What structure in the occipital lobe is involved in vision?

From the Guidelines

The primary structure in the occipital lobe involved in vision is the secondary visual cortex, specifically area V2, which plays a distinct role in early visual processing, including detecting orientation, contours/edges, and colors of objects. This is based on recent meta-analytic evidence from 2021, which found heightened occipital activity in autistic individuals compared to non-autistic control groups, localized to area V2 or the secondary visual cortex (BA18) 1. The V2 receives feedforward sensory input from the V1 (i.e., the primary visual cortex) and feeds back predictions and inferences to V1 in a well-defined, hierarchical manner.

Some key points to consider when evaluating the role of the occipital lobe in vision include:

• The extrastriate V2 plays a critical role in early visual processing, with reference to detecting orientation, contours/edges, and colors of objects 1
• The V2 receives feedforward sensory input from the V1 and feeds back predictions and inferences to V1 in a hierarchical manner 1
• Damage to the occipital lobe, particularly to V1, can result in various visual field defects or even cortical blindness, despite having normally functioning eyes
• The occipital lobe contains multiple secondary visual processing areas (V2-V5) that handle increasingly complex aspects of visual perception

In terms of the specific structure involved in vision, area V2 is a critical component of the visual processing pathway, and its dysfunction has been implicated in various visual processing deficits, including those observed in autistic individuals 1. Overall, the evidence suggests that the secondary visual cortex, specifically area V2, plays a key role in vision, and its function is critical for normal visual processing.

From the Research

Structure Involved in Vision

The structure in the occipital lobe involved in vision is the striate cortex, also known as area V1 of the visual cortex.

• This area is responsible for processing basic aspects of visual information, such as line orientation and movement 2.
• Damage to the striate cortex can result in homonymous hemifield defects, where a person loses vision in one half of their visual field 2.
• The striate cortex is not the sole recipient of visual signals and is not essential for conscious vision 2.

Alternative Pathways

In cases where the striate cortex is damaged, alternative pathways can mediate residual visual responses.

• The Middle Temporal area (MT) of the extrastriate visual cortex is involved in visually-guided behaviors and can contribute to preserved visual perception in individuals with early-life injury to V1 3.
• The inferior pulvinar (PI) and its connection to MT can also play a role in affording preserved visual capacity following an early-life lesion of V1 3.
• Other studies have found that dorsal extrastriate areas can represent the visual field around the lower vertical meridian in individuals with damage to primary visual cortex 4.

Representation of the Visual Field

The representation of the visual field in the occipital lobe is complex and can be affected by damage to the primary visual cortex.

• The foveal region is unilaterally represented in the primary human visual cortex, with a major portion of the striate cortex dedicated to the central 10 degrees of vision 5.
• The horizontal meridian of the visual field is represented deep within the calcarine banks at the fissure base 5.
• Spared calcarine cortex and lateral occipital cortex can contribute to residual visual responses in individuals with cortical lesions 6.