Inferior temporal sulcus

At a glance

English

Inferior temporal sulcus

Latin (TA2)

Sulcus temporalis inferior

System

Brain and spinal cord

Region

Head

Side

Paired, left and right

About the inferior temporal sulcus

The inferior temporal sulcus runs from front to back along the lower part of the lateral surface of the temporal lobe, roughly parallel to the superior temporal sulcus above it. It starts a short way behind the temporal pole and runs back towards the occipital lobe, reaching nearly to the occipital pole. Along its length it is often interrupted by small bridging gyri, so that it may appear as a chain of shorter segments rather than one continuous groove.

Above the sulcus lies the middle temporal gyrus; below it lies the inferior temporal gyrus, which curves around the lower border of the hemisphere onto its inferior surface. The basal surface of the lobe, hollowed from side to side, and carries further grooves, the occipitotemporal and collateral sulci, which run in the same front-to-back direction. Behind, the inferior temporal sulcus fades into the lateral occipital region, where the temporal and occipital lobes merge without a sharp border.

The sulcus itself is a landmark rather than a functional unit, but the cortex in its banks belongs to the ventral visual stream, the pathway concerned with recognising what things are. In the back part of the sulcus, near its junction with the occipital lobe, lies a motion-sensitive visual area (often labelled V5 or MT+) that analyses the speed and direction of moving objects. Further forward, the cortex of the sulcus and the inferior temporal gyrus responds to complex shapes, objects and faces.

Damage to the posterior end of the sulcus on both sides, for example from strokes or trauma, can cause akinetopsia, a rare loss of the ability to see movement, in which moving objects appear as a series of still frames. More anterior damage can impair recognition of objects or faces. In surgery for temporal lobe epilepsy, the sulcus helps define how much lateral cortex is removed.

Function and supply

Function

Surface landmark between the middle and inferior temporal gyri; the cortex in its banks belongs to the ventral visual stream and includes motion-sensitive areas at its back end.

Blood supply

Temporal branches of the middle cerebral artery laterally, with inferior temporal branches of the posterior cerebral artery near the lower border.