Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics
in 2 minutes or less.
In this installment I will discuss the motor cortex.
The motor cortex is a region of cortex in the frontal lobe that is involved with voluntary
It is located anterior to a large sulcus called the central sulcus and is often divided into
two major regions: the primary motor cortex and the nonprimary motor cortex.
The primary motor cortex is found in the strip of cortex known as the precentral gyrus, which
is located just anterior to the central sulcus.
The primary motor cortex is arranged such that different parts of the region are associated
with motor control of different parts of the body and thus is said to contain a motor map
of the body.
Most of the neurons that travel from the primary motor cortex carrying signals regarding movement
will enter one of two major motor pathways: the corticospinal or corticobulbar tracts.
The corticospinal tract carries movement-related signals to the spinal cord to cause movement
of the body, while the corticobulbar tract carries signals to the brainstem to cause
movement of the head, neck, and face.
The nonprimary motor cortex is often divided into two main regions: the supplementary motor
cortex and the premotor cortex.
Although the functions of these areas are not well understood, it is thought the supplementary
motor cortex may be involved with the execution of sequences of movement, the attainment of
motor skills, and the selection of movements based on incoming sensory information.
The premotor cortex contributes about 30% of the neurons that enter the corticospinal
tract, but seems to be more active during the planning of, rather than the execution