The premotor cortex is a crucial part of the brain, which is believed to have direct control over the physical movements of voluntary muscles. In this article, we will learn about the location, function, and structure of the premotor cortex.
Did You Know?
While the primary motor cortex is responsible for simple movements of the body parts, the application of higher levels of current on the supplementary motor area and the premotor cortex for longer than one-thousandth of a second can lead to more complex movements.
Known for preparing the primary motor cortex and other function related parts of the brain to send signals to the various parts of the body, the premotor cortex plays a very essential part in our day-to-day lives. It is used in basic tasks such as just walking around, tying shoe laces, or any activity which requires a person to move a part of their body. Let us take a look at where these neural processes take place and how the premotor cortex works.
Location of the Premotor Cortex
The premotor cortex is a part of the motor cortex which lies in the frontal lobe of the brain, towards the anterior of the primary motor cortex. It is part of Brodmann’s Area 6. It consists of a ventral, lateral, and a medial area, which act as neural pathways to the primary motor cortex.
The premotor cortex can be differentiated from the primary motor cortex by studying the structure of the cells. While the primary motor cortex is mostly made up of giant pyramidal cells, the pyramidal cells in the premotor cortex are smaller and lesser in number. While the primary motor cortex does not have any granular cells, the premotor cortex has a very thin layer of granule cells.
The premotor cortex can be generally divided in four parts: the upper and lower, i.e., dorsal and ventral premotor cortex, both of which are further divided into the region towards the front of the brain and the region towards the back, named the rostral premotor cortex and caudal premotor cortex, respectively.
The premotor cortex primarily works to prepare and execute movements of the limbs, through coordination with other parts of the brain in choosing the appropriate motions. The ventral and lateral areas anticipate and direct the movements of the body in response to external stimuli, such as visual and audio inputs, while on the other hand, the medial area responds to internal stimuli from other parts of the brain, such as memories, and acts as a relay station to perform a particular physical act. It is also important in learning, through the practice of imitation, and skills of social cognition through empathy. Let us take a look at the functions of each of the sections of the premotor cortex more closely.
Premotor Dorsal Rostral Region: This region is primary related to providing responses to random stimuli. For example, this region is partly responsible for eye movement, through the effect of electric impulses.
Premotor Dorsal Caudal Region: The neurons of this region has been seen to mainly work towards the preparation and the actual movements of the arms through the shoulder, arm, and hand muscles, to reach out and grasp objects.
Premotor Ventral Rostral Region: The neurons of this region have often been studied to see its role in controlling the muscles of the hands while grasping objects, and also hand and mouth coordination. Also, one can find mirror neurons in this region, which are used to understand the actions made by others, by the practice of imitation.
Premotor Dorsal Caudal Region: This region uses the senses of touch, sight, and hearing to absorb the various stimuli to record the objects that are in the near vicinity of the person. This kind of stimuli is used to guide the actions of the body with respect to the objects that are near the body.
Once the information has been generated by the premotor area, it is passed to the primary motor cortex, where signals are passed directly through the spinal cord to the skeletal muscles for execution of physical actions.
Although the findings of research on the premotor cortex is inconclusive, future studies shall be able to confirm many theories, and get us closer to understanding the working of the human mind better.