Superior occipital gyri

At a glance

English

Superior occipital gyri

Latin (TA2)

Gyri occipitales superiores

System

Brain and spinal cord

Region

Head

Side

Paired, left and right

About the superior occipital gyri

The lateral surface of the occipital lobe is crossed by roughly parallel convolutions arranged from top to bottom as the superior, middle and inferior occipital gyri. The superior occipital gyrus is the highest of these. It runs back towards the occipital pole beside the superior border of the hemisphere and is separated from the middle occipital gyrus below by the intraoccipital (superior occipital) sulcus, which continues back from the intraparietal sulcus. In front it joins the superior parietal lobule, often through a curved bridge of cortex, the parieto-occipital arch, around the lateral end of the parieto-occipital sulcus. Its pattern is irregular and it is often broken into several short pieces, which is why it is sometimes named in the plural.

Further back it is crossed by the transverse occipital sulcus, and at its edge it passes over onto the medial surface into the cuneus above the calcarine sulcus. Its cortex belongs to the visual association areas, mostly Brodmann area 19 and parts of area 18, which surround the primary visual cortex.

As part of the dorsal visual stream, the upper occipital cortex deals with where things are and how they move rather than what they are. It passes information forward to the parietal lobe for guiding the eyes and hands in space, and it is active during tasks that need spatial attention and visually guided reaching. The middle and inferior gyri below it are more concerned with recognising objects and faces, the inferior gyrus holding the occipital face area. In people blind from an early age the occipital cortex is recruited for hearing and touch tasks, keeping a bias towards spatial processing.

Damage high on the lateral occipital surface, often at the border with the parietal lobe, can impair visually guided reaching and the perception of motion and depth, and when both sides are affected may contribute to Balint syndrome.

Function and supply

Function

Visual association cortex of the dorsal stream, processing location, motion and spatial relations to guide eye and hand movements.

Blood supply

Mainly branches of the posterior cerebral artery, with the lateral border supplied by the middle cerebral artery.