great respect for Drew. An African-American doctor, his research helped improve the way we store blood, which, in turn, helped us to create the necessary blood banks for World War II. Moreover, Drew argued that blood should not be separated by donor color in blood banks.

 8. Orvan Hess. An antibiotic pioneer, Hess with another doctor successfully treated the first patient with penicillin. He went on to create a fetal heart monitor to better monitor pregnant women. His design is still the basic one used in OB units today.

 9. Joseph Lister. For years, doctors couldn't understand why wounds became infected after surgery. Lister completed a huge body of research on how infection is created, and designed many of the hygienic procedures used in hospitals today to keep infection rates to a minimum.