All parts of the brain › Premotor cortex

Where is the premotor cortex?

The premotor cortex is in the frontal lobe, just in front of the primary motor cortex, on the outer (lateral) side of each hemisphere. It is the lateral part of Brodmann area 6, which reaches onto the rear parts of the superior and middle frontal gyri. [1][2]

The 3D brain needs JavaScript. The text below still says where the premotor cortex is and what it does.

Lit: the whole superior frontal and middle frontal gyri, on both sides.

Slice

The superior frontal and middle frontal gyri are lit together; the premotor cortex is not drawn on its own. The top (axial) slice button cuts through them. Drag to turn, pinch or scroll to zoom, tap any part to name it; .

Lit: the whole superior frontal and middle frontal gyri, on both sides. The area is part of these gyri; its exact border is not drawn. Brodmann area 6 extends onto the rear (caudal) parts of the superior and middle frontal gyri, and also onto the parts of the precentral gyrus that area 4, the primary motor cortex, leaves free. The model has no shape for area 6, so the two frontal gyri are lit whole and the precentral gyrus is left unlit. [2][3]

Held by the superior frontal gyrus and the middle frontal gyrus — see each whole gyrus on its own page.

Takes part in: movement — see every part of each lit together.

Where it is

It lies in the frontal lobe just in front of (anterior to) the primary motor cortex, Brodmann area 4. [1]
It is the part of Brodmann area 6 on the lateral surface of the hemisphere; the medial extension of area 6, onto the midline surface, is the supplementary motor area. [1]
Area 6 extends onto the rear (caudal) portions of the superior and middle frontal gyri and runs from the cingulate sulcus on the inner face of the hemisphere to the lateral sulcus on its outer face. [2]
Area 6 lies in front of area 4 across the superior and middle frontal gyri and includes the lateral premotor cortex; on the medial wall it takes in the supplementary and pre-supplementary motor areas. [4]
The superior frontal gyrus makes up about a third of the frontal lobe and is bounded at its side by the superior frontal sulcus; the middle frontal gyrus lies below it, between the superior and inferior frontal sulci, with the precentral sulcus behind it. [5][6]
In front of it lies Brodmann area 46 of the prefrontal cortex: the premotor cortex is a transition between the agranular motor cortex behind it, which lacks a layer IV, and the granular six-layered prefrontal cortex in front, with only a faint layer IV of its own. [1]
It is divided into an upper (dorsal) and a lower (ventral) premotor cortex, each with a front (rostral) and a back (caudal) part; these divisions were described mainly in monkeys, and how exactly they correspond in the human brain is not yet clear. [1]

What it does

Its functions are diverse and not fully understood: it may help plan movement, guide movement in space and by the senses, understand the actions of others and use abstract rules to perform tasks. [1]
It projects directly to the spinal cord, so it may take part in the direct control of behaviour, with a relative emphasis on the trunk muscles. [1]
Signals from it cause much more complex patterns of movement than the discrete patterns from the primary motor cortex. [1]
In monkeys trained to reach for targets, neurons of the dorsal caudal part (PMDc) are active while the reach is prepared and while it is made, each firing best for one direction. [1]
The dorsal premotor cortex (PMd) contributes to planning reaches and choosing between competing directions; the ventral premotor cortex (PMv) is heavily involved in shaping the hand for a grasp. [4]
The ventral premotor cortex has been linked to motor vocabularies in speech and in hand gestures, including a “mental syllabary” of the most-used syllables of a language. [1]

Connections

It has strong input and output links with the primary motor cortex, the supplementary motor area, the superior and inferior parietal cortex and the prefrontal cortex. [1]
Below the cortex it projects to the spinal cord, the striatum and the motor thalamus, among other structures. [1]

Other names

The lateral part of Brodmann area 6 (BA6); area 6 as a whole is the premotor cortex plus, medially, the supplementary motor area. [1][2]
Its four parts are written PMDr, PMDc, PMVr and PMVc (premotor dorsal or ventral, rostral or caudal); work on the ventral areas also calls them F7, F2, F5 and F4. [1]

Size

The model has no shape for the premotor cortex itself, so it is not measured here. The whole left superior frontal and middle frontal gyri that hold it measure, together, about 116 mm front to back, 78 mm top to bottom and 49 mm side to side on this model (the box they fit in, not their volume). [3]

Sources

Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.