3. visual perception - disorders

There are several disorders of perception. One of which is commonly known as Agnosia, a condition in which a patient is unable to recognize stimuli belonging to a particular sensory modality.
Bauer (1993) defined Agnosia as 'a failure of recognition that cannot be attributed to elementary sensory effects, mental deterioration, attentional disturbances, aphasic misnaming, or unfamiliarity with sensorially presented stimuli.'
This type of condition can be broken down in to several principal agnosias and their different neural basis. The most commonly studied are visual agnosia, auditory agnosia and tactile agnosia.
When looking in to Visual Agnosia, it can be understood that Lissauer (1890) suggested two distinct forms of agnosia known as apperceptive agnosia and associative agnosia.Apperceptive agnosia is a severe type of agnosia and describes an inability to recognize visual objects that can only be seen. Associative agnosia is a less severe form of agnosia and it describes the difficulty to recognize objects percepts with its meaning.
Here is a video in relation to associative agnosia. 

Another type of agnosia is prosopagnosia  also known as faceblindness and facial agnosia: Patients cannot consciously recognize familiar faces, sometimes even including their own. This is often misunderstood as an inability to remember names.
a useful link, as mentioned in the video below, is https://www.faceblind.org/research/index.html. which can be used to provide more knowledge on the topics as well as a test that can be carried out to investigate you're own recognition of faces. 

The FEF (frontal eye field) plays an important role in terms of attention and eye movement. It is an area in the frontal cortex involved in the generation of motor commands for pointing the eyes, and therefore the foveas, toward desired target locations.
Moore and Armstrong conducted a study where they placed a visual stimulus in the receptive field of a given V4 which is in the extrastriate visual cortical area.
Findings suggest that the FEF plays a central role in directing spatial attention and that this process is directly linked to the generation of eye movement commands, however questions still remain.