The premotor cortex occupies the part of Brodmann area 6 that lies on the lateral surface of the cerebral hemisphere.

Second, the primary motor cortex is agranular: it lacks a layer IV marked by the presence of granule cells.

Subcortically it projects to the spinal cord, the striatum, and the motor thalamus among other structures.

In the study of neurolinguistics, the ventral premotor cortex has been implicated in motor vocabularies in both speech and manual gestures.

A mental syllabary — a repository of gestural scores for the most highly used syllables in a language — has been linked to the ventral premotor cortex in a large-scale meta-analysis of functional imaging studies[citation needed].

A recent prospective fMRI study that was designed to distinguish phonemic and syllable representations in motor codes provided further evidence for this view by demonstrating adaptation effects in the ventral premotor cortex to repeating syllables[citation needed].

These subdivisions of premotor cortex were originally described and remain primarily studied in the monkey brain.

Electrical stimulation of these neurons causes an apparent defensive movement as if protecting the body surface.

[19][20] This premotor region may be part of a larger circuit for maintaining a margin of safety around the body and guiding movement with respect to nearby objects.

[9][19] Mirror neurons were first discovered in area F5 in the monkey brain by Rizzolatti and colleagues.

Instead M1 was considered to be a single map of the body, perhaps with complex properties, arranged along the central sulcus.

Roland and colleagues[31][32] studied the dorsal premotor cortex and the supplementary motor area in humans while blood flow in the brain was monitored in a positron emission scanner.

When people made complex sensory-guided movements such as following verbal instructions, more blood flow was measured in the dorsal premotor cortex.

When people made internally paced sequences of movements, more blood flow was measured in the supplementary motor area.

When people made simple movements that required little planning, such as palpating an object with the hand, the blood flow was more limited to the primary motor cortex.

[4][22] By implication, at least three different cortical fields may exist, each one performing its own special function in relation to the fingers and wrist.

Some project to the spinal cord and may play a direct role in movement control, whereas others do not.

Graziano and colleagues suggested an alternative principle of organization for the primary motor cortex and the caudal part of the premotor cortex, all regions that project directly to the spinal cord and that were included in the Penfield and Woolsey definition of M1.

In this alternative proposal, the motor cortex is organized as a map of the natural behavioral repertoire.

In this view the more complex movements, especially multi-segmental movements, come to be emphasized in the more anterior part of the motor map because that cortex emphasizes the musculature of the back and neck which serves as the coordinating link between body parts.

In contrast the simpler parts of the movement repertoire that tend to focus more on the distal musculature are emphasized in the more posterior cortex.

In this alternative view, though movements of lesser complexity are emphasized in the primary motor cortex and movements of greater complexity are emphasized in the caudal premotor cortex, this difference does not necessarily imply a control hierarchy.