Visual Pathway

• Contralateralization of the eye refers to Objects presented in the left visual field (left side of the body) will be captured by the right side of the eye's retina while the left side will capture the objects presented in the right visual field
• Retina Geniculate Striate Pathway:

  
  

  Eye lenses > Retina > Lateral Geniculate Body (Thalamus) > Parvocellular/Magnocellular > Primary Visual Cortex (V1) > Secondary Visual Cortex (V2)
• Parvocellular system receives the fine details of visual stimuli such as the color and shape
• Magnocellular system receives the information about

  the depth perception, location and movement of the object.
• From the thalamus the impulses will be projected to the primary visual cortex located at the posterior end of the occipital lobe and will be further processed by the Secondary Visual Cortex. Secondary Visual Cortex also called as V2, is the area where the pathway diverges into 2 streams, namely the dorsal stream and the ventral
• Dorsal Stream:

  
  

  Secondary Visual Cortex > V5/MT> Posterior Parietal Cortex
• From the secondary visual cortex, the impulses will pass through V5 or medial temporal gyrus, an area sensitive to movement, and will reach Posterior Parietal Cortex, an association area which integrates vision to other sensory modality, particularly the somato-sensation
• Dorsal Stream (Occipito – Parietal Pathway) refers to Depth perception and location of objects in space
• Ventral Stream (Occipito – Temporal Pathway) – responsible for finer details, color and geometric shapes of visual stimuli
• Ventral Stream

  Secondary Visual Cortex > V4 > Inferior Temporal Lobe
• From Secondary Visual Cortex, the impulses will proceed to V4, an area where color is further processed. It helps us to know the real color of objects despite of the color of the

  lighting in the environment where the objects are presented. After color processing, the impulses will reach inferior temporal lobe which helps us identify the object.
• Visual information is transmitted to extra striate cortex (termed visual association cortex) via two streams
• Dorsal stream is where objects receives mostly as magnocellular inputs and projects to post parietal association cortex
• Ventral stream receives a mix of magnocellular and parvocellular input. It also projects to extra striate cortex (V2, V3, V4, V5) and the inferior temporal cortex (TEO, TE, STS)
• Agnosia refers to failure to perceive or identify as a stimulus by means of a sensory modality
• Apperceptive Visual Agnosia is a failure higher level perception — Person has a normal visual acuity, but cannot recognize person based on their shape