Lab 7 - Visual System

The Cortex

Before continuing review the boundaries of the occipital lobe from previous labs. Identify the parieto-occipital sulcus, the preoccipital notch, and the calcarine sulcus. The primary visual receiving area, i.e., the calcarine or striate cortex, is located medially in the walls of the calcarine sulcus and in adjacent portions of the cuneate and lingual gyri. The extrastriate cortex extends from the medial surface of the occipital lobe to occupy most of the lateral surface of this lobe. Parietal and temporal cortical areas adjacent to the extrastriate cortex form visual association areas important for perceiving the spatial location and movement of objects (parietal association area) and for perceiving the shape and color of objects and recognizing and naming objects (temporal association area). The occipitotemporal eye field include portions of the rostral extrastriate cortex (Brodmann's area 19) and caudal parts of the superior temporal and middle temporal gyri (Brodmann's areas 39 and 37). The occipitotemporal eye fields are important for the visual guidance of smooth pursuit (tracking) eye movements. On the lateral surface of the hemisected brain locate the frontal eye field. It includes the caudal part of the middle frontal gyrus and adjacent areas of the inferior frontal gyrus. The frontal eye fields are important for initiating voluntary (guided) saccadic eye movements.