Now that you have a better understanding of the frontal lobe, the various cortices within it,
the various functions of those cortices and lesions, now let’s do the same with the parietal
lobe. The parietal lobe has a primary somatosensory cortex that lies on the postcentral
gyrus. That is shown right in through here in this darker blue area. So the central sulcus
then separates the primary motor area in the precentral sulcus or gyrus from the primary
somatosensory cortex on the postcentral gyrus. There is a little man or homunculus
associated with it that looks very similar to the one on the precentral gyrus but for simplicity,
that is not shown in the illustration. The primary somatosensory cortex is the cortical area
that’s going to receive somatosensory input from the opposite side. So this sense is the
left primary somatosensory cortex. The sensory input is coming from the right side of the body.
A lesion here would result in contralateral anesthesia, so we would not be able to have a good
sense of the senses coming from the right side if this is the left as it is. Another area or
cortical area of the parietal lobe is the parietal association area that is shown in through here.
This is involved functionally in stereognosis. It also helps us to maintain an awareness
of our contralateral self and our surroundings. A lesion of this particular area can result
in astereognosis. Also, it can cause us to neglect our contralateral self and our
surroundings. This is another area that can result in apraxia. Wernicke's area is an important
region of the parietal lobe. That is shown here in this area. This is important in the
comprehension of language. So, it allows us to make sense of what we hear and what we read.
A lesion will damage our ability or inhibit our ability to comprehend language. As a result,
an individual will have what is termed receptive aphasia. Another term for this is fluent aphasia.
So, they have the motor control but the words they use would be like a solid mix.
They don’t make sense but the words themselves are produced perfectly.