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?