Lingual gyrus

The lingual gyrus, also known as the lingula, is a cerebral gyrus in the back part of the brain called the occipital lobe. You can see it on the inner surface of the occipital lobe, where it is separated from the cuneus (or cuneate gyrus) above it, by the calcarine sulcus.

To understand the role of the lingual gyrus in visual processing, it is important to know that within the occipital cortex, the primary visual area, known as Broadman's area 17, is found on both sides of the calcarine sulcus, spreading across the lingual gyrus and the cuneus. The lingual gyrus forms the lower lip of the calcarine sulcus, while the cuneus forms the upper lip.

It is important to note that visual information from the upper part of the visual field, which is projected onto the lower part of the retina, is received by the lingual gyrus through the inferior optic radiations in the primary visual area within the lower lip of the calcarine sulcus. Furthermore, the right visual field is processed by the left occipital cortex, while the left visual field is processed by the right occipital cortex. In essence, the visual field can be divided into four quadrants. In the case of the lingual gyrus on the left side, it receives visual information from the upper quadrants of the right visual field. If there is damage to this area, it can result in a condition called right superior homonymous quadrantanopia (with or without macular sparing).