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2-Minute Neuroscience: Primary Somatosensory Cortex

Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics

in 2 minutes or less.

In this installment I will discuss the primary somatosensory cortex.

The primary somatosensory cortex is located in a ridge of cortex called the postcentral

gyrus.

It is situated just posterior to the central sulcus, a prominent fissure that runs down

the side of the cerebral cortex.

The primary somatosensory cortex is responsible for processing somatic sensations, or sensations

from the body that include touch, proprioception or the position of the body in space, nociception

or pain, and temperature.

When receptors detect one of these sensations, the information is sent to the thalamus and

then to the primary somatosensory cortex.

The primary somatosensory cortex is typically divided into 4 areas: area 3a, 3b, 1, and

2.

Area 3 receives the majority of somatosensory input directly from the thalamus, and the

initial processing of information occurs here.

Area 3b is primarily concerned with basic processing of touch sensations, while area

3a responds to information from proprioceptors.

Area 3b is densely connected to areas 1 and 2, and when area 3b receives touch information,

that information is then sent to areas 1 and 2 for more complex processing.

Area 2 is also involved with proprioception.

Each of the four areas of the primary somatosensory cortex is arranged such that a particular

location in that area receives information from a particular part of the body.

This arrangement is referred to as somatotopic, and the full body is represented in this way

in each of the four regions of the somatosensory cortex.

More sensitive areas of the body take up a disproportionate amount of space in this somatotopic

arrangement.