American scientists have found that conscious perception of visual images is not always accompanies their treatment. It managed to show the example of a man with metamorphopsia — neurological disorder in which people cannot perceive objects or symbols of a certain form or category (in this case — Arabic numerals from 2 to 9). When he showed his face and the words for large numbers, he could not determine what he sees, although it evoked potentials of the brain pointed to the fact that the stimuli it processes correctly. Article published in the journal Proceedings of the National Academy of Sciences.
The perception of any sensory stimulus can be divided into two main stages. First, there is primary processing of senses: due to her information about all the possible characteristics of a stimulus in the form of an electrical signal gets to the parts of the brain responsible for specific processing of certain stimuli (e.g. visual or auditory). After this secondary treatment, and she is slightly more complicated: if the case, for example, applies to any visual stimulus, the visual cortex needs to process separately each feature (color, shape, position in space).
At the same time, however, the processing does not end, and after passing the first two stages of the incentive you need to recognize that is to understand exactly what he is: so the set of shapes and colors, the brain recognizes a photo of a wellknown person, and the set of notes — favorite song. However, it is unclear at what point the border between the first two stages and the last stage of perception: in other words, is it possible to somehow share and what part of the whole process lost.
Michael McCloskey (Michael McCloskey) from Johns Hopkins University and his colleagues managed to conduct a study on a patient with a rare neurological impairment — metamorphopsia. Patient R. F. C. (researchers cite only the initials) because of the death of tissue in the parietal lobe of the left hemisphere is not able to recognize numbers from 2 to 8 instead of numbers, he sees a confusion of lines, although his arithmetical ability is not broken, and it recognizes almost all letters of the English alphabet and the numbers 0 and 1 (due to their similarity with the letters O and I, with whom he has no problems). The patient is also trained in a special system in which classical Arabic digits are replaced by the characters from the sticks: the authors reported that due to the R. F. C. she even managed to continue the work of the engineering geologist before retirement in 2014.