The human cerebrum accounts for roughly 80% of total brain mass and is essential for language, cognition, memory, consciousness, and awareness of surrounding. In this article, our main focus is the cortex, the outer layer of the cerebrum, which is responsible for voluntary movements and cognitive functions. Generally, you can establish the idea that the cortex has three functioning areas- sensory, association, and motor areas, and is characterized into four regions, or lobes- frontal, temporal, occipital, and parietal lobes.
Before I confuse you with the different lobes of the cerebral cortex, let’s first talk about how the cerebral cortex receives and processes sensory information. Since we are still not familiar with the processing of memory and all that, scientists can only focus on the study of sensory information, which they developed through a method called functional imaging, brain scanning that assists the observation of active brain regions in response to a certain stimulus. Hence, let’s only deal with sensory information for now.
The human cerebral cortex receives sensory information from two sources. The first is somatosensory receptors (soma=body). Somatosensory receptors are “body” receptors that provide information about touch, pain, pressure, temperature, and the position of muscles and limbs. The other is sensory organs such as the eyes and nose, which clusters of receptor neurons are organized. Most sensory information coming into the cortex is directed via the thalamus to primary sensory areas within the brain lobes, which is then passed along to nearby association areas where processes of sensory input take place.
Now that we’ve talked about how and where sensory information is received, let’s take a brief view on the lobes of the cerebral cortex. Generally, the parietal, temporal, and occipital lobes are regions that deal with specific sensory information (auditory, touch, visual, odor, etc.), whereas the frontal lobe carries out processed information into action (movement). When constructing this concept in your brain, be sure to realize that every lobe consists of two parts, left and right, and the left and right side may have different functions that are not illustrated in the figure. For instance, the temporal lobe is responsible for the processing of both auditory, odor, etc., so don’t let the figure below limit your understanding. In addition, the parietal, temporal, and occipital lobes have what we characterized as “primary sensory areas” and “association areas,” which correlates with what we’ve mentioned about the receiving and processing of information in the prior paragraph. Keep in mind that these “areas” are defined through functional imaging (brain scanning); in other words, these areas are active when information is received and processed. And that’s all we know. In summary, what we’ve discussed is only the broad, general view regarding the functions of the lobes. The frontal lobe, for instance, plays other roles, such as managing memory; however, this subject, as well as many others, are still too blur for us to fully grasp. As a result, the idea above is pretty much what you should know, unless you are interested in pursuing neuroscience. It would be useful if you can draw and organize the above information yourself, so it is integrated into your mind.
Reference:
Campbell, et al. Biology: A Global Approach. 11th ed., Pearson, 2017.
