The premotor cortex is an area of motor cortex

Motor cortex

Motor cortex is a term that describes regions of the cerebral cortex involved in the planning, control, and execution of voluntary motor functions.-Anatomy of the motor cortex :The motor cortex can be divided into four main parts:...

 lying within the frontal lobe

Frontal lobe

The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...

 of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. It extends 3 mm anterior to the primary motor cortex

Primary motor cortex

The primary motor cortex is a brain region that in humans is located in the posterior portion of the frontal lobe. Itworks in association with pre-motor areas to plan and execute movements. M1 contains large neurons known as Betz cells, which send long axons down the spinal cord to synapse onto...

, near the Sylvian fissure(lateral sulcus), before narrowing to approximately 1 mm near the medial longitudinal fissure

Medial longitudinal fissure

The great longitudinal fissure is the deep groove which separates the two hemispheres of the vertebrate brain....

, which serves as the posterior border for the prefrontal cortex

Prefrontal cortex

The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...

. The premotor cortex is largely equivalent to Brodmann area 6

Brodmann area 6

- Human :Brodmann area 6 is part of the frontal cortex in the human brain. Situated just anterior to the primary motor cortex , it is composed of the premotor cortex and, medially, the supplementary motor area, or SMA...

. Activity within this region is critical to the sensory guidance of movement and control of proximal and trunk muscles of the body.

Anatomy and structure

The premotor cortex is dysgranular (a transition between the agranular motor cortex and the granular eulaminate frontal cortex), which means that there is only a faint granular lamina IV. This corresponds to Brodmann area 6

Brodmann area 6

- Human :Brodmann area 6 is part of the frontal cortex in the human brain. Situated just anterior to the primary motor cortex , it is composed of the premotor cortex and, medially, the supplementary motor area, or SMA...

, with the exception that the medial surface of this area is the site of the accessory motor cortex (also known as the supplementary motor area

Supplementary motor area

The supplementary motor area is a part of the sensorimotor cerebral cortex . It was included, on purely cytoarchitectonic arguments, in area 6 of Brodmann and the Vogts...

, or SMA).

Cortical

The premotor cortex receives inputs originating from other areas of the cortex, including the inferior and superior parietal lobules (from which it receives multimodal sensory information) and the frontal cortex (from which it receives information related to attention and motivation)

Striatum

Axons of the Vth layer contribute to the corticostriate connection ; a massive connection involving almost all parts of the cortex

Thalamus

The premotor cortex sends axons to the motor thalamus

Thalamus

The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

. This comprises a part receiving cerebellar axons (nucleus Ventralis Intermedius Vim or VL), a part receiving pallidal axons (nucleus Ventralis oralis VO) and a part receiving nigral axons (nucleus Ventralis anterio VA). The Vim is separated into two parts one ventrolateral and one mediodorsal VImM. The premotor cortex sends axons electively to VImM and VO

Physiology

Mirror neuron

Mirror neuron

A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behaviour of the other, as though the observer were itself acting. Such neurons have been directly observed in primate and other...

s are cells located in the premotor cortex, the part of the brain relevant to the planning, selection and execution of actions. It is a part of the Cerebral cortex

Cerebral cortex

The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

.