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Visual attention in the human cortex and its' mechanisms.

Visual attention in the brain refers to exclusively focusing on a specific visual scene in the brain rather than its' entirety. The human brain's capability to focus attention on visual scenes is actually very limited according to scientists. Some studies have shown and made it possible for scientists to realize that certain eye-tracking based methods can ignore the very complicated and difficult process that happens in the brain's social perception, memory recognition and visual eye recovery. The visual attention in the human brain has been studied for a very long time, however according to scientist Grace Lindsay she described the study of attention in the human brain to be "“far from a clear or unified concept".

Control processes in the cortex
One thing that all scientists and researchers in the field of studying the visual attention in the brain can agree on is that the visual attention in the brain has huge effects on the ability to focus, both positive and negative. Scientists have come to the conclusion that there are two types of control processes that the attention in the brain uses to fully utilize its' limited capacity and capability, the two processess that the demonstration in the brain uses are called overtly and covertly. In the covert attention method that the brain uses to focus on a visual scene, the brain will calculate and weigh the information it recieves and percieves without moving the fovea (the area in the retina of the human eye in which the visual density and attention is the strongest and most powerful). In the overt method the brain uses to focus the attention on the visual scene, the brain locates the fovea in both retinas of the eyes and focuses and fixates it on a visually percieved area by utilizing the saccades in the eye (the very quick and instantaneous movement on both eyes to focus the attention in a specific direction).

Studies perfmored on the monkey cortex and its relation to the human cortex
Most of our knowledge so far about how the human cortex works comes from studies perfmored on monkeys. Those studies can be split into 3 categories: physiological, behav- ioral, and anatomical. The studies that were performed on monkey have come to the conclusion that the monkey brain has in total 30 seperate areas in the cortex that focuses on visual attention. Those 30 areas are all focused on 2 very specific and strong pathaways that focuses the visual attention in the monkey brain in order to percieve the image and object infront of the animal. The two pathways are called the occipitotemporal pathaway, and the occipi- toparieta pathaway. Both pathways reside in the same area in the cortex of the monkey brain called the V1. The first pathway, the occipitotemporal, likes to focus on identifying the objects in the field of view of the creature and spends and focuses a lot of the attention on identifying different colours and imagery. The second pathway in the cortex of the monkey brain, which is called the occipi-toparieta pathway, likes to focus more on the movement and guidance of the objects. Other scientific terms for both pathways are the ventral stream and the dosal stream.

Competitiveness and stimuli suppression
There is a lot of competition that happens in the retina of humans and monkeys when it comes to identifying objects in the possible field of view and focusing the attention. Both the ventral and dosal stream in the pathaways of the cortex and retinas of humans and monkeys have a lot of competition when it comes to percieving objects around you. Further studies on monkeys have proved that when presented with a single object and multipled objects infront of the monkey, the stimuli and response that happens in both the dosal and ventral both have very high firing rate and strong competitiion no matter the amount of objects presented. There is a sort of suppression of stimuli that happens in the retina of the monkey especially when presented with 2 or more objects, and strong attempts are made in the dosal and ventral stream to unify the image and focus the attention of the retina on a singular thing. Sensory suppression is not just present in monkeys, some studies were done on humans as well and scientiests have come to the conclusion that the same thing happens as well in the dosal and ventral pathways of the human eye, there is also strong competition and fierce sensory suppression that occurs in the processes of focusing visual attention and the actual number of objects presented is irrelevant.

Unnecessary information and how the brain filters it
Each visual scene that we percieve in our eyes contains more than one stimuli. Each stimlu that we have in our retina or cortex all compete againts each other in order to process the information that we percieve and focus the visual attention and maximize its' mechanism. fMRI studies have shown (Kastner et al 1997, 1998a). that in both single-cell recordings and multiple cell recordings that competition can be regulated in order to process certain information. Recent fMRI studies have also shown and confirmed that the same exact stimuli and competition present in the cortex of a monkey can also be found in the cortex of a human. Both attended and unattended information have pretty much the same density and both of them can be controlled and regulated using specific eye-tracking methods. The visual conditions can be two types, sequential and simultaneous. in the sequential and simultaneous conditions, one thing they both had in common is that the focused attention could reduce and suppress the stimuli and response.

Activity in the visual cortex
Further studies were made on the human cortex and scientists have found out that the level of the visual attention and activity accumulated in the visual cortex of the human can be controlled and manipulated using certain methods and percieved experiments. During the absence of any visual activity in the retina, single-cell recordings in the human cortex have shown that the the firing rates and stimuli were 30% higher for nuerons in both the dosal and ventral stream of the human and monkey cortex. Sensory-suppressed interactions and the complete absence of any visual stimulation have also shown a very big increase in activity in the visual cortex

In conclusion
Although the exact mechanisms of the visual attention in the human cortex is still unkown and not fully identified, this does not stop the scientists and researchers from mimicking the many feautures of visual attention to advance and further their studies. Because of the huge success of the attention-based models when it comes to the experiments and studies performed, scientists will focus their studies on that type of model because they produce the best results. In the end, the human brain is always the most fascinating thing in the universe.