Hemispheric lateralisation (Week 7)

This weeks lecture was about the hemispheric lateralisation of the human brain. The human brain is divided in two parts, the right and the left hemisphere, connected by the corpus callosum. Both hemisphere structures are identical to each other, however their functions are managed in different terms. It can be identified that the right hemisphere is dealing with judgement and decision making, such as including the age,spatial skills, facial properties and is also involved in contextual language and numerical computation (e.g. estimation and number comparison). Whereas the left hemisphere has been identified as a less inferior part on vocal tasks, on how our speech develops, the processing of speech and grammar/vocabulary. Today knows as Broca's area, that was found in 1861 by Pierre Paul Broca who distinguished after his patients death that because of syphilitic lesions in his left hemisphere the speech production of his patient could never develop. Later theories about the asymmetry of the brain has brought attention towards the brain lateralization that explains why most people are right handed and less are left handed. Studies on split-brain patients have been done which shows that when looking at something, the right hemisphere is active and the information, travels to the left side to pursue language and patients correctly identified what was on the screen. Now when information was presented to the left side of the hemisphere, the information travels to the right side of the brain, which does notch control language, and that proved that patients could not identify the object presented correctly.  So it seems like that split-brain patients have two brains, which is for us one brain with both sides different functions, seems for those patients more like two different systems not working together, and can deal with task separately and in different ways.   

This picture just shows the brain split into two parts and makes clear how the left hand side is responsible for information given on the right and how the right hemisphere deals with processing on the left. 

During the seminar this week we learned about the experiment that was based on Levy, Heller, Banich, & Burton (1983) first experiment, which is now replicated by  Rueckert (2005). I did the experiment myself and found that when being presented with the two chimeric faces, i had to press a key for which i thought was younger or older. Without even knowing which one to pick, unconsciously i pressed one key. The truth was that the two chimeric faces were always the identical mirror images of each other. So I gained a 100 % certainty when picking the image, my left hemisphere was working and i am right handed.  

Emotion (Week 6)

Emotion, a quit simple term but hard to define. In this weeks lecture and seminar we discussed the different characerizations of emotions and how humans get emotional. Many previous done research suggests that the amygdala is responsible for our emotions (Adolphs, 1999). The amygdala is a small part of the hippocampus that takes in information that is provided by our senses and experiences from the outside world and  processes these information. The amygdala is linked to the higher cognitive processor  and the lower cognitive processor, also know as hypothalamic and brainstem systems. It can be said that based on all the cognitive functions the amygdala has been given, a emotional reaction is the outcome. However it can still be argued that the amygdala is not the only important system that is related to the retrieving and processing of information for our emotions. The additional reading i did for this week, Adolphs (1999) also suggested that the amygdala is responsible for decision-making and the dealing with memory. 

Information retrieved from: 

Adolphs, R. (1999). The Human Amygdala and Emotion. Neuroscientist, 5: 125

A very good video that helped me to understand the different theories on how our emotion is retrieved and processed in the brain:

http://youtu.be/ozQN3jVUHGM

In the seminar, we did a fantastic experiment on emotion. Viewing some pictures of faces, that showed an emotion and afterwards stating what emotion that was. It was really interesting to to such experiment, which i had never done before. afterwards we discussed the gambling task, which we had to perform before too. The gambling task, and so was about that there were four deck cards and you were asked to make the most money by choosing in each round one card, however some of the cards also carry a negative outcome, like 50 US Dollars minus the money you had already gained. after a while I did notice though that if you either press A or C you gain money and if you press B or D you would loose, yo automatically, because i want to win, kept on pressing A, which made me very happy. The outcome of this experiment, which had been replicated by a few researches showed that decision-making is an important process of emotions, either conscious or unconscious. It can be argued if emotions are necessary to make such decision or decisions in general or if it would be better to see everything from the outside and have no emotional response to things at all.

Movement Disorders (Week 5)

The human movement is the basic framwork of the prefrontal and premotor cortex. Different routes in our brain are responsible for diverse actions that create control of thought and cognition. Movement is controlled by our spatial reference frame that involves knowledge about the location of the body in space and of course about the object you are paying attention for, such as grasping for a pen, your eyes focus on the object, your hand reaches out and makes the correct hand movement to grasp for it, this process is also called as sensory-motor transformation. Our premotor areas, are mainly dealing with internal and external events from our day to day life, also involved in specific goal targets, also called achievement, these are lying to the back of the prefrontal cortex. The prefrontal cortex is occupied with tasks like planning and decision-making, paying attention and deals more with general actions than object specific. The occipital lobes is involved with our visual system, where projections from the retrina are received where different types of neurons provide certain information for colour, orientation and motion. Two important pathways are responsible for our conscious information, the dorsal stream transmits to the to the parietal lobes and identifies where objects are located and the ventral stream provides information to the temporal lobes and categorizes what objects are. If damage to the ventral stream has occurred, visual agnosia can develop and also impairment in identifying objects, colour etc is highly likely. Another form of damage are movement disorders, that occur due to damage in the left hemisphere in the brain and cause physical impairment of movement, like gestures and grasping. If there has been damage to the Basal Ganglia, impairments in movement are expected. Different disorders are Parkinson’s, Huntington's and apraxia. Research has found that most patients with practical and dissociative impairment deal with more than one symptom, and it can also be said that that when a patient deals with more indications of the illness it might be quit mysterious how these come together, such as walking problems, twitches and uncontrollable arm movement called tremor. 

This model of movement disorders I'll find enormously helpful, to identify, of what brain area the disorder comes from  and also the yellow and red markings help to understand which ones are "positive" and "negative. Whereas positive and negative are the wrong terms to use, as its too extreme, all disorders are negative, however some have further damage than others.  

For the movement disorder, Parkinsons Disease what mainly affects elderly people, I have found a really good and interesting article by BBC, which made me smile today. I felt that even within all these sad disorder theories, a surgery of an elderly man with parkinsons disease was successful and he has 95% of his life back:

                       http://news.bbc.co.uk/1/hi/england/south_yorkshire/7243974.stm

I also have found an interesting page towards functional movement disorders, that support people with the disorder and help to adapt to the real world, as psychological seen some patients believe that the disorder develops as they would have done something wrong in their life, which is not true. 


    http://www.neurosymptoms.org/#/movement-disorders/4533053142


I have read the paper about, "Abnormalities in the awareness of action" by Blakemore,Wolpert and Frith (2002). A particular model was designed to establish motor learning and control in individuals to identify which parts of our motor control are responsible for the human awareness. It has been found that individuals not always have conscious motor control of things. Such as picking up a pen, you are targeted towards the pen, and already make the correct hand movement, grasping for it. So you are consciously aware for that but unconsciously there goes far more work into one movement, like strengthen and loosing your muscle tone. Abnormalities in movement are described as a dismissed control of action. One of the abnormalities is called "optic Ataxia", I´ll find that one a slightly confusing as i thought the patient would not be able to see the object properly, but actually the subject has problems grasping the item, so the individual can see quit good, just cannot focus completely on the object. However that does not mean if you character wise a bit clumsy that you have a disorder. Another abnormality, I´ll find quit fascinating is the "utilization behavior" which means that patients use some objects at the wrong time, like it is raining outside and the patient wants to wear its swimming costume, which obviously is not really wrong but in that moment, it would be used inappropriately. However there are some other abnormalities that are being discussed in the paper and i have also read some more about them, I do feel that the model itself and topics addressed by the researcher are sometimes controversial, as not enough evidence has been found to what circumstances does our awareness becomes more central for the model, to conclude the paper, I feel that some more research has to be done and belief that neurological and psychiatric factors have to be more systematically evaluated to complete the model to understand the main principles of motor control and awareness. 

VISUAL PERCEPTION (DISORDER PART 2)

Spatial neglect also talked about as unilateral spatial neglect or hemi-inattention, that is a seizure to failing respond to events in the hemifield contralateral to a previous happened damage to the brain. The more common one of neglect is the visual neglect, which occurs to most patients after having a stroke. Patients tend to see only half of the world, depending on where in the brain the lesion is, e.g. the patient does not acknowledge the left side of the world, as he has right hemisphere damage in his brain. 

This is a classic example of a "copying" and
"spontaneous drawing" task by a patient with visual neglect
of the brain. In the copying task, it shows clearly, the denial
of the left world, and even in the spontanious drawing
task, the patient ignores the fact that there is a left piece to
his drawings.  

Patients that have spatial neglect “ignore” the other half of the world in a way that many experiments on measuring eye movements, line bisection, where the patient is asked to place a mark  in the centre of a straight line, here it is assumed that the patient with neglect, moves either more to the right, or when the lines are vertical, the patients drawings tend to move away from the body. Another experiment that has been done was, where the patient was asked to find all the Ts within a letter mix of Ts and Ls. The patient with the neglect on the right side does not know that the left side even exists anymore. Interesting is also the anatomy of the neglect as I believe that the parietal lobe not always played a critical role in human life. Research suggests that the parietal lobe actually nothing to do with the spatial neglect, researcher are more concerned with the temporal lobe and also focal lesions of the right inferior frontal lobe can lead to spatial neglect, therefore it can be said that the biological theories on where neglect actually takes place are controversial. Tests have been done on monkey’s brain that revealed that direct attention and eye movements to a three-dimensional target are linked with neuronal responses due to their dorsal visual stream, which is part of the parietal cortex that can be critical towards spatial action and vision, the same is expected in human individuals where lesions of the parietal cortex can be related with spatial deficits. Neglect is modulated. There is complexity of the visual scene and patients with lesions in their right hemisphere also have weakened recognition on their right side. 

In terms of the deepness of the hemineglect, there also dysfunction of memory in patients, where the patients where asked to look at a map from the cathedral in milan and describe what they see when looked at the front of the church, patients only described the right part of the map, then when the examiner turned the map around and asked the patient to describe what they see by looking at the cathedral from the back, they also described the right part, which i think is quit funny in terms of that, that is the actual side their brain " abandoned" before and never acknowledges that, that side even exists. also what i just realised, when a patient has a neglect for the left side, what happens when the patient would turn its head, wouldn't he than see what he actually missed the whole time, or is it like a circle that even though he does turn, his view on the world and what exists and what doesn't exists stays the same?  

Visual Perception (Disorder Part) Week 3

This week we evaluated the functional specialization of the brain and if our mind moves before our eyes do regarding the article by Treue and Martinez (2003). There are two main pathways that deal with our visual perception, the Parvo pathway deals with color and detail, such as what is this object i am holding, what type of color is it, so we know the definition of objects and faces too. also called object perception, lesions on that pathway can relate to visual agnosia. The second one is the Magno pathway, which deals with motion, we know through that how to navigate and also seen as the where pathway. Problems on this spatial perceptions pathway are optic ataxia, which are mutations in reaching and grasping. People with brain lesions, cannot put the name towards an objects straight away. Injury or mutation that is related to one specific part of the brain, affects the process of storing and releasing information. different experiments have been conducted to track exe movement, measuring the suppression in our visual system. These also record fixation, as when the participant looks at the picture, it records on what part of the picture the participants eyes are concentrating on. So it could be said that our attention filters our recognition and responds to it. It is like a concept of fluent energy when being conscious. Is there a limited capacity of attention we can observe or naturally have? As I imagend that our attention works like a memory card, and when things are not neccessary any more they are erased. However there are some attention impairments such as Agnosia and Memory loss. Agnosia is the impairment of recognition, its like "ignorance" of basic objects, due to injury in the brain. In visual agnosia the patient know that something is going on and an object there but its hard for them to place, identify and cannot see anything. Next week we will be talking about Prosopagnosia also seen as face blindness, where the essay question is on. 


I will now address some short answers to the questions that were discussed in the seminar to the article "cognitive Physiology: Moving the Mind´s eye before the Heads eye" by Treue and Martinez (2003). I also have read in the Neuropychology Textbook and some additional reading for this topic., with what i answered these questions. 


1. Why do we need to move our eyes across a scene? 
Our high spatial resolution is confirmed to a small fraction of the retrain, the fovea. This is a dedicated motor system, as we in general don't see everything at once. The retrain periphery covers a large amount of the visual environment and can monitor for high contrast, low spatial frequency and fast changing. 


2. Would it not be easier if we could see the whole scene at once?
Possibly yes, but implementing the foveal resolution abilities across the whole retrina, it would be enourmously stressful and very difficult resulting in the flood of information reaching the brain would be impossible to process, react and deal with the approaching situation at once. 


3. What does FEF mean? 
FEF means the "fractal eye field", an area in the frontal cortex involved in the generation, that coordinates the pointing and directing the eyes across one presented scene. FEF plays a central role in the directed spatial attention of the human brain and is directly linked  to the generation of eye movement commands when FEF is activated the eye movement is triggered. 

Neuroscience- the New Philosophy (Week 2)

The matter of neurology and psychiatry is coming more to light, all these different approaches show a different perspectiv such as the evolutionary theory, which has always been there, but only recent scientists approached this matter from the darwinian standpoint. Especially called as evolutionary neuro-psychiatry. I was wondering why this hasn't been approached before, MRI ad PET scan were found a long time ago and  scientists already knew than that the different scans can show the inactive/ active parts of the brain. A classic example used is that people with a classic psychological disturbance,such as Hysteria are seen with a mental illness, that illness is seen strictly medical, as the person developed a paralysis of his arm or leg, when you then test the patient in neurological terms, such as MRI or PET scans there are no deficits, nothing seems to be wrong, however where does these symptoms the patient claims to have, come from? Things like hysteria have been examined many many times, and mainly it is assumed that it comes from previous experienced emotional traumas that are impede him from moving arm or leg. So is that how we are going to explain mental illness these days? One particular word was stuck in my head for the last week, epiphenomenalism, which i didn't understand at first but than, it means that the individuals willingness in the brain is like a shadow that always accompanies you, but is never the cause. 

History of Neuropsychology (Week 1)

While reading the given article I was surprised how early past scientist were trying to understand the human skull with different procedures, such as Trephanation also seen as one of the first surgical procedures, to release evil spirits while cutting and chiselling the skull. The scraping method seems, even though healing and possible living longer for the patient quit serious. A few years back I took part as a visitor in one of my dad’s surgeries, how he was cracking the skull with professional instruments of one of his patients was impressive and so I cant imagine the pain and effort for everyone during such procedure and to the patients without any anaesthetic plus the healing process must be quit harming.  Another theory by the ancient Greeks suggested that the human heart was the main function of the body whereas every other organ was there to “cool” the heart. Pythagoras was one of the first to encounter that soul and major functions come from the brain. I do believe that ancient Greeks did a lot of research on behalf of previous found theories, as Hippocrates who was influenced by Socrates, he made up his mind of the imbalance of the body when the four humours (blood, black bile, yellow bile and phlegm) where not in balance. That is one of the first theories I had learned in high school about psychology and the influence of the brain. I learned and also experienced that humans like to identify themselves with one of the four humours and belief that the individual has more strength in one than another. We all know that neuropsychology bases on the relationship between brain function and the human behaviour, it is really interesting to read more about its history and how scientists managed to gain so much knowledge with such limited material. I have attached a table for those who like to have a look of the four humours, i think it is quit unbelievable that someone could come up with such theory. 

source: http://en.wikipedia.org/wiki/Humorism

Humour	Season	Element	Organ	Qualities	Ancient name	Modern	MBTI	Ancient characteristics
Blood	spring	air	liver	warm & moist	sanguine	artisan	SP	courageous, hopeful, amorous
Yellow bile	summer	fire	gall bladder	warm & dry	choleric	idealist	NF	easily angered, bad tempered
Black bile	autumn	earth	spleen	cold & dry	melancholic	guardian	SJ	despondent, sleepless, irritable
Phlegm	winter	water	brain/lungs	cold & moist	phlegmatic	rational	NT	calm, unemotional