Motor and sensory cortical homunculus
This study unit will help you to:
- Determine the location of the primary motor cortex and understand the distribution of the motor control within it.
- Identify the location of the primary somatosensory cortex and understand the distribution of the sensory innervation within the primary sensory cortical center.
The motor cortex is a region of the cerebral cortex in the frontal lobe involved in the control of voluntary movement. The motor cortex can be divided into two major regions: the primary motor cortex and the secondary motor areas. The primary motor cortex (Brodmann area 4) is situated in the precentral gyrus, just anterior/rostral to the central sulcus. It is somatotopically arranged such that different parts of this gyrus are associated with the motor control of the different parts of the contralateral side of the human body. A spatial map of the body in the primary motor cortex is referred to as the motor homunculus.
The somatosensory cortex is located in the parietal lobe and is divided into two main regions: the primary somatosensory cortex and the secondary somatosensory cortex. The primary somatosensory cortex (Brodmann areas 1,2,3) is located in the postcentral gyrus, just posterior to the central sulcus. This area receives the sensory input from specific areas of the body that correlate to the specific regions of the cortex.
Similar to the motor control in the primary motor cortex, the neurons in the primary somatosensory cortex form a sensory map of the body called the sensory homunculus.
This video tutorial will provide you with an overview of motor and sensory homunculus.
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Take a closer look at the motor and sensory homunculus in the galleries below.
|Definition||Topographically organized map of the sensory innervation and motor control of the body|
|Location||Motor homunculus: Precentral gyrus (frontal lobe)
Sensory homunculus: Postcentral gyrus (parietal lobe)
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